https://chemwiki.ch.ic.ac.uk/api.php?action=feedcontributions&feedformat=atom&user=Kjf05ChemWiki - User contributions [en]2026-04-05T18:28:14ZUser contributionsMediaWiki 1.43.0https://chemwiki.ch.ic.ac.uk/index.php?title=It:Schrock&diff=7455It:Schrock2006-12-07T12:39:30Z<p>Kjf05: /* Schrock's Metathesis Catalyst */</p>
<hr />
<div>==Introduction==<br />
[[Image:Schrock2.jpg|thumb|left|General example, commercially available example<sup>2<sup>]]<br />
<br />
<br />
'''Richard R. Schrock''' won the 2005 Nobel Prize in Chemistry.<br />
<br />
His nobel prize speech can be viewed through the following link:[http://nobelprize.org/nobel_prizes/chemistry/laureates/2005/schrock-lecture.html]<br />
<br />
<br />
<br />
This is an important discovery as the catalysts used before were sensitive to air and moisture, created side reactions and were relatively short-lived.<sup>2</sup> Schrock's discovery of the catalysts using tungsten provided one of the first stable metathesis catalyst.<sup>2<sup><br />
<br />
<br />
<br />
= Background Story =<br />
<br />
Metathesis was first discovered in the early 1950s but the chemistry was then understood only by 1971. Chauvin had then proposed a reaction mechanism, whereby the double bonds were cleaved and synthesised between C atoms in a way that the atom groups change positions, just as dance couples change partners. However, this is only possible in the presence of special catalyst molecules. <br />
<br />
With the mechanism in place, there was a need to develop these catalysts and Schrock was the first to attempt it. In his own words, before these catalysts there was no way to do the metathesis reaction simply. The use of catalysts gives shorter synthetic routes and thus fewer byproducts and better control of the reaction overall.<br />
<br />
=Scheme=<br />
<br />
[[Image:Olefin1.gif]]<br />
<br />
* Chauvin-type mechanism<br />
<br />
[[Image:Olefin2.gif]]<br />
<br />
* Well defined catalyst systems<br />
<br />
[[Image:Olefin3.gif]]<br />
<br />
<br />
= Metal Carbenes =<br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Olefin4.gif]]<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
* Transition metal has a formal metal to a C=C<br />
* X and Y can be any alkyl or aryl or heteroatom<br />
* There are 2 types of carbenes: Fischer or Schrock-type<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
[[Image:Olefin5.gif]]<br />
* TM has a high oxidation state<br />
<br />
* Ligands are good sigma or pi donors<br />
<br />
* Nucleophilic: attacks at C<sub>carbene</sub> by electrophiles<br />
<br />
* C<sub>carbene</sub> is X<sub>2</sub>-type ligand: Metal oxidation state changed by +2<br />
<br />
[[Image:Olefin6.gif]]<br />
<br />
<br />
= Schrock's Metathesis Catalyst =<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
* Must be handled under Ar or N<sub>2</sub> using dry solvents<br />
* Reactive towards protons on heteroatoms but tolerant of S, P and nitrile groups<br />
* Mo(VI) centre electron deficient, pseudo-tetrahedral. <br />
* Alkoxides needed to enhance the electrophilicity of metal cenre. <br />
[[Image:Olefin7.gif]]<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
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</td><br />
<br />
</tr><br />
</table><br />
<br />
= Basic Metathesis Reactions =<br />
<br />
[[Image:Olefin8.gif]]<br />
<br />
<br />
= Influence of Ligand set on Reactivity of Schrock's Catalyst =<br />
<br />
* 2 Rotamers the syn or anti<br />
<br />
[[Image:Olefin9.gif]]<br />
<br />
* Between these 2 rotamers, the rate of interconversion depends on ligands and substrate<br />
<br />
[[Image:Olefin10.gif]]<br />
<br />
<br />
= Other catalytic systems =<br />
<br />
There are a variety of different catalytic commercially available systems for the metathesis of olefins. Another famous catalyst is the Grubb's Metathesis Catalyst where the central metal is Ruthenium surrounded by phosphines and chloride ligands. It is believed that this catalyst is superior to the former due to higher functional group tolerance, lower reactivity and relative stability to water and oxygen. <br />
<br />
Many variations to the catalyst have been made, for instance, ruthenium containing N-Heterocyclic Carbene ligands which is even more stable than the Grubb's catalyst itself. <br />
<br />
The choice of catalyst is important depending on the mechanism of the olefin metathesis as shown above. Other experimental conditions have to be considered as well. Generally, ruthenium based catalysts are favoured due to the ease of handling. <br />
<br />
Lastly, more detailed reactions and choices of catalysts can be found in the reference.<br />
<br />
<br />
= Reference =<br />
<br />
Wendy Jen, MacMillan Group Meeting, Jan 17 2001, Olefin Metathesis in Organic Synthesis<br />
<br />
<jmol><br />
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<size>400</size><br />
<color>white</color><br />
<script>zoom 100; cpk on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER CSD ENTRY XICKAV<br />
CRYST1 8.5594 6.0337 11.0220 90.00 105.97 90.00 P21/c<br />
SCALE1 0.116831 -0.000000 0.033428 0.000000<br />
SCALE2 -0.000000 0.165736 -0.000000 0.000000<br />
SCALE3 -0.000000 0.000000 0.094368 0.000000<br />
<br />
HEADER NONAME 20-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 20-Nov-06 0 NONE 4<br />
ATOM 1 C 0 2.963 -1.542 0.211 0.00 0.00 C+0<br />
ATOM 2 C 0 1.711 -2.418 0.287 0.00 0.00 C+0<br />
ATOM 3 C 0 1.225 -2.737 -1.129 0.00 0.00 C+0<br />
ATOM 4 C 0 2.043 -3.720 1.018 0.00 0.00 C+0<br />
ATOM 5 O 0 0.685 -1.722 0.997 0.00 0.00 O+0<br />
ATOM 6 W 0 0.327 -0.023 -0.017 0.00 0.00 W+0<br />
ATOM 7 N 0 -1.038 0.906 0.803 0.00 0.00 N+0<br />
ATOM 8 C 0 -2.234 0.351 0.930 0.00 0.00 C+0<br />
ATOM 9 C 0 -3.290 1.059 1.560 0.00 0.00 C+0<br />
ATOM 10 C 0 -4.515 0.474 1.682 0.00 0.00 C+0<br />
ATOM 11 C 0 -4.733 -0.808 1.195 0.00 0.00 C+0<br />
ATOM 12 C 0 -3.710 -1.515 0.576 0.00 0.00 C+0<br />
ATOM 13 C 0 -2.475 -0.955 0.432 0.00 0.00 C+0<br />
ATOM 14 O 0 1.989 1.107 -0.037 0.00 0.00 O+0<br />
ATOM 15 C 0 1.961 1.904 1.149 0.00 0.00 C+0<br />
ATOM 16 C 0 1.778 0.998 2.368 0.00 0.00 C+0<br />
ATOM 17 C 0 3.278 2.673 1.277 0.00 0.00 C+0<br />
ATOM 18 C 0 0.798 2.895 1.070 0.00 0.00 C+0<br />
ATOM 19 C 0 -0.176 -0.444 -1.804 0.00 0.00 C+0<br />
ATOM 20 C 0 -0.600 0.653 -2.746 0.00 0.00 C+0<br />
ATOM 21 C 0 -0.395 2.011 -2.072 0.00 0.00 C+0<br />
ATOM 22 C 0 0.243 0.584 -4.021 0.00 0.00 C+0<br />
ATOM 23 C 0 -2.078 0.478 -3.101 0.00 0.00 C+0<br />
ATOM 24 H 0 2.744 -0.644 -0.367 0.00 0.00 H+0<br />
ATOM 25 H 0 3.270 -1.260 1.217 0.00 0.00 H+0<br />
ATOM 26 H 0 3.766 -2.098 -0.272 0.00 0.00 H+0<br />
ATOM 27 H 0 1.773 -3.596 -1.516 0.00 0.00 H+0<br />
ATOM 28 H 0 0.160 -2.967 -1.104 0.00 0.00 H+0<br />
ATOM 29 H 0 1.396 -1.876 -1.774 0.00 0.00 H+0<br />
ATOM 30 H 0 2.389 -3.493 2.026 0.00 0.00 H+0<br />
ATOM 31 H 0 1.151 -4.344 1.072 0.00 0.00 H+0<br />
ATOM 32 H 0 2.826 -4.251 0.476 0.00 0.00 H+0<br />
ATOM 33 H 0 -3.123 2.056 1.940 0.00 0.00 H+0<br />
ATOM 34 H 0 -5.321 1.010 2.162 0.00 0.00 H+0<br />
ATOM 35 H 0 -5.708 -1.261 1.298 0.00 0.00 H+0<br />
ATOM 36 H 0 -3.894 -2.512 0.202 0.00 0.00 H+0<br />
ATOM 37 H 0 -1.681 -1.507 -0.049 0.00 0.00 H+0<br />
ATOM 38 H 0 2.649 0.351 2.473 0.00 0.00 H+0<br />
ATOM 39 H 0 1.670 1.610 3.263 0.00 0.00 H+0<br />
ATOM 40 H 0 0.885 0.387 2.236 0.00 0.00 H+0<br />
ATOM 41 H 0 3.408 3.318 0.409 0.00 0.00 H+0<br />
ATOM 42 H 0 3.257 3.280 2.182 0.00 0.00 H+0<br />
ATOM 43 H 0 4.107 1.967 1.333 0.00 0.00 H+0<br />
ATOM 44 H 0 -0.135 2.378 1.296 0.00 0.00 H+0<br />
ATOM 45 H 0 0.953 3.696 1.793 0.00 0.00 H+0<br />
ATOM 46 H 0 0.746 3.316 0.066 0.00 0.00 H+0<br />
ATOM 47 H 0 -0.158 -1.470 -2.142 0.00 0.00 H+0<br />
ATOM 48 H 0 0.658 2.136 -1.818 0.00 0.00 H+0<br />
ATOM 49 H 0 -0.702 2.805 -2.753 0.00 0.00 H+0<br />
ATOM 50 H 0 -0.996 2.060 -1.163 0.00 0.00 H+0<br />
ATOM 51 H 0 0.032 -0.348 -4.546 0.00 0.00 H+0<br />
ATOM 52 H 0 -0.004 1.428 -4.665 0.00 0.00 H+0<br />
ATOM 53 H 0 1.300 0.623 -3.760 0.00 0.00 H+0<br />
ATOM 54 H 0 -2.678 0.527 -2.192 0.00 0.00 H+0<br />
ATOM 55 H 0 -2.384 1.271 -3.782 0.00 0.00 H+0<br />
ATOM 56 H 0 -2.224 -0.490 -3.581 0.00 0.00 H+0<br />
CONECT 1 2 24 25 26 NONE 61<br />
CONECT 2 1 3 4 5 NONE 62<br />
CONECT 3 2 27 28 29 NONE 63<br />
CONECT 4 2 30 31 32 NONE 64<br />
CONECT 5 2 6 0 0 NONE 65<br />
CONECT 6 5 7 14 19 NONE 66<br />
CONECT 7 6 8 0 0 NONE 67<br />
CONECT 8 7 13 9 0 NONE 68<br />
CONECT 9 8 10 33 0 NONE 69<br />
CONECT 10 9 11 34 0 NONE 70<br />
CONECT 11 10 12 35 0 NONE 71<br />
CONECT 12 11 13 36 0 NONE 72<br />
CONECT 13 12 8 37 0 NONE 73<br />
CONECT 14 6 15 0 0 NONE 74<br />
CONECT 15 14 16 17 18 NONE 75<br />
CONECT 16 15 38 39 40 NONE 76<br />
CONECT 17 15 41 42 43 NONE 77<br />
CONECT 18 15 44 45 46 NONE 78<br />
CONECT 19 6 20 47 0 NONE 79<br />
CONECT 20 19 21 22 23 NONE 80<br />
CONECT 21 20 48 49 50 NONE 81<br />
CONECT 22 20 51 52 53 NONE 82<br />
CONECT 23 20 54 55 56 NONE 83<br />
END</inlineContents><br />
</jmolApplet><br />
</jmol><br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
Reference<br />
<br />
1.http://www.rsc.org/chemistryworld/restricted/2005/November/prize.asp</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Schrock&diff=7454It:Schrock2006-12-07T12:38:44Z<p>Kjf05: /* Schrock's Metathesis Catalyst */</p>
<hr />
<div>==Introduction==<br />
[[Image:Schrock2.jpg|thumb|left|General example, commercially available example<sup>2<sup>]]<br />
<br />
<br />
'''Richard R. Schrock''' won the 2005 Nobel Prize in Chemistry.<br />
<br />
His nobel prize speech can be viewed through the following link:[http://nobelprize.org/nobel_prizes/chemistry/laureates/2005/schrock-lecture.html]<br />
<br />
<br />
<br />
This is an important discovery as the catalysts used before were sensitive to air and moisture, created side reactions and were relatively short-lived.<sup>2</sup> Schrock's discovery of the catalysts using tungsten provided one of the first stable metathesis catalyst.<sup>2<sup><br />
<br />
<br />
<br />
= Background Story =<br />
<br />
Metathesis was first discovered in the early 1950s but the chemistry was then understood only by 1971. Chauvin had then proposed a reaction mechanism, whereby the double bonds were cleaved and synthesised between C atoms in a way that the atom groups change positions, just as dance couples change partners. However, this is only possible in the presence of special catalyst molecules. <br />
<br />
With the mechanism in place, there was a need to develop these catalysts and Schrock was the first to attempt it. In his own words, before these catalysts there was no way to do the metathesis reaction simply. The use of catalysts gives shorter synthetic routes and thus fewer byproducts and better control of the reaction overall.<br />
<br />
=Scheme=<br />
<br />
[[Image:Olefin1.gif]]<br />
<br />
* Chauvin-type mechanism<br />
<br />
[[Image:Olefin2.gif]]<br />
<br />
* Well defined catalyst systems<br />
<br />
[[Image:Olefin3.gif]]<br />
<br />
<br />
= Metal Carbenes =<br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Olefin4.gif]]<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
* Transition metal has a formal metal to a C=C<br />
* X and Y can be any alkyl or aryl or heteroatom<br />
* There are 2 types of carbenes: Fischer or Schrock-type<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
[[Image:Olefin5.gif]]<br />
* TM has a high oxidation state<br />
<br />
* Ligands are good sigma or pi donors<br />
<br />
* Nucleophilic: attacks at C<sub>carbene</sub> by electrophiles<br />
<br />
* C<sub>carbene</sub> is X<sub>2</sub>-type ligand: Metal oxidation state changed by +2<br />
<br />
[[Image:Olefin6.gif]]<br />
<br />
<br />
= Schrock's Metathesis Catalyst =<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
* Must be handled under Ar or N<sub>2</sub> using dry solvents<br />
* Reactive towards protons on heteroatoms but tolerant of S, P and nitrile groups<br />
* Mo(VI) centre electron deficient, pseudo-tetrahedral. <br />
* Alkoxides needed to enhance the electrophilicity of metal cenre. <br />
[[Image:Olefin7.gif]]<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
!<center><jmol><br />
<jmolApplet><br />
<title>Schrock's Metathesis Catalyst</title><color>white</color><br />
<uploadedFileContents>Schrock.mol</uploadedFileContents><br />
</jmolApplet><br />
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<item><text>Start spinning</text><script>spin on</script></item><br />
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<menuHeight>-1</menuHeight><br />
</jmolMenu><br />
<jmolButton><br />
<script>console</script><br />
<text>open a console window</text><br />
</jmolButton><br />
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<br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
= Basic Metathesis Reactions =<br />
<br />
[[Image:Olefin8.gif]]<br />
<br />
<br />
= Influence of Ligand set on Reactivity of Schrock's Catalyst =<br />
<br />
* 2 Rotamers the syn or anti<br />
<br />
[[Image:Olefin9.gif]]<br />
<br />
* Between these 2 rotamers, the rate of interconversion depends on ligands and substrate<br />
<br />
[[Image:Olefin10.gif]]<br />
<br />
<br />
= Other catalytic systems =<br />
<br />
There are a variety of different catalytic commercially available systems for the metathesis of olefins. Another famous catalyst is the Grubb's Metathesis Catalyst where the central metal is Ruthenium surrounded by phosphines and chloride ligands. It is believed that this catalyst is superior to the former due to higher functional group tolerance, lower reactivity and relative stability to water and oxygen. <br />
<br />
Many variations to the catalyst have been made, for instance, ruthenium containing N-Heterocyclic Carbene ligands which is even more stable than the Grubb's catalyst itself. <br />
<br />
The choice of catalyst is important depending on the mechanism of the olefin metathesis as shown above. Other experimental conditions have to be considered as well. Generally, ruthenium based catalysts are favoured due to the ease of handling. <br />
<br />
Lastly, more detailed reactions and choices of catalysts can be found in the reference.<br />
<br />
<br />
= Reference =<br />
<br />
Wendy Jen, MacMillan Group Meeting, Jan 17 2001, Olefin Metathesis in Organic Synthesis<br />
<br />
<jmol><br />
<jmolApplet><br />
<size>400</size><br />
<color>white</color><br />
<script>zoom 100; cpk on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER CSD ENTRY XICKAV<br />
CRYST1 8.5594 6.0337 11.0220 90.00 105.97 90.00 P21/c<br />
SCALE1 0.116831 -0.000000 0.033428 0.000000<br />
SCALE2 -0.000000 0.165736 -0.000000 0.000000<br />
SCALE3 -0.000000 0.000000 0.094368 0.000000<br />
<br />
HEADER NONAME 20-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 20-Nov-06 0 NONE 4<br />
ATOM 1 C 0 2.963 -1.542 0.211 0.00 0.00 C+0<br />
ATOM 2 C 0 1.711 -2.418 0.287 0.00 0.00 C+0<br />
ATOM 3 C 0 1.225 -2.737 -1.129 0.00 0.00 C+0<br />
ATOM 4 C 0 2.043 -3.720 1.018 0.00 0.00 C+0<br />
ATOM 5 O 0 0.685 -1.722 0.997 0.00 0.00 O+0<br />
ATOM 6 W 0 0.327 -0.023 -0.017 0.00 0.00 W+0<br />
ATOM 7 N 0 -1.038 0.906 0.803 0.00 0.00 N+0<br />
ATOM 8 C 0 -2.234 0.351 0.930 0.00 0.00 C+0<br />
ATOM 9 C 0 -3.290 1.059 1.560 0.00 0.00 C+0<br />
ATOM 10 C 0 -4.515 0.474 1.682 0.00 0.00 C+0<br />
ATOM 11 C 0 -4.733 -0.808 1.195 0.00 0.00 C+0<br />
ATOM 12 C 0 -3.710 -1.515 0.576 0.00 0.00 C+0<br />
ATOM 13 C 0 -2.475 -0.955 0.432 0.00 0.00 C+0<br />
ATOM 14 O 0 1.989 1.107 -0.037 0.00 0.00 O+0<br />
ATOM 15 C 0 1.961 1.904 1.149 0.00 0.00 C+0<br />
ATOM 16 C 0 1.778 0.998 2.368 0.00 0.00 C+0<br />
ATOM 17 C 0 3.278 2.673 1.277 0.00 0.00 C+0<br />
ATOM 18 C 0 0.798 2.895 1.070 0.00 0.00 C+0<br />
ATOM 19 C 0 -0.176 -0.444 -1.804 0.00 0.00 C+0<br />
ATOM 20 C 0 -0.600 0.653 -2.746 0.00 0.00 C+0<br />
ATOM 21 C 0 -0.395 2.011 -2.072 0.00 0.00 C+0<br />
ATOM 22 C 0 0.243 0.584 -4.021 0.00 0.00 C+0<br />
ATOM 23 C 0 -2.078 0.478 -3.101 0.00 0.00 C+0<br />
ATOM 24 H 0 2.744 -0.644 -0.367 0.00 0.00 H+0<br />
ATOM 25 H 0 3.270 -1.260 1.217 0.00 0.00 H+0<br />
ATOM 26 H 0 3.766 -2.098 -0.272 0.00 0.00 H+0<br />
ATOM 27 H 0 1.773 -3.596 -1.516 0.00 0.00 H+0<br />
ATOM 28 H 0 0.160 -2.967 -1.104 0.00 0.00 H+0<br />
ATOM 29 H 0 1.396 -1.876 -1.774 0.00 0.00 H+0<br />
ATOM 30 H 0 2.389 -3.493 2.026 0.00 0.00 H+0<br />
ATOM 31 H 0 1.151 -4.344 1.072 0.00 0.00 H+0<br />
ATOM 32 H 0 2.826 -4.251 0.476 0.00 0.00 H+0<br />
ATOM 33 H 0 -3.123 2.056 1.940 0.00 0.00 H+0<br />
ATOM 34 H 0 -5.321 1.010 2.162 0.00 0.00 H+0<br />
ATOM 35 H 0 -5.708 -1.261 1.298 0.00 0.00 H+0<br />
ATOM 36 H 0 -3.894 -2.512 0.202 0.00 0.00 H+0<br />
ATOM 37 H 0 -1.681 -1.507 -0.049 0.00 0.00 H+0<br />
ATOM 38 H 0 2.649 0.351 2.473 0.00 0.00 H+0<br />
ATOM 39 H 0 1.670 1.610 3.263 0.00 0.00 H+0<br />
ATOM 40 H 0 0.885 0.387 2.236 0.00 0.00 H+0<br />
ATOM 41 H 0 3.408 3.318 0.409 0.00 0.00 H+0<br />
ATOM 42 H 0 3.257 3.280 2.182 0.00 0.00 H+0<br />
ATOM 43 H 0 4.107 1.967 1.333 0.00 0.00 H+0<br />
ATOM 44 H 0 -0.135 2.378 1.296 0.00 0.00 H+0<br />
ATOM 45 H 0 0.953 3.696 1.793 0.00 0.00 H+0<br />
ATOM 46 H 0 0.746 3.316 0.066 0.00 0.00 H+0<br />
ATOM 47 H 0 -0.158 -1.470 -2.142 0.00 0.00 H+0<br />
ATOM 48 H 0 0.658 2.136 -1.818 0.00 0.00 H+0<br />
ATOM 49 H 0 -0.702 2.805 -2.753 0.00 0.00 H+0<br />
ATOM 50 H 0 -0.996 2.060 -1.163 0.00 0.00 H+0<br />
ATOM 51 H 0 0.032 -0.348 -4.546 0.00 0.00 H+0<br />
ATOM 52 H 0 -0.004 1.428 -4.665 0.00 0.00 H+0<br />
ATOM 53 H 0 1.300 0.623 -3.760 0.00 0.00 H+0<br />
ATOM 54 H 0 -2.678 0.527 -2.192 0.00 0.00 H+0<br />
ATOM 55 H 0 -2.384 1.271 -3.782 0.00 0.00 H+0<br />
ATOM 56 H 0 -2.224 -0.490 -3.581 0.00 0.00 H+0<br />
CONECT 1 2 24 25 26 NONE 61<br />
CONECT 2 1 3 4 5 NONE 62<br />
CONECT 3 2 27 28 29 NONE 63<br />
CONECT 4 2 30 31 32 NONE 64<br />
CONECT 5 2 6 0 0 NONE 65<br />
CONECT 6 5 7 14 19 NONE 66<br />
CONECT 7 6 8 0 0 NONE 67<br />
CONECT 8 7 13 9 0 NONE 68<br />
CONECT 9 8 10 33 0 NONE 69<br />
CONECT 10 9 11 34 0 NONE 70<br />
CONECT 11 10 12 35 0 NONE 71<br />
CONECT 12 11 13 36 0 NONE 72<br />
CONECT 13 12 8 37 0 NONE 73<br />
CONECT 14 6 15 0 0 NONE 74<br />
CONECT 15 14 16 17 18 NONE 75<br />
CONECT 16 15 38 39 40 NONE 76<br />
CONECT 17 15 41 42 43 NONE 77<br />
CONECT 18 15 44 45 46 NONE 78<br />
CONECT 19 6 20 47 0 NONE 79<br />
CONECT 20 19 21 22 23 NONE 80<br />
CONECT 21 20 48 49 50 NONE 81<br />
CONECT 22 20 51 52 53 NONE 82<br />
CONECT 23 20 54 55 56 NONE 83<br />
END</inlineContents><br />
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<br />
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<br />
<br />
Reference<br />
<br />
1.http://www.rsc.org/chemistryworld/restricted/2005/November/prize.asp</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=File:Schrock.mol&diff=7453File:Schrock.mol2006-12-07T12:36:54Z<p>Kjf05: </p>
<hr />
<div></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Gossypol&diff=6902It:Gossypol2006-12-05T11:41:15Z<p>Kjf05: /* Structure */</p>
<hr />
<div>== Abstract ==<br />
<br />
<br />
Gossypol is a polyphenol extracted from plants of the genus Gossypium, Malvaceae (commonly known as cottonseed plant). Gossypol is believed to act as an inhibitor of dehydrogenases and thus destroys cellular energy. One of the main applications of Gossypol in the industry is as a male contraceptive, most widely manufactured in China.<br />
<br />
<br />
Chemical name: 2,2'-bis-(Formyl-1,6,7-trihydroxy-5-isopropyl-3-methylnaphthalene)<br />
<br />
The (-) isomer of acts as a contraceptive whereas the (+) isomer is a toxin.<br />
<br />
== Structure ==<br />
{| class="toccolours" border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
|+ '''Gossypol'''<br />
! [[Image:Wiki_gosspol.gif|300px]]!!<br />
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|- align="center"<br />
| '''2D Structure''' <br />
| '''3D Structure''' <br />
|}<br />
<br />
Molecular Weight: 518.5634<br /><br />
Molecular Formula: C<sub>30</sub>H<sub>30</sub>O<sub>8</sub><br /><br />
Melting Point: 177 - 182 C<br />
<br />
== How Gossypol Works ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
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<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:CLBphoto5.jpg|thumb|150px|center|Gossypol Expression in Cotton]]<br />
|-<br />
! ''[http://www.anbg.gov.au anbg.gov.au]''<br />
|}<br />
</td><br />
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<td><br />
<div align=justify><br />
'''Gossypol suppresses P24Ag in semen.'''<br /><br />
<br />
Appropriate quantities of Gossypol acetate (gp) suppress P24Ag in semen of HIV(+) men. Gp has shown its role as an inhibitor on the replication of HIV. It has been found that 15 out of 18 test subjects have shown P24Ag (-) in their semen and it remained consistent while taking gp. However this test was discontinued when AIDs symptoms was found in 10 of the 18 patients and 5 developed infections including PCP, pulmonary tuberculosis, cryptosporidium and CMV enteritis, esophageal candida.<br />
</div><br />
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<br />
== Uses and Dosage == <br />
<br />
The amount of Gossypol to intake depends on the strength of the medicine and the reason for intake. Follow the instructions on the medicine bottle if not advised by a caregiver or doctor.<br />
<br />
<br />
Heat or moisture might lead to breakdown of the medicine and it might not function as normal. Keep the medicine locked and beyond the reach of children.<br />
Do not take Gossypol without a doctor's advice if you are taking:<br />
* Digoxin<br />
* Water Pills<br />
* Iron<br />
* Isoproterenol<br />
* Medicine for pain or swelling<br />
* Potassium<br />
* Alcohol / Breastfeeding<br />
<br />
Possible Side Effects:<br />
* Breathing problems or chest pains<br />
* Hives, rash and swollen skin<br />
* Muscle Weakness<br />
* Hair Loss, nausea, or bowel problems.<br />
<br />
== Synthetic Studies ==<br />
<br />
Various studies have undertaken the task of the total synthesis of Gossypol. In 1937 Adams and Geissman<sup>1</sup> proposed the following scheme which synthesises Gossypol via its derivative desapogossypolone tetramethyl ether.<br />
<br />
[[Image:gossypolsynthesis.gif]]<br />
<br />
More recently, Shirley and Dean<sup>2</sup> successfully synthesised 1,1',6,6',7,7'-hexamethoxy-3,3'-dimethyl-2,2'-binaphthyl which was matched to desapogossypol hexamethyl ether, a degradation product of Gossypol. This result also confirmed the 2,2' position of the binaphthyl linkage in Gossypol which was previously believed to be at the 3,3' location.<br />
<br />
[[Image:desapogossypolhexamethylether.gif]]<br />
Desapogossypol Hexamethyl Ether<br />
<br />
<br />
== History of Gossypol ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
'''Gossypol was once believed to cause female infertility.'''<br /><br />
<br />
Once upon a time, gossypol has been regarded as a toxic waste in the handling of cotton. In 1957, in the Wang Village in Jiangsu, China, it was reported that there was no newborn for a span of 10 years from 1930s to 1940s. The cause of this unprolific years was the change from soybean oil to crude cottonseed oil used in their cooking due to economic reasons. This evidence had caused scientists to believe that Gossypol might had caused female infertility, supported by the fact that the female villagers suffered from menstrual disturbances. Later, it was discovered by the Hubei Provincial Group the antispermatogenic effects of crude cottonseed oil in rats and primates, and since then, many workers had been investigating and simultaneously documented the antifertility effect in males instead. The work on gossypol as an antifertility agent stimulated nationwide interest followed by universal attraction after the publication of gossypol by the National Coordinating Group.<br />
</td><br />
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<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Gossypol3.jpg|thumb|150px|center|Gossypol as a Powder]]<br />
|-<br />
! ''[http://www.ars.usda.gov/is/graphics/photos/jul05/d106-18.htm]''<br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
== The Chemistry of Gossypol ==<br />
<br />
Gossypol gives 3 unique crystalline substances with different melting points when recrystallised with different solvents. These substances all possess different optical properties and crystalline structures but do not display significant differences in both spectral and chemical properties. This suggests that the 3 structures do not differ much in chemical structures, yet, many reactions of gossypol cannot be explained by a simple chemical structure as propsosed above.<br />
<br />
Adams and Geissman proposed 3 tautomeric forms of gossypol in attempt to explain the vast number of reactions: the aldehyde, the ketonoid and the hemiacetal (see Figure below).<br />
<br />
[[Image:Gossypol4.gif]]<br />
<br />
In inert solvents, the aldehyde form of Gossypol predominates, whereas in polar solvents like DMSO, the aldehyde form exist in equilibrium with the hemiacetal counterpart.<br />
<br />
== Gossypol's antifertility effect on laboratory animals ==<br />
<br />
Three forms of Gossypol has been used in laboratory testing, namely gossypol, gossypol acetic acid and gossypol formic acid. Different animal species have different sensitivity towards gossypol. Among the animals tested, hamsters displayed the highest sensitivity, followed by rats, monkeys, dogs in decreasing order. <br />
