ChemWiki - User contributions [en]

User talk:Np1612

2015-03-16T18:16:40Z

Rea12: /* Atropisomerism of Taxol (0.25) 92% */

= Comments =

== Cyclopentadiene (0.20) 100% ==

== Atropisomerism of Taxol (0.25) 92% ==

"A hypothesis to explain the greater stability of molecule 10 could be the antiperiplanar orientation of the C=O bond with the neighbouring C-H bond."

Good discussion!

"The Total Energy results of the optimised molecule 18 conformation was compared with colleagues and it was found that the lowest energy optimised molecule 18 conformation had a Total Energy of 402 kJmol-1."

Nice approach!

"Table 5. 1H NMR Data of a Taxol Intermediate 18 "

This would be much easier to read if your sorted it by shift.

"The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically."

Well, yes and no - you make it sound like it's the experiment's fault that the calculation doesn't match - maybe phrase that more carefully next time.

It's not very likely that the different conformers interconvert into ech other. You can only say that if you've got evidence that for the molecule there's no kinetic barriers between the conformations.

It's actually more likely that the lowest energy conformation in solution is a different one from your (calculated) vacuum-model.

"However, the chemical shift values reported in the literature[4] are not assigned to each hydrogen in each multiplet, therefore literature values were also averaged to obtain a mean shift for each multiplet"

I'm not quite sure I understand what you did there. But there's no need to average the literature. HNMR is a highly reliable technique and in this case you should treat the literature as 'hard fact' (as opposed e.g. to alpha values in optical rotation).

You explained what you did and why you did it, and that's okay.
However, I'd like to give you a general warning. Any changes to the experimental data 'to make it match better' could end up being viewed as trying to change reality, i.e. cheating.

What is actually happening is that you have a model that's not in agreement with experimental data.
I understand your intentions here, but you should really know that if you do something like this in a thesis or a paper that will at the least be viewed as a bad scientific work style.
So, once again, I'm not implying anything, just warning not to mess with 'hard data'.

In any case, adding the original literature values to the table would have been helpful. Make it easy on your readers to verify your thought-process without having to look up the data themselves. ;)

" The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically. "

Same thing again, you mentioned in your intro already that it takes time to convert from one isomer to another. That indicates a kinetic barrier of sufficient height between the conformers. Again, it will be the difference between computation 'in vacuo' and experiment in solution.

== Crystal structures(0.05) 100% ==

good!

== Epoxide NMR (0.05) 40% ==

Discussion missing.

== Optical Rotation and TS (0.35) 35% ==

Discussion missing and the thermal energy values missing..

== QTAIM, NCI and product suggestion (0.10) 0% ==

==.==
Sorry, wish I could give you a better grade.

User talk:Np1612

2015-03-16T18:04:10Z

Rea12: /* QTAIM, NCI and product suggestion (0.10) 0% */

= Comments =

== Cyclopentadiene (0.20) 100% ==

== Atropisomerism of Taxol (0.25) 92% ==

"A hypothesis to explain the greater stability of molecule 10 could be the antiperiplanar orientation of the C=O bond with the neighbouring C-H bond."

Good discussion!

"The Total Energy results of the optimised molecule 18 conformation was compared with colleagues and it was found that the lowest energy optimised molecule 18 conformation had a Total Energy of 402 kJmol-1."

Nice approach!

"Table 5. 1H NMR Data of a Taxol Intermediate 18 "

This would be much easier to read if your sorted it by shift.

"The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically."

Well, yes and no - you make it sound like it's the experiment's fault that the calculation doesn't match - maybe phrase that more carefully next time.

It's not very likely that the different conformers interconvert into ech other. You can only say that if you've got evidence that for the molecule there's no kinetic barriers between the conformations.

It's actually more likely that the lowest energy conformation in solution is a different one from your (calculated) vacuum-model.

"However, the chemical shift values reported in the literature[4] are not assigned to each hydrogen in each multiplet, therefore literature values were also averaged to obtain a mean shift for each multiplet"

I'm not quite sure I understand what you did there. But there's no need to average the literature. HNMR is a highly reliable technique and in this case you should treat the literature as 'hard fact' (as opposed e.g. to alpha values in optical rotation).

You explained what you did and why you did it, and that's okay.
However, I'd like to give you a general warning. Any changes to the experimental data 'to make it match better' could end up being viewed as trying to change reality, i.e. cheating.