<br />
Rhesus monkeys, given a dose of 4mg/kg per day for 2 years, were moderately sensitive to the antispermatogenic action of gossypol. Out of 3 monkeys, spermatogenesis was entirely inhibited in 2 of them with a few normal spermatids and spermatozoa found in the tubules of the third. in cynomolgus monkeys, gossypol only reduced the sperm count and motility.<br />
<br />
<br />
== Conclusion ==<br />
<br />
Gossypol is indeed a very useful antifertility drug for certain animals and humans. Cottonseed being widely available, cheap and requiring simple and uncomplicated processing procedure makes preparation of Gossypol simple. However, the toxicity of Gossypol is a serious consideration before it can be produced in a large scale, below are a few important points:<br />
<br />
* more knowledge of the contributing factors to Hypokalemia <br />
<br />
* means to prevent irreversibility, for eg. chronic sterility<br />
<br />
* adverse effects on the main organs like liver, heart and endocrine systems as well as carcinogenic effects<br />
<br />
* Investigation of the mechanism of action of Gossypol<br />
<br />
== Extra Information ==<br />
* [http://cdmrp.army.mil/scripts/get_item.asp?item=abstract&log_no=PC030753&type=public Congressionally Medical Research Program]<br />
* [http://www.fasebj.org/cgi/content/summary/20/12/2147 Gossypol induces Bax/Bak-independent activation of apoptosis and cytochrome c release via a conformational change in Bcl-2]<br />
* [http://www.utexas.edu/centers/nfic/natnews/2005/Nov.2005.nat.htm 2005 Nat News]<br />
* [http://www.ndt.net/article/v11n06/paiziev2/paiziev2.htm Structural Features of Stony Cotton Seeds]<br />
<br />
== References ==<br />
<br />
1. R. Adams, T. A. Geissman; Structure of Gossypol. XXIII. Attempts to Prepare Desapogossypolone Tetramethyl Ether. Condensation of Hexadiene-2,4 with Dibenzoethylene; J. Am Chem. Soc., 1939, 2038<br />
<br />
2. D. A. Shirley, W. L. Dean; The Structure and Reactions of Gossypol. IV. The Synthesis of Desapogossypol Hexamethyl Ether; J. Am. Chem. Soc., 1956, 1205<br />
<br />
3. [http://www.jbc.org/cgi/reprint/93/2/381.pdf Studies on the Toxicity of Gossypol]<br />
<br />
4. [http://arjournals.annualreviews.org/doi/pdf/10.1146/annurev.pa.24.040184.001553 A Potential Antifertility Agent for Males]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=File:Gossypol.mol&diff=6900File:Gossypol.mol2006-12-05T11:38:25Z<p>Kjf05: </p>
<hr />
<div></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Schrock&diff=6899It:Schrock2006-12-05T11:37:40Z<p>Kjf05: /* Schrock's Metathesis Catalyst */</p>
<hr />
<div>==Introduction==<br />
[[Image:Schrock2.jpg|thumb|left|General example, commercially available example<sup>2<sup>]]<br />
<br />
<br />
'''Richard R. Schrock''' won the 2005 Nobel Prize in Chemistry.<br />
<br />
His nobel prize speech can be viewed through the following link:[http://nobelprize.org/nobel_prizes/chemistry/laureates/2005/schrock-lecture.html]<br />
<br />
<br />
<br />
This is an important discovery as the catalysts used before were sensitive to air and moisture, created side reactions and were relatively short-lived.<sup>2</sup> Schrock's discovery of the catalysts using tungsten provided one of the first stable metathesis catalyst.<sup>2<sup><br />
<br />
<br />
<br />
= Background Story =<br />
<br />
Metathesis was first discovered in the early 1950s but the chemistry was then understood only by 1971. Chauvin had then proposed a reaction mechanism, whereby the double bonds were cleaved and synthesised between C atoms in a way that the atom groups change positions, just as dance couples change partners. However, this is only possible in the presence of special catalyst molecules. <br />
<br />
With the mechanism in place, there was a need to develop these catalysts and Schrock was the first to attempt it. In his own words, before these catalysts there was no way to do the metathesis reaction simply. The use of catalysts gives shorter synthetic routes and thus fewer byproducts and better control of the reaction overall.<br />
<br />
=Scheme=<br />
<br />
[[Image:Olefin1.gif]]<br />
<br />
* Chauvin-type mechanism<br />
<br />
[[Image:Olefin2.gif]]<br />
<br />
* Well defined catalyst systems<br />
<br />
[[Image:Olefin3.gif]]<br />
<br />
<br />
= Metal Carbenes =<br />
<br />
<table border="0" cellpadding=10><br />
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<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Olefin4.gif]]<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
* Transition metal has a formal metal to a C=C<br />
* X and Y can be any alkyl or aryl or heteroatom<br />
* There are 2 types of carbenes: Fischer or Schrock-type<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
[[Image:Olefin5.gif]]<br />
* TM has a high oxidation state<br />
<br />
* Ligands are good sigma or pi donors<br />
<br />
* Nucleophilic: attacks at C<sub>carbene</sub> by electrophiles<br />
<br />
* C<sub>carbene</sub> is X<sub>2</sub>-type ligand: Metal oxidation state changed by +2<br />
<br />
[[Image:Olefin6.gif]]<br />
<br />
<br />
= Schrock's Metathesis Catalyst =<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
* Must be handled under Ar or N<sub>2</sub> using dry solvents<br />
* Reactive towards protons on heteroatoms but tolerant of S, P and nitrile groups<br />
* Mo(VI) centre electron deficient, pseudo-tetrahedral. <br />
* Alkoxides needed to enhance the electrophilicity of metal cenre. <br />
[[Image:Olefin7.gif]]<br />
</td><br />
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<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
!<jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 100; bns on; cpk on;frame 2; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER NONAME 05-Dec-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 05-Dec-06 0 NONE 4<br />
ATOM 1 C 0 4.878 1.367 -2.180 0.00 0.00 C+0<br />
ATOM 2 C 0 3.623 0.636 -2.661 0.00 0.00 C+0<br />
ATOM 3 C 0 2.441 1.568 -2.593 0.00 0.00 C+0<br />
ATOM 4 C 0 2.480 2.773 -3.230 0.00 0.00 C+0<br />
ATOM 5 C 0 1.393 3.634 -3.169 0.00 0.00 C+0<br />
ATOM 6 C 0 0.249 3.285 -2.461 0.00 0.00 C+0<br />
ATOM 7 C 0 0.179 2.087 -1.814 0.00 0.00 C+0<br />
ATOM 8 C 0 -1.063 1.712 -1.048 0.00 0.00 C+0<br />
ATOM 9 C 0 -1.653 2.961 -0.390 0.00 0.00 C+0<br />
ATOM 10 C 0 -2.091 1.107 -2.007 0.00 0.00 C+0<br />
ATOM 11 C 0 1.279 1.194 -1.871 0.00 0.00 C+0<br />
ATOM 12 N 0 1.225 0.026 -1.247 0.00 0.00 N+0<br />
ATOM 13 Mo 0 -0.209 -0.378 -0.178 0.00 0.00 Mo+0<br />
ATOM 14 O 0 -0.564 1.148 1.065 0.00 0.00 O+0<br />
ATOM 15 C 0 0.566 1.243 1.935 0.00 0.00 C+0<br />
ATOM 16 C 0 1.630 2.136 1.294 0.00 0.00 C+0<br />
ATOM 17 F 0 1.051 3.352 0.914 0.00 0.00 F+0<br />
ATOM 18 F 0 2.655 2.375 2.215 0.00 0.00 F+0<br />
ATOM 19 F 0 2.156 1.498 0.166 0.00 0.00 F+0<br />
ATOM 20 C 0 0.131 1.848 3.272 0.00 0.00 C+0<br />
ATOM 21 F 0 -0.842 1.031 3.858 0.00 0.00 F+0<br />
ATOM 22 F 0 1.237 1.941 4.124 0.00 0.00 F+0<br />
ATOM 23 F 0 -0.400 3.124 3.055 0.00 0.00 F+0<br />
ATOM 24 C 0 1.147 -0.152 2.172 0.00 0.00 C+0<br />
ATOM 25 O 0 -1.821 -0.698 -1.318 0.00 0.00 O+0<br />
ATOM 26 C 0 -2.881 -1.073 -0.437 0.00 0.00 C+0<br />
ATOM 27 C 0 -4.169 -1.261 -1.241 0.00 0.00 C+0<br />
ATOM 28 F 0 -3.980 -2.265 -2.197 0.00 0.00 F+0<br />
ATOM 29 F 0 -5.208 -1.629 -0.378 0.00 0.00 F+0<br />
ATOM 30 F 0 -4.498 -0.062 -1.882 0.00 0.00 F+0<br />
ATOM 31 C 0 -2.522 -2.384 0.265 0.00 0.00 C+0<br />
ATOM 32 C 0 -3.088 0.025 0.609 0.00 0.00 C+0<br />
ATOM 33 F 0 -3.066 1.275 -0.018 0.00 0.00 F+0<br />
ATOM 34 F 0 -4.324 -0.159 1.239 0.00 0.00 F+0<br />
ATOM 35 F 0 -2.065 -0.039 1.561 0.00 0.00 F+0<br />
ATOM 36 C 0 0.173 -1.936 0.828 0.00 0.00 C+0<br />
ATOM 37 C 0 0.625 -3.192 0.129 0.00 0.00 C+0<br />
ATOM 38 C 0 2.055 -3.487 0.501 0.00 0.00 C+0<br />
ATOM 39 C 0 2.727 -4.531 -0.108 0.00 0.00 C+0<br />
ATOM 40 C 0 4.039 -4.801 0.234 0.00 0.00 C+0<br />
ATOM 41 C 0 4.680 -4.027 1.183 0.00 0.00 C+0<br />
ATOM 42 C 0 4.009 -2.982 1.791 0.00 0.00 C+0<br />
ATOM 43 C 0 2.698 -2.709 1.446 0.00 0.00 C+0<br />
ATOM 44 C 0 -0.264 -4.362 0.556 0.00 0.00 C+0<br />
ATOM 45 C 0 0.521 -2.999 -1.385 0.00 0.00 C+0<br />
ATOM 46 C 0 3.825 0.172 -4.105 0.00 0.00 C+0<br />
ATOM 47 H 0 4.734 1.697 -1.151 0.00 0.00 H+0<br />
ATOM 48 H 0 5.733 0.693 -2.229 0.00 0.00 H+0<br />
ATOM 49 H 0 5.060 2.233 -2.817 0.00 0.00 H+0<br />
ATOM 50 H 0 3.441 -0.230 -2.024 0.00 0.00 H+0<br />
ATOM 51 H 0 3.362 3.059 -3.784 0.00 0.00 H+0<br />
ATOM 52 H 0 1.436 4.586 -3.678 0.00 0.00 H+0<br />
ATOM 53 H 0 -0.588 3.966 -2.423 0.00 0.00 H+0<br />
ATOM 54 H 0 -0.810 0.981 -0.280 0.00 0.00 H+0<br />
ATOM 55 H 0 -2.005 3.646 -1.161 0.00 0.00 H+0<br />
ATOM 56 H 0 -2.488 2.674 0.250 0.00 0.00 H+0<br />
ATOM 57 H 0 -0.887 3.451 0.211 0.00 0.00 H+0<br />
ATOM 58 H 0 -1.614 0.333 -2.609 0.00 0.00 H+0<br />
ATOM 59 H 0 -2.909 0.669 -1.434 0.00 0.00 H+0<br />
ATOM 60 H 0 -2.482 1.887 -2.660 0.00 0.00 H+0<br />
ATOM 61 H 0 1.463 -0.580 1.221 0.00 0.00 H+0<br />
ATOM 62 H 0 2.004 -0.080 2.841 0.00 0.00 H+0<br />
ATOM 63 H 0 0.387 -0.790 2.623 0.00 0.00 H+0<br />
ATOM 64 H 0 -1.583 -2.262 0.806 0.00 0.00 H+0<br />
ATOM 65 H 0 -3.313 -2.650 0.966 0.00 0.00 H+0<br />
ATOM 66 H 0 -2.413 -3.175 -0.477 0.00 0.00 H+0<br />
ATOM 67 H 0 0.066 -1.924 1.903 0.00 0.00 H+0<br />
ATOM 68 H 0 2.226 -5.135 -0.849 0.00 0.00 H+0<br />
ATOM 69 H 0 4.563 -5.617 -0.241 0.00 0.00 H+0<br />
ATOM 70 H 0 5.705 -4.238 1.450 0.00 0.00 H+0<br />
ATOM 71 H 0 4.509 -2.378 2.533 0.00 0.00 H+0<br />
ATOM 72 H 0 2.174 -1.893 1.921 0.00 0.00 H+0<br />
ATOM 73 H 0 -1.281 -4.192 0.203 0.00 0.00 H+0<br />
ATOM 74 H 0 0.120 -5.286 0.126 0.00 0.00 H+0<br />
ATOM 75 H 0 -0.265 -4.439 1.643 0.00 0.00 H+0<br />
ATOM 76 H 0 1.155 -2.166 -1.689 0.00 0.00 H+0<br />
ATOM 77 H 0 0.848 -3.907 -1.891 0.00 0.00 H+0<br />
ATOM 78 H 0 -0.513 -2.786 -1.654 0.00 0.00 H+0<br />
ATOM 79 H 0 2.931 -0.349 -4.447 0.00 0.00 H+0<br />
ATOM 80 H 0 4.007 1.038 -4.742 0.00 0.00 H+0<br />
ATOM 81 H 0 4.680 -0.502 -4.154 0.00 0.00 H+0<br />
CONECT 1 2 47 48 49 NONE 86<br />
CONECT 2 1 3 46 50 NONE 87<br />
CONECT 3 2 11 4 0 NONE 88<br />
CONECT 4 3 5 51 0 NONE 89<br />
CONECT 5 4 6 52 0 NONE 90<br />
CONECT 6 5 7 53 0 NONE 91<br />
CONECT 7 6 8 11 0 NONE 92<br />
CONECT 8 7 9 10 54 NONE 93<br />
CONECT 9 8 55 56 57 NONE 94<br />
CONECT 10 8 58 59 60 NONE 95<br />
CONECT 11 7 3 12 0 NONE 96<br />
CONECT 12 11 13 0 0 NONE 97<br />
CONECT 13 12 14 25 36 NONE 98<br />
CONECT 14 13 15 0 0 NONE 99<br />
CONECT 15 14 16 20 24 NONE 100<br />
CONECT 16 15 17 18 19 NONE 101<br />
CONECT 17 16 0 0 0 NONE 102<br />
CONECT 18 16 0 0 0 NONE 103<br />
CONECT 19 16 0 0 0 NONE 104<br />
CONECT 20 15 21 22 23 NONE 105<br />
CONECT 21 20 0 0 0 NONE 106<br />
CONECT 22 20 0 0 0 NONE 107<br />
CONECT 23 20 0 0 0 NONE 108<br />
CONECT 24 15 61 62 63 NONE 109<br />
CONECT 25 13 26 0 0 NONE 110<br />
CONECT 26 25 27 31 32 NONE 111<br />
CONECT 27 26 28 29 30 NONE 112<br />
CONECT 28 27 0 0 0 NONE 113<br />
CONECT 29 27 0 0 0 NONE 114<br />
CONECT 30 27 0 0 0 NONE 115<br />
CONECT 31 26 64 65 66 NONE 116<br />
CONECT 32 26 33 34 35 NONE 117<br />
CONECT 33 32 0 0 0 NONE 118<br />
CONECT 34 32 0 0 0 NONE 119<br />
CONECT 35 32 0 0 0 NONE 120<br />
CONECT 36 13 37 67 0 NONE 121<br />
CONECT 37 36 38 44 45 NONE 122<br />
CONECT 38 37 43 39 0 NONE 123<br />
CONECT 39 38 40 68 0 NONE 124<br />
CONECT 40 39 41 69 0 NONE 125<br />
CONECT 41 40 42 70 0 NONE 126<br />
CONECT 42 41 43 71 0 NONE 127<br />
CONECT 43 42 38 72 0 NONE 128<br />
CONECT 44 37 73 74 75 NONE 129<br />
CONECT 45 37 76 77 78 NONE 130<br />
CONECT 46 2 79 80 81 NONE 131<br />
END<br />
</inlineContents><br />
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</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
= Basic Metathesis Reactions =<br />
<br />
[[Image:Olefin8.gif]]<br />
<br />
<br />
= Influence of Ligand set on Reactivity of Schrock's Catalyst =<br />
<br />
* 2 Rotamers the syn or anti<br />
<br />
[[Image:Olefin9.gif]]<br />
<br />
* Between these 2 rotamers, the rate of interconversion depends on ligands and substrate<br />
<br />
[[Image:Olefin10.gif]]<br />
<br />
<br />
= Other catalytic systems =<br />
<br />
There are a variety of different catalytic commercially available systems for the metathesis of olefins. Another famous catalyst is the Grubb's Metathesis Catalyst where the central metal is Ruthenium surrounded by phosphines and chloride ligands. It is believed that this catalyst is superior to the former due to higher functional group tolerance, lower reactivity and relative stability to water and oxygen. <br />
<br />
Many variations to the catalyst have been made, for instance, ruthenium containing N-Heterocyclic Carbene ligands which is even more stable than the Grubb's catalyst itself. <br />
<br />
The choice of catalyst is important depending on the mechanism of the olefin metathesis as shown above. Other experimental conditions have to be considered as well. Generally, ruthenium based catalysts are favoured due to the ease of handling. <br />
<br />
Lastly, more detailed reactions and choices of catalysts can be found in the reference.<br />
<br />
<br />
= Reference =<br />
<br />
Wendy Jen, MacMillan Group Meeting, Jan 17 2001, Olefin Metathesis in Organic Synthesis<br />
<br />
<jmol><br />
<jmolApplet><br />
<size>400</size><br />
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<script>zoom 100; cpk on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER CSD ENTRY XICKAV<br />
CRYST1 8.5594 6.0337 11.0220 90.00 105.97 90.00 P21/c<br />
SCALE1 0.116831 -0.000000 0.033428 0.000000<br />
SCALE2 -0.000000 0.165736 -0.000000 0.000000<br />
SCALE3 -0.000000 0.000000 0.094368 0.000000<br />
<br />
HEADER NONAME 20-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 20-Nov-06 0 NONE 4<br />
ATOM 1 C 0 2.963 -1.542 0.211 0.00 0.00 C+0<br />
ATOM 2 C 0 1.711 -2.418 0.287 0.00 0.00 C+0<br />
ATOM 3 C 0 1.225 -2.737 -1.129 0.00 0.00 C+0<br />
ATOM 4 C 0 2.043 -3.720 1.018 0.00 0.00 C+0<br />
ATOM 5 O 0 0.685 -1.722 0.997 0.00 0.00 O+0<br />
ATOM 6 W 0 0.327 -0.023 -0.017 0.00 0.00 W+0<br />
ATOM 7 N 0 -1.038 0.906 0.803 0.00 0.00 N+0<br />
ATOM 8 C 0 -2.234 0.351 0.930 0.00 0.00 C+0<br />
ATOM 9 C 0 -3.290 1.059 1.560 0.00 0.00 C+0<br />
ATOM 10 C 0 -4.515 0.474 1.682 0.00 0.00 C+0<br />
ATOM 11 C 0 -4.733 -0.808 1.195 0.00 0.00 C+0<br />
ATOM 12 C 0 -3.710 -1.515 0.576 0.00 0.00 C+0<br />
ATOM 13 C 0 -2.475 -0.955 0.432 0.00 0.00 C+0<br />
ATOM 14 O 0 1.989 1.107 -0.037 0.00 0.00 O+0<br />
ATOM 15 C 0 1.961 1.904 1.149 0.00 0.00 C+0<br />
ATOM 16 C 0 1.778 0.998 2.368 0.00 0.00 C+0<br />
ATOM 17 C 0 3.278 2.673 1.277 0.00 0.00 C+0<br />
ATOM 18 C 0 0.798 2.895 1.070 0.00 0.00 C+0<br />
ATOM 19 C 0 -0.176 -0.444 -1.804 0.00 0.00 C+0<br />
ATOM 20 C 0 -0.600 0.653 -2.746 0.00 0.00 C+0<br />
ATOM 21 C 0 -0.395 2.011 -2.072 0.00 0.00 C+0<br />
ATOM 22 C 0 0.243 0.584 -4.021 0.00 0.00 C+0<br />
ATOM 23 C 0 -2.078 0.478 -3.101 0.00 0.00 C+0<br />
ATOM 24 H 0 2.744 -0.644 -0.367 0.00 0.00 H+0<br />
ATOM 25 H 0 3.270 -1.260 1.217 0.00 0.00 H+0<br />
ATOM 26 H 0 3.766 -2.098 -0.272 0.00 0.00 H+0<br />
ATOM 27 H 0 1.773 -3.596 -1.516 0.00 0.00 H+0<br />
ATOM 28 H 0 0.160 -2.967 -1.104 0.00 0.00 H+0<br />
ATOM 29 H 0 1.396 -1.876 -1.774 0.00 0.00 H+0<br />
ATOM 30 H 0 2.389 -3.493 2.026 0.00 0.00 H+0<br />
ATOM 31 H 0 1.151 -4.344 1.072 0.00 0.00 H+0<br />
ATOM 32 H 0 2.826 -4.251 0.476 0.00 0.00 H+0<br />
ATOM 33 H 0 -3.123 2.056 1.940 0.00 0.00 H+0<br />
ATOM 34 H 0 -5.321 1.010 2.162 0.00 0.00 H+0<br />
ATOM 35 H 0 -5.708 -1.261 1.298 0.00 0.00 H+0<br />
ATOM 36 H 0 -3.894 -2.512 0.202 0.00 0.00 H+0<br />
ATOM 37 H 0 -1.681 -1.507 -0.049 0.00 0.00 H+0<br />
ATOM 38 H 0 2.649 0.351 2.473 0.00 0.00 H+0<br />
ATOM 39 H 0 1.670 1.610 3.263 0.00 0.00 H+0<br />
ATOM 40 H 0 0.885 0.387 2.236 0.00 0.00 H+0<br />
ATOM 41 H 0 3.408 3.318 0.409 0.00 0.00 H+0<br />
ATOM 42 H 0 3.257 3.280 2.182 0.00 0.00 H+0<br />
ATOM 43 H 0 4.107 1.967 1.333 0.00 0.00 H+0<br />
ATOM 44 H 0 -0.135 2.378 1.296 0.00 0.00 H+0<br />
ATOM 45 H 0 0.953 3.696 1.793 0.00 0.00 H+0<br />
ATOM 46 H 0 0.746 3.316 0.066 0.00 0.00 H+0<br />
ATOM 47 H 0 -0.158 -1.470 -2.142 0.00 0.00 H+0<br />
ATOM 48 H 0 0.658 2.136 -1.818 0.00 0.00 H+0<br />
ATOM 49 H 0 -0.702 2.805 -2.753 0.00 0.00 H+0<br />
ATOM 50 H 0 -0.996 2.060 -1.163 0.00 0.00 H+0<br />
ATOM 51 H 0 0.032 -0.348 -4.546 0.00 0.00 H+0<br />
ATOM 52 H 0 -0.004 1.428 -4.665 0.00 0.00 H+0<br />
ATOM 53 H 0 1.300 0.623 -3.760 0.00 0.00 H+0<br />
ATOM 54 H 0 -2.678 0.527 -2.192 0.00 0.00 H+0<br />
ATOM 55 H 0 -2.384 1.271 -3.782 0.00 0.00 H+0<br />
ATOM 56 H 0 -2.224 -0.490 -3.581 0.00 0.00 H+0<br />
CONECT 1 2 24 25 26 NONE 61<br />
CONECT 2 1 3 4 5 NONE 62<br />
CONECT 3 2 27 28 29 NONE 63<br />
CONECT 4 2 30 31 32 NONE 64<br />
CONECT 5 2 6 0 0 NONE 65<br />
CONECT 6 5 7 14 19 NONE 66<br />
CONECT 7 6 8 0 0 NONE 67<br />
CONECT 8 7 13 9 0 NONE 68<br />
CONECT 9 8 10 33 0 NONE 69<br />
CONECT 10 9 11 34 0 NONE 70<br />
CONECT 11 10 12 35 0 NONE 71<br />
CONECT 12 11 13 36 0 NONE 72<br />
CONECT 13 12 8 37 0 NONE 73<br />
CONECT 14 6 15 0 0 NONE 74<br />
CONECT 15 14 16 17 18 NONE 75<br />
CONECT 16 15 38 39 40 NONE 76<br />
CONECT 17 15 41 42 43 NONE 77<br />
CONECT 18 15 44 45 46 NONE 78<br />
CONECT 19 6 20 47 0 NONE 79<br />
CONECT 20 19 21 22 23 NONE 80<br />
CONECT 21 20 48 49 50 NONE 81<br />
CONECT 22 20 51 52 53 NONE 82<br />
CONECT 23 20 54 55 56 NONE 83<br />
END</inlineContents><br />
</jmolApplet><br />
</jmol><br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
Reference<br />
<br />
1.http://www.rsc.org/chemistryworld/restricted/2005/November/prize.asp</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=File:Schrock.pbd&diff=6898File:Schrock.pbd2006-12-05T11:34:05Z<p>Kjf05: </p>
<hr />
<div></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Gossypol&diff=6584It:Gossypol2006-12-01T15:35:50Z<p>Kjf05: /* Structure */</p>
<hr />
<div>== Abstract ==<br />
<br />
<br />
Gossypol is a polyphenol extracted from plants of the genus Gossypium, Malvaceae (commonly known as cottonseed plant). Gossypol is believed to act as an inhibitor of dehydrogenases and thus destroys cellular energy. One of the main applications of Gossypol in the industry is as a male contraceptive, most widely manufactured in China.<br />
<br />
<br />
Chemical name: 2,2'-bis-(Formyl-1,6,7-trihydroxy-5-isopropyl-3-methylnaphthalene)<br />
<br />
The (-) isomer of acts as a contraceptive whereas the (+) isomer is a toxin.<br />
<br />
== Structure ==<br />
{| class="toccolours" border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
|+ '''Gossypol'''<br />
! [[Image:Wiki_gosspol.gif|300px]]!! <jmol><br />
<jmolApplet><br />
<size>300</size><br />
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<inlineContents>water.mol<br />
title1<br />
title2<br />
71 70 0 0 0 0 0 0 0 0 0 0<br />
0.7498 0.7380 0.5973 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.2538 -0.5230 0.3153 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.7008 -1.6210 1.0873 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6328 -1.4230 2.0673 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.2158 -0.0000 3.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.6718 1.2570 3.5933 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.1688 2.3950 2.9433 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.2128 2.3060 1.9403 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6918 0.9850 1.6193 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.1768 -0.1500 2.3483 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.1712 -0.9620 -2.0767 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.6912 -0.7180 -0.8287 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.0982 -0.6810 -0.6647 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.8902 -0.9380 -1.7477 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.2422 -1.4910 -4.1577 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.6942 -1.6870 -5.3787 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-1.3042 -1.5370 -5.6077 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.4272 -1.2510 -4.5697 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9672 -1.1180 -3.2377 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.3732 -1.1800 -3.0437 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.1358 -3.0140 0.8133 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.7938 3.5600 1.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.8168 -1.1790 4.0863 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.2908 -1.3470 3.8143 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.5188 -1.1650 5.5613 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.7042 -0.3820 0.7003 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.9438 -0.9780 -4.9517 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.7402 -1.6550 -3.9647 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.5372 -0.6900 -4.7897 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.1692 -3.0650 -4.1717 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.3338 1.8200 -0.1267 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.2348 4.6650 1.6713 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.6998 3.5580 3.3573 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
4.6318 1.4810 4.5573 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.1938 -1.1050 -2.2307 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.3808 -1.1380 -6.0917 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9042 -1.6750 -6.8807 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.4602 -2.0440 -6.4577 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.9638 -2.2670 2.6513 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.9612 -0.9580 -1.6057 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9002 -3.0690 1.0983 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.6968 -3.7660 1.3393 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.2498 -3.1330 -0.2807 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.0488 3.5230 0.5623 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.3968 -2.0370 3.7753 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.3518 -1.4990 2.7583 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.6928 -2.2640 4.2303 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.7998 -0.4280 4.1903 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.5358 -0.9760 5.7973 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
4.0508 -0.2240 5.8903 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.8668 -2.0240 6.0913 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.6592 -0.3550 0.6033 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.4422 0.6230 0.9773 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.3242 -1.1830 1.2853 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6208 -0.6090 -4.1897 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.9462 -1.4070 -2.9317 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.2242 0.2920 -4.3637 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-6.5322 -0.7500 -4.4837 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.4112 -0.7890 -5.9167 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.6452 -3.7870 -3.6137 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.9552 -3.3100 -5.2607 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-6.1692 -3.1490 -3.9887 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.1652 1.5730 -0.8157 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.1858 4.2730 2.7443 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.0608 2.4590 4.4183 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.5708 -0.9000 -1.5387 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.0858 -1.4660 -6.9737 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.8932 -1.8450 -7.1217 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.4154 -0.8438 -5.8415 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.9355 -3.2804 -5.1934 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
4.9775 0.6403 4.8661 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1 2 2 0 0 0 0<br />
1 9 4 0 0 0 0<br />
1 31 1 0 0 0 0<br />
2 3 4 0 0 0 0<br />
2 12 1 0 0 0 0<br />
3 4 2 0 0 0 0<br />
3 21 1 0 0 0 0<br />
4 10 4 0 0 0 0<br />
4 39 1 0 0 0 0<br />
5 6 2 0 0 0 0<br />
5 10 4 0 0 0 0<br />
5 23 1 0 0 0 0<br />
6 7 4 0 0 0 0<br />
6 34 1 0 0 0 0<br />
7 8 4 0 0 0 0<br />
7 33 4 0 0 0 0<br />
8 9 1 0 0 0 0<br />
8 22 1 0 0 0 0<br />
9 10 4 0 0 0 0<br />
11 12 2 0 0 0 0<br />
11 19 4 0 0 0 0<br />
11 35 1 0 0 0 0<br />
12 13 4 0 0 0 0<br />
13 14 2 0 0 0 0<br />
13 26 1 0 0 0 0<br />
14 20 4 0 0 0 0<br />
14 40 1 0 0 0 0<br />
15 16 2 0 0 0 0<br />
15 20 4 0 0 0 0<br />
15 28 1 0 0 0 0<br />
16 17 4 0 0 0 0<br />
16 38 1 0 0 0 0<br />
17 18 4 0 0 0 0<br />
17 37 4 0 0 0 0<br />
18 19 4 0 0 0 0<br />
18 27 1 0 0 0 0<br />
19 20 4 0 0 0 0<br />
21 41 1 0 0 0 0<br />
21 42 1 0 0 0 0<br />
21 43 1 0 0 0 0<br />
22 32 2 0 0 0 0<br />
22 44 1 0 0 0 0<br />
23 24 1 0 0 0 0<br />
23 25 1 0 0 0 0<br />
23 45 1 0 0 0 0<br />
24 46 1 0 0 0 0<br />
24 47 1 0 0 0 0<br />
24 48 1 0 0 0 0<br />
25 49 1 0 0 0 0<br />
25 50 1 0 0 0 0<br />
25 51 1 0 0 0 0<br />
26 52 1 0 0 0 0<br />
26 53 1 0 0 0 0<br />
26 54 1 0 0 0 0<br />
27 36 2 0 0 0 0<br />
27 55 1 0 0 0 0<br />
28 29 1 0 0 0 0<br />
28 30 1 0 0 0 0<br />
28 56 1 0 0 0 0<br />
29 57 1 0 0 0 0<br />
29 58 1 0 0 0 0<br />
29 69 1 0 0 0 0<br />
30 60 1 0 0 0 0<br />
30 62 1 0 0 0 0<br />
30 70 1 0 0 0 0<br />
31 63 1 0 0 0 0<br />
34 71 1 0 0 0 0<br />
35 66 1 0 0 0 0<br />
37 67 1 0 0 0 0<br />
38 68 1 0 0 0 0<br />
M END</inlineContents><br />
</jmolApplet><br />
</jmol> <br />
|- align="center"<br />
| '''2D Structure''' <br />
| '''3D Structure''' <br />
|}<br />
<br />
Molecular Weight: 518.5634<br /><br />
Molecular Formula: C<sub>30</sub>H<sub>30</sub>O<sub>8</sub><br /><br />
Melting Point: 177 - 182 C<br />
<br />
== How Gossypol Works ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:CLBphoto5.jpg|thumb|150px|center|Gossypol Expression in Cotton]]<br />
|-<br />
! ''[http://www.anbg.gov.au anbg.gov.au]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
'''Gossypol suppresses P24Ag in semen.'''<br /><br />
<br />
Appropriate quantities of Gossypol acetate (gp) suppress P24Ag in semen of HIV(+) men. Gp has shown its role as an inhibitor on the replication of HIV. It has been found that 15 out of 18 test subjects have shown P24Ag (-) in their semen and it remained consistent while taking gp. However this test was discontinued when AIDs symptoms was found in 10 of the 18 patients and 5 developed infections including PCP, pulmonary tuberculosis, cryptosporidium and CMV enteritis, esophageal candida.<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
== Uses and Dosage == <br />
<br />
The amount of Gossypol to intake depends on the strength of the medicine and the reason for intake. Follow the instructions on the medicine bottle if not advised by a caregiver or doctor.<br />
<br />
<br />
Heat or moisture might lead to breakdown of the medicine and it might not function as normal. Keep the medicine locked and beyond the reach of children.<br />
Do not take Gossypol without a doctor's advice if you are taking:<br />
* Digoxin<br />
* Water Pills<br />
* Iron<br />
* Isoproterenol<br />
* Medicine for pain or swelling<br />
* Potassium<br />
* Alcohol / Breastfeeding<br />
<br />
Possible Side Effects:<br />
* Breathing problems or chest pains<br />
* Hives, rash and swollen skin<br />
* Muscle Weakness<br />
* Hair Loss, nausea, or bowel problems.<br />
<br />
== Synthetic Studies ==<br />
<br />
Various studies have undertaken the task of the total synthesis of Gossypol. In 1937 Adams and Geissman<sup>1</sup> proposed the following scheme which synthesises Gossypol via its derivative desapogossypolone tetramethyl ether.<br />
<br />
[[Image:gossypolsynthesis.gif]]<br />
<br />
More recently, Shirley and Dean<sup>2</sup> successfully synthesised 1,1',6,6',7,7'-hexamethoxy-3,3'-dimethyl-2,2'-binaphthyl which was matched to desapogossypol hexamethyl ether, a degradation product of Gossypol. This result also confirmed the 2,2' position of the binaphthyl linkage in Gossypol which was previously believed to be at the 3,3' location.<br />
<br />
[[Image:desapogossypolhexamethylether.gif]]<br />
Desapogossypol Hexamethyl Ether<br />
<br />
<br />
== History of Gossypol ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
'''Gossypol was once believed to cause female infertility.'''<br /><br />
<br />
Once upon a time, gossypol has been regarded as a toxic waste in the handling of cotton. In 1957, in the Wang Village in Jiangsu, China, it was reported that there was no newborn for a span of 10 years from 1930s to 1940s. The cause of this unprolific years was the change from soybean oil to crude cottonseed oil used in their cooking due to economic reasons. This evidence had caused scientists to believe that Gossypol might had caused female infertility, supported by the fact that the female villagers suffered from menstrual disturbances. Later, it was discovered by the Hubei Provincial Group the antispermatogenic effects of crude cottonseed oil in rats and primates, and since then, many workers had been investigating and simultaneously documented the antifertility effect in males instead. The work on gossypol as an antifertility agent stimulated nationwide interest followed by universal attraction after the publication of gossypol by the National Coordinating Group.<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Gossypol3.jpg|thumb|150px|center|Gossypol as a Powder]]<br />
|-<br />
! ''[http://www.ars.usda.gov/is/graphics/photos/jul05/d106-18.htm]''<br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
== The Chemistry of Gossypol ==<br />
<br />
Gossypol gives 3 unique crystalline substances with different melting points when recrystallised with different solvents. These substances all possess different optical properties and crystalline structures but do not display significant differences in both spectral and chemical properties. This suggests that the 3 structures do not differ much in chemical structures, yet, many reactions of gossypol cannot be explained by a simple chemical structure as propsosed above.<br />
<br />
Adams and Geissman proposed 3 tautomeric forms of gossypol in attempt to explain the vast number of reactions: the aldehyde, the ketonoid and the hemiacetal (see Figure below).<br />
<br />
[[Image:Gossypol4.gif]]<br />
<br />
In inert solvents, the aldehyde form of Gossypol predominates, whereas in polar solvents like DMSO, the aldehyde form exist in equilibrium with the hemiacetal counterpart.<br />
<br />
== Gossypol's antifertility effect on laboratory animals ==<br />
<br />
Three forms of Gossypol has been used in laboratory testing, namely gossypol, gossypol acetic acid and gossypol formic acid. Different animal species have different sensitivity towards gossypol. Among the animals tested, hamsters displayed the highest sensitivity, followed by rats, monkeys, dogs in decreasing order. <br />
<br />
Rhesus monkeys, given a dose of 4mg/kg per day for 2 years, were moderately sensitive to the antispermatogenic action of gossypol. Out of 3 monkeys, spermatogenesis was entirely inhibited in 2 of them with a few normal spermatids and spermatozoa found in the tubules of the third. in cynomolgus monkeys, gossypol only reduced the sperm count and motility.<br />
<br />
<br />
== Conclusion ==<br />
<br />
Gossypol is indeed a very useful antifertility drug for certain animals and humans. Cottonseed being widely available, cheap and requiring simple and uncomplicated processing procedure makes preparation of Gossypol simple. However, the toxicity of Gossypol is a serious consideration before it can be produced in a large scale, below are a few important points:<br />
<br />
* more knowledge of the contributing factors to Hypokalemia <br />
<br />
* means to prevent irreversibility, for eg. chronic sterility<br />
<br />
* adverse effects on the main organs like liver, heart and endocrine systems as well as carcinogenic effects<br />
<br />
* Investigation of the mechanism of action of Gossypol<br />
<br />
== Extra Information ==<br />
* [http://cdmrp.army.mil/scripts/get_item.asp?item=abstract&log_no=PC030753&type=public Congressionally Medical Research Program]<br />
* [http://www.fasebj.org/cgi/content/summary/20/12/2147 Gossypol induces Bax/Bak-independent activation of apoptosis and cytochrome c release via a conformational change in Bcl-2]<br />
* [http://www.utexas.edu/centers/nfic/natnews/2005/Nov.2005.nat.htm 2005 Nat News]<br />
* [http://www.ndt.net/article/v11n06/paiziev2/paiziev2.htm Structural Features of Stony Cotton Seeds]<br />
<br />
== References ==<br />
<br />
1. R. Adams, T. A. Geissman; Structure of Gossypol. XXIII. Attempts to Prepare Desapogossypolone Tetramethyl Ether. Condensation of Hexadiene-2,4 with Dibenzoethylene; J. Am Chem. Soc., 1939, 2038<br />
<br />
2. D. A. Shirley, W. L. Dean; The Structure and Reactions of Gossypol. IV. The Synthesis of Desapogossypol Hexamethyl Ether; J. Am. Chem. Soc., 1956, 1205<br />
<br />
3. [http://www.jbc.org/cgi/reprint/93/2/381.pdf Studies on the Toxicity of Gossypol]<br />
<br />
4. [http://arjournals.annualreviews.org/doi/pdf/10.1146/annurev.pa.24.040184.001553 A Potential Antifertility Agent for Males]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Gossypol&diff=6583It:Gossypol2006-12-01T15:35:37Z<p>Kjf05: /* Structure */</p>
<hr />
<div>== Abstract ==<br />
<br />
<br />
Gossypol is a polyphenol extracted from plants of the genus Gossypium, Malvaceae (commonly known as cottonseed plant). Gossypol is believed to act as an inhibitor of dehydrogenases and thus destroys cellular energy. One of the main applications of Gossypol in the industry is as a male contraceptive, most widely manufactured in China.<br />
<br />
<br />
Chemical name: 2,2'-bis-(Formyl-1,6,7-trihydroxy-5-isopropyl-3-methylnaphthalene)<br />
<br />
The (-) isomer of acts as a contraceptive whereas the (+) isomer is a toxin.<br />
<br />
== Structure ==<br />
{| class="toccolours" border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
|+ '''Gossypol'''<br />
! [[Image:Wiki_gosspol.gif|200px]]!! <jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 80; bns on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>water.mol<br />
title1<br />
title2<br />
71 70 0 0 0 0 0 0 0 0 0 0<br />
0.7498 0.7380 0.5973 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.2538 -0.5230 0.3153 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.7008 -1.6210 1.0873 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6328 -1.4230 2.0673 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.2158 -0.0000 3.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.6718 1.2570 3.5933 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.1688 2.3950 2.9433 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.2128 2.3060 1.9403 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6918 0.9850 1.6193 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.1768 -0.1500 2.3483 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.1712 -0.9620 -2.0767 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.6912 -0.7180 -0.8287 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.0982 -0.6810 -0.6647 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.8902 -0.9380 -1.7477 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.2422 -1.4910 -4.1577 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.6942 -1.6870 -5.3787 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-1.3042 -1.5370 -5.6077 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.4272 -1.2510 -4.5697 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9672 -1.1180 -3.2377 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.3732 -1.1800 -3.0437 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.1358 -3.0140 0.8133 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.7938 3.5600 1.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.8168 -1.1790 4.0863 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.2908 -1.3470 3.8143 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.5188 -1.1650 5.5613 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.7042 -0.3820 0.7003 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.9438 -0.9780 -4.9517 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.7402 -1.6550 -3.9647 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.5372 -0.6900 -4.7897 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.1692 -3.0650 -4.1717 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.3338 1.8200 -0.1267 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.2348 4.6650 1.6713 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.6998 3.5580 3.3573 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
4.6318 1.4810 4.5573 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.1938 -1.1050 -2.2307 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.3808 -1.1380 -6.0917 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9042 -1.6750 -6.8807 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.4602 -2.0440 -6.4577 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.9638 -2.2670 2.6513 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.9612 -0.9580 -1.6057 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9002 -3.0690 1.0983 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.6968 -3.7660 1.3393 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.2498 -3.1330 -0.2807 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.0488 3.5230 0.5623 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.3968 -2.0370 3.7753 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.3518 -1.4990 2.7583 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.6928 -2.2640 4.2303 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.7998 -0.4280 4.1903 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.5358 -0.9760 5.7973 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
4.0508 -0.2240 5.8903 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.8668 -2.0240 6.0913 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.6592 -0.3550 0.6033 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.4422 0.6230 0.9773 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.3242 -1.1830 1.2853 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6208 -0.6090 -4.1897 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.9462 -1.4070 -2.9317 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.2242 0.2920 -4.3637 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-6.5322 -0.7500 -4.4837 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.4112 -0.7890 -5.9167 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.6452 -3.7870 -3.6137 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.9552 -3.3100 -5.2607 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-6.1692 -3.1490 -3.9887 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.1652 1.5730 -0.8157 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.1858 4.2730 2.7443 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.0608 2.4590 4.4183 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.5708 -0.9000 -1.5387 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.0858 -1.4660 -6.9737 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.8932 -1.8450 -7.1217 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.4154 -0.8438 -5.8415 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.9355 -3.2804 -5.1934 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
4.9775 0.6403 4.8661 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1 2 2 0 0 0 0<br />
1 9 4 0 0 0 0<br />
1 31 1 0 0 0 0<br />
2 3 4 0 0 0 0<br />
2 12 1 0 0 0 0<br />
3 4 2 0 0 0 0<br />
3 21 1 0 0 0 0<br />
4 10 4 0 0 0 0<br />
4 39 1 0 0 0 0<br />
5 6 2 0 0 0 0<br />
5 10 4 0 0 0 0<br />
5 23 1 0 0 0 0<br />
6 7 4 0 0 0 0<br />
6 34 1 0 0 0 0<br />
7 8 4 0 0 0 0<br />
7 33 4 0 0 0 0<br />
8 9 1 0 0 0 0<br />
8 22 1 0 0 0 0<br />
9 10 4 0 0 0 0<br />
11 12 2 0 0 0 0<br />
11 19 4 0 0 0 0<br />
11 35 1 0 0 0 0<br />
12 13 4 0 0 0 0<br />
13 14 2 0 0 0 0<br />
13 26 1 0 0 0 0<br />
14 20 4 0 0 0 0<br />
14 40 1 0 0 0 0<br />
15 16 2 0 0 0 0<br />
15 20 4 0 0 0 0<br />
15 28 1 0 0 0 0<br />
16 17 4 0 0 0 0<br />
16 38 1 0 0 0 0<br />
17 18 4 0 0 0 0<br />
17 37 4 0 0 0 0<br />
18 19 4 0 0 0 0<br />
18 27 1 0 0 0 0<br />
19 20 4 0 0 0 0<br />
21 41 1 0 0 0 0<br />
21 42 1 0 0 0 0<br />
21 43 1 0 0 0 0<br />
22 32 2 0 0 0 0<br />
22 44 1 0 0 0 0<br />
23 24 1 0 0 0 0<br />
23 25 1 0 0 0 0<br />
23 45 1 0 0 0 0<br />
24 46 1 0 0 0 0<br />
24 47 1 0 0 0 0<br />
24 48 1 0 0 0 0<br />
25 49 1 0 0 0 0<br />
25 50 1 0 0 0 0<br />
25 51 1 0 0 0 0<br />
26 52 1 0 0 0 0<br />
26 53 1 0 0 0 0<br />
26 54 1 0 0 0 0<br />
27 36 2 0 0 0 0<br />
27 55 1 0 0 0 0<br />
28 29 1 0 0 0 0<br />
28 30 1 0 0 0 0<br />
28 56 1 0 0 0 0<br />
29 57 1 0 0 0 0<br />
29 58 1 0 0 0 0<br />
29 69 1 0 0 0 0<br />
30 60 1 0 0 0 0<br />
30 62 1 0 0 0 0<br />
30 70 1 0 0 0 0<br />
31 63 1 0 0 0 0<br />
34 71 1 0 0 0 0<br />
35 66 1 0 0 0 0<br />
37 67 1 0 0 0 0<br />
38 68 1 0 0 0 0<br />
M END</inlineContents><br />
</jmolApplet><br />
</jmol> <br />
|- align="center"<br />
| '''2D Structure''' <br />
| '''3D Structure''' <br />
|}<br />
<br />
Molecular Weight: 518.5634<br /><br />
Molecular Formula: C<sub>30</sub>H<sub>30</sub>O<sub>8</sub><br /><br />
Melting Point: 177 - 182 C<br />
<br />
== How Gossypol Works ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:CLBphoto5.jpg|thumb|150px|center|Gossypol Expression in Cotton]]<br />
|-<br />
! ''[http://www.anbg.gov.au anbg.gov.au]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
'''Gossypol suppresses P24Ag in semen.'''<br /><br />
<br />
Appropriate quantities of Gossypol acetate (gp) suppress P24Ag in semen of HIV(+) men. Gp has shown its role as an inhibitor on the replication of HIV. It has been found that 15 out of 18 test subjects have shown P24Ag (-) in their semen and it remained consistent while taking gp. However this test was discontinued when AIDs symptoms was found in 10 of the 18 patients and 5 developed infections including PCP, pulmonary tuberculosis, cryptosporidium and CMV enteritis, esophageal candida.<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
== Uses and Dosage == <br />
<br />
The amount of Gossypol to intake depends on the strength of the medicine and the reason for intake. Follow the instructions on the medicine bottle if not advised by a caregiver or doctor.<br />
<br />
<br />
Heat or moisture might lead to breakdown of the medicine and it might not function as normal. Keep the medicine locked and beyond the reach of children.<br />
Do not take Gossypol without a doctor's advice if you are taking:<br />
* Digoxin<br />
* Water Pills<br />
* Iron<br />
* Isoproterenol<br />
* Medicine for pain or swelling<br />
* Potassium<br />
* Alcohol / Breastfeeding<br />
<br />
Possible Side Effects:<br />
* Breathing problems or chest pains<br />
* Hives, rash and swollen skin<br />
* Muscle Weakness<br />
* Hair Loss, nausea, or bowel problems.<br />
<br />
== Synthetic Studies ==<br />
<br />
Various studies have undertaken the task of the total synthesis of Gossypol. In 1937 Adams and Geissman<sup>1</sup> proposed the following scheme which synthesises Gossypol via its derivative desapogossypolone tetramethyl ether.<br />
<br />
[[Image:gossypolsynthesis.gif]]<br />
<br />
More recently, Shirley and Dean<sup>2</sup> successfully synthesised 1,1',6,6',7,7'-hexamethoxy-3,3'-dimethyl-2,2'-binaphthyl which was matched to desapogossypol hexamethyl ether, a degradation product of Gossypol. This result also confirmed the 2,2' position of the binaphthyl linkage in Gossypol which was previously believed to be at the 3,3' location.<br />
<br />
[[Image:desapogossypolhexamethylether.gif]]<br />
Desapogossypol Hexamethyl Ether<br />
<br />
<br />
== History of Gossypol ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
'''Gossypol was once believed to cause female infertility.'''<br /><br />
<br />
Once upon a time, gossypol has been regarded as a toxic waste in the handling of cotton. In 1957, in the Wang Village in Jiangsu, China, it was reported that there was no newborn for a span of 10 years from 1930s to 1940s. The cause of this unprolific years was the change from soybean oil to crude cottonseed oil used in their cooking due to economic reasons. This evidence had caused scientists to believe that Gossypol might had caused female infertility, supported by the fact that the female villagers suffered from menstrual disturbances. Later, it was discovered by the Hubei Provincial Group the antispermatogenic effects of crude cottonseed oil in rats and primates, and since then, many workers had been investigating and simultaneously documented the antifertility effect in males instead. The work on gossypol as an antifertility agent stimulated nationwide interest followed by universal attraction after the publication of gossypol by the National Coordinating Group.<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Gossypol3.jpg|thumb|150px|center|Gossypol as a Powder]]<br />
|-<br />
! ''[http://www.ars.usda.gov/is/graphics/photos/jul05/d106-18.htm]''<br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
== The Chemistry of Gossypol ==<br />
<br />
Gossypol gives 3 unique crystalline substances with different melting points when recrystallised with different solvents. These substances all possess different optical properties and crystalline structures but do not display significant differences in both spectral and chemical properties. This suggests that the 3 structures do not differ much in chemical structures, yet, many reactions of gossypol cannot be explained by a simple chemical structure as propsosed above.<br />
<br />
Adams and Geissman proposed 3 tautomeric forms of gossypol in attempt to explain the vast number of reactions: the aldehyde, the ketonoid and the hemiacetal (see Figure below).<br />
<br />
[[Image:Gossypol4.gif]]<br />
<br />
In inert solvents, the aldehyde form of Gossypol predominates, whereas in polar solvents like DMSO, the aldehyde form exist in equilibrium with the hemiacetal counterpart.<br />
<br />
== Gossypol's antifertility effect on laboratory animals ==<br />
<br />
Three forms of Gossypol has been used in laboratory testing, namely gossypol, gossypol acetic acid and gossypol formic acid. Different animal species have different sensitivity towards gossypol. Among the animals tested, hamsters displayed the highest sensitivity, followed by rats, monkeys, dogs in decreasing order. <br />
<br />
Rhesus monkeys, given a dose of 4mg/kg per day for 2 years, were moderately sensitive to the antispermatogenic action of gossypol. Out of 3 monkeys, spermatogenesis was entirely inhibited in 2 of them with a few normal spermatids and spermatozoa found in the tubules of the third. in cynomolgus monkeys, gossypol only reduced the sperm count and motility.<br />
<br />
<br />
== Conclusion ==<br />
<br />
Gossypol is indeed a very useful antifertility drug for certain animals and humans. Cottonseed being widely available, cheap and requiring simple and uncomplicated processing procedure makes preparation of Gossypol simple. However, the toxicity of Gossypol is a serious consideration before it can be produced in a large scale, below are a few important points:<br />
<br />
* more knowledge of the contributing factors to Hypokalemia <br />
<br />
* means to prevent irreversibility, for eg. chronic sterility<br />
<br />
* adverse effects on the main organs like liver, heart and endocrine systems as well as carcinogenic effects<br />
<br />
* Investigation of the mechanism of action of Gossypol<br />
<br />
== Extra Information ==<br />
* [http://cdmrp.army.mil/scripts/get_item.asp?item=abstract&log_no=PC030753&type=public Congressionally Medical Research Program]<br />
* [http://www.fasebj.org/cgi/content/summary/20/12/2147 Gossypol induces Bax/Bak-independent activation of apoptosis and cytochrome c release via a conformational change in Bcl-2]<br />
* [http://www.utexas.edu/centers/nfic/natnews/2005/Nov.2005.nat.htm 2005 Nat News]<br />
* [http://www.ndt.net/article/v11n06/paiziev2/paiziev2.htm Structural Features of Stony Cotton Seeds]<br />
<br />
== References ==<br />
<br />
1. R. Adams, T. A. Geissman; Structure of Gossypol. XXIII. Attempts to Prepare Desapogossypolone Tetramethyl Ether. Condensation of Hexadiene-2,4 with Dibenzoethylene; J. Am Chem. Soc., 1939, 2038<br />
<br />
2. D. A. Shirley, W. L. Dean; The Structure and Reactions of Gossypol. IV. The Synthesis of Desapogossypol Hexamethyl Ether; J. Am. Chem. Soc., 1956, 1205<br />
<br />
3. [http://www.jbc.org/cgi/reprint/93/2/381.pdf Studies on the Toxicity of Gossypol]<br />
<br />
4. [http://arjournals.annualreviews.org/doi/pdf/10.1146/annurev.pa.24.040184.001553 A Potential Antifertility Agent for Males]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Gossypol&diff=6581It:Gossypol2006-12-01T15:35:08Z<p>Kjf05: /* Conclusion */</p>
<hr />
<div>== Abstract ==<br />
<br />
<br />
Gossypol is a polyphenol extracted from plants of the genus Gossypium, Malvaceae (commonly known as cottonseed plant). Gossypol is believed to act as an inhibitor of dehydrogenases and thus destroys cellular energy. One of the main applications of Gossypol in the industry is as a male contraceptive, most widely manufactured in China.<br />
<br />
<br />
Chemical name: 2,2'-bis-(Formyl-1,6,7-trihydroxy-5-isopropyl-3-methylnaphthalene)<br />
<br />
The (-) isomer of acts as a contraceptive whereas the (+) isomer is a toxin.<br />
<br />
== Structure ==<br />
{| class="toccolours" border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
|+ '''Gossypol'''<br />
! [[Image:Wiki_gosspol.gif]]!! <jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 80; bns on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>water.mol<br />
title1<br />
title2<br />
71 70 0 0 0 0 0 0 0 0 0 0<br />