What is actually happening is that you have a model that's not in agreement with experimental data.
I understand your intentions here, but you should really know that if you do something like this in a thesis or a paper that will at the least be viewed as a bad scientific work style.
So, once again, I'm not implying anything, just warning not to mess with 'hard data'.

In any case, adding the original literature values to the table would have been helpful. Make it easy on your readers to verify your thought-process without having to look up the data themselves. ;)

" The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically. "

Same thing again, you mentioned in your intro already that it takes time to convert from one isomer to another. THat indicates a kinetic barrier of sufficient height between the conformers. Again, it will be the

== Crystal structures(0.05) 100% ==

good!

== Epoxide NMR (0.05) 40% ==

Discussion missing.

== Optical Rotation and TS (0.35) 35% ==

Discussion missing and the thermal energy values missing..

== QTAIM, NCI and product suggestion (0.10) 0% ==

==.==
Sorry, wish I could give you a better grade.

User talk:Np1612

2015-03-16T18:03:27Z

Rea12: /* QTAIM, NCI and product suggestion (0.10) */

= Comments =

== Cyclopentadiene (0.20) 100% ==

== Atropisomerism of Taxol (0.25) 92% ==

"A hypothesis to explain the greater stability of molecule 10 could be the antiperiplanar orientation of the C=O bond with the neighbouring C-H bond."

Good discussion!

"The Total Energy results of the optimised molecule 18 conformation was compared with colleagues and it was found that the lowest energy optimised molecule 18 conformation had a Total Energy of 402 kJmol-1."

Nice approach!

"Table 5. 1H NMR Data of a Taxol Intermediate 18 "

This would be much easier to read if your sorted it by shift.

"The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically."

Well, yes and no - you make it sound like it's the experiment's fault that the calculation doesn't match - maybe phrase that more carefully next time.

It's not very likely that the different conformers interconvert into ech other. You can only say that if you've got evidence that for the molecule there's no kinetic barriers between the conformations.

It's actually more likely that the lowest energy conformation in solution is a different one from your (calculated) vacuum-model.

"However, the chemical shift values reported in the literature[4] are not assigned to each hydrogen in each multiplet, therefore literature values were also averaged to obtain a mean shift for each multiplet"

I'm not quite sure I understand what you did there. But there's no need to average the literature. HNMR is a highly reliable technique and in this case you should treat the literature as 'hard fact' (as opposed e.g. to alpha values in optical rotation).

You explained what you did and why you did it, and that's okay.
However, I'd like to give you a general warning. Any changes to the experimental data 'to make it match better' could end up being viewed as trying to change reality, i.e. cheating.

What is actually happening is that you have a model that's not in agreement with experimental data.
I understand your intentions here, but you should really know that if you do something like this in a thesis or a paper that will at the least be viewed as a bad scientific work style.
So, once again, I'm not implying anything, just warning not to mess with 'hard data'.

In any case, adding the original literature values to the table would have been helpful. Make it easy on your readers to verify your thought-process without having to look up the data themselves. ;)

" The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically. "

Same thing again, you mentioned in your intro already that it takes time to convert from one isomer to another. THat indicates a kinetic barrier of sufficient height between the conformers. Again, it will be the

== Crystal structures(0.05) 100% ==

good!

== Epoxide NMR (0.05) 40% ==

Discussion missing.

== Optical Rotation and TS (0.35) 35% ==

Discussion missing and the thermal energy values missing..

== QTAIM, NCI and product suggestion (0.10) 0% ==

User talk:Np1612

2015-03-16T18:03:18Z

Rea12: /* Optical Rotation and TS (0.35) */

= Comments =

== Cyclopentadiene (0.20) 100% ==

== Atropisomerism of Taxol (0.25) 92% ==

"A hypothesis to explain the greater stability of molecule 10 could be the antiperiplanar orientation of the C=O bond with the neighbouring C-H bond."

Good discussion!

"The Total Energy results of the optimised molecule 18 conformation was compared with colleagues and it was found that the lowest energy optimised molecule 18 conformation had a Total Energy of 402 kJmol-1."

Nice approach!

"Table 5. 1H NMR Data of a Taxol Intermediate 18 "

This would be much easier to read if your sorted it by shift.

"The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically."

Well, yes and no - you make it sound like it's the experiment's fault that the calculation doesn't match - maybe phrase that more carefully next time.

It's not very likely that the different conformers interconvert into ech other. You can only say that if you've got evidence that for the molecule there's no kinetic barriers between the conformations.