0.7498 0.7380 0.5973 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.2538 -0.5230 0.3153 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.7008 -1.6210 1.0873 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6328 -1.4230 2.0673 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.2158 -0.0000 3.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.6718 1.2570 3.5933 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.1688 2.3950 2.9433 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.2128 2.3060 1.9403 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6918 0.9850 1.6193 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.1768 -0.1500 2.3483 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.1712 -0.9620 -2.0767 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.6912 -0.7180 -0.8287 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.0982 -0.6810 -0.6647 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.8902 -0.9380 -1.7477 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.2422 -1.4910 -4.1577 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.6942 -1.6870 -5.3787 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-1.3042 -1.5370 -5.6077 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.4272 -1.2510 -4.5697 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9672 -1.1180 -3.2377 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.3732 -1.1800 -3.0437 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.1358 -3.0140 0.8133 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.7938 3.5600 1.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.8168 -1.1790 4.0863 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.2908 -1.3470 3.8143 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.5188 -1.1650 5.5613 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
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M END</inlineContents><br />
</jmolApplet><br />
</jmol> <br />
|- align="center"<br />
| '''2D Structure''' <br />
| '''3D Structure''' <br />
|}<br />
<br />
Molecular Weight: 518.5634<br /><br />
Molecular Formula: C<sub>30</sub>H<sub>30</sub>O<sub>8</sub><br /><br />
Melting Point: 177 - 182 C<br />
<br />
== How Gossypol Works ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:CLBphoto5.jpg|thumb|150px|center|Gossypol Expression in Cotton]]<br />
|-<br />
! ''[http://www.anbg.gov.au anbg.gov.au]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
'''Gossypol suppresses P24Ag in semen.'''<br /><br />
<br />
Appropriate quantities of Gossypol acetate (gp) suppress P24Ag in semen of HIV(+) men. Gp has shown its role as an inhibitor on the replication of HIV. It has been found that 15 out of 18 test subjects have shown P24Ag (-) in their semen and it remained consistent while taking gp. However this test was discontinued when AIDs symptoms was found in 10 of the 18 patients and 5 developed infections including PCP, pulmonary tuberculosis, cryptosporidium and CMV enteritis, esophageal candida.<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
== Uses and Dosage == <br />
<br />
The amount of Gossypol to intake depends on the strength of the medicine and the reason for intake. Follow the instructions on the medicine bottle if not advised by a caregiver or doctor.<br />
<br />
<br />
Heat or moisture might lead to breakdown of the medicine and it might not function as normal. Keep the medicine locked and beyond the reach of children.<br />
Do not take Gossypol without a doctor's advice if you are taking:<br />
* Digoxin<br />
* Water Pills<br />
* Iron<br />
* Isoproterenol<br />
* Medicine for pain or swelling<br />
* Potassium<br />
* Alcohol / Breastfeeding<br />
<br />
Possible Side Effects:<br />
* Breathing problems or chest pains<br />
* Hives, rash and swollen skin<br />
* Muscle Weakness<br />
* Hair Loss, nausea, or bowel problems.<br />
<br />
== Synthetic Studies ==<br />
<br />
Various studies have undertaken the task of the total synthesis of Gossypol. In 1937 Adams and Geissman<sup>1</sup> proposed the following scheme which synthesises Gossypol via its derivative desapogossypolone tetramethyl ether.<br />
<br />
[[Image:gossypolsynthesis.gif]]<br />
<br />
More recently, Shirley and Dean<sup>2</sup> successfully synthesised 1,1',6,6',7,7'-hexamethoxy-3,3'-dimethyl-2,2'-binaphthyl which was matched to desapogossypol hexamethyl ether, a degradation product of Gossypol. This result also confirmed the 2,2' position of the binaphthyl linkage in Gossypol which was previously believed to be at the 3,3' location.<br />
<br />
[[Image:desapogossypolhexamethylether.gif]]<br />
Desapogossypol Hexamethyl Ether<br />
<br />
<br />
== History of Gossypol ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
'''Gossypol was once believed to cause female infertility.'''<br /><br />
<br />
Once upon a time, gossypol has been regarded as a toxic waste in the handling of cotton. In 1957, in the Wang Village in Jiangsu, China, it was reported that there was no newborn for a span of 10 years from 1930s to 1940s. The cause of this unprolific years was the change from soybean oil to crude cottonseed oil used in their cooking due to economic reasons. This evidence had caused scientists to believe that Gossypol might had caused female infertility, supported by the fact that the female villagers suffered from menstrual disturbances. Later, it was discovered by the Hubei Provincial Group the antispermatogenic effects of crude cottonseed oil in rats and primates, and since then, many workers had been investigating and simultaneously documented the antifertility effect in males instead. The work on gossypol as an antifertility agent stimulated nationwide interest followed by universal attraction after the publication of gossypol by the National Coordinating Group.<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Gossypol3.jpg|thumb|150px|center|Gossypol as a Powder]]<br />
|-<br />
! ''[http://www.ars.usda.gov/is/graphics/photos/jul05/d106-18.htm]''<br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
== The Chemistry of Gossypol ==<br />
<br />
Gossypol gives 3 unique crystalline substances with different melting points when recrystallised with different solvents. These substances all possess different optical properties and crystalline structures but do not display significant differences in both spectral and chemical properties. This suggests that the 3 structures do not differ much in chemical structures, yet, many reactions of gossypol cannot be explained by a simple chemical structure as propsosed above.<br />
<br />
Adams and Geissman proposed 3 tautomeric forms of gossypol in attempt to explain the vast number of reactions: the aldehyde, the ketonoid and the hemiacetal (see Figure below).<br />
<br />
[[Image:Gossypol4.gif]]<br />
<br />
In inert solvents, the aldehyde form of Gossypol predominates, whereas in polar solvents like DMSO, the aldehyde form exist in equilibrium with the hemiacetal counterpart.<br />
<br />
== Gossypol's antifertility effect on laboratory animals ==<br />
<br />
Three forms of Gossypol has been used in laboratory testing, namely gossypol, gossypol acetic acid and gossypol formic acid. Different animal species have different sensitivity towards gossypol. Among the animals tested, hamsters displayed the highest sensitivity, followed by rats, monkeys, dogs in decreasing order. <br />
<br />
Rhesus monkeys, given a dose of 4mg/kg per day for 2 years, were moderately sensitive to the antispermatogenic action of gossypol. Out of 3 monkeys, spermatogenesis was entirely inhibited in 2 of them with a few normal spermatids and spermatozoa found in the tubules of the third. in cynomolgus monkeys, gossypol only reduced the sperm count and motility.<br />
<br />
<br />
== Conclusion ==<br />
<br />
Gossypol is indeed a very useful antifertility drug for certain animals and humans. Cottonseed being widely available, cheap and requiring simple and uncomplicated processing procedure makes preparation of Gossypol simple. However, the toxicity of Gossypol is a serious consideration before it can be produced in a large scale, below are a few important points:<br />
<br />
* more knowledge of the contributing factors to Hypokalemia <br />
<br />
* means to prevent irreversibility, for eg. chronic sterility<br />
<br />
* adverse effects on the main organs like liver, heart and endocrine systems as well as carcinogenic effects<br />
<br />
* Investigation of the mechanism of action of Gossypol<br />
<br />
== Extra Information ==<br />
* [http://cdmrp.army.mil/scripts/get_item.asp?item=abstract&log_no=PC030753&type=public Congressionally Medical Research Program]<br />
* [http://www.fasebj.org/cgi/content/summary/20/12/2147 Gossypol induces Bax/Bak-independent activation of apoptosis and cytochrome c release via a conformational change in Bcl-2]<br />
* [http://www.utexas.edu/centers/nfic/natnews/2005/Nov.2005.nat.htm 2005 Nat News]<br />
* [http://www.ndt.net/article/v11n06/paiziev2/paiziev2.htm Structural Features of Stony Cotton Seeds]<br />
<br />
== References ==<br />
<br />
1. R. Adams, T. A. Geissman; Structure of Gossypol. XXIII. Attempts to Prepare Desapogossypolone Tetramethyl Ether. Condensation of Hexadiene-2,4 with Dibenzoethylene; J. Am Chem. Soc., 1939, 2038<br />
<br />
2. D. A. Shirley, W. L. Dean; The Structure and Reactions of Gossypol. IV. The Synthesis of Desapogossypol Hexamethyl Ether; J. Am. Chem. Soc., 1956, 1205<br />
<br />
3. [http://www.jbc.org/cgi/reprint/93/2/381.pdf Studies on the Toxicity of Gossypol]<br />
<br />
4. [http://arjournals.annualreviews.org/doi/pdf/10.1146/annurev.pa.24.040184.001553 A Potential Antifertility Agent for Males]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Gossypol&diff=6580It:Gossypol2006-12-01T15:34:53Z<p>Kjf05: /* Gossypol's antifertility effect on laboratory animals */</p>
<hr />
<div>== Abstract ==<br />
<br />
<br />
Gossypol is a polyphenol extracted from plants of the genus Gossypium, Malvaceae (commonly known as cottonseed plant). Gossypol is believed to act as an inhibitor of dehydrogenases and thus destroys cellular energy. One of the main applications of Gossypol in the industry is as a male contraceptive, most widely manufactured in China.<br />
<br />
<br />
Chemical name: 2,2'-bis-(Formyl-1,6,7-trihydroxy-5-isopropyl-3-methylnaphthalene)<br />
<br />
The (-) isomer of acts as a contraceptive whereas the (+) isomer is a toxin.<br />
<br />
== Structure ==<br />
{| class="toccolours" border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
|+ '''Gossypol'''<br />
! [[Image:Wiki_gosspol.gif]]!! <jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 80; bns on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>water.mol<br />
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24 48 1 0 0 0 0<br />
25 49 1 0 0 0 0<br />
25 50 1 0 0 0 0<br />
25 51 1 0 0 0 0<br />
26 52 1 0 0 0 0<br />
26 53 1 0 0 0 0<br />
26 54 1 0 0 0 0<br />
27 36 2 0 0 0 0<br />
27 55 1 0 0 0 0<br />
28 29 1 0 0 0 0<br />
28 30 1 0 0 0 0<br />
28 56 1 0 0 0 0<br />
29 57 1 0 0 0 0<br />
29 58 1 0 0 0 0<br />
29 69 1 0 0 0 0<br />
30 60 1 0 0 0 0<br />
30 62 1 0 0 0 0<br />
30 70 1 0 0 0 0<br />
31 63 1 0 0 0 0<br />
34 71 1 0 0 0 0<br />
35 66 1 0 0 0 0<br />
37 67 1 0 0 0 0<br />
38 68 1 0 0 0 0<br />
M END</inlineContents><br />
</jmolApplet><br />
</jmol> <br />
|- align="center"<br />
| '''2D Structure''' <br />
| '''3D Structure''' <br />
|}<br />
<br />
Molecular Weight: 518.5634<br /><br />
Molecular Formula: C<sub>30</sub>H<sub>30</sub>O<sub>8</sub><br /><br />
Melting Point: 177 - 182 C<br />
<br />
== How Gossypol Works ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:CLBphoto5.jpg|thumb|150px|center|Gossypol Expression in Cotton]]<br />
|-<br />
! ''[http://www.anbg.gov.au anbg.gov.au]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
'''Gossypol suppresses P24Ag in semen.'''<br /><br />
<br />
Appropriate quantities of Gossypol acetate (gp) suppress P24Ag in semen of HIV(+) men. Gp has shown its role as an inhibitor on the replication of HIV. It has been found that 15 out of 18 test subjects have shown P24Ag (-) in their semen and it remained consistent while taking gp. However this test was discontinued when AIDs symptoms was found in 10 of the 18 patients and 5 developed infections including PCP, pulmonary tuberculosis, cryptosporidium and CMV enteritis, esophageal candida.<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
== Uses and Dosage == <br />
<br />
The amount of Gossypol to intake depends on the strength of the medicine and the reason for intake. Follow the instructions on the medicine bottle if not advised by a caregiver or doctor.<br />
<br />
<br />
Heat or moisture might lead to breakdown of the medicine and it might not function as normal. Keep the medicine locked and beyond the reach of children.<br />
Do not take Gossypol without a doctor's advice if you are taking:<br />
* Digoxin<br />
* Water Pills<br />
* Iron<br />
* Isoproterenol<br />
* Medicine for pain or swelling<br />
* Potassium<br />
* Alcohol / Breastfeeding<br />
<br />
Possible Side Effects:<br />
* Breathing problems or chest pains<br />
* Hives, rash and swollen skin<br />
* Muscle Weakness<br />
* Hair Loss, nausea, or bowel problems.<br />
<br />
== Synthetic Studies ==<br />
<br />
Various studies have undertaken the task of the total synthesis of Gossypol. In 1937 Adams and Geissman<sup>1</sup> proposed the following scheme which synthesises Gossypol via its derivative desapogossypolone tetramethyl ether.<br />
<br />
[[Image:gossypolsynthesis.gif]]<br />
<br />
More recently, Shirley and Dean<sup>2</sup> successfully synthesised 1,1',6,6',7,7'-hexamethoxy-3,3'-dimethyl-2,2'-binaphthyl which was matched to desapogossypol hexamethyl ether, a degradation product of Gossypol. This result also confirmed the 2,2' position of the binaphthyl linkage in Gossypol which was previously believed to be at the 3,3' location.<br />
<br />
[[Image:desapogossypolhexamethylether.gif]]<br />
Desapogossypol Hexamethyl Ether<br />
<br />
<br />
== History of Gossypol ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
'''Gossypol was once believed to cause female infertility.'''<br /><br />
<br />
Once upon a time, gossypol has been regarded as a toxic waste in the handling of cotton. In 1957, in the Wang Village in Jiangsu, China, it was reported that there was no newborn for a span of 10 years from 1930s to 1940s. The cause of this unprolific years was the change from soybean oil to crude cottonseed oil used in their cooking due to economic reasons. This evidence had caused scientists to believe that Gossypol might had caused female infertility, supported by the fact that the female villagers suffered from menstrual disturbances. Later, it was discovered by the Hubei Provincial Group the antispermatogenic effects of crude cottonseed oil in rats and primates, and since then, many workers had been investigating and simultaneously documented the antifertility effect in males instead. The work on gossypol as an antifertility agent stimulated nationwide interest followed by universal attraction after the publication of gossypol by the National Coordinating Group.<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Gossypol3.jpg|thumb|150px|center|Gossypol as a Powder]]<br />
|-<br />
! ''[http://www.ars.usda.gov/is/graphics/photos/jul05/d106-18.htm]''<br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
== The Chemistry of Gossypol ==<br />
<br />
Gossypol gives 3 unique crystalline substances with different melting points when recrystallised with different solvents. These substances all possess different optical properties and crystalline structures but do not display significant differences in both spectral and chemical properties. This suggests that the 3 structures do not differ much in chemical structures, yet, many reactions of gossypol cannot be explained by a simple chemical structure as propsosed above.<br />
<br />
Adams and Geissman proposed 3 tautomeric forms of gossypol in attempt to explain the vast number of reactions: the aldehyde, the ketonoid and the hemiacetal (see Figure below).<br />
<br />
[[Image:Gossypol4.gif]]<br />
<br />
In inert solvents, the aldehyde form of Gossypol predominates, whereas in polar solvents like DMSO, the aldehyde form exist in equilibrium with the hemiacetal counterpart.<br />
<br />
== Gossypol's antifertility effect on laboratory animals ==<br />
<br />
Three forms of Gossypol has been used in laboratory testing, namely gossypol, gossypol acetic acid and gossypol formic acid. Different animal species have different sensitivity towards gossypol. Among the animals tested, hamsters displayed the highest sensitivity, followed by rats, monkeys, dogs in decreasing order. <br />
<br />
Rhesus monkeys, given a dose of 4mg/kg per day for 2 years, were moderately sensitive to the antispermatogenic action of gossypol. Out of 3 monkeys, spermatogenesis was entirely inhibited in 2 of them with a few normal spermatids and spermatozoa found in the tubules of the third. in cynomolgus monkeys, gossypol only reduced the sperm count and motility.<br />
<br />
<br />
== Conclusion ==<br />
<br />
Gossypol is indeed a very useful antifertility drug for certain animals and humans. Cottonseed being widely available, cheap and requiring simple and uncomplicated processing procedure makes preparation of Gossypol simple. However, the toxicity of Gossypol is a serious consideration before it can be produced in a large scale, below are a few important points:<br />
<br />
* more knowledge of the contributing factors to Hypokalemia <br />
<br />
* means to prevent irreversibility, for eg. chronic sterility<br />
<br />
* adverse effects on the main organs like liver, heart and endocrine systems as well as carcinogenic effects<br />
<br />
* Investigation of the mechanism of action of Gossypol<br />
<br />
== Extra Information ==<br />
* [http://cdmrp.army.mil/scripts/get_item.asp?item=abstract&log_no=PC030753&type=public Congressionally Medical Research Program]<br />
* [http://www.fasebj.org/cgi/content/summary/20/12/2147 Gossypol induces Bax/Bak-independent activation of apoptosis and cytochrome c release via a conformational change in Bcl-2]<br />
* [http://www.utexas.edu/centers/nfic/natnews/2005/Nov.2005.nat.htm 2005 Nat News]<br />
* [http://www.ndt.net/article/v11n06/paiziev2/paiziev2.htm Structural Features of Stony Cotton Seeds]<br />
<br />
== References ==<br />
<br />
1. R. Adams, T. A. Geissman; Structure of Gossypol. XXIII. Attempts to Prepare Desapogossypolone Tetramethyl Ether. Condensation of Hexadiene-2,4 with Dibenzoethylene; J. Am Chem. Soc., 1939, 2038<br />
<br />
2. D. A. Shirley, W. L. Dean; The Structure and Reactions of Gossypol. IV. The Synthesis of Desapogossypol Hexamethyl Ether; J. Am. Chem. Soc., 1956, 1205<br />
<br />
3. [http://www.jbc.org/cgi/reprint/93/2/381.pdf Studies on the Toxicity of Gossypol]<br />
<br />
4. [http://arjournals.annualreviews.org/doi/pdf/10.1146/annurev.pa.24.040184.001553 A Potential Antifertility Agent for Males]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Gossypol&diff=6577It:Gossypol2006-12-01T15:27:29Z<p>Kjf05: /* References */</p>
<hr />
<div>== Abstract ==<br />
<br />
<br />
Gossypol is a polyphenol extracted from plants of the genus Gossypium, Malvaceae (commonly known as cottonseed plant). Gossypol is believed to act as an inhibitor of dehydrogenases and thus destroys cellular energy. One of the main applications of Gossypol in the industry is as a male contraceptive, most widely manufactured in China.<br />
<br />
<br />
Chemical name: 2,2'-bis-(Formyl-1,6,7-trihydroxy-5-isopropyl-3-methylnaphthalene)<br />
<br />
The (-) isomer of acts as a contraceptive whereas the (+) isomer is a toxin.<br />
<br />
== Structure ==<br />
{| class="toccolours" border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
|+ '''Gossypol'''<br />
! [[Image:Wiki_gosspol.gif]]!! <jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 80; bns on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>water.mol<br />
title1<br />
title2<br />
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1.6328 -1.4230 2.0673 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.2158 -0.0000 3.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.6718 1.2570 3.5933 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
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3.8168 -1.1790 4.0863 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
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-4.7402 -1.6550 -3.9647 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
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0.3338 1.8200 -0.1267 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.2348 4.6650 1.6713 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.6998 3.5580 3.3573 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
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1.1938 -1.1050 -2.2307 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
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-0.9042 -1.6750 -6.8807 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
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-5.2242 0.2920 -4.3637 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-6.5322 -0.7500 -4.4837 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.4112 -0.7890 -5.9167 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.6452 -3.7870 -3.6137 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
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-0.1652 1.5730 -0.8157 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.1858 4.2730 2.7443 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.0608 2.4590 4.4183 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.5708 -0.9000 -1.5387 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.0858 -1.4660 -6.9737 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.8932 -1.8450 -7.1217 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.4154 -0.8438 -5.8415 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.9355 -3.2804 -5.1934 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
4.9775 0.6403 4.8661 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
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19 20 4 0 0 0 0<br />
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21 43 1 0 0 0 0<br />
22 32 2 0 0 0 0<br />
22 44 1 0 0 0 0<br />
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23 25 1 0 0 0 0<br />
23 45 1 0 0 0 0<br />
24 46 1 0 0 0 0<br />
24 47 1 0 0 0 0<br />
24 48 1 0 0 0 0<br />
25 49 1 0 0 0 0<br />
25 50 1 0 0 0 0<br />
25 51 1 0 0 0 0<br />
26 52 1 0 0 0 0<br />
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27 36 2 0 0 0 0<br />
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M END</inlineContents><br />
</jmolApplet><br />
</jmol> <br />
|- align="center"<br />
| '''2D Structure''' <br />
| '''3D Structure''' <br />
|}<br />
<br />
Molecular Weight: 518.5634<br /><br />
Molecular Formula: C<sub>30</sub>H<sub>30</sub>O<sub>8</sub><br /><br />
Melting Point: 177 - 182 C<br />
<br />
== How Gossypol Works ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:CLBphoto5.jpg|thumb|150px|center|Gossypol Expression in Cotton]]<br />
|-<br />
! ''[http://www.anbg.gov.au anbg.gov.au]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
'''Gossypol suppresses P24Ag in semen.'''<br /><br />
<br />
Appropriate quantities of Gossypol acetate (gp) suppress P24Ag in semen of HIV(+) men. Gp has shown its role as an inhibitor on the replication of HIV. It has been found that 15 out of 18 test subjects have shown P24Ag (-) in their semen and it remained consistent while taking gp. However this test was discontinued when AIDs symptoms was found in 10 of the 18 patients and 5 developed infections including PCP, pulmonary tuberculosis, cryptosporidium and CMV enteritis, esophageal candida.<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
== Uses and Dosage == <br />
<br />
The amount of Gossypol to intake depends on the strength of the medicine and the reason for intake. Follow the instructions on the medicine bottle if not advised by a caregiver or doctor.<br />
<br />
<br />
Heat or moisture might lead to breakdown of the medicine and it might not function as normal. Keep the medicine locked and beyond the reach of children.<br />
Do not take Gossypol without a doctor's advice if you are taking:<br />
* Digoxin<br />
* Water Pills<br />
* Iron<br />
* Isoproterenol<br />
* Medicine for pain or swelling<br />
* Potassium<br />
* Alcohol / Breastfeeding<br />
<br />
Possible Side Effects:<br />
* Breathing problems or chest pains<br />
* Hives, rash and swollen skin<br />
* Muscle Weakness<br />
* Hair Loss, nausea, or bowel problems.<br />
<br />
== Synthetic Studies ==<br />
<br />
Various studies have undertaken the task of the total synthesis of Gossypol. In 1937 Adams and Geissman<sup>1</sup> proposed the following scheme which synthesises Gossypol via its derivative desapogossypolone tetramethyl ether.<br />
<br />
[[Image:gossypolsynthesis.gif]]<br />
<br />
More recently, Shirley and Dean<sup>2</sup> successfully synthesised 1,1',6,6',7,7'-hexamethoxy-3,3'-dimethyl-2,2'-binaphthyl which was matched to desapogossypol hexamethyl ether, a degradation product of Gossypol. This result also confirmed the 2,2' position of the binaphthyl linkage in Gossypol which was previously believed to be at the 3,3' location.<br />
<br />
[[Image:desapogossypolhexamethylether.gif]]<br />
Desapogossypol Hexamethyl Ether<br />
<br />
<br />
== History of Gossypol ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
'''Gossypol was once believed to cause female infertility.'''<br /><br />
<br />