It's actually more likely that the lowest energy conformation in solution is a different one from your (calculated) vacuum-model.

"However, the chemical shift values reported in the literature[4] are not assigned to each hydrogen in each multiplet, therefore literature values were also averaged to obtain a mean shift for each multiplet"

I'm not quite sure I understand what you did there. But there's no need to average the literature. HNMR is a highly reliable technique and in this case you should treat the literature as 'hard fact' (as opposed e.g. to alpha values in optical rotation).

You explained what you did and why you did it, and that's okay.
However, I'd like to give you a general warning. Any changes to the experimental data 'to make it match better' could end up being viewed as trying to change reality, i.e. cheating.

What is actually happening is that you have a model that's not in agreement with experimental data.
I understand your intentions here, but you should really know that if you do something like this in a thesis or a paper that will at the least be viewed as a bad scientific work style.
So, once again, I'm not implying anything, just warning not to mess with 'hard data'.

In any case, adding the original literature values to the table would have been helpful. Make it easy on your readers to verify your thought-process without having to look up the data themselves. ;)

" The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically. "

Same thing again, you mentioned in your intro already that it takes time to convert from one isomer to another. THat indicates a kinetic barrier of sufficient height between the conformers. Again, it will be the

== Crystal structures(0.05) 100% ==

good!

== Epoxide NMR (0.05) 40% ==

Discussion missing.

== Optical Rotation and TS (0.35) 35% ==

Discussion missing and the thermal energy values missing..

== QTAIM, NCI and product suggestion (0.10) ==

User talk:Np1612

2015-03-16T18:02:03Z

Rea12: /* Epoxide NMR (0.05) */

= Comments =

== Cyclopentadiene (0.20) 100% ==

== Atropisomerism of Taxol (0.25) 92% ==

"A hypothesis to explain the greater stability of molecule 10 could be the antiperiplanar orientation of the C=O bond with the neighbouring C-H bond."

Good discussion!

"The Total Energy results of the optimised molecule 18 conformation was compared with colleagues and it was found that the lowest energy optimised molecule 18 conformation had a Total Energy of 402 kJmol-1."

Nice approach!

"Table 5. 1H NMR Data of a Taxol Intermediate 18 "

This would be much easier to read if your sorted it by shift.

"The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically."

Well, yes and no - you make it sound like it's the experiment's fault that the calculation doesn't match - maybe phrase that more carefully next time.

It's not very likely that the different conformers interconvert into ech other. You can only say that if you've got evidence that for the molecule there's no kinetic barriers between the conformations.

It's actually more likely that the lowest energy conformation in solution is a different one from your (calculated) vacuum-model.

"However, the chemical shift values reported in the literature[4] are not assigned to each hydrogen in each multiplet, therefore literature values were also averaged to obtain a mean shift for each multiplet"

I'm not quite sure I understand what you did there. But there's no need to average the literature. HNMR is a highly reliable technique and in this case you should treat the literature as 'hard fact' (as opposed e.g. to alpha values in optical rotation).

You explained what you did and why you did it, and that's okay.
However, I'd like to give you a general warning. Any changes to the experimental data 'to make it match better' could end up being viewed as trying to change reality, i.e. cheating.

What is actually happening is that you have a model that's not in agreement with experimental data.
I understand your intentions here, but you should really know that if you do something like this in a thesis or a paper that will at the least be viewed as a bad scientific work style.
So, once again, I'm not implying anything, just warning not to mess with 'hard data'.

In any case, adding the original literature values to the table would have been helpful. Make it easy on your readers to verify your thought-process without having to look up the data themselves. ;)

" The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically. "

Same thing again, you mentioned in your intro already that it takes time to convert from one isomer to another. THat indicates a kinetic barrier of sufficient height between the conformers. Again, it will be the

== Crystal structures(0.05) 100% ==

good!

== Epoxide NMR (0.05) 40% ==

Discussion missing.

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

User talk:Np1612

2015-03-16T17:51:55Z

Rea12: /* Crystal structures(0.05) */

= Comments =

== Cyclopentadiene (0.20) 100% ==

== Atropisomerism of Taxol (0.25) 92% ==

"A hypothesis to explain the greater stability of molecule 10 could be the antiperiplanar orientation of the C=O bond with the neighbouring C-H bond."

Good discussion!