Once upon a time, gossypol has been regarded as a toxic waste in the handling of cotton. In 1957, in the Wang Village in Jiangsu, China, it was reported that there was no newborn for a span of 10 years from 1930s to 1940s. The cause of this unprolific years was the change from soybean oil to crude cottonseed oil used in their cooking due to economic reasons. This evidence had caused scientists to believe that Gossypol might had caused female infertility, supported by the fact that the female villagers suffered from menstrual disturbances. Later, it was discovered by the Hubei Provincial Group the antispermatogenic effects of crude cottonseed oil in rats and primates, and since then, many workers had been investigating and simultaneously documented the antifertility effect in males instead. The work on gossypol as an antifertility agent stimulated nationwide interest followed by universal attraction after the publication of gossypol by the National Coordinating Group.<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Gossypol3.jpg|thumb|150px|center|Gossypol as a Powder]]<br />
|-<br />
! ''[http://www.ars.usda.gov/is/graphics/photos/jul05/d106-18.htm]''<br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
== The Chemistry of Gossypol ==<br />
<br />
Gossypol gives 3 unique crystalline substances with different melting points when recrystallised with different solvents. These substances all possess different optical properties and crystalline structures but do not display significant differences in both spectral and chemical properties. This suggests that the 3 structures do not differ much in chemical structures, yet, many reactions of gossypol cannot be explained by a simple chemical structure as propsosed above.<br />
<br />
Adams and Geissman proposed 3 tautomeric forms of gossypol in attempt to explain the vast number of reactions: the aldehyde, the ketonoid and the hemiacetal (see Figure below).<br />
<br />
[[Image:Gossypol4.gif]]<br />
<br />
In inert solvents, the aldehyde form of Gossypol predominates, whereas in polar solvents like DMSO, the aldehyde form exist in equilibrium with the hemiacetal counterpart.<br />
<br />
== Gossypol's antifertility effect on laboratory animals ==<br />
<br />
Three forms of Gossypol has been used in laboratory testing, namely gossypol, gossypol acetic acid and gossypol formic acid. Different animal species have different sensitivity towards gossypol. Among the animals tested, hamsters displayed the highest sensitivity, followed by rats, monkeys, dogs in decreasing order. <br />
<br />
Rhesus monkeys, given a dose of 4mg/kg per day for 2 years, were moderately sensitive to the antispermatogenic action of gossypol. Out of 3 monkeys, spermatogenesis was entirely inhibited in 2 of them with a few normal spermatids and spermatozoa found in the tubules of the third. in cynomolgus monkeys, gossypol only reduced the sperm count and motility.<br />
<br />
== Extra Information ==<br />
* [http://cdmrp.army.mil/scripts/get_item.asp?item=abstract&log_no=PC030753&type=public Congressionally Medical Research Program]<br />
* [http://www.fasebj.org/cgi/content/summary/20/12/2147 Gossypol induces Bax/Bak-independent activation of apoptosis and cytochrome c release via a conformational change in Bcl-2]<br />
* [http://www.utexas.edu/centers/nfic/natnews/2005/Nov.2005.nat.htm 2005 Nat News]<br />
* [http://www.ndt.net/article/v11n06/paiziev2/paiziev2.htm Structural Features of Stony Cotton Seeds]<br />
<br />
== References ==<br />
<br />
1. R. Adams, T. A. Geissman; Structure of Gossypol. XXIII. Attempts to Prepare Desapogossypolone Tetramethyl Ether. Condensation of Hexadiene-2,4 with Dibenzoethylene; J. Am Chem. Soc., 1939, 2038<br />
<br />
2. D. A. Shirley, W. L. Dean; The Structure and Reactions of Gossypol. IV. The Synthesis of Desapogossypol Hexamethyl Ether; J. Am. Chem. Soc., 1956, 1205<br />
<br />
3. [http://www.jbc.org/cgi/reprint/93/2/381.pdf Studies on the Toxicity of Gossypol]<br />
<br />
4. [http://arjournals.annualreviews.org/doi/pdf/10.1146/annurev.pa.24.040184.001553 A Potential Antifertility Agent for Males]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Gossypol&diff=6576It:Gossypol2006-12-01T15:26:12Z<p>Kjf05: /* The Chemistry of Gossypol */</p>
<hr />
<div>== Abstract ==<br />
<br />
<br />
Gossypol is a polyphenol extracted from plants of the genus Gossypium, Malvaceae (commonly known as cottonseed plant). Gossypol is believed to act as an inhibitor of dehydrogenases and thus destroys cellular energy. One of the main applications of Gossypol in the industry is as a male contraceptive, most widely manufactured in China.<br />
<br />
<br />
Chemical name: 2,2'-bis-(Formyl-1,6,7-trihydroxy-5-isopropyl-3-methylnaphthalene)<br />
<br />
The (-) isomer of acts as a contraceptive whereas the (+) isomer is a toxin.<br />
<br />
== Structure ==<br />
{| class="toccolours" border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
|+ '''Gossypol'''<br />
! [[Image:Wiki_gosspol.gif]]!! <jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 80; bns on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>water.mol<br />
title1<br />
title2<br />
71 70 0 0 0 0 0 0 0 0 0 0<br />
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0.2538 -0.5230 0.3153 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.7008 -1.6210 1.0873 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6328 -1.4230 2.0673 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.2158 -0.0000 3.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.6718 1.2570 3.5933 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.1688 2.3950 2.9433 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
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-2.8902 -0.9380 -1.7477 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.2422 -1.4910 -4.1577 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.6942 -1.6870 -5.3787 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
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0.1358 -3.0140 0.8133 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.7938 3.5600 1.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.8168 -1.1790 4.0863 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.2908 -1.3470 3.8143 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.5188 -1.1650 5.5613 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.7042 -0.3820 0.7003 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
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-4.7402 -1.6550 -3.9647 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.5372 -0.6900 -4.7897 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.1692 -3.0650 -4.1717 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.3338 1.8200 -0.1267 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.2348 4.6650 1.6713 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
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4.6318 1.4810 4.5573 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.1938 -1.1050 -2.2307 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.3808 -1.1380 -6.0917 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9042 -1.6750 -6.8807 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.4602 -2.0440 -6.4577 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.9638 -2.2670 2.6513 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.9612 -0.9580 -1.6057 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9002 -3.0690 1.0983 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.6968 -3.7660 1.3393 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.2498 -3.1330 -0.2807 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.0488 3.5230 0.5623 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.3968 -2.0370 3.7753 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.3518 -1.4990 2.7583 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.6928 -2.2640 4.2303 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.7998 -0.4280 4.1903 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.5358 -0.9760 5.7973 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
4.0508 -0.2240 5.8903 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.8668 -2.0240 6.0913 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.6592 -0.3550 0.6033 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.4422 0.6230 0.9773 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.3242 -1.1830 1.2853 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6208 -0.6090 -4.1897 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.9462 -1.4070 -2.9317 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.2242 0.2920 -4.3637 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-6.5322 -0.7500 -4.4837 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.4112 -0.7890 -5.9167 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.6452 -3.7870 -3.6137 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.9552 -3.3100 -5.2607 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-6.1692 -3.1490 -3.9887 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.1652 1.5730 -0.8157 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.1858 4.2730 2.7443 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.0608 2.4590 4.4183 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.5708 -0.9000 -1.5387 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.0858 -1.4660 -6.9737 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.8932 -1.8450 -7.1217 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.4154 -0.8438 -5.8415 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.9355 -3.2804 -5.1934 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
4.9775 0.6403 4.8661 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
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8 22 1 0 0 0 0<br />
9 10 4 0 0 0 0<br />
11 12 2 0 0 0 0<br />
11 19 4 0 0 0 0<br />
11 35 1 0 0 0 0<br />
12 13 4 0 0 0 0<br />
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14 40 1 0 0 0 0<br />
15 16 2 0 0 0 0<br />
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18 27 1 0 0 0 0<br />
19 20 4 0 0 0 0<br />
21 41 1 0 0 0 0<br />
21 42 1 0 0 0 0<br />
21 43 1 0 0 0 0<br />
22 32 2 0 0 0 0<br />
22 44 1 0 0 0 0<br />
23 24 1 0 0 0 0<br />
23 25 1 0 0 0 0<br />
23 45 1 0 0 0 0<br />
24 46 1 0 0 0 0<br />
24 47 1 0 0 0 0<br />
24 48 1 0 0 0 0<br />
25 49 1 0 0 0 0<br />
25 50 1 0 0 0 0<br />
25 51 1 0 0 0 0<br />
26 52 1 0 0 0 0<br />
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26 54 1 0 0 0 0<br />
27 36 2 0 0 0 0<br />
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28 29 1 0 0 0 0<br />
28 30 1 0 0 0 0<br />
28 56 1 0 0 0 0<br />
29 57 1 0 0 0 0<br />
29 58 1 0 0 0 0<br />
29 69 1 0 0 0 0<br />
30 60 1 0 0 0 0<br />
30 62 1 0 0 0 0<br />
30 70 1 0 0 0 0<br />
31 63 1 0 0 0 0<br />
34 71 1 0 0 0 0<br />
35 66 1 0 0 0 0<br />
37 67 1 0 0 0 0<br />
38 68 1 0 0 0 0<br />
M END</inlineContents><br />
</jmolApplet><br />
</jmol> <br />
|- align="center"<br />
| '''2D Structure''' <br />
| '''3D Structure''' <br />
|}<br />
<br />
Molecular Weight: 518.5634<br /><br />
Molecular Formula: C<sub>30</sub>H<sub>30</sub>O<sub>8</sub><br /><br />
Melting Point: 177 - 182 C<br />
<br />
== How Gossypol Works ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:CLBphoto5.jpg|thumb|150px|center|Gossypol Expression in Cotton]]<br />
|-<br />
! ''[http://www.anbg.gov.au anbg.gov.au]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
'''Gossypol suppresses P24Ag in semen.'''<br /><br />
<br />
Appropriate quantities of Gossypol acetate (gp) suppress P24Ag in semen of HIV(+) men. Gp has shown its role as an inhibitor on the replication of HIV. It has been found that 15 out of 18 test subjects have shown P24Ag (-) in their semen and it remained consistent while taking gp. However this test was discontinued when AIDs symptoms was found in 10 of the 18 patients and 5 developed infections including PCP, pulmonary tuberculosis, cryptosporidium and CMV enteritis, esophageal candida.<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
== Uses and Dosage == <br />
<br />
The amount of Gossypol to intake depends on the strength of the medicine and the reason for intake. Follow the instructions on the medicine bottle if not advised by a caregiver or doctor.<br />
<br />
<br />
Heat or moisture might lead to breakdown of the medicine and it might not function as normal. Keep the medicine locked and beyond the reach of children.<br />
Do not take Gossypol without a doctor's advice if you are taking:<br />
* Digoxin<br />
* Water Pills<br />
* Iron<br />
* Isoproterenol<br />
* Medicine for pain or swelling<br />
* Potassium<br />
* Alcohol / Breastfeeding<br />
<br />
Possible Side Effects:<br />
* Breathing problems or chest pains<br />
* Hives, rash and swollen skin<br />
* Muscle Weakness<br />
* Hair Loss, nausea, or bowel problems.<br />
<br />
== Synthetic Studies ==<br />
<br />
Various studies have undertaken the task of the total synthesis of Gossypol. In 1937 Adams and Geissman<sup>1</sup> proposed the following scheme which synthesises Gossypol via its derivative desapogossypolone tetramethyl ether.<br />
<br />
[[Image:gossypolsynthesis.gif]]<br />
<br />
More recently, Shirley and Dean<sup>2</sup> successfully synthesised 1,1',6,6',7,7'-hexamethoxy-3,3'-dimethyl-2,2'-binaphthyl which was matched to desapogossypol hexamethyl ether, a degradation product of Gossypol. This result also confirmed the 2,2' position of the binaphthyl linkage in Gossypol which was previously believed to be at the 3,3' location.<br />
<br />
[[Image:desapogossypolhexamethylether.gif]]<br />
Desapogossypol Hexamethyl Ether<br />
<br />
<br />
== History of Gossypol ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
'''Gossypol was once believed to cause female infertility.'''<br /><br />
<br />
Once upon a time, gossypol has been regarded as a toxic waste in the handling of cotton. In 1957, in the Wang Village in Jiangsu, China, it was reported that there was no newborn for a span of 10 years from 1930s to 1940s. The cause of this unprolific years was the change from soybean oil to crude cottonseed oil used in their cooking due to economic reasons. This evidence had caused scientists to believe that Gossypol might had caused female infertility, supported by the fact that the female villagers suffered from menstrual disturbances. Later, it was discovered by the Hubei Provincial Group the antispermatogenic effects of crude cottonseed oil in rats and primates, and since then, many workers had been investigating and simultaneously documented the antifertility effect in males instead. The work on gossypol as an antifertility agent stimulated nationwide interest followed by universal attraction after the publication of gossypol by the National Coordinating Group.<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Gossypol3.jpg|thumb|150px|center|Gossypol as a Powder]]<br />
|-<br />
! ''[http://www.ars.usda.gov/is/graphics/photos/jul05/d106-18.htm]''<br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
== The Chemistry of Gossypol ==<br />
<br />
Gossypol gives 3 unique crystalline substances with different melting points when recrystallised with different solvents. These substances all possess different optical properties and crystalline structures but do not display significant differences in both spectral and chemical properties. This suggests that the 3 structures do not differ much in chemical structures, yet, many reactions of gossypol cannot be explained by a simple chemical structure as propsosed above.<br />
<br />
Adams and Geissman proposed 3 tautomeric forms of gossypol in attempt to explain the vast number of reactions: the aldehyde, the ketonoid and the hemiacetal (see Figure below).<br />
<br />
[[Image:Gossypol4.gif]]<br />
<br />
In inert solvents, the aldehyde form of Gossypol predominates, whereas in polar solvents like DMSO, the aldehyde form exist in equilibrium with the hemiacetal counterpart.<br />
<br />
== Gossypol's antifertility effect on laboratory animals ==<br />
<br />
Three forms of Gossypol has been used in laboratory testing, namely gossypol, gossypol acetic acid and gossypol formic acid. Different animal species have different sensitivity towards gossypol. Among the animals tested, hamsters displayed the highest sensitivity, followed by rats, monkeys, dogs in decreasing order. <br />
<br />
Rhesus monkeys, given a dose of 4mg/kg per day for 2 years, were moderately sensitive to the antispermatogenic action of gossypol. Out of 3 monkeys, spermatogenesis was entirely inhibited in 2 of them with a few normal spermatids and spermatozoa found in the tubules of the third. in cynomolgus monkeys, gossypol only reduced the sperm count and motility.<br />
<br />
== Extra Information ==<br />
* [http://cdmrp.army.mil/scripts/get_item.asp?item=abstract&log_no=PC030753&type=public Congressionally Medical Research Program]<br />
* [http://www.fasebj.org/cgi/content/summary/20/12/2147 Gossypol induces Bax/Bak-independent activation of apoptosis and cytochrome c release via a conformational change in Bcl-2]<br />
* [http://www.utexas.edu/centers/nfic/natnews/2005/Nov.2005.nat.htm 2005 Nat News]<br />
* [http://www.ndt.net/article/v11n06/paiziev2/paiziev2.htm Structural Features of Stony Cotton Seeds]<br />
<br />
== References ==<br />
<br />
1. R. Adams, T. A. Geissman; Structure of Gossypol. XXIII. Attempts to Prepare Desapogossypolone Tetramethyl Ether. Condensation of Hexadiene-2,4 with Dibenzoethylene; J. Am Chem. Soc., 1939, 2038<br />
<br />
2. D. A. Shirley, W. L. Dean; The Structure and Reactions of Gossypol. IV. The Synthesis of Desapogossypol Hexamethyl Ether; J. Am. Chem. Soc., 1956, 1205<br />
<br />
3. [http://www.jbc.org/cgi/reprint/93/2/381.pdf Studies on the Toxicity of Gossypol]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Gossypol&diff=6575It:Gossypol2006-12-01T15:25:34Z<p>Kjf05: /* References */</p>
<hr />
<div>== Abstract ==<br />
<br />
<br />
Gossypol is a polyphenol extracted from plants of the genus Gossypium, Malvaceae (commonly known as cottonseed plant). Gossypol is believed to act as an inhibitor of dehydrogenases and thus destroys cellular energy. One of the main applications of Gossypol in the industry is as a male contraceptive, most widely manufactured in China.<br />
<br />
<br />
Chemical name: 2,2'-bis-(Formyl-1,6,7-trihydroxy-5-isopropyl-3-methylnaphthalene)<br />
<br />
The (-) isomer of acts as a contraceptive whereas the (+) isomer is a toxin.<br />
<br />
== Structure ==<br />
{| class="toccolours" border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
|+ '''Gossypol'''<br />
! [[Image:Wiki_gosspol.gif]]!! <jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 80; bns on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>water.mol<br />
title1<br />
title2<br />
71 70 0 0 0 0 0 0 0 0 0 0<br />
0.7498 0.7380 0.5973 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.2538 -0.5230 0.3153 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.7008 -1.6210 1.0873 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6328 -1.4230 2.0673 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.2158 -0.0000 3.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.6718 1.2570 3.5933 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.1688 2.3950 2.9433 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.2128 2.3060 1.9403 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.6918 0.9850 1.6193 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.1768 -0.1500 2.3483 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.1712 -0.9620 -2.0767 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.6912 -0.7180 -0.8287 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.0982 -0.6810 -0.6647 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.8902 -0.9380 -1.7477 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.2422 -1.4910 -4.1577 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.6942 -1.6870 -5.3787 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-1.3042 -1.5370 -5.6077 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.4272 -1.2510 -4.5697 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9672 -1.1180 -3.2377 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.3732 -1.1800 -3.0437 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.1358 -3.0140 0.8133 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.7938 3.5600 1.3443 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.8168 -1.1790 4.0863 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
5.2908 -1.3470 3.8143 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.5188 -1.1650 5.5613 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.7042 -0.3820 0.7003 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.9438 -0.9780 -4.9517 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-4.7402 -1.6550 -3.9647 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.5372 -0.6900 -4.7897 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
-5.1692 -3.0650 -4.1717 C 0 0 0 0 0 0 0 0 0 0 0 0<br />
0.3338 1.8200 -0.1267 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
2.2348 4.6650 1.6713 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
3.6998 3.5580 3.3573 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
4.6318 1.4810 4.5573 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.1938 -1.1050 -2.2307 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.3808 -1.1380 -6.0917 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
-0.9042 -1.6750 -6.8807 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
-3.4602 -2.0440 -6.4577 O 0 0 0 0 0 0 0 0 0 0 0 0<br />
1.9638 -2.2670 2.6513 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
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-2.4422 0.6230 0.9773 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.3242 -1.1830 1.2853 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
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-5.2242 0.2920 -4.3637 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
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-0.1652 1.5730 -0.8157 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
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5.0608 2.4590 4.4183 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
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0.0858 -1.4660 -6.9737 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
-2.8932 -1.8450 -7.1217 H 0 0 0 0 0 0 0 0 0 0 0 0<br />
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M END</inlineContents><br />
</jmolApplet><br />
</jmol> <br />
|- align="center"<br />
| '''2D Structure''' <br />
| '''3D Structure''' <br />
|}<br />
<br />
Molecular Weight: 518.5634<br /><br />
Molecular Formula: C<sub>30</sub>H<sub>30</sub>O<sub>8</sub><br /><br />
Melting Point: 177 - 182 C<br />
<br />
== How Gossypol Works ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:CLBphoto5.jpg|thumb|150px|center|Gossypol Expression in Cotton]]<br />
|-<br />
! ''[http://www.anbg.gov.au anbg.gov.au]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
'''Gossypol suppresses P24Ag in semen.'''<br /><br />
<br />
Appropriate quantities of Gossypol acetate (gp) suppress P24Ag in semen of HIV(+) men. Gp has shown its role as an inhibitor on the replication of HIV. It has been found that 15 out of 18 test subjects have shown P24Ag (-) in their semen and it remained consistent while taking gp. However this test was discontinued when AIDs symptoms was found in 10 of the 18 patients and 5 developed infections including PCP, pulmonary tuberculosis, cryptosporidium and CMV enteritis, esophageal candida.<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
== Uses and Dosage == <br />
<br />
The amount of Gossypol to intake depends on the strength of the medicine and the reason for intake. Follow the instructions on the medicine bottle if not advised by a caregiver or doctor.<br />
<br />
<br />
Heat or moisture might lead to breakdown of the medicine and it might not function as normal. Keep the medicine locked and beyond the reach of children.<br />
Do not take Gossypol without a doctor's advice if you are taking:<br />
* Digoxin<br />
* Water Pills<br />
* Iron<br />
* Isoproterenol<br />
* Medicine for pain or swelling<br />
* Potassium<br />
* Alcohol / Breastfeeding<br />
<br />
Possible Side Effects:<br />
* Breathing problems or chest pains<br />
* Hives, rash and swollen skin<br />
* Muscle Weakness<br />
* Hair Loss, nausea, or bowel problems.<br />
<br />
== Synthetic Studies ==<br />
<br />
Various studies have undertaken the task of the total synthesis of Gossypol. In 1937 Adams and Geissman<sup>1</sup> proposed the following scheme which synthesises Gossypol via its derivative desapogossypolone tetramethyl ether.<br />
<br />
[[Image:gossypolsynthesis.gif]]<br />
<br />
More recently, Shirley and Dean<sup>2</sup> successfully synthesised 1,1',6,6',7,7'-hexamethoxy-3,3'-dimethyl-2,2'-binaphthyl which was matched to desapogossypol hexamethyl ether, a degradation product of Gossypol. This result also confirmed the 2,2' position of the binaphthyl linkage in Gossypol which was previously believed to be at the 3,3' location.<br />
<br />
[[Image:desapogossypolhexamethylether.gif]]<br />
Desapogossypol Hexamethyl Ether<br />
<br />
<br />
== History of Gossypol ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
'''Gossypol was once believed to cause female infertility.'''<br /><br />
<br />
Once upon a time, gossypol has been regarded as a toxic waste in the handling of cotton. In 1957, in the Wang Village in Jiangsu, China, it was reported that there was no newborn for a span of 10 years from 1930s to 1940s. The cause of this unprolific years was the change from soybean oil to crude cottonseed oil used in their cooking due to economic reasons. This evidence had caused scientists to believe that Gossypol might had caused female infertility, supported by the fact that the female villagers suffered from menstrual disturbances. Later, it was discovered by the Hubei Provincial Group the antispermatogenic effects of crude cottonseed oil in rats and primates, and since then, many workers had been investigating and simultaneously documented the antifertility effect in males instead. The work on gossypol as an antifertility agent stimulated nationwide interest followed by universal attraction after the publication of gossypol by the National Coordinating Group.<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Gossypol3.jpg|thumb|150px|center|Gossypol as a Powder]]<br />
|-<br />
! ''[http://www.ars.usda.gov/is/graphics/photos/jul05/d106-18.htm]''<br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
== The Chemistry of Gossypol ==<br />
<br />
Gossypol gives 3 unique crystalline substances with different melting points if recrystallised with different solvents. These substances have different optical properties and crystalline structures but do not display significant differences in both spectral and chemical properties. This suggests that the 3 structures do not differ much in chemical structures, yet, many reactions of gossypol cannot be explained by a simple chemical structure as propsosed above.<br />
<br />
Adams and Geissman proposed 3 tautomeric forms of gossypol in attempt to explain the vast number of reactions: the aldehyde, the ketonoid and the hemiacetal (see Figure below).<br />
<br />
[[Image:Gossypol4.gif]]<br />
<br />
In inert solvents, the aldehyde form of Gossypol predominates, whereas in polar solvents like DMSO, the aldehyde form exist in equilibrium with the hemiacetal counterpart. <br />
<br />
<br />
== Gossypol's antifertility effect on laboratory animals ==<br />
<br />
Three forms of Gossypol has been used in laboratory testing, namely gossypol, gossypol acetic acid and gossypol formic acid. Different animal species have different sensitivity towards gossypol. Among the animals tested, hamsters displayed the highest sensitivity, followed by rats, monkeys, dogs in decreasing order. <br />
<br />
Rhesus monkeys, given a dose of 4mg/kg per day for 2 years, were moderately sensitive to the antispermatogenic action of gossypol. Out of 3 monkeys, spermatogenesis was entirely inhibited in 2 of them with a few normal spermatids and spermatozoa found in the tubules of the third. in cynomolgus monkeys, gossypol only reduced the sperm count and motility.<br />
<br />
== Extra Information ==<br />
* [http://cdmrp.army.mil/scripts/get_item.asp?item=abstract&log_no=PC030753&type=public Congressionally Medical Research Program]<br />
* [http://www.fasebj.org/cgi/content/summary/20/12/2147 Gossypol induces Bax/Bak-independent activation of apoptosis and cytochrome c release via a conformational change in Bcl-2]<br />
* [http://www.utexas.edu/centers/nfic/natnews/2005/Nov.2005.nat.htm 2005 Nat News]<br />
* [http://www.ndt.net/article/v11n06/paiziev2/paiziev2.htm Structural Features of Stony Cotton Seeds]<br />
<br />
== References ==<br />
<br />
1. R. Adams, T. A. Geissman; Structure of Gossypol. XXIII. Attempts to Prepare Desapogossypolone Tetramethyl Ether. Condensation of Hexadiene-2,4 with Dibenzoethylene; J. Am Chem. Soc., 1939, 2038<br />
<br />
2. D. A. Shirley, W. L. Dean; The Structure and Reactions of Gossypol. IV. The Synthesis of Desapogossypol Hexamethyl Ether; J. Am. Chem. Soc., 1956, 1205<br />
<br />
3. [http://www.jbc.org/cgi/reprint/93/2/381.pdf Studies on the Toxicity of Gossypol]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Gossypol&diff=6574It:Gossypol2006-12-01T15:18:36Z<p>Kjf05: /* Structure */</p>
<hr />
<div>== Abstract ==<br />
<br />
<br />
Gossypol is a polyphenol extracted from plants of the genus Gossypium, Malvaceae (commonly known as cottonseed plant). Gossypol is believed to act as an inhibitor of dehydrogenases and thus destroys cellular energy. One of the main applications of Gossypol in the industry is as a male contraceptive, most widely manufactured in China.<br />
<br />
<br />
Chemical name: 2,2'-bis-(Formyl-1,6,7-trihydroxy-5-isopropyl-3-methylnaphthalene)<br />
<br />
The (-) isomer of acts as a contraceptive whereas the (+) isomer is a toxin.<br />
<br />
== Structure ==<br />
{| class="toccolours" border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
|+ '''Gossypol'''<br />
! [[Image:Wiki_gosspol.gif]]!! <jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 80; bns on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>water.mol<br />
title1<br />
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38 68 1 0 0 0 0<br />
M END</inlineContents><br />
</jmolApplet><br />
</jmol> <br />
|- align="center"<br />
| '''2D Structure''' <br />
| '''3D Structure''' <br />
|}<br />
<br />
Molecular Weight: 518.5634<br /><br />
Molecular Formula: C<sub>30</sub>H<sub>30</sub>O<sub>8</sub><br /><br />
Melting Point: 177 - 182 C<br />
<br />
== How Gossypol Works ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:CLBphoto5.jpg|thumb|150px|center|Gossypol Expression in Cotton]]<br />
|-<br />
! ''[http://www.anbg.gov.au anbg.gov.au]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
'''Gossypol suppresses P24Ag in semen.'''<br /><br />
<br />
Appropriate quantities of Gossypol acetate (gp) suppress P24Ag in semen of HIV(+) men. Gp has shown its role as an inhibitor on the replication of HIV. It has been found that 15 out of 18 test subjects have shown P24Ag (-) in their semen and it remained consistent while taking gp. However this test was discontinued when AIDs symptoms was found in 10 of the 18 patients and 5 developed infections including PCP, pulmonary tuberculosis, cryptosporidium and CMV enteritis, esophageal candida.<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
== Uses and Dosage == <br />
<br />
The amount of Gossypol to intake depends on the strength of the medicine and the reason for intake. Follow the instructions on the medicine bottle if not advised by a caregiver or doctor.<br />
<br />
<br />
Heat or moisture might lead to breakdown of the medicine and it might not function as normal. Keep the medicine locked and beyond the reach of children.<br />
Do not take Gossypol without a doctor's advice if you are taking:<br />
* Digoxin<br />
* Water Pills<br />
* Iron<br />
* Isoproterenol<br />
* Medicine for pain or swelling<br />
* Potassium<br />
* Alcohol / Breastfeeding<br />
<br />
Possible Side Effects:<br />
* Breathing problems or chest pains<br />
* Hives, rash and swollen skin<br />
* Muscle Weakness<br />
* Hair Loss, nausea, or bowel problems.<br />
<br />
== Synthetic Studies ==<br />
<br />
Various studies have undertaken the task of the total synthesis of Gossypol. In 1937 Adams and Geissman<sup>1</sup> proposed the following scheme which synthesises Gossypol via its derivative desapogossypolone tetramethyl ether.<br />
<br />
[[Image:gossypolsynthesis.gif]]<br />
<br />
More recently, Shirley and Dean<sup>2</sup> successfully synthesised 1,1',6,6',7,7'-hexamethoxy-3,3'-dimethyl-2,2'-binaphthyl which was matched to desapogossypol hexamethyl ether, a degradation product of Gossypol. This result also confirmed the 2,2' position of the binaphthyl linkage in Gossypol which was previously believed to be at the 3,3' location.<br />
<br />
[[Image:desapogossypolhexamethylether.gif]]<br />
Desapogossypol Hexamethyl Ether<br />
<br />
<br />
== History of Gossypol ==<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
'''Gossypol was once believed to cause female infertility.'''<br /><br />
<br />
Once upon a time, gossypol has been regarded as a toxic waste in the handling of cotton. In 1957, in the Wang Village in Jiangsu, China, it was reported that there was no newborn for a span of 10 years from 1930s to 1940s. The cause of this unprolific years was the change from soybean oil to crude cottonseed oil used in their cooking due to economic reasons. This evidence had caused scientists to believe that Gossypol might had caused female infertility, supported by the fact that the female villagers suffered from menstrual disturbances. Later, it was discovered by the Hubei Provincial Group the antispermatogenic effects of crude cottonseed oil in rats and primates, and since then, many workers had been investigating and simultaneously documented the antifertility effect in males instead. The work on gossypol as an antifertility agent stimulated nationwide interest followed by universal attraction after the publication of gossypol by the National Coordinating Group.<br />
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{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Gossypol3.jpg|thumb|150px|center|Gossypol as a Powder]]<br />
|-<br />
! ''[http://www.ars.usda.gov/is/graphics/photos/jul05/d106-18.htm]''<br />
|}<br />
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</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
== The Chemistry of Gossypol ==<br />
<br />
Gossypol gives 3 unique crystalline substances with different melting points if recrystallised with different solvents. These substances have different optical properties and crystalline structures but do not display significant differences in both spectral and chemical properties. This suggests that the 3 structures do not differ much in chemical structures, yet, many reactions of gossypol cannot be explained by a simple chemical structure as propsosed above.<br />
<br />
Adams and Geissman proposed 3 tautomeric forms of gossypol in attempt to explain the vast number of reactions: the aldehyde, the ketonoid and the hemiacetal (see Figure below).<br />
<br />
[[Image:Gossypol4.gif]]<br />
<br />
In inert solvents, the aldehyde form of Gossypol predominates, whereas in polar solvents like DMSO, the aldehyde form exist in equilibrium with the hemiacetal counterpart. <br />
<br />
<br />
== Gossypol's antifertility effect on laboratory animals ==<br />
<br />
Three forms of Gossypol has been used in laboratory testing, namely gossypol, gossypol acetic acid and gossypol formic acid. Different animal species have different sensitivity towards gossypol. Among the animals tested, hamsters displayed the highest sensitivity, followed by rats, monkeys, dogs in decreasing order. <br />
<br />
Rhesus monkeys, given a dose of 4mg/kg per day for 2 years, were moderately sensitive to the antispermatogenic action of gossypol. Out of 3 monkeys, spermatogenesis was entirely inhibited in 2 of them with a few normal spermatids and spermatozoa found in the tubules of the third. in cynomolgus monkeys, gossypol only reduced the sperm count and motility.<br />
<br />
== References ==<br />
<br />
1. R. Adams, T. A. Geissman; Structure of Gossypol. XXIII. Attempts to Prepare Desapogossypolone Tetramethyl Ether. Condensation of Hexadiene-2,4 with Dibenzoethylene; J. Am Chem. Soc., 1939, 2038<br />
<br />
2. D. A. Shirley, W. L. Dean; The Structure and Reactions of Gossypol. IV. The Synthesis of Desapogossypol Hexamethyl Ether; J. Am. Chem. Soc., 1956, 1205</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Schrock&diff=6573It:Schrock2006-12-01T15:17:15Z<p>Kjf05: /* Background Story */</p>
<hr />
<div>==Introduction==<br />
[[Image:Schrock2.jpg|thumb|left|General example, commercially available example<sup>2<sup>]]<br />
<br />
<br />
'''Richard R. Schrock''' won the 2005 Nobel Prize in Chemistry.<br />
<br />
His nobel prize speech can be viewed through the following link:[http://nobelprize.org/nobel_prizes/chemistry/laureates/2005/schrock-lecture.html]<br />
<br />
<br />
<br />
This is an important discovery as the catalysts used before were sensitive to air and moisture, created side reactions and were relatively short-lived.<sup>2</sup> Schrock's discovery of the catalysts using tungsten provided one of the first stable metathesis catalyst.<sup>2<sup><br />
<br />
<br />
<br />
= Background Story =<br />
<br />
Metathesis was first discovered in the early 1950s but the chemistry was then understood only by 1971. Chauvin had then proposed a reaction mechanism, whereby the double bonds were cleaved and synthesised between C atoms in a way that the atom groups change positions, just as dance couples change partners. However, this is only possible in the presence of special catalyst molecules. <br />
<br />
With the mechanism in place, there was a need to develop these catalysts and Schrock was the first to attempt it. In his own words, before these catalysts there was no way to do the metathesis reaction simply. The use of catalysts gives shorter synthetic routes and thus fewer byproducts and better control of the reaction overall.<br />
<br />
=Scheme=<br />
<br />
[[Image:Olefin1.gif]]<br />
<br />
* Chauvin-type mechanism<br />
<br />
[[Image:Olefin2.gif]]<br />
<br />
* Well defined catalyst systems<br />
<br />
[[Image:Olefin3.gif]]<br />
<br />
<br />
= Metal Carbenes =<br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Olefin4.gif]]<br />
|}<br />
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<br />
<td><br />
<div align=justify><br />
* Transition metal has a formal metal to a C=C<br />
* X and Y can be any alkyl or aryl or heteroatom<br />
* There are 2 types of carbenes: Fischer or Schrock-type<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
[[Image:Olefin5.gif]]<br />
* TM has a high oxidation state<br />
<br />
* Ligands are good sigma or pi donors<br />
<br />
* Nucleophilic: attacks at C<sub>carbene</sub> by electrophiles<br />
<br />
* C<sub>carbene</sub> is X<sub>2</sub>-type ligand: Metal oxidation state changed by +2<br />
<br />
[[Image:Olefin6.gif]]<br />
<br />
<br />
= Schrock's Metathesis Catalyst =<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
* Must be handled under Ar or N<sub>2</sub> using dry solvents<br />
* Reactive towards protons on heteroatoms but tolerant of S, P and nitrile groups<br />
* Mo(VI) centre electron deficient, pseudo-tetrahedral. <br />
* Alkoxides needed to enhance the electrophilicity of metal cenre. <br />
[[Image:Olefin7.gif]]<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
!<jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 100; bns on; cpk on;frame 2; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER NONAME 30-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 30-Nov-06 0 NONE 4<br />
ATOM 1 Mo 0 -0.095 -0.300 0.294 0.00 0.00 Mo+0<br />
ATOM 2 N 0 1.232 0.201 -0.868 0.00 0.00 N+0<br />
ATOM 3 C 0 2.502 0.118 -0.498 0.00 0.00 C+0<br />
ATOM 4 C 0 3.279 1.293 -0.337 0.00 0.00 C+0<br />
ATOM 5 C 0 2.665 2.648 -0.584 0.00 0.00 C+0<br />
ATOM 6 C 0 2.741 3.483 0.696 0.00 0.00 C+0<br />
ATOM 7 C 0 3.429 3.358 -1.702 0.00 0.00 C+0<br />
ATOM 8 C 0 4.584 1.192 0.044 0.00 0.00 C+0<br />
ATOM 9 C 0 5.153 -0.055 0.273 0.00 0.00 C+0<br />
ATOM 10 C 0 4.406 -1.215 0.118 0.00 0.00 C+0<br />
ATOM 11 C 0 3.096 -1.146 -0.255 0.00 0.00 C+0<br />
ATOM 12 C 0 2.288 -2.408 -0.422 0.00 0.00 C+0<br />
ATOM 13 C 0 2.908 -3.268 -1.524 0.00 0.00 C+0<br />
ATOM 14 C 0 2.285 -3.189 0.894 0.00 0.00 C+0<br />
ATOM 15 C 0 -1.595 0.833 0.066 0.00 0.00 C+0<br />
ATOM 16 C 0 -2.828 0.629 0.908 0.00 0.00 C+0<br />
ATOM 17 C 0 -2.608 -0.549 1.858 0.00 0.00 C+0<br />
ATOM 18 C 0 -3.106 1.896 1.720 0.00 0.00 C+0<br />
ATOM 19 C 0 -4.005 0.339 0.012 0.00 0.00 C+0<br />
ATOM 20 C 0 -5.254 0.116 0.562 0.00 0.00 C+0<br />
ATOM 21 C 0 -6.333 -0.151 -0.259 0.00 0.00 C+0<br />
ATOM 22 C 0 -6.165 -0.193 -1.630 0.00 0.00 C+0<br />
ATOM 23 C 0 -4.917 0.031 -2.180 0.00 0.00 C+0<br />
ATOM 24 C 0 -3.838 0.301 -1.359 0.00 0.00 C+0<br />
ATOM 25 H 0 1.622 2.526 -0.876 0.00 0.00 H+0<br />
ATOM 26 H 0 3.784 3.605 0.989 0.00 0.00 H+0<br />
ATOM 27 H 0 2.297 4.462 0.518 0.00 0.00 H+0<br />
ATOM 28 H 0 2.196 2.977 1.493 0.00 0.00 H+0<br />
ATOM 29 H 0 4.472 3.479 -1.410 0.00 0.00 H+0<br />
ATOM 30 H 0 3.375 2.763 -2.614 0.00 0.00 H+0<br />
ATOM 31 H 0 2.986 4.337 -1.881 0.00 0.00 H+0<br />
ATOM 32 H 0 5.179 2.085 0.167 0.00 0.00 H+0<br />
ATOM 33 H 0 6.188 -0.122 0.574 0.00 0.00 H+0<br />
ATOM 34 H 0 4.862 -2.177 0.299 0.00 0.00 H+0<br />
ATOM 35 H 0 1.264 -2.150 -0.694 0.00 0.00 H+0<br />
ATOM 36 H 0 3.889 -3.619 -1.204 0.00 0.00 H+0<br />
ATOM 37 H 0 2.263 -4.124 -1.723 0.00 0.00 H+0<br />
ATOM 38 H 0 3.013 -2.675 -2.433 0.00 0.00 H+0<br />
ATOM 39 H 0 3.307 -3.460 1.158 0.00 0.00 H+0<br />
ATOM 40 H 0 1.858 -2.570 1.683 0.00 0.00 H+0<br />
ATOM 41 H 0 1.688 -4.093 0.778 0.00 0.00 H+0<br />
ATOM 42 H 0 -1.567 1.625 -0.668 0.00 0.00 H+0<br />
ATOM 43 H 0 -1.757 -0.339 2.506 0.00 0.00 H+0<br />
ATOM 44 H 0 -3.500 -0.696 2.467 0.00 0.00 H+0<br />
ATOM 45 H 0 -2.410 -1.451 1.280 0.00 0.00 H+0<br />
ATOM 46 H 0 -3.263 2.735 1.043 0.00 0.00 H+0<br />
ATOM 47 H 0 -3.998 1.748 2.329 0.00 0.00 H+0<br />
ATOM 48 H 0 -2.255 2.106 2.368 0.00 0.00 H+0<br />
ATOM 49 H 0 -5.386 0.149 1.634 0.00 0.00 H+0<br />
ATOM 50 H 0 -7.309 -0.326 0.171 0.00 0.00 H+0<br />
ATOM 51 H 0 -7.008 -0.402 -2.272 0.00 0.00 H+0<br />
ATOM 52 H 0 -4.785 -0.003 -3.252 0.00 0.00 H+0<br />
ATOM 53 H 0 -2.863 0.476 -1.789 0.00 0.00 H+0<br />
CONECT 1 1 2 16 15 NONE 58<br />
CONECT 2 1 3 0 0 NONE 59<br />
CONECT 3 2 11 4 0 NONE 60<br />
CONECT 4 3 5 8 0 NONE 61<br />
CONECT 5 4 6 7 25 NONE 62<br />
CONECT 6 5 26 27 28 NONE 63<br />
CONECT 7 5 29 30 31 NONE 64<br />
CONECT 8 4 9 32 0 NONE 65<br />
CONECT 9 8 10 33 0 NONE 66<br />
CONECT 10 9 11 34 0 NONE 67<br />
CONECT 11 10 3 12 0 NONE 68<br />
CONECT 12 11 13 14 35 NONE 69<br />
CONECT 13 12 36 37 38 NONE 70<br />
CONECT 14 12 39 40 41 NONE 71<br />
CONECT 15 1 16 42 0 NONE 72<br />
CONECT 16 15 17 18 19 NONE 73<br />
CONECT 17 16 43 44 45 NONE 74<br />
CONECT 18 16 46 47 48 NONE 75<br />
CONECT 19 16 24 20 0 NONE 76<br />
CONECT 20 19 21 49 0 NONE 77<br />
CONECT 21 20 22 50 0 NONE 78<br />
CONECT 22 21 23 51 0 NONE 79<br />
CONECT 23 22 24 52 0 NONE 80<br />
CONECT 24 23 19 53 0 NONE 81<br />
END NONE 82<br />
</inlineContents><br />
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</table><br />
<br />
<br />
= Basic Metathesis Reactions =<br />
<br />
[[Image:Olefin8.gif]]<br />
<br />
<br />
= Influence of Ligand set on Reactivity of Schrock's Catalyst =<br />
<br />
* 2 Rotamers the syn or anti<br />
<br />
[[Image:Olefin9.gif]]<br />
<br />
* Between these 2 rotamers, the rate of interconversion depends on ligands and substrate<br />
<br />
[[Image:Olefin10.gif]]<br />
<br />
<br />
= Other catalytic systems =<br />
<br />
There are a variety of different catalytic commercially available systems for the metathesis of olefins. Another famous catalyst is the Grubb's Metathesis Catalyst where the central metal is Ruthenium surrounded by phosphines and chloride ligands. It is believed that this catalyst is superior to the former due to higher functional group tolerance, lower reactivity and relative stability to water and oxygen. <br />
<br />
Many variations to the catalyst have been made, for instance, ruthenium containing N-Heterocyclic Carbene ligands which is even more stable than the Grubb's catalyst itself. <br />
<br />
The choice of catalyst is important depending on the mechanism of the olefin metathesis as shown above. Other experimental conditions have to be considered as well. Generally, ruthenium based catalysts are favoured due to the ease of handling. <br />
<br />
Lastly, more detailed reactions and choices of catalysts can be found in the reference.<br />
<br />
<br />
= Reference =<br />
<br />
Wendy Jen, MacMillan Group Meeting, Jan 17 2001, Olefin Metathesis in Organic Synthesis<br />
<br />
<jmol><br />
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<inlineContents>HEADER CSD ENTRY XICKAV<br />
CRYST1 8.5594 6.0337 11.0220 90.00 105.97 90.00 P21/c<br />
SCALE1 0.116831 -0.000000 0.033428 0.000000<br />
SCALE2 -0.000000 0.165736 -0.000000 0.000000<br />
SCALE3 -0.000000 0.000000 0.094368 0.000000<br />
<br />
HEADER NONAME 20-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 20-Nov-06 0 NONE 4<br />
ATOM 1 C 0 2.963 -1.542 0.211 0.00 0.00 C+0<br />
ATOM 2 C 0 1.711 -2.418 0.287 0.00 0.00 C+0<br />
ATOM 3 C 0 1.225 -2.737 -1.129 0.00 0.00 C+0<br />
ATOM 4 C 0 2.043 -3.720 1.018 0.00 0.00 C+0<br />
ATOM 5 O 0 0.685 -1.722 0.997 0.00 0.00 O+0<br />
ATOM 6 W 0 0.327 -0.023 -0.017 0.00 0.00 W+0<br />
ATOM 7 N 0 -1.038 0.906 0.803 0.00 0.00 N+0<br />
ATOM 8 C 0 -2.234 0.351 0.930 0.00 0.00 C+0<br />
ATOM 9 C 0 -3.290 1.059 1.560 0.00 0.00 C+0<br />
ATOM 10 C 0 -4.515 0.474 1.682 0.00 0.00 C+0<br />
ATOM 11 C 0 -4.733 -0.808 1.195 0.00 0.00 C+0<br />
ATOM 12 C 0 -3.710 -1.515 0.576 0.00 0.00 C+0<br />
ATOM 13 C 0 -2.475 -0.955 0.432 0.00 0.00 C+0<br />
ATOM 14 O 0 1.989 1.107 -0.037 0.00 0.00 O+0<br />
ATOM 15 C 0 1.961 1.904 1.149 0.00 0.00 C+0<br />
ATOM 16 C 0 1.778 0.998 2.368 0.00 0.00 C+0<br />
ATOM 17 C 0 3.278 2.673 1.277 0.00 0.00 C+0<br />
ATOM 18 C 0 0.798 2.895 1.070 0.00 0.00 C+0<br />
ATOM 19 C 0 -0.176 -0.444 -1.804 0.00 0.00 C+0<br />
ATOM 20 C 0 -0.600 0.653 -2.746 0.00 0.00 C+0<br />
ATOM 21 C 0 -0.395 2.011 -2.072 0.00 0.00 C+0<br />
ATOM 22 C 0 0.243 0.584 -4.021 0.00 0.00 C+0<br />
ATOM 23 C 0 -2.078 0.478 -3.101 0.00 0.00 C+0<br />
ATOM 24 H 0 2.744 -0.644 -0.367 0.00 0.00 H+0<br />
ATOM 25 H 0 3.270 -1.260 1.217 0.00 0.00 H+0<br />
ATOM 26 H 0 3.766 -2.098 -0.272 0.00 0.00 H+0<br />
ATOM 27 H 0 1.773 -3.596 -1.516 0.00 0.00 H+0<br />
ATOM 28 H 0 0.160 -2.967 -1.104 0.00 0.00 H+0<br />
ATOM 29 H 0 1.396 -1.876 -1.774 0.00 0.00 H+0<br />
ATOM 30 H 0 2.389 -3.493 2.026 0.00 0.00 H+0<br />
ATOM 31 H 0 1.151 -4.344 1.072 0.00 0.00 H+0<br />
ATOM 32 H 0 2.826 -4.251 0.476 0.00 0.00 H+0<br />
ATOM 33 H 0 -3.123 2.056 1.940 0.00 0.00 H+0<br />
ATOM 34 H 0 -5.321 1.010 2.162 0.00 0.00 H+0<br />
ATOM 35 H 0 -5.708 -1.261 1.298 0.00 0.00 H+0<br />
ATOM 36 H 0 -3.894 -2.512 0.202 0.00 0.00 H+0<br />
ATOM 37 H 0 -1.681 -1.507 -0.049 0.00 0.00 H+0<br />
ATOM 38 H 0 2.649 0.351 2.473 0.00 0.00 H+0<br />
ATOM 39 H 0 1.670 1.610 3.263 0.00 0.00 H+0<br />
ATOM 40 H 0 0.885 0.387 2.236 0.00 0.00 H+0<br />
ATOM 41 H 0 3.408 3.318 0.409 0.00 0.00 H+0<br />
ATOM 42 H 0 3.257 3.280 2.182 0.00 0.00 H+0<br />
ATOM 43 H 0 4.107 1.967 1.333 0.00 0.00 H+0<br />
ATOM 44 H 0 -0.135 2.378 1.296 0.00 0.00 H+0<br />
ATOM 45 H 0 0.953 3.696 1.793 0.00 0.00 H+0<br />
ATOM 46 H 0 0.746 3.316 0.066 0.00 0.00 H+0<br />
ATOM 47 H 0 -0.158 -1.470 -2.142 0.00 0.00 H+0<br />
ATOM 48 H 0 0.658 2.136 -1.818 0.00 0.00 H+0<br />
ATOM 49 H 0 -0.702 2.805 -2.753 0.00 0.00 H+0<br />
ATOM 50 H 0 -0.996 2.060 -1.163 0.00 0.00 H+0<br />
ATOM 51 H 0 0.032 -0.348 -4.546 0.00 0.00 H+0<br />
ATOM 52 H 0 -0.004 1.428 -4.665 0.00 0.00 H+0<br />
ATOM 53 H 0 1.300 0.623 -3.760 0.00 0.00 H+0<br />
ATOM 54 H 0 -2.678 0.527 -2.192 0.00 0.00 H+0<br />
ATOM 55 H 0 -2.384 1.271 -3.782 0.00 0.00 H+0<br />
ATOM 56 H 0 -2.224 -0.490 -3.581 0.00 0.00 H+0<br />
CONECT 1 2 24 25 26 NONE 61<br />
CONECT 2 1 3 4 5 NONE 62<br />
CONECT 3 2 27 28 29 NONE 63<br />
CONECT 4 2 30 31 32 NONE 64<br />
CONECT 5 2 6 0 0 NONE 65<br />
CONECT 6 5 7 14 19 NONE 66<br />
CONECT 7 6 8 0 0 NONE 67<br />
CONECT 8 7 13 9 0 NONE 68<br />
CONECT 9 8 10 33 0 NONE 69<br />
CONECT 10 9 11 34 0 NONE 70<br />
CONECT 11 10 12 35 0 NONE 71<br />
CONECT 12 11 13 36 0 NONE 72<br />
CONECT 13 12 8 37 0 NONE 73<br />
CONECT 14 6 15 0 0 NONE 74<br />
CONECT 15 14 16 17 18 NONE 75<br />
CONECT 16 15 38 39 40 NONE 76<br />
CONECT 17 15 41 42 43 NONE 77<br />
CONECT 18 15 44 45 46 NONE 78<br />
CONECT 19 6 20 47 0 NONE 79<br />
CONECT 20 19 21 22 23 NONE 80<br />
CONECT 21 20 48 49 50 NONE 81<br />
CONECT 22 20 51 52 53 NONE 82<br />
CONECT 23 20 54 55 56 NONE 83<br />
END</inlineContents><br />
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Reference<br />
<br />
1.http://www.rsc.org/chemistryworld/restricted/2005/November/prize.asp</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6572It:knots2006-12-01T15:15:32Z<p>Kjf05: /* Knot Theory */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links came from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a potential model for atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and 3D template effects, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|400px|center|Assumption: Groups on the surface are in a square lattice]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Tying a Molecular Knot =<br />
[[Image:Knots5.GIF]]<br />
<br />
= Conclusion =<br />
<br />
The synthesis of molecular knots relies on complicated mathematical calculations. Molecular knots are believed to represent the local minima on potential energy hypersurfaces.<br />
<br />
<br />
= Acknowledgement and References =<br />
[http://http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6 Molecular knots, links, and fabrics: prediction of existence and suggestion of a synthetic route by Dirk Andrae]<br />
<br />
Pictures of tying a molecular knot can be found in the following link:<br />
[http://www.nature.com/nature/journal/v399/n6735/full/399446a0.html Tying a molecular knot with optical tweezers]<br />
<br />