"The Total Energy results of the optimised molecule 18 conformation was compared with colleagues and it was found that the lowest energy optimised molecule 18 conformation had a Total Energy of 402 kJmol-1."

Nice approach!

"Table 5. 1H NMR Data of a Taxol Intermediate 18 "

This would be much easier to read if your sorted it by shift.

"The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically."

Well, yes and no - you make it sound like it's the experiment's fault that the calculation doesn't match - maybe phrase that more carefully next time.

It's not very likely that the different conformers interconvert into ech other. You can only say that if you've got evidence that for the molecule there's no kinetic barriers between the conformations.

It's actually more likely that the lowest energy conformation in solution is a different one from your (calculated) vacuum-model.

"However, the chemical shift values reported in the literature[4] are not assigned to each hydrogen in each multiplet, therefore literature values were also averaged to obtain a mean shift for each multiplet"

I'm not quite sure I understand what you did there. But there's no need to average the literature. HNMR is a highly reliable technique and in this case you should treat the literature as 'hard fact' (as opposed e.g. to alpha values in optical rotation).

You explained what you did and why you did it, and that's okay.
However, I'd like to give you a general warning. Any changes to the experimental data 'to make it match better' could end up being viewed as trying to change reality, i.e. cheating.

What is actually happening is that you have a model that's not in agreement with experimental data.
I understand your intentions here, but you should really know that if you do something like this in a thesis or a paper that will at the least be viewed as a bad scientific work style.
So, once again, I'm not implying anything, just warning not to mess with 'hard data'.

In any case, adding the original literature values to the table would have been helpful. Make it easy on your readers to verify your thought-process without having to look up the data themselves. ;)

" The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically. "

Same thing again, you mentioned in your intro already that it takes time to convert from one isomer to another. THat indicates a kinetic barrier of sufficient height between the conformers. Again, it will be the

== Crystal structures(0.05) 100% ==

good!

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

User talk:Np1612

2015-03-16T16:31:45Z

Rea12: /* Atropisomerism of Taxol (0.25) */

= Comments =

== Cyclopentadiene (0.20) 100% ==

== Atropisomerism of Taxol (0.25) 92% ==

"A hypothesis to explain the greater stability of molecule 10 could be the antiperiplanar orientation of the C=O bond with the neighbouring C-H bond."

Good discussion!

"The Total Energy results of the optimised molecule 18 conformation was compared with colleagues and it was found that the lowest energy optimised molecule 18 conformation had a Total Energy of 402 kJmol-1."

Nice approach!

"Table 5. 1H NMR Data of a Taxol Intermediate 18 "

This would be much easier to read if your sorted it by shift.

"The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically."

Well, yes and no - you make it sound like it's the experiment's fault that the calculation doesn't match - maybe phrase that more carefully next time.

It's not very likely that the different conformers interconvert into ech other. You can only say that if you've got evidence that for the molecule there's no kinetic barriers between the conformations.

It's actually more likely that the lowest energy conformation in solution is a different one from your (calculated) vacuum-model.

"However, the chemical shift values reported in the literature[4] are not assigned to each hydrogen in each multiplet, therefore literature values were also averaged to obtain a mean shift for each multiplet"

I'm not quite sure I understand what you did there. But there's no need to average the literature. HNMR is a highly reliable technique and in this case you should treat the literature as 'hard fact' (as opposed e.g. to alpha values in optical rotation).

You explained what you did and why you did it, and that's okay.
However, I'd like to give you a general warning. Any changes to the experimental data 'to make it match better' could end up being viewed as trying to change reality, i.e. cheating.

What is actually happening is that you have a model that's not in agreement with experimental data.
I understand your intentions here, but you should really know that if you do something like this in a thesis or a paper that will at the least be viewed as a bad scientific work style.
So, once again, I'm not implying anything, just warning not to mess with 'hard data'.

In any case, adding the original literature values to the table would have been helpful. Make it easy on your readers to verify your thought-process without having to look up the data themselves. ;)

" The reason for this large discrepancy between values is that the chemical shifts reported in literature were obtained experimentally. Hence, they reflect a time-weighted average of all the possible conformations of Taxol intermediate 18 yet, only one conformer was used to generate the 1H NMR quantum mechanically. "

Same thing again, you mentioned in your intro already that it takes time to convert from one isomer to another. THat indicates a kinetic barrier of sufficient height between the conformers. Again, it will be the

== Crystal structures(0.05) ==

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

User talk:Np1612

2015-03-16T14:36:27Z

Rea12: /* Crystal structures(0.05) */

= Comments =

== Cyclopentadiene (0.20) 100% ==

== Atropisomerism of Taxol (0.25) ==

"A hypothesis to explain the greater stability of molecule 10 could be the antiperiplanar orientation of the C=O bond with the neighbouring C-H bond."