and [http://www.lps.ens.fr/~vincent/smb/PDF/kino-knot.pdf Journal on Tying a molecular knot with optical tweezers]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6570It:knots2006-12-01T15:14:01Z<p>Kjf05: /* Acknowledgement and References */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|400px|center|Assumption: Groups on the surface are in a square lattice]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Tying a Molecular Knot =<br />
[[Image:Knots5.GIF]]<br />
<br />
= Conclusion =<br />
<br />
The synthesis of molecular knots relies on complicated mathematical calculations. Molecular knots are believed to represent the local minima on potential energy hypersurfaces.<br />
<br />
<br />
= Acknowledgement and References =<br />
[http://http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6 Molecular knots, links, and fabrics: prediction of existence and suggestion of a synthetic route by Dirk Andrae]<br />
<br />
Pictures of tying a molecular knot can be found in the following link:<br />
[http://www.nature.com/nature/journal/v399/n6735/full/399446a0.html Tying a molecular knot with optical tweezers]<br />
<br />
and [http://www.lps.ens.fr/~vincent/smb/PDF/kino-knot.pdf Journal on Tying a molecular knot with optical tweezers]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6569It:knots2006-12-01T15:12:48Z<p>Kjf05: /* Tying a Molecular Knot */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|400px|center|Assumption: Groups on the surface are in a square lattice]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Tying a Molecular Knot =<br />
[[Image:Knots5.GIF]]<br />
<br />
= Conclusion =<br />
<br />
The synthesis of molecular knots relies on complicated mathematical calculations. Molecular knots are believed to represent the local minima on potential energy hypersurfaces.<br />
<br />
<br />
= Acknowledgement and References =<br />
[http://http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6 Molecular knots, links, and fabrics: prediction of existence and suggestion of a synthetic route by Dirk Andrae]<br />
<br />
Pictures of tying a molecular knot can be found in the following link:<br />
[http://www.nature.com/nature/journal/v399/n6735/full/399446a0.html Tying a molecular knot with optical tweezers]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6567It:knots2006-12-01T15:11:49Z<p>Kjf05: /* Tying a Molecular Knot */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|400px|center|Assumption: Groups on the surface are in a square lattice]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Tying a Molecular Knot =<br />
[[Image:Knots5.gif]]<br />
<br />
= Conclusion =<br />
<br />
The synthesis of molecular knots relies on complicated mathematical calculations. Molecular knots are believed to represent the local minima on potential energy hypersurfaces.<br />
<br />
<br />
= Acknowledgement and References =<br />
[http://http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6 Molecular knots, links, and fabrics: prediction of existence and suggestion of a synthetic route by Dirk Andrae]<br />
<br />
Pictures of tying a molecular knot can be found in the following link:<br />
[http://www.nature.com/nature/journal/v399/n6735/full/399446a0.html Tying a molecular knot with optical tweezers]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=File:Knots5.GIF&diff=6566File:Knots5.GIF2006-12-01T15:11:20Z<p>Kjf05: </p>
<hr />
<div></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6565It:knots2006-12-01T15:11:07Z<p>Kjf05: /* Synthesis of Knots and Links */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|400px|center|Assumption: Groups on the surface are in a square lattice]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Tying a Molecular Knot =<br />
<br />
= Conclusion =<br />
<br />
The synthesis of molecular knots relies on complicated mathematical calculations. Molecular knots are believed to represent the local minima on potential energy hypersurfaces.<br />
<br />
<br />
= Acknowledgement and References =<br />
[http://http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6 Molecular knots, links, and fabrics: prediction of existence and suggestion of a synthetic route by Dirk Andrae]<br />
<br />
Pictures of tying a molecular knot can be found in the following link:<br />
[http://www.nature.com/nature/journal/v399/n6735/full/399446a0.html Tying a molecular knot with optical tweezers]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6564It:knots2006-12-01T15:08:23Z<p>Kjf05: /* Acknowledgement and References */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|400px|center|Assumption: Groups on the surface are in a square lattice]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Conclusion =<br />
<br />
The synthesis of molecular knots relies on complicated mathematical calculations. Molecular knots are believed to represent the local minima on potential energy hypersurfaces.<br />
<br />
<br />
= Acknowledgement and References =<br />
[http://http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6 Molecular knots, links, and fabrics: prediction of existence and suggestion of a synthetic route by Dirk Andrae]<br />
<br />
Pictures of tying a molecular knot can be found in the following link:<br />
[http://www.nature.com/nature/journal/v399/n6735/full/399446a0.html Tying a molecular knot with optical tweezers]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6561It:knots2006-12-01T15:02:50Z<p>Kjf05: /* Conclusion */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|400px|center|Assumption: Groups on the surface are in a square lattice]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Conclusion =<br />
<br />
The synthesis of molecular knots relies on complicated mathematical calculations. Molecular knots are believed to represent the local minima on potential energy hypersurfaces.<br />
<br />
<br />
= Acknowledgement and References =<br />
[http://http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6 Molecular knots, links, and fabrics: prediction of existence and suggestion of a synthetic route by Dirk Andrae]</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6559It:knots2006-12-01T15:01:31Z<p>Kjf05: /* Synthesis of Knots and Links */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|400px|center|Assumption: Groups on the surface are in a square lattice]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Conclusion =<br />
<br />
The synthesis of molecular knots relies on complicated mathematical calculations. Molecular knots are believed to represent the local minima on potential energy hypersurfaces.</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6552It:knots2006-12-01T14:57:45Z<p>Kjf05: /* Synthesis of Knots and Links */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|400px|center|Assumption: Groups on the surface are in a square lattice]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6550It:knots2006-12-01T14:55:16Z<p>Kjf05: /* Synthesis of Knots and Links */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|400px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6549It:knots2006-12-01T14:55:02Z<p>Kjf05: /* Synthesis of Knots and Links */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots4.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=File:Knots4.gif&diff=6548File:Knots4.gif2006-12-01T14:53:56Z<p>Kjf05: </p>
<hr />
<div></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6547It:knots2006-12-01T14:53:17Z<p>Kjf05: /* Synthesis of Knots and Links */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =<br />
<br />
Many synthetic routes have been suggested. One suggested route involves covering surface regularly with linker groups. The arrangement of these groups then offers a template for the systematic directed and controlled synthesis of knots at a molecular scale. This technique is known as the surface template technique.<br />
<br />
Prior to employment of this technique requires the matery of sophisticated chemical experimental skills, some of which have already been established, while some are still under development in the field of nanotechnology. The application of surface template can only be performed at ease with further development of these skills.<br />
<br />
Protection group, tunneling microscope and single-molecule detection and manipulation techniques are also required. Only now can it be possible to use a range of both organic and inorganic monomers to form homo- and hetero-oligomeric states of knots and links.<br />
<br />
The figure below displays the surface technique with 4 exmaples of the generation of molecular knots: trivial 0<sub>1</sub>, trefoil 3<sub>1</sub>, Hopf link 2<sup>2</sup><sub>1</sub> and "fabric in plain weave"-like knot. In each synthesis, 4 steps of the techniques are shown.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6540It:knots2006-12-01T14:38:08Z<p>Kjf05: /* Knot Theory */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
<br />
<br />
= Synthesis of Knots and Links =</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6539It:knots2006-12-01T14:32:03Z<p>Kjf05: /* Knot Theory */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|300px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6538It:knots2006-12-01T14:31:41Z<p>Kjf05: /* Knot Theory */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots3.gif|thumb|500px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6536It:knots2006-12-01T14:31:22Z<p>Kjf05: /* Knot Theory */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|500px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=File:Knots3.gif&diff=6535File:Knots3.gif2006-12-01T14:30:44Z<p>Kjf05: </p>
<hr />
<div></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6534It:knots2006-12-01T14:30:17Z<p>Kjf05: /* Knot Theory */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
Today, different types of knotted molecules can be successfully synthesised under controlled conditions. They depend on self-assembly and template effects in the 3D, the effect in metal-ligand complexes, the directional nature of hyderogen bonds ,the pi-pi stacking interaction in aromatic systems and the self-assemply of amide groups. <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
The following figure shows molecules that can only be understood theoretically: hydrogenated sections of single-walled carbon nanotubes, new forms of P and S, and a [2]-catenane created from 2 cycloalkanethiole molecules.</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6530It:knots2006-12-01T14:22:43Z<p>Kjf05: /* Knot Theory */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6529It:knots2006-12-01T14:22:15Z<p>Kjf05: /* Knot Theory */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots2.gif|thumb|100px|center|Particular Representation]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=File:Knots2.gif&diff=6528File:Knots2.gif2006-12-01T14:21:39Z<p>Kjf05: </p>
<hr />
<div></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6527It:knots2006-12-01T14:21:16Z<p>Kjf05: /* Introduction */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
= Knot Theory =<br />
<br />
The mathematical theory, the knot theory, of knots and links was evolved from physics. W. Thromson (later known as Lord Kelvin) started studying knots as a promising model of atoms in the last third of the 19th century. He prepared tabulations of knots with crossing number n, prime knots n<sub>k</sub>, where k is a counting index for prime knots and n ranges from 3 to 7 (as shown in the figure of knots above). The prime knots can be combined to create more complex knots, called composite knots n<sub>k</sub>m<sub>l</sub> or l-component links, n<sup>l</sup><sub>k</sub>.<br />
Today the knot theory is mostly used to classify knots and to find knot invariants. These invariants allow us to decide whether 2 given knots are identical or interconvertible. <br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
A universal invariant has not been discovered but many different levels of invariants are already well-studied. The knot theory is a well established part of topology, and from such a viewpoint, representing a particular knot or link with a rope, or necklace-like string with beads has become entirely unimportant(shown on the right). <br />
</td><br />
<br />
<td><br />
<div align=justify><br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|100px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|} <br />
</div><br />
</td><br />
<br />
</tr><br />
</table></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6524It:knots2006-12-01T14:05:45Z<p>Kjf05: /* Introduction */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|200px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6523It:knots2006-12-01T14:04:22Z<p>Kjf05: /* Introduction */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|300px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6522It:knots2006-12-01T14:04:01Z<p>Kjf05: /* Introduction */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|150px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6521It:knots2006-12-01T14:03:29Z<p>Kjf05: /* Introduction */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.<br />
<br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Knots.gif|thumb|150px|center|Types of knots]]<br />
|-<br />
! ''[http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=NJ&Year=2006&ManuscriptID=b601895e&Iss=6]''<br />
|}</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=File:Knots.gif&diff=6520File:Knots.gif2006-12-01T14:00:49Z<p>Kjf05: </p>
<hr />
<div></div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:knots&diff=6519It:knots2006-12-01T14:00:30Z<p>Kjf05: /* knots */</p>
<hr />
<div>===knots===<br />
<br />
[[Image:knots.jpg|thumb|left|300|reference1]]<br />
The simplest knotted molecule so far.<br />
<br />
Reference<br />
1. http://plus.maths.org/issue15/features/knots/index.html<br />
<br />
<br />
= Introduction =<br />
<br />
Knots are objects with no loose ends and can be tied together to create complicated knots or links. Do such objects exist at a molecular scale and if possible, how can such objects be explained by theory and investigated experimentally? A set of methods is needed for the synthesis of molecular knots.</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Schrock&diff=6509It:Schrock2006-12-01T13:30:11Z<p>Kjf05: /* Other catalytic systems */</p>
<hr />
<div>==Introduction==<br />
[[Image:Schrock2.jpg|thumb|left|General example, commercially available example<sup>2<sup>]]<br />
<br />
<br />
'''Richard R. Schrock''' won the 2005 Nobel Prize in Chemistry.<br />
<br />
His nobel prize speech can be viewed through the following link:[http://nobelprize.org/nobel_prizes/chemistry/laureates/2005/schrock-lecture.html]<br />
<br />
<br />
<br />
This is an important discovery as the catalysts used before were sensitive to air and moisture, created side reactions and were relatively short-lived.<sup>2</sup> Schrock's discovery of the catalysts using tungsten provided one of the first stable metathesis catalyst.<sup>2<sup><br />
<br />
<br />
<br />
= Background Story =<br />
<br />
Metathesis was first discovered in the early 1950s but the chemistry was only fully understood by 1971. Chauvin had then proposed a reaction mechanism, whereby the double bonds were cleaved and synthesised between C atoms in such a way that the atom groups change positions, just as dance couples change partners. However, this is only possible in the presence of special catalyst molecules. <br />
<br />
With the mechanism in place, there was a need to develop these catalysts and Schrock was the first to attempt it. In his own words, before these catalysts there was no way to do the metathesis reaction simply. The use of catalysts gives shorter synthetic routes and thus fewer byproducts and better control of the reaction overall.<br />
<br />
=Scheme=<br />
<br />
[[Image:Olefin1.gif]]<br />
<br />
* Chauvin-type mechanism<br />
<br />
[[Image:Olefin2.gif]]<br />
<br />
* Well defined catalyst systems<br />
<br />
[[Image:Olefin3.gif]]<br />
<br />
<br />
= Metal Carbenes =<br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Olefin4.gif]]<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
* Transition metal has a formal metal to a C=C<br />
* X and Y can be any alkyl or aryl or heteroatom<br />
* There are 2 types of carbenes: Fischer or Schrock-type<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
[[Image:Olefin5.gif]]<br />
* TM has a high oxidation state<br />
<br />
* Ligands are good sigma or pi donors<br />
<br />
* Nucleophilic: attacks at C<sub>carbene</sub> by electrophiles<br />
<br />
* C<sub>carbene</sub> is X<sub>2</sub>-type ligand: Metal oxidation state changed by +2<br />
<br />
[[Image:Olefin6.gif]]<br />
<br />
<br />
= Schrock's Metathesis Catalyst =<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
* Must be handled under Ar or N<sub>2</sub> using dry solvents<br />
* Reactive towards protons on heteroatoms but tolerant of S, P and nitrile groups<br />
* Mo(VI) centre electron deficient, pseudo-tetrahedral. <br />
* Alkoxides needed to enhance the electrophilicity of metal cenre. <br />
[[Image:Olefin7.gif]]<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
!<jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 100; bns on; cpk on;frame 2; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER NONAME 30-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 30-Nov-06 0 NONE 4<br />
ATOM 1 Mo 0 -0.095 -0.300 0.294 0.00 0.00 Mo+0<br />
ATOM 2 N 0 1.232 0.201 -0.868 0.00 0.00 N+0<br />
ATOM 3 C 0 2.502 0.118 -0.498 0.00 0.00 C+0<br />
ATOM 4 C 0 3.279 1.293 -0.337 0.00 0.00 C+0<br />
ATOM 5 C 0 2.665 2.648 -0.584 0.00 0.00 C+0<br />
ATOM 6 C 0 2.741 3.483 0.696 0.00 0.00 C+0<br />
ATOM 7 C 0 3.429 3.358 -1.702 0.00 0.00 C+0<br />
ATOM 8 C 0 4.584 1.192 0.044 0.00 0.00 C+0<br />
ATOM 9 C 0 5.153 -0.055 0.273 0.00 0.00 C+0<br />
ATOM 10 C 0 4.406 -1.215 0.118 0.00 0.00 C+0<br />
ATOM 11 C 0 3.096 -1.146 -0.255 0.00 0.00 C+0<br />
ATOM 12 C 0 2.288 -2.408 -0.422 0.00 0.00 C+0<br />
ATOM 13 C 0 2.908 -3.268 -1.524 0.00 0.00 C+0<br />
ATOM 14 C 0 2.285 -3.189 0.894 0.00 0.00 C+0<br />
ATOM 15 C 0 -1.595 0.833 0.066 0.00 0.00 C+0<br />
ATOM 16 C 0 -2.828 0.629 0.908 0.00 0.00 C+0<br />
ATOM 17 C 0 -2.608 -0.549 1.858 0.00 0.00 C+0<br />
ATOM 18 C 0 -3.106 1.896 1.720 0.00 0.00 C+0<br />
ATOM 19 C 0 -4.005 0.339 0.012 0.00 0.00 C+0<br />
ATOM 20 C 0 -5.254 0.116 0.562 0.00 0.00 C+0<br />
ATOM 21 C 0 -6.333 -0.151 -0.259 0.00 0.00 C+0<br />
ATOM 22 C 0 -6.165 -0.193 -1.630 0.00 0.00 C+0<br />
ATOM 23 C 0 -4.917 0.031 -2.180 0.00 0.00 C+0<br />
ATOM 24 C 0 -3.838 0.301 -1.359 0.00 0.00 C+0<br />
ATOM 25 H 0 1.622 2.526 -0.876 0.00 0.00 H+0<br />
ATOM 26 H 0 3.784 3.605 0.989 0.00 0.00 H+0<br />
ATOM 27 H 0 2.297 4.462 0.518 0.00 0.00 H+0<br />
ATOM 28 H 0 2.196 2.977 1.493 0.00 0.00 H+0<br />
ATOM 29 H 0 4.472 3.479 -1.410 0.00 0.00 H+0<br />
ATOM 30 H 0 3.375 2.763 -2.614 0.00 0.00 H+0<br />
ATOM 31 H 0 2.986 4.337 -1.881 0.00 0.00 H+0<br />
ATOM 32 H 0 5.179 2.085 0.167 0.00 0.00 H+0<br />
ATOM 33 H 0 6.188 -0.122 0.574 0.00 0.00 H+0<br />
ATOM 34 H 0 4.862 -2.177 0.299 0.00 0.00 H+0<br />
ATOM 35 H 0 1.264 -2.150 -0.694 0.00 0.00 H+0<br />
ATOM 36 H 0 3.889 -3.619 -1.204 0.00 0.00 H+0<br />
ATOM 37 H 0 2.263 -4.124 -1.723 0.00 0.00 H+0<br />
ATOM 38 H 0 3.013 -2.675 -2.433 0.00 0.00 H+0<br />
ATOM 39 H 0 3.307 -3.460 1.158 0.00 0.00 H+0<br />
ATOM 40 H 0 1.858 -2.570 1.683 0.00 0.00 H+0<br />
ATOM 41 H 0 1.688 -4.093 0.778 0.00 0.00 H+0<br />
ATOM 42 H 0 -1.567 1.625 -0.668 0.00 0.00 H+0<br />
ATOM 43 H 0 -1.757 -0.339 2.506 0.00 0.00 H+0<br />
ATOM 44 H 0 -3.500 -0.696 2.467 0.00 0.00 H+0<br />
ATOM 45 H 0 -2.410 -1.451 1.280 0.00 0.00 H+0<br />
ATOM 46 H 0 -3.263 2.735 1.043 0.00 0.00 H+0<br />
ATOM 47 H 0 -3.998 1.748 2.329 0.00 0.00 H+0<br />
ATOM 48 H 0 -2.255 2.106 2.368 0.00 0.00 H+0<br />
ATOM 49 H 0 -5.386 0.149 1.634 0.00 0.00 H+0<br />
ATOM 50 H 0 -7.309 -0.326 0.171 0.00 0.00 H+0<br />
ATOM 51 H 0 -7.008 -0.402 -2.272 0.00 0.00 H+0<br />
ATOM 52 H 0 -4.785 -0.003 -3.252 0.00 0.00 H+0<br />
ATOM 53 H 0 -2.863 0.476 -1.789 0.00 0.00 H+0<br />
CONECT 1 1 2 16 15 NONE 58<br />
CONECT 2 1 3 0 0 NONE 59<br />
CONECT 3 2 11 4 0 NONE 60<br />
CONECT 4 3 5 8 0 NONE 61<br />
CONECT 5 4 6 7 25 NONE 62<br />
CONECT 6 5 26 27 28 NONE 63<br />
CONECT 7 5 29 30 31 NONE 64<br />
CONECT 8 4 9 32 0 NONE 65<br />
CONECT 9 8 10 33 0 NONE 66<br />
CONECT 10 9 11 34 0 NONE 67<br />
CONECT 11 10 3 12 0 NONE 68<br />
CONECT 12 11 13 14 35 NONE 69<br />
CONECT 13 12 36 37 38 NONE 70<br />
CONECT 14 12 39 40 41 NONE 71<br />
CONECT 15 1 16 42 0 NONE 72<br />
CONECT 16 15 17 18 19 NONE 73<br />
CONECT 17 16 43 44 45 NONE 74<br />
CONECT 18 16 46 47 48 NONE 75<br />
CONECT 19 16 24 20 0 NONE 76<br />
CONECT 20 19 21 49 0 NONE 77<br />
CONECT 21 20 22 50 0 NONE 78<br />
CONECT 22 21 23 51 0 NONE 79<br />
CONECT 23 22 24 52 0 NONE 80<br />
CONECT 24 23 19 53 0 NONE 81<br />
END NONE 82<br />
</inlineContents><br />
</jmolApplet><br />
</jmol><br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
= Basic Metathesis Reactions =<br />
<br />
[[Image:Olefin8.gif]]<br />
<br />
<br />
= Influence of Ligand set on Reactivity of Schrock's Catalyst =<br />
<br />
* 2 Rotamers the syn or anti<br />
<br />
[[Image:Olefin9.gif]]<br />
<br />
* Between these 2 rotamers, the rate of interconversion depends on ligands and substrate<br />
<br />
[[Image:Olefin10.gif]]<br />
<br />
<br />
= Other catalytic systems =<br />
<br />
There are a variety of different catalytic commercially available systems for the metathesis of olefins. Another famous catalyst is the Grubb's Metathesis Catalyst where the central metal is Ruthenium surrounded by phosphines and chloride ligands. It is believed that this catalyst is superior to the former due to higher functional group tolerance, lower reactivity and relative stability to water and oxygen. <br />
<br />
Many variations to the catalyst have been made, for instance, ruthenium containing N-Heterocyclic Carbene ligands which is even more stable than the Grubb's catalyst itself. <br />
<br />
The choice of catalyst is important depending on the mechanism of the olefin metathesis as shown above. Other experimental conditions have to be considered as well. Generally, ruthenium based catalysts are favoured due to the ease of handling. <br />
<br />
Lastly, more detailed reactions and choices of catalysts can be found in the reference.<br />
<br />
<br />
= Reference =<br />
<br />
Wendy Jen, MacMillan Group Meeting, Jan 17 2001, Olefin Metathesis in Organic Synthesis<br />
<br />
<jmol><br />
<jmolApplet><br />
<size>400</size><br />
<color>white</color><br />
<script>zoom 100; cpk on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER CSD ENTRY XICKAV<br />
CRYST1 8.5594 6.0337 11.0220 90.00 105.97 90.00 P21/c<br />
SCALE1 0.116831 -0.000000 0.033428 0.000000<br />
SCALE2 -0.000000 0.165736 -0.000000 0.000000<br />
SCALE3 -0.000000 0.000000 0.094368 0.000000<br />
<br />
HEADER NONAME 20-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 20-Nov-06 0 NONE 4<br />
ATOM 1 C 0 2.963 -1.542 0.211 0.00 0.00 C+0<br />
ATOM 2 C 0 1.711 -2.418 0.287 0.00 0.00 C+0<br />
ATOM 3 C 0 1.225 -2.737 -1.129 0.00 0.00 C+0<br />
ATOM 4 C 0 2.043 -3.720 1.018 0.00 0.00 C+0<br />
ATOM 5 O 0 0.685 -1.722 0.997 0.00 0.00 O+0<br />
ATOM 6 W 0 0.327 -0.023 -0.017 0.00 0.00 W+0<br />
ATOM 7 N 0 -1.038 0.906 0.803 0.00 0.00 N+0<br />
ATOM 8 C 0 -2.234 0.351 0.930 0.00 0.00 C+0<br />
ATOM 9 C 0 -3.290 1.059 1.560 0.00 0.00 C+0<br />
ATOM 10 C 0 -4.515 0.474 1.682 0.00 0.00 C+0<br />
ATOM 11 C 0 -4.733 -0.808 1.195 0.00 0.00 C+0<br />
ATOM 12 C 0 -3.710 -1.515 0.576 0.00 0.00 C+0<br />
ATOM 13 C 0 -2.475 -0.955 0.432 0.00 0.00 C+0<br />
ATOM 14 O 0 1.989 1.107 -0.037 0.00 0.00 O+0<br />
ATOM 15 C 0 1.961 1.904 1.149 0.00 0.00 C+0<br />
ATOM 16 C 0 1.778 0.998 2.368 0.00 0.00 C+0<br />
ATOM 17 C 0 3.278 2.673 1.277 0.00 0.00 C+0<br />
ATOM 18 C 0 0.798 2.895 1.070 0.00 0.00 C+0<br />
ATOM 19 C 0 -0.176 -0.444 -1.804 0.00 0.00 C+0<br />
ATOM 20 C 0 -0.600 0.653 -2.746 0.00 0.00 C+0<br />
ATOM 21 C 0 -0.395 2.011 -2.072 0.00 0.00 C+0<br />
ATOM 22 C 0 0.243 0.584 -4.021 0.00 0.00 C+0<br />
ATOM 23 C 0 -2.078 0.478 -3.101 0.00 0.00 C+0<br />
ATOM 24 H 0 2.744 -0.644 -0.367 0.00 0.00 H+0<br />
ATOM 25 H 0 3.270 -1.260 1.217 0.00 0.00 H+0<br />
ATOM 26 H 0 3.766 -2.098 -0.272 0.00 0.00 H+0<br />
ATOM 27 H 0 1.773 -3.596 -1.516 0.00 0.00 H+0<br />
ATOM 28 H 0 0.160 -2.967 -1.104 0.00 0.00 H+0<br />
ATOM 29 H 0 1.396 -1.876 -1.774 0.00 0.00 H+0<br />
ATOM 30 H 0 2.389 -3.493 2.026 0.00 0.00 H+0<br />
ATOM 31 H 0 1.151 -4.344 1.072 0.00 0.00 H+0<br />
ATOM 32 H 0 2.826 -4.251 0.476 0.00 0.00 H+0<br />
ATOM 33 H 0 -3.123 2.056 1.940 0.00 0.00 H+0<br />
ATOM 34 H 0 -5.321 1.010 2.162 0.00 0.00 H+0<br />
ATOM 35 H 0 -5.708 -1.261 1.298 0.00 0.00 H+0<br />
ATOM 36 H 0 -3.894 -2.512 0.202 0.00 0.00 H+0<br />
ATOM 37 H 0 -1.681 -1.507 -0.049 0.00 0.00 H+0<br />
ATOM 38 H 0 2.649 0.351 2.473 0.00 0.00 H+0<br />
ATOM 39 H 0 1.670 1.610 3.263 0.00 0.00 H+0<br />
ATOM 40 H 0 0.885 0.387 2.236 0.00 0.00 H+0<br />
ATOM 41 H 0 3.408 3.318 0.409 0.00 0.00 H+0<br />
ATOM 42 H 0 3.257 3.280 2.182 0.00 0.00 H+0<br />
ATOM 43 H 0 4.107 1.967 1.333 0.00 0.00 H+0<br />
ATOM 44 H 0 -0.135 2.378 1.296 0.00 0.00 H+0<br />
ATOM 45 H 0 0.953 3.696 1.793 0.00 0.00 H+0<br />