Good discussion!

Nice section.

== Crystal structures(0.05) ==

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

User talk:Np1612

2015-03-16T14:33:56Z

Rea12: /* Atropisomerism of Taxol (0.25) */

User talk:Np1612

2015-03-16T14:29:05Z

Rea12: /* Cyclopentadiene (0.20) */

= Comments =

== Cyclopentadiene (0.20) 100% ==

== Atropisomerism of Taxol (0.25) ==

== Crystal structures(0.05) ==

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

User talk:Np1612

2015-03-16T14:20:59Z

Rea12: Created page with "= Comments = == Cyclopentadiene (0.20) == == Atropisomerism of Taxol (0.25) == == Crystal structures(0.05) == == Epoxide NMR (0.05) == == Optical Rotation and..."

= Comments =

== Cyclopentadiene (0.20) ==

== Atropisomerism of Taxol (0.25) ==

== Crystal structures(0.05) ==

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

Talk:Mod:NB1C

2015-03-15T19:40:21Z

Rea12: /* QTAIM, NCI and product suggestion (0.10) */

= Comments =

== Cyclopentadiene (0.20) 100% ==
good

== Atropisomerism of Taxol (0.25) 100% ==

"The larger ring is not of concern and does not need to be adjusted manually as typically in the presence of a smaller ring with a set conformation, the larger ring adapts its geometry to favor the smaller ring best.[4]"

Good!

"The reasons behind their reduced reactivity (i.e. why the alkene reacts slowly) is not chemically known and cannot be put down to the usual factors of steric hindrance or p-bond energy.[4]"

This phenomenon can be described physically. There is no "driving force" for the reaction because the the gain in free enthalpy or the increase in entropy is very low.

== Crystal structures(0.05) 100% ==

"Although for the structure obtained from PubChem this does not appear to be the case. "
I think the two molecules that you find in the unit cell are different from each other.

Jacobsen: good section!

== Epoxide NMR (0.05) 100% ==

Good.

Re averaging: Yeah, it is somewhat difficult to compare literature and computational study. In the end there's just not a whole lot of things to say.

Anyhow, well done!

== Optical Rotation and TS (0.35) 90% ==

"On comparison of the literature optical rotation values with the computed values it is clear they are not in agreement. It needs to be considered that the optical rotation is very sensitive to temperature and literature should not be presumed correct. Although in this case as the values differ greatly it seems the method used is not very reliable. "

Yes, it'S even worse. You could have looked up some more values in Reaxys (takes five minutes) for the molecules. Styrene oxide reports lie between 5 - 50deg, TBMSO between 20-60deg.

Also, the alpha value below 100° is not very reliable (see toolbox).

Why do you put in VCD spectra if you don't discuss them?

"From literature, the primary drawback to quantum mechanical calculations in comparison to computational force field methods is the calculation time, besides this the method tends to be widely accurate for modelling of enantiomers.[11] On analysis of the results obtained for this section, unfortunately they do not follow the expected trend."

That might have to do with the fact that you actually compared the highest energy transition states (negative signs => high numeric values). ;)

You're making up for it with a very good discussion, though, highlighting your expectations and giving good reasons as to why the results are different than expected. Also, you put a emphasis on explaining the math behind the problem, which is really good!

== QTAIM, NCI and product suggestion (0.10) 85% ==

Good section!

WHowever, with the new candidate the required OR was >300°. Anything below 100° would be not suitable. The method used is only reliable above 100° - which you would have known if you had read the info in the toolbox (and included that in your report for that matter). ;)

Just by the by, the compound is rather very toxic, corrosive and carcinogenic. We'd probably not use that in an undergraduate experiment. :)

Talk:Mod:NB1C

2015-03-15T19:30:08Z

Rea12: /* Optical Rotation and TS (0.35) */

Talk:Mod:NB1C

2015-03-15T19:08:25Z

Rea12: /* Epoxide NMR (0.05) */

Talk:Mod:NB1C

2015-03-15T19:08:17Z

Rea12: /* Crystal structures(0.05) */

Talk:Mod:NB1C

2015-03-15T19:08:06Z

Rea12: /* Atropisomerism of Taxol (0.25) */

Talk:Mod:NB1C

2015-03-15T19:07:52Z

Rea12: /* Epoxide NMR (0.05) */

= Comments =

== Cyclopentadiene (0.20) 100% ==
good

== Atropisomerism of Taxol (0.25) ==

"The larger ring is not of concern and does not need to be adjusted manually as typically in the presence of a smaller ring with a set conformation, the larger ring adapts its geometry to favor the smaller ring best.[4]"

Good!

"The reasons behind their reduced reactivity (i.e. why the alkene reacts slowly) is not chemically known and cannot be put down to the usual factors of steric hindrance or p-bond energy.[4]"

This phenomenon can be described physically. There is no "driving force" for the reaction because the the gain in free enthalpy or the increase in entropy is very low.

== Crystal structures(0.05) ==

"Although for the structure obtained from PubChem this does not appear to be the case. "
I think the two molecules that you find in the unit cell are different from each other.

Jacobsen: good section!

== Epoxide NMR (0.05) ==

Good.

Re averaging: Yeah, it is somewhat difficult to compare literature and computational study. In the end there's just not a whole lot of things to say.

Anyhow, well done!

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

Talk:Mod:NB1C

2015-03-15T19:06:32Z

Rea12: /* Optical Rotation and TS (0.35) */

= Comments =

== Cyclopentadiene (0.20) 100% ==
good

== Atropisomerism of Taxol (0.25) ==

"The larger ring is not of concern and does not need to be adjusted manually as typically in the presence of a smaller ring with a set conformation, the larger ring adapts its geometry to favor the smaller ring best.[4]"

Good!

"The reasons behind their reduced reactivity (i.e. why the alkene reacts slowly) is not chemically known and cannot be put down to the usual factors of steric hindrance or p-bond energy.[4]"

This phenomenon can be described physically. There is no "driving force" for the reaction because the the gain in free enthalpy or the increase in entropy is very low.

== Crystal structures(0.05) ==

"Although for the structure obtained from PubChem this does not appear to be the case. "
I think the two molecules that you find in the unit cell are different from each other.

Jacobsen: good section!

== Epoxide NMR (0.05) ==

Good.

Re avergaing: Yeah, it is somewhat difficult to compare literature and computational study. In the end there's not a whole lot of stuff to say.

Well done!

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

Talk:Mod:NB1C

2015-03-15T19:05:20Z

Rea12: /* Epoxide NMR (0.05) */

= Comments =

== Cyclopentadiene (0.20) 100% ==
good

== Atropisomerism of Taxol (0.25) ==

"The larger ring is not of concern and does not need to be adjusted manually as typically in the presence of a smaller ring with a set conformation, the larger ring adapts its geometry to favor the smaller ring best.[4]"

Good!

"The reasons behind their reduced reactivity (i.e. why the alkene reacts slowly) is not chemically known and cannot be put down to the usual factors of steric hindrance or p-bond energy.[4]"

This phenomenon can be described physically. There is no "driving force" for the reaction because the the gain in free enthalpy or the increase in entropy is very low.

== Crystal structures(0.05) ==

"Although for the structure obtained from PubChem this does not appear to be the case. "
I think the two molecules that you find in the unit cell are different from each other.

Jacobsen: good section!

== Epoxide NMR (0.05) ==

Good.

Re avergaing: Yeah, it is somewhat difficult to compare literature and computational study. In the end there's not a whole lot of stuff to say.

Well done!

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

Talk:Mod:NB1C

2015-03-15T19:04:20Z

Rea12: /* Crystal structures(0.05) */

= Comments =

== Cyclopentadiene (0.20) 100% ==
good

== Atropisomerism of Taxol (0.25) ==

"The larger ring is not of concern and does not need to be adjusted manually as typically in the presence of a smaller ring with a set conformation, the larger ring adapts its geometry to favor the smaller ring best.[4]"

Good!

"The reasons behind their reduced reactivity (i.e. why the alkene reacts slowly) is not chemically known and cannot be put down to the usual factors of steric hindrance or p-bond energy.[4]"

This phenomenon can be described physically. There is no "driving force" for the reaction because the the gain in free enthalpy or the increase in entropy is very low.

== Crystal structures(0.05) ==

"Although for the structure obtained from PubChem this does not appear to be the case. "
I think the two molecules that you find in the unit cell are different from each other.