ATOM 46 H 0 0.746 3.316 0.066 0.00 0.00 H+0<br />
ATOM 47 H 0 -0.158 -1.470 -2.142 0.00 0.00 H+0<br />
ATOM 48 H 0 0.658 2.136 -1.818 0.00 0.00 H+0<br />
ATOM 49 H 0 -0.702 2.805 -2.753 0.00 0.00 H+0<br />
ATOM 50 H 0 -0.996 2.060 -1.163 0.00 0.00 H+0<br />
ATOM 51 H 0 0.032 -0.348 -4.546 0.00 0.00 H+0<br />
ATOM 52 H 0 -0.004 1.428 -4.665 0.00 0.00 H+0<br />
ATOM 53 H 0 1.300 0.623 -3.760 0.00 0.00 H+0<br />
ATOM 54 H 0 -2.678 0.527 -2.192 0.00 0.00 H+0<br />
ATOM 55 H 0 -2.384 1.271 -3.782 0.00 0.00 H+0<br />
ATOM 56 H 0 -2.224 -0.490 -3.581 0.00 0.00 H+0<br />
CONECT 1 2 24 25 26 NONE 61<br />
CONECT 2 1 3 4 5 NONE 62<br />
CONECT 3 2 27 28 29 NONE 63<br />
CONECT 4 2 30 31 32 NONE 64<br />
CONECT 5 2 6 0 0 NONE 65<br />
CONECT 6 5 7 14 19 NONE 66<br />
CONECT 7 6 8 0 0 NONE 67<br />
CONECT 8 7 13 9 0 NONE 68<br />
CONECT 9 8 10 33 0 NONE 69<br />
CONECT 10 9 11 34 0 NONE 70<br />
CONECT 11 10 12 35 0 NONE 71<br />
CONECT 12 11 13 36 0 NONE 72<br />
CONECT 13 12 8 37 0 NONE 73<br />
CONECT 14 6 15 0 0 NONE 74<br />
CONECT 15 14 16 17 18 NONE 75<br />
CONECT 16 15 38 39 40 NONE 76<br />
CONECT 17 15 41 42 43 NONE 77<br />
CONECT 18 15 44 45 46 NONE 78<br />
CONECT 19 6 20 47 0 NONE 79<br />
CONECT 20 19 21 22 23 NONE 80<br />
CONECT 21 20 48 49 50 NONE 81<br />
CONECT 22 20 51 52 53 NONE 82<br />
CONECT 23 20 54 55 56 NONE 83<br />
END</inlineContents><br />
</jmolApplet><br />
</jmol><br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
Reference<br />
<br />
1.http://www.rsc.org/chemistryworld/restricted/2005/November/prize.asp</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Schrock&diff=6508It:Schrock2006-12-01T13:23:59Z<p>Kjf05: /* Influence of Ligand set on Reactivity of Schrock's Catalyst */</p>
<hr />
<div>==Introduction==<br />
[[Image:Schrock2.jpg|thumb|left|General example, commercially available example<sup>2<sup>]]<br />
<br />
<br />
'''Richard R. Schrock''' won the 2005 Nobel Prize in Chemistry.<br />
<br />
His nobel prize speech can be viewed through the following link:[http://nobelprize.org/nobel_prizes/chemistry/laureates/2005/schrock-lecture.html]<br />
<br />
<br />
<br />
This is an important discovery as the catalysts used before were sensitive to air and moisture, created side reactions and were relatively short-lived.<sup>2</sup> Schrock's discovery of the catalysts using tungsten provided one of the first stable metathesis catalyst.<sup>2<sup><br />
<br />
<br />
<br />
= Background Story =<br />
<br />
Metathesis was first discovered in the early 1950s but the chemistry was only fully understood by 1971. Chauvin had then proposed a reaction mechanism, whereby the double bonds were cleaved and synthesised between C atoms in such a way that the atom groups change positions, just as dance couples change partners. However, this is only possible in the presence of special catalyst molecules. <br />
<br />
With the mechanism in place, there was a need to develop these catalysts and Schrock was the first to attempt it. In his own words, before these catalysts there was no way to do the metathesis reaction simply. The use of catalysts gives shorter synthetic routes and thus fewer byproducts and better control of the reaction overall.<br />
<br />
=Scheme=<br />
<br />
[[Image:Olefin1.gif]]<br />
<br />
* Chauvin-type mechanism<br />
<br />
[[Image:Olefin2.gif]]<br />
<br />
* Well defined catalyst systems<br />
<br />
[[Image:Olefin3.gif]]<br />
<br />
<br />
= Metal Carbenes =<br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Olefin4.gif]]<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
* Transition metal has a formal metal to a C=C<br />
* X and Y can be any alkyl or aryl or heteroatom<br />
* There are 2 types of carbenes: Fischer or Schrock-type<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
[[Image:Olefin5.gif]]<br />
* TM has a high oxidation state<br />
<br />
* Ligands are good sigma or pi donors<br />
<br />
* Nucleophilic: attacks at C<sub>carbene</sub> by electrophiles<br />
<br />
* C<sub>carbene</sub> is X<sub>2</sub>-type ligand: Metal oxidation state changed by +2<br />
<br />
[[Image:Olefin6.gif]]<br />
<br />
<br />
= Schrock's Metathesis Catalyst =<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
* Must be handled under Ar or N<sub>2</sub> using dry solvents<br />
* Reactive towards protons on heteroatoms but tolerant of S, P and nitrile groups<br />
* Mo(VI) centre electron deficient, pseudo-tetrahedral. <br />
* Alkoxides needed to enhance the electrophilicity of metal cenre. <br />
[[Image:Olefin7.gif]]<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
!<jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 100; bns on; cpk on;frame 2; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER NONAME 30-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 30-Nov-06 0 NONE 4<br />
ATOM 1 Mo 0 -0.095 -0.300 0.294 0.00 0.00 Mo+0<br />
ATOM 2 N 0 1.232 0.201 -0.868 0.00 0.00 N+0<br />
ATOM 3 C 0 2.502 0.118 -0.498 0.00 0.00 C+0<br />
ATOM 4 C 0 3.279 1.293 -0.337 0.00 0.00 C+0<br />
ATOM 5 C 0 2.665 2.648 -0.584 0.00 0.00 C+0<br />
ATOM 6 C 0 2.741 3.483 0.696 0.00 0.00 C+0<br />
ATOM 7 C 0 3.429 3.358 -1.702 0.00 0.00 C+0<br />
ATOM 8 C 0 4.584 1.192 0.044 0.00 0.00 C+0<br />
ATOM 9 C 0 5.153 -0.055 0.273 0.00 0.00 C+0<br />
ATOM 10 C 0 4.406 -1.215 0.118 0.00 0.00 C+0<br />
ATOM 11 C 0 3.096 -1.146 -0.255 0.00 0.00 C+0<br />
ATOM 12 C 0 2.288 -2.408 -0.422 0.00 0.00 C+0<br />
ATOM 13 C 0 2.908 -3.268 -1.524 0.00 0.00 C+0<br />
ATOM 14 C 0 2.285 -3.189 0.894 0.00 0.00 C+0<br />
ATOM 15 C 0 -1.595 0.833 0.066 0.00 0.00 C+0<br />
ATOM 16 C 0 -2.828 0.629 0.908 0.00 0.00 C+0<br />
ATOM 17 C 0 -2.608 -0.549 1.858 0.00 0.00 C+0<br />
ATOM 18 C 0 -3.106 1.896 1.720 0.00 0.00 C+0<br />
ATOM 19 C 0 -4.005 0.339 0.012 0.00 0.00 C+0<br />
ATOM 20 C 0 -5.254 0.116 0.562 0.00 0.00 C+0<br />
ATOM 21 C 0 -6.333 -0.151 -0.259 0.00 0.00 C+0<br />
ATOM 22 C 0 -6.165 -0.193 -1.630 0.00 0.00 C+0<br />
ATOM 23 C 0 -4.917 0.031 -2.180 0.00 0.00 C+0<br />
ATOM 24 C 0 -3.838 0.301 -1.359 0.00 0.00 C+0<br />
ATOM 25 H 0 1.622 2.526 -0.876 0.00 0.00 H+0<br />
ATOM 26 H 0 3.784 3.605 0.989 0.00 0.00 H+0<br />
ATOM 27 H 0 2.297 4.462 0.518 0.00 0.00 H+0<br />
ATOM 28 H 0 2.196 2.977 1.493 0.00 0.00 H+0<br />
ATOM 29 H 0 4.472 3.479 -1.410 0.00 0.00 H+0<br />
ATOM 30 H 0 3.375 2.763 -2.614 0.00 0.00 H+0<br />
ATOM 31 H 0 2.986 4.337 -1.881 0.00 0.00 H+0<br />
ATOM 32 H 0 5.179 2.085 0.167 0.00 0.00 H+0<br />
ATOM 33 H 0 6.188 -0.122 0.574 0.00 0.00 H+0<br />
ATOM 34 H 0 4.862 -2.177 0.299 0.00 0.00 H+0<br />
ATOM 35 H 0 1.264 -2.150 -0.694 0.00 0.00 H+0<br />
ATOM 36 H 0 3.889 -3.619 -1.204 0.00 0.00 H+0<br />
ATOM 37 H 0 2.263 -4.124 -1.723 0.00 0.00 H+0<br />
ATOM 38 H 0 3.013 -2.675 -2.433 0.00 0.00 H+0<br />
ATOM 39 H 0 3.307 -3.460 1.158 0.00 0.00 H+0<br />
ATOM 40 H 0 1.858 -2.570 1.683 0.00 0.00 H+0<br />
ATOM 41 H 0 1.688 -4.093 0.778 0.00 0.00 H+0<br />
ATOM 42 H 0 -1.567 1.625 -0.668 0.00 0.00 H+0<br />
ATOM 43 H 0 -1.757 -0.339 2.506 0.00 0.00 H+0<br />
ATOM 44 H 0 -3.500 -0.696 2.467 0.00 0.00 H+0<br />
ATOM 45 H 0 -2.410 -1.451 1.280 0.00 0.00 H+0<br />
ATOM 46 H 0 -3.263 2.735 1.043 0.00 0.00 H+0<br />
ATOM 47 H 0 -3.998 1.748 2.329 0.00 0.00 H+0<br />
ATOM 48 H 0 -2.255 2.106 2.368 0.00 0.00 H+0<br />
ATOM 49 H 0 -5.386 0.149 1.634 0.00 0.00 H+0<br />
ATOM 50 H 0 -7.309 -0.326 0.171 0.00 0.00 H+0<br />
ATOM 51 H 0 -7.008 -0.402 -2.272 0.00 0.00 H+0<br />
ATOM 52 H 0 -4.785 -0.003 -3.252 0.00 0.00 H+0<br />
ATOM 53 H 0 -2.863 0.476 -1.789 0.00 0.00 H+0<br />
CONECT 1 1 2 16 15 NONE 58<br />
CONECT 2 1 3 0 0 NONE 59<br />
CONECT 3 2 11 4 0 NONE 60<br />
CONECT 4 3 5 8 0 NONE 61<br />
CONECT 5 4 6 7 25 NONE 62<br />
CONECT 6 5 26 27 28 NONE 63<br />
CONECT 7 5 29 30 31 NONE 64<br />
CONECT 8 4 9 32 0 NONE 65<br />
CONECT 9 8 10 33 0 NONE 66<br />
CONECT 10 9 11 34 0 NONE 67<br />
CONECT 11 10 3 12 0 NONE 68<br />
CONECT 12 11 13 14 35 NONE 69<br />
CONECT 13 12 36 37 38 NONE 70<br />
CONECT 14 12 39 40 41 NONE 71<br />
CONECT 15 1 16 42 0 NONE 72<br />
CONECT 16 15 17 18 19 NONE 73<br />
CONECT 17 16 43 44 45 NONE 74<br />
CONECT 18 16 46 47 48 NONE 75<br />
CONECT 19 16 24 20 0 NONE 76<br />
CONECT 20 19 21 49 0 NONE 77<br />
CONECT 21 20 22 50 0 NONE 78<br />
CONECT 22 21 23 51 0 NONE 79<br />
CONECT 23 22 24 52 0 NONE 80<br />
CONECT 24 23 19 53 0 NONE 81<br />
END NONE 82<br />
</inlineContents><br />
</jmolApplet><br />
</jmol><br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
= Basic Metathesis Reactions =<br />
<br />
[[Image:Olefin8.gif]]<br />
<br />
<br />
= Influence of Ligand set on Reactivity of Schrock's Catalyst =<br />
<br />
* 2 Rotamers the syn or anti<br />
<br />
[[Image:Olefin9.gif]]<br />
<br />
* Between these 2 rotamers, the rate of interconversion depends on ligands and substrate<br />
<br />
[[Image:Olefin10.gif]]<br />
<br />
<br />
= Other catalytic systems =<br />
<br />
<br />
<jmol><br />
<jmolApplet><br />
<size>400</size><br />
<color>white</color><br />
<script>zoom 100; cpk on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER CSD ENTRY XICKAV<br />
CRYST1 8.5594 6.0337 11.0220 90.00 105.97 90.00 P21/c<br />
SCALE1 0.116831 -0.000000 0.033428 0.000000<br />
SCALE2 -0.000000 0.165736 -0.000000 0.000000<br />
SCALE3 -0.000000 0.000000 0.094368 0.000000<br />
<br />
HEADER NONAME 20-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 20-Nov-06 0 NONE 4<br />
ATOM 1 C 0 2.963 -1.542 0.211 0.00 0.00 C+0<br />
ATOM 2 C 0 1.711 -2.418 0.287 0.00 0.00 C+0<br />
ATOM 3 C 0 1.225 -2.737 -1.129 0.00 0.00 C+0<br />
ATOM 4 C 0 2.043 -3.720 1.018 0.00 0.00 C+0<br />
ATOM 5 O 0 0.685 -1.722 0.997 0.00 0.00 O+0<br />
ATOM 6 W 0 0.327 -0.023 -0.017 0.00 0.00 W+0<br />
ATOM 7 N 0 -1.038 0.906 0.803 0.00 0.00 N+0<br />
ATOM 8 C 0 -2.234 0.351 0.930 0.00 0.00 C+0<br />
ATOM 9 C 0 -3.290 1.059 1.560 0.00 0.00 C+0<br />
ATOM 10 C 0 -4.515 0.474 1.682 0.00 0.00 C+0<br />
ATOM 11 C 0 -4.733 -0.808 1.195 0.00 0.00 C+0<br />
ATOM 12 C 0 -3.710 -1.515 0.576 0.00 0.00 C+0<br />
ATOM 13 C 0 -2.475 -0.955 0.432 0.00 0.00 C+0<br />
ATOM 14 O 0 1.989 1.107 -0.037 0.00 0.00 O+0<br />
ATOM 15 C 0 1.961 1.904 1.149 0.00 0.00 C+0<br />
ATOM 16 C 0 1.778 0.998 2.368 0.00 0.00 C+0<br />
ATOM 17 C 0 3.278 2.673 1.277 0.00 0.00 C+0<br />
ATOM 18 C 0 0.798 2.895 1.070 0.00 0.00 C+0<br />
ATOM 19 C 0 -0.176 -0.444 -1.804 0.00 0.00 C+0<br />
ATOM 20 C 0 -0.600 0.653 -2.746 0.00 0.00 C+0<br />
ATOM 21 C 0 -0.395 2.011 -2.072 0.00 0.00 C+0<br />
ATOM 22 C 0 0.243 0.584 -4.021 0.00 0.00 C+0<br />
ATOM 23 C 0 -2.078 0.478 -3.101 0.00 0.00 C+0<br />
ATOM 24 H 0 2.744 -0.644 -0.367 0.00 0.00 H+0<br />
ATOM 25 H 0 3.270 -1.260 1.217 0.00 0.00 H+0<br />
ATOM 26 H 0 3.766 -2.098 -0.272 0.00 0.00 H+0<br />
ATOM 27 H 0 1.773 -3.596 -1.516 0.00 0.00 H+0<br />
ATOM 28 H 0 0.160 -2.967 -1.104 0.00 0.00 H+0<br />
ATOM 29 H 0 1.396 -1.876 -1.774 0.00 0.00 H+0<br />
ATOM 30 H 0 2.389 -3.493 2.026 0.00 0.00 H+0<br />
ATOM 31 H 0 1.151 -4.344 1.072 0.00 0.00 H+0<br />
ATOM 32 H 0 2.826 -4.251 0.476 0.00 0.00 H+0<br />
ATOM 33 H 0 -3.123 2.056 1.940 0.00 0.00 H+0<br />
ATOM 34 H 0 -5.321 1.010 2.162 0.00 0.00 H+0<br />
ATOM 35 H 0 -5.708 -1.261 1.298 0.00 0.00 H+0<br />
ATOM 36 H 0 -3.894 -2.512 0.202 0.00 0.00 H+0<br />
ATOM 37 H 0 -1.681 -1.507 -0.049 0.00 0.00 H+0<br />
ATOM 38 H 0 2.649 0.351 2.473 0.00 0.00 H+0<br />
ATOM 39 H 0 1.670 1.610 3.263 0.00 0.00 H+0<br />
ATOM 40 H 0 0.885 0.387 2.236 0.00 0.00 H+0<br />
ATOM 41 H 0 3.408 3.318 0.409 0.00 0.00 H+0<br />
ATOM 42 H 0 3.257 3.280 2.182 0.00 0.00 H+0<br />
ATOM 43 H 0 4.107 1.967 1.333 0.00 0.00 H+0<br />
ATOM 44 H 0 -0.135 2.378 1.296 0.00 0.00 H+0<br />
ATOM 45 H 0 0.953 3.696 1.793 0.00 0.00 H+0<br />
ATOM 46 H 0 0.746 3.316 0.066 0.00 0.00 H+0<br />
ATOM 47 H 0 -0.158 -1.470 -2.142 0.00 0.00 H+0<br />
ATOM 48 H 0 0.658 2.136 -1.818 0.00 0.00 H+0<br />
ATOM 49 H 0 -0.702 2.805 -2.753 0.00 0.00 H+0<br />
ATOM 50 H 0 -0.996 2.060 -1.163 0.00 0.00 H+0<br />
ATOM 51 H 0 0.032 -0.348 -4.546 0.00 0.00 H+0<br />
ATOM 52 H 0 -0.004 1.428 -4.665 0.00 0.00 H+0<br />
ATOM 53 H 0 1.300 0.623 -3.760 0.00 0.00 H+0<br />
ATOM 54 H 0 -2.678 0.527 -2.192 0.00 0.00 H+0<br />
ATOM 55 H 0 -2.384 1.271 -3.782 0.00 0.00 H+0<br />
ATOM 56 H 0 -2.224 -0.490 -3.581 0.00 0.00 H+0<br />
CONECT 1 2 24 25 26 NONE 61<br />
CONECT 2 1 3 4 5 NONE 62<br />
CONECT 3 2 27 28 29 NONE 63<br />
CONECT 4 2 30 31 32 NONE 64<br />
CONECT 5 2 6 0 0 NONE 65<br />
CONECT 6 5 7 14 19 NONE 66<br />
CONECT 7 6 8 0 0 NONE 67<br />
CONECT 8 7 13 9 0 NONE 68<br />
CONECT 9 8 10 33 0 NONE 69<br />
CONECT 10 9 11 34 0 NONE 70<br />
CONECT 11 10 12 35 0 NONE 71<br />
CONECT 12 11 13 36 0 NONE 72<br />
CONECT 13 12 8 37 0 NONE 73<br />
CONECT 14 6 15 0 0 NONE 74<br />
CONECT 15 14 16 17 18 NONE 75<br />
CONECT 16 15 38 39 40 NONE 76<br />
CONECT 17 15 41 42 43 NONE 77<br />
CONECT 18 15 44 45 46 NONE 78<br />
CONECT 19 6 20 47 0 NONE 79<br />
CONECT 20 19 21 22 23 NONE 80<br />
CONECT 21 20 48 49 50 NONE 81<br />
CONECT 22 20 51 52 53 NONE 82<br />
CONECT 23 20 54 55 56 NONE 83<br />
END</inlineContents><br />
</jmolApplet><br />
</jmol><br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
Reference<br />
<br />
1.http://www.rsc.org/chemistryworld/restricted/2005/November/prize.asp</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=It:Schrock&diff=6507It:Schrock2006-12-01T13:21:22Z<p>Kjf05: /* Influence of Ligand set on Reactivity of Schrock's Catalyst */</p>
<hr />
<div>==Introduction==<br />
[[Image:Schrock2.jpg|thumb|left|General example, commercially available example<sup>2<sup>]]<br />
<br />
<br />
'''Richard R. Schrock''' won the 2005 Nobel Prize in Chemistry.<br />
<br />
His nobel prize speech can be viewed through the following link:[http://nobelprize.org/nobel_prizes/chemistry/laureates/2005/schrock-lecture.html]<br />
<br />
<br />
<br />
This is an important discovery as the catalysts used before were sensitive to air and moisture, created side reactions and were relatively short-lived.<sup>2</sup> Schrock's discovery of the catalysts using tungsten provided one of the first stable metathesis catalyst.<sup>2<sup><br />
<br />
<br />
<br />
= Background Story =<br />
<br />
Metathesis was first discovered in the early 1950s but the chemistry was only fully understood by 1971. Chauvin had then proposed a reaction mechanism, whereby the double bonds were cleaved and synthesised between C atoms in such a way that the atom groups change positions, just as dance couples change partners. However, this is only possible in the presence of special catalyst molecules. <br />
<br />
With the mechanism in place, there was a need to develop these catalysts and Schrock was the first to attempt it. In his own words, before these catalysts there was no way to do the metathesis reaction simply. The use of catalysts gives shorter synthetic routes and thus fewer byproducts and better control of the reaction overall.<br />
<br />
=Scheme=<br />
<br />
[[Image:Olefin1.gif]]<br />
<br />
* Chauvin-type mechanism<br />
<br />
[[Image:Olefin2.gif]]<br />
<br />
* Well defined catalyst systems<br />
<br />
[[Image:Olefin3.gif]]<br />
<br />
<br />
= Metal Carbenes =<br />
<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
! [[Image:Olefin4.gif]]<br />
|}<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
* Transition metal has a formal metal to a C=C<br />
* X and Y can be any alkyl or aryl or heteroatom<br />
* There are 2 types of carbenes: Fischer or Schrock-type<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
[[Image:Olefin5.gif]]<br />
* TM has a high oxidation state<br />
<br />
* Ligands are good sigma or pi donors<br />
<br />
* Nucleophilic: attacks at C<sub>carbene</sub> by electrophiles<br />
<br />
* C<sub>carbene</sub> is X<sub>2</sub>-type ligand: Metal oxidation state changed by +2<br />
<br />
[[Image:Olefin6.gif]]<br />
<br />
<br />
= Schrock's Metathesis Catalyst =<br />
<table border="0" cellpadding=10><br />
<tr><br />
<br />
<td><br />
* Must be handled under Ar or N<sub>2</sub> using dry solvents<br />
* Reactive towards protons on heteroatoms but tolerant of S, P and nitrile groups<br />
* Mo(VI) centre electron deficient, pseudo-tetrahedral. <br />
* Alkoxides needed to enhance the electrophilicity of metal cenre. <br />
[[Image:Olefin7.gif]]<br />
</td><br />
<br />
<td><br />
<div align=justify><br />
{| border="1" style="fix: right; clear: left; margin: 1 1 1em 1em; border-collapse: collapse;"<br />
!<jmol><br />
<jmolApplet><br />
<size>300</size><br />
<color>white</color><br />
<script>zoom 100; bns on; cpk on;frame 2; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER NONAME 30-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 30-Nov-06 0 NONE 4<br />
ATOM 1 Mo 0 -0.095 -0.300 0.294 0.00 0.00 Mo+0<br />
ATOM 2 N 0 1.232 0.201 -0.868 0.00 0.00 N+0<br />
ATOM 3 C 0 2.502 0.118 -0.498 0.00 0.00 C+0<br />
ATOM 4 C 0 3.279 1.293 -0.337 0.00 0.00 C+0<br />
ATOM 5 C 0 2.665 2.648 -0.584 0.00 0.00 C+0<br />
ATOM 6 C 0 2.741 3.483 0.696 0.00 0.00 C+0<br />
ATOM 7 C 0 3.429 3.358 -1.702 0.00 0.00 C+0<br />
ATOM 8 C 0 4.584 1.192 0.044 0.00 0.00 C+0<br />
ATOM 9 C 0 5.153 -0.055 0.273 0.00 0.00 C+0<br />
ATOM 10 C 0 4.406 -1.215 0.118 0.00 0.00 C+0<br />
ATOM 11 C 0 3.096 -1.146 -0.255 0.00 0.00 C+0<br />
ATOM 12 C 0 2.288 -2.408 -0.422 0.00 0.00 C+0<br />
ATOM 13 C 0 2.908 -3.268 -1.524 0.00 0.00 C+0<br />
ATOM 14 C 0 2.285 -3.189 0.894 0.00 0.00 C+0<br />
ATOM 15 C 0 -1.595 0.833 0.066 0.00 0.00 C+0<br />
ATOM 16 C 0 -2.828 0.629 0.908 0.00 0.00 C+0<br />
ATOM 17 C 0 -2.608 -0.549 1.858 0.00 0.00 C+0<br />
ATOM 18 C 0 -3.106 1.896 1.720 0.00 0.00 C+0<br />
ATOM 19 C 0 -4.005 0.339 0.012 0.00 0.00 C+0<br />
ATOM 20 C 0 -5.254 0.116 0.562 0.00 0.00 C+0<br />
ATOM 21 C 0 -6.333 -0.151 -0.259 0.00 0.00 C+0<br />
ATOM 22 C 0 -6.165 -0.193 -1.630 0.00 0.00 C+0<br />
ATOM 23 C 0 -4.917 0.031 -2.180 0.00 0.00 C+0<br />
ATOM 24 C 0 -3.838 0.301 -1.359 0.00 0.00 C+0<br />
ATOM 25 H 0 1.622 2.526 -0.876 0.00 0.00 H+0<br />
ATOM 26 H 0 3.784 3.605 0.989 0.00 0.00 H+0<br />
ATOM 27 H 0 2.297 4.462 0.518 0.00 0.00 H+0<br />
ATOM 28 H 0 2.196 2.977 1.493 0.00 0.00 H+0<br />
ATOM 29 H 0 4.472 3.479 -1.410 0.00 0.00 H+0<br />
ATOM 30 H 0 3.375 2.763 -2.614 0.00 0.00 H+0<br />
ATOM 31 H 0 2.986 4.337 -1.881 0.00 0.00 H+0<br />
ATOM 32 H 0 5.179 2.085 0.167 0.00 0.00 H+0<br />
ATOM 33 H 0 6.188 -0.122 0.574 0.00 0.00 H+0<br />
ATOM 34 H 0 4.862 -2.177 0.299 0.00 0.00 H+0<br />
ATOM 35 H 0 1.264 -2.150 -0.694 0.00 0.00 H+0<br />
ATOM 36 H 0 3.889 -3.619 -1.204 0.00 0.00 H+0<br />
ATOM 37 H 0 2.263 -4.124 -1.723 0.00 0.00 H+0<br />
ATOM 38 H 0 3.013 -2.675 -2.433 0.00 0.00 H+0<br />
ATOM 39 H 0 3.307 -3.460 1.158 0.00 0.00 H+0<br />
ATOM 40 H 0 1.858 -2.570 1.683 0.00 0.00 H+0<br />
ATOM 41 H 0 1.688 -4.093 0.778 0.00 0.00 H+0<br />
ATOM 42 H 0 -1.567 1.625 -0.668 0.00 0.00 H+0<br />
ATOM 43 H 0 -1.757 -0.339 2.506 0.00 0.00 H+0<br />
ATOM 44 H 0 -3.500 -0.696 2.467 0.00 0.00 H+0<br />
ATOM 45 H 0 -2.410 -1.451 1.280 0.00 0.00 H+0<br />
ATOM 46 H 0 -3.263 2.735 1.043 0.00 0.00 H+0<br />
ATOM 47 H 0 -3.998 1.748 2.329 0.00 0.00 H+0<br />
ATOM 48 H 0 -2.255 2.106 2.368 0.00 0.00 H+0<br />
ATOM 49 H 0 -5.386 0.149 1.634 0.00 0.00 H+0<br />
ATOM 50 H 0 -7.309 -0.326 0.171 0.00 0.00 H+0<br />
ATOM 51 H 0 -7.008 -0.402 -2.272 0.00 0.00 H+0<br />
ATOM 52 H 0 -4.785 -0.003 -3.252 0.00 0.00 H+0<br />
ATOM 53 H 0 -2.863 0.476 -1.789 0.00 0.00 H+0<br />
CONECT 1 1 2 16 15 NONE 58<br />
CONECT 2 1 3 0 0 NONE 59<br />
CONECT 3 2 11 4 0 NONE 60<br />
CONECT 4 3 5 8 0 NONE 61<br />
CONECT 5 4 6 7 25 NONE 62<br />
CONECT 6 5 26 27 28 NONE 63<br />
CONECT 7 5 29 30 31 NONE 64<br />
CONECT 8 4 9 32 0 NONE 65<br />
CONECT 9 8 10 33 0 NONE 66<br />
CONECT 10 9 11 34 0 NONE 67<br />
CONECT 11 10 3 12 0 NONE 68<br />
CONECT 12 11 13 14 35 NONE 69<br />
CONECT 13 12 36 37 38 NONE 70<br />
CONECT 14 12 39 40 41 NONE 71<br />
CONECT 15 1 16 42 0 NONE 72<br />
CONECT 16 15 17 18 19 NONE 73<br />
CONECT 17 16 43 44 45 NONE 74<br />
CONECT 18 16 46 47 48 NONE 75<br />
CONECT 19 16 24 20 0 NONE 76<br />
CONECT 20 19 21 49 0 NONE 77<br />
CONECT 21 20 22 50 0 NONE 78<br />
CONECT 22 21 23 51 0 NONE 79<br />
CONECT 23 22 24 52 0 NONE 80<br />
CONECT 24 23 19 53 0 NONE 81<br />
END NONE 82<br />
</inlineContents><br />
</jmolApplet><br />
</jmol><br />
|}<br />
<br />
</div><br />
</td><br />
<br />
</tr><br />
</table><br />
<br />
<br />
= Basic Metathesis Reactions =<br />
<br />
[[Image:Olefin8.gif]]<br />
<br />
<br />
= Influence of Ligand set on Reactivity of Schrock's Catalyst =<br />
<br />
* 2 Rotamers the syn or anti<br />
<br />
[[Image:Olefin9.gif]]<br />
<br />
* Between these 2 rotamers, the rate of interconversion depends on ligands and substrate<br />
<br />
[[Image:Olefin10.gif]]<br />
<br />
<jmol><br />
<jmolApplet><br />
<size>400</size><br />
<color>white</color><br />
<script>zoom 100; cpk on;frame 1; move 10 -20 10 0 0 0 0 0 3; delay 1;</script><br />
<inlineContents>HEADER CSD ENTRY XICKAV<br />
CRYST1 8.5594 6.0337 11.0220 90.00 105.97 90.00 P21/c<br />
SCALE1 0.116831 -0.000000 0.033428 0.000000<br />
SCALE2 -0.000000 0.165736 -0.000000 0.000000<br />
SCALE3 -0.000000 0.000000 0.094368 0.000000<br />
<br />
HEADER NONAME 20-Nov-06 NONE 1<br />
TITLE NONE 2<br />
AUTHOR WWW daemon apache NONE 3<br />
REVDAT 1 20-Nov-06 0 NONE 4<br />
ATOM 1 C 0 2.963 -1.542 0.211 0.00 0.00 C+0<br />
ATOM 2 C 0 1.711 -2.418 0.287 0.00 0.00 C+0<br />
ATOM 3 C 0 1.225 -2.737 -1.129 0.00 0.00 C+0<br />
ATOM 4 C 0 2.043 -3.720 1.018 0.00 0.00 C+0<br />
ATOM 5 O 0 0.685 -1.722 0.997 0.00 0.00 O+0<br />
ATOM 6 W 0 0.327 -0.023 -0.017 0.00 0.00 W+0<br />
ATOM 7 N 0 -1.038 0.906 0.803 0.00 0.00 N+0<br />
ATOM 8 C 0 -2.234 0.351 0.930 0.00 0.00 C+0<br />
ATOM 9 C 0 -3.290 1.059 1.560 0.00 0.00 C+0<br />
ATOM 10 C 0 -4.515 0.474 1.682 0.00 0.00 C+0<br />
ATOM 11 C 0 -4.733 -0.808 1.195 0.00 0.00 C+0<br />
ATOM 12 C 0 -3.710 -1.515 0.576 0.00 0.00 C+0<br />
ATOM 13 C 0 -2.475 -0.955 0.432 0.00 0.00 C+0<br />
ATOM 14 O 0 1.989 1.107 -0.037 0.00 0.00 O+0<br />
ATOM 15 C 0 1.961 1.904 1.149 0.00 0.00 C+0<br />
ATOM 16 C 0 1.778 0.998 2.368 0.00 0.00 C+0<br />
ATOM 17 C 0 3.278 2.673 1.277 0.00 0.00 C+0<br />
ATOM 18 C 0 0.798 2.895 1.070 0.00 0.00 C+0<br />
ATOM 19 C 0 -0.176 -0.444 -1.804 0.00 0.00 C+0<br />
ATOM 20 C 0 -0.600 0.653 -2.746 0.00 0.00 C+0<br />
ATOM 21 C 0 -0.395 2.011 -2.072 0.00 0.00 C+0<br />
ATOM 22 C 0 0.243 0.584 -4.021 0.00 0.00 C+0<br />
ATOM 23 C 0 -2.078 0.478 -3.101 0.00 0.00 C+0<br />
ATOM 24 H 0 2.744 -0.644 -0.367 0.00 0.00 H+0<br />
ATOM 25 H 0 3.270 -1.260 1.217 0.00 0.00 H+0<br />
ATOM 26 H 0 3.766 -2.098 -0.272 0.00 0.00 H+0<br />
ATOM 27 H 0 1.773 -3.596 -1.516 0.00 0.00 H+0<br />
ATOM 28 H 0 0.160 -2.967 -1.104 0.00 0.00 H+0<br />
ATOM 29 H 0 1.396 -1.876 -1.774 0.00 0.00 H+0<br />
ATOM 30 H 0 2.389 -3.493 2.026 0.00 0.00 H+0<br />
ATOM 31 H 0 1.151 -4.344 1.072 0.00 0.00 H+0<br />
ATOM 32 H 0 2.826 -4.251 0.476 0.00 0.00 H+0<br />
ATOM 33 H 0 -3.123 2.056 1.940 0.00 0.00 H+0<br />
ATOM 34 H 0 -5.321 1.010 2.162 0.00 0.00 H+0<br />
ATOM 35 H 0 -5.708 -1.261 1.298 0.00 0.00 H+0<br />
ATOM 36 H 0 -3.894 -2.512 0.202 0.00 0.00 H+0<br />
ATOM 37 H 0 -1.681 -1.507 -0.049 0.00 0.00 H+0<br />
ATOM 38 H 0 2.649 0.351 2.473 0.00 0.00 H+0<br />
ATOM 39 H 0 1.670 1.610 3.263 0.00 0.00 H+0<br />
ATOM 40 H 0 0.885 0.387 2.236 0.00 0.00 H+0<br />
ATOM 41 H 0 3.408 3.318 0.409 0.00 0.00 H+0<br />
ATOM 42 H 0 3.257 3.280 2.182 0.00 0.00 H+0<br />
ATOM 43 H 0 4.107 1.967 1.333 0.00 0.00 H+0<br />
ATOM 44 H 0 -0.135 2.378 1.296 0.00 0.00 H+0<br />
ATOM 45 H 0 0.953 3.696 1.793 0.00 0.00 H+0<br />
ATOM 46 H 0 0.746 3.316 0.066 0.00 0.00 H+0<br />
ATOM 47 H 0 -0.158 -1.470 -2.142 0.00 0.00 H+0<br />
ATOM 48 H 0 0.658 2.136 -1.818 0.00 0.00 H+0<br />
ATOM 49 H 0 -0.702 2.805 -2.753 0.00 0.00 H+0<br />
ATOM 50 H 0 -0.996 2.060 -1.163 0.00 0.00 H+0<br />
ATOM 51 H 0 0.032 -0.348 -4.546 0.00 0.00 H+0<br />
ATOM 52 H 0 -0.004 1.428 -4.665 0.00 0.00 H+0<br />
ATOM 53 H 0 1.300 0.623 -3.760 0.00 0.00 H+0<br />
ATOM 54 H 0 -2.678 0.527 -2.192 0.00 0.00 H+0<br />
ATOM 55 H 0 -2.384 1.271 -3.782 0.00 0.00 H+0<br />
ATOM 56 H 0 -2.224 -0.490 -3.581 0.00 0.00 H+0<br />
CONECT 1 2 24 25 26 NONE 61<br />
CONECT 2 1 3 4 5 NONE 62<br />
CONECT 3 2 27 28 29 NONE 63<br />
CONECT 4 2 30 31 32 NONE 64<br />
CONECT 5 2 6 0 0 NONE 65<br />
CONECT 6 5 7 14 19 NONE 66<br />
CONECT 7 6 8 0 0 NONE 67<br />
CONECT 8 7 13 9 0 NONE 68<br />
CONECT 9 8 10 33 0 NONE 69<br />
CONECT 10 9 11 34 0 NONE 70<br />
CONECT 11 10 12 35 0 NONE 71<br />
CONECT 12 11 13 36 0 NONE 72<br />
CONECT 13 12 8 37 0 NONE 73<br />
CONECT 14 6 15 0 0 NONE 74<br />
CONECT 15 14 16 17 18 NONE 75<br />
CONECT 16 15 38 39 40 NONE 76<br />
CONECT 17 15 41 42 43 NONE 77<br />
CONECT 18 15 44 45 46 NONE 78<br />
CONECT 19 6 20 47 0 NONE 79<br />
CONECT 20 19 21 22 23 NONE 80<br />
CONECT 21 20 48 49 50 NONE 81<br />
CONECT 22 20 51 52 53 NONE 82<br />
CONECT 23 20 54 55 56 NONE 83<br />
END</inlineContents><br />
</jmolApplet><br />
</jmol><br />
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Reference<br />
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1.http://www.rsc.org/chemistryworld/restricted/2005/November/prize.asp</div>Kjf05https://chemwiki.ch.ic.ac.uk/index.php?title=File:Olefin10.gif&diff=6506File:Olefin10.gif2006-12-01T13:20:24Z<p>Kjf05: </p>
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<div></div>Kjf05