Jacobsen: good section!

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

Talk:Mod:NB1C

2015-03-15T19:02:09Z

Rea12: /* Atropisomerism of Taxol (0.25) */

Talk:Mod:NB1C

2015-03-15T18:47:56Z

Rea12: /* Cyclopentadiene (0.20) */

= Comments =

== Cyclopentadiene (0.20) 100% ==
good

== Atropisomerism of Taxol (0.25) ==

== Crystal structures(0.05) ==

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM, NCI and product suggestion (0.10) ==

Talk:Mod:NB1C

2015-03-15T18:34:59Z

Rea12: Created page with "= Comments = == Cyclopentadiene (0.20) == == Atropisomerism of Taxol (0.25) == == Crystal structures(0.05) == == Epoxide NMR (0.05) == == Optical Rotation an..."

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T18:30:59Z

Rea12: /* Final thoughts */

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) 90% ==

nice use of references

"One example of atropisomerism is that encountered for the cycloctene molecule and another are the two conformers 5 & 6, a derivative from Taxol."

Grammar is a bit misleading here, maybe you can write something along the lines of:

"One well-known example of atropisomerism is that encountered for the cyclooctene molecule; another one, investigated in this report, is that of the two different taxol derivatives 5 & 6 (in Scheme 3)."

"... bridgehead olefins ARE preferred. These SHOWED remarkable ..."

"Table 5. HNMR raw data"

Very good work. But as we discussed, having the literature values tabulated would have been very helpful.

Also, we talked about being careful with "statistic" explanations. So, earlier defined "more ambiguous" and "less ambiguous" signals, but you average them all, regardless of your findings and without discussing the effect how different functional groups might lead to greater deviations. These are things that you really have to put into your discussion.

"HNMR simulations are far better (<0.1 ppm) than those for CNMR (5-6 ppm)."
We talked about that as well. Relatively speaking, a deviation of 5 out of 100ppm and 0.5 out of 10 would be very comparible.

These deviations are not very large, but they're acceptable.

"Hence, the average of the absolute deviation is a better representation of the deviation of the HNMR simulation."

Better than what? I'm not sure what you want to say here.

"This is unexpected since the twist up conformer is the highest energy conformation."
How would you explain that?
You put in a lot of work to lead up to that point in your discussion and you just end in saying, it is unexpected?

You should discuss potential reasons for that. And we talked about them all - be more critical on solvent effects, temperature and what they mean.

You mention them later on in the next paragraph, but from the placement within your report they seem very general and more like an afterthought. You should really embed them in your discussion directly and be more critical about what that means.

== Crystal structures(0.05) 95% ==

Good section!

"Table 9. Bond lengths"
Better use three digits for the values

Also, if you talk about "C8" etc., please refer to the picture this is shown in.
You should always aim at making it easy for your reader to navigate through your findings "at one glance". ;)

Very nice pictures on the different approach vectors!

== Epoxide NMR (0.05) 100% ==

"It would be expected that the proximity of the H7 proton to the epoxide function would deshield this proton further."

Yes and no, while this is generally true for aliphatic system, extended pi-systems - such as this benzene subunit - do have a lot of interaction going on thorugh the extended pi system.
It might be, that the epoxide deactivates the ring's meta-postion. There's many effects going on at the same time

It is also impossible to determine which atom is which in experiment, if you don't take the multiplicity into consideration (singlets, doublets, triplets...)

Good discussion of your findings.

== Optical Rotation and TS (0.35) 90% ==

A quick search on Reaxys showed Dihydronaphtalene oxide (39 deg - 140 deg) and Stilbene oxide (240 - 250deg). All in chloroform.

It is reasonably accurate, but your ignoring all the hints in the instructions.

Just because you find one agreement, doesn't mean that the method is accurate.

There's many literature references that disagree with your findings. Also, you need to discuss how exact the method is for values below/above 100deg. Effects of solvents, concentration temperature, to name a few.

Good intro on TS.

"The calculated ee values for the two substrates and catalysts are presented in table 15 above."

Please put "stilbene" in the table's caption!

Good effort on using the NCI here already, makes for a very nice discussion!

I'm missing the comparison to literature values, though!
You're saying it's in agreement with literature? Then please show the literature data and discuss how/why it's differing.

== QTAIM, NCI and product suggestion (0.10) 60% ==

You're missing the product suggestion.

== Final thoughts ==

In an almost, but not entirely unrelated response to your dedication:

1) I completely agree, a PhD degree is really not all that it's cracked up to be - that can refer to both the degree itself or the person holding it.

2) People (psychologists, ethnologists, historians, philosophers etc.) have for quite a while been discussing the difference between rationality and intelligence and how the two aren't the same.
I also seem to remember reading a quote on the internet saying that the idea of stupidity and intelligence being two opposites of the same thing is actually an invention of the 19th century bourgeoisie - I've got no idea if that's actually the case, but it sounds very fancy!

3) If you choose an answer to the following question at random, what is the chance you will be correct? A) 25% B) 50% C) 60% D) 25%

<code>;)</code>

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T18:28:09Z

Rea12: /* Final thoughts */

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) 90% ==

nice use of references

"One example of atropisomerism is that encountered for the cycloctene molecule and another are the two conformers 5 & 6, a derivative from Taxol."

Grammar is a bit misleading here, maybe you can write something along the lines of:

"One well-known example of atropisomerism is that encountered for the cyclooctene molecule; another one, investigated in this report, is that of the two different taxol derivatives 5 & 6 (in Scheme 3)."

"... bridgehead olefins ARE preferred. These SHOWED remarkable ..."

"Table 5. HNMR raw data"

Very good work. But as we discussed, having the literature values tabulated would have been very helpful.

Also, we talked about being careful with "statistic" explanations. So, earlier defined "more ambiguous" and "less ambiguous" signals, but you average them all, regardless of your findings and without discussing the effect how different functional groups might lead to greater deviations. These are things that you really have to put into your discussion.

"HNMR simulations are far better (<0.1 ppm) than those for CNMR (5-6 ppm)."
We talked about that as well. Relatively speaking, a deviation of 5 out of 100ppm and 0.5 out of 10 would be very comparible.

These deviations are not very large, but they're acceptable.

"Hence, the average of the absolute deviation is a better representation of the deviation of the HNMR simulation."

Better than what? I'm not sure what you want to say here.

"This is unexpected since the twist up conformer is the highest energy conformation."
How would you explain that?
You put in a lot of work to lead up to that point in your discussion and you just end in saying, it is unexpected?

You should discuss potential reasons for that. And we talked about them all - be more critical on solvent effects, temperature and what they mean.

You mention them later on in the next paragraph, but from the placement within your report they seem very general and more like an afterthought. You should really embed them in your discussion directly and be more critical about what that means.

== Crystal structures(0.05) 95% ==

Good section!

"Table 9. Bond lengths"
Better use three digits for the values

Also, if you talk about "C8" etc., please refer to the picture this is shown in.
You should always aim at making it easy for your reader to navigate through your findings "at one glance". ;)

Very nice pictures on the different approach vectors!

== Epoxide NMR (0.05) 100% ==

"It would be expected that the proximity of the H7 proton to the epoxide function would deshield this proton further."

Yes and no, while this is generally true for aliphatic system, extended pi-systems - such as this benzene subunit - do have a lot of interaction going on thorugh the extended pi system.
It might be, that the epoxide deactivates the ring's meta-postion. There's many effects going on at the same time

It is also impossible to determine which atom is which in experiment, if you don't take the multiplicity into consideration (singlets, doublets, triplets...)

Good discussion of your findings.

== Optical Rotation and TS (0.35) 90% ==

A quick search on Reaxys showed Dihydronaphtalene oxide (39 deg - 140 deg) and Stilbene oxide (240 - 250deg). All in chloroform.

It is reasonably accurate, but your ignoring all the hints in the instructions.

Just because you find one agreement, doesn't mean that the method is accurate.

There's many literature references that disagree with your findings. Also, you need to discuss how exact the method is for values below/above 100deg. Effects of solvents, concentration temperature, to name a few.

Good intro on TS.

"The calculated ee values for the two substrates and catalysts are presented in table 15 above."

Please put "stilbene" in the table's caption!

Good effort on using the NCI here already, makes for a very nice discussion!

I'm missing the comparison to literature values, though!
You're saying it's in agreement with literature? Then please show the literature data and discuss how/why it's differing.

== QTAIM, NCI and product suggestion (0.10) 60% ==

You're missing the product suggestion.

== Final thoughts ==

In an almost, but not entirely unrelated response to your dedication:

1) I completely agree, a PhD degree is really not all that it's cracked up to be - that can refer to both the degree itself or the person holding it.

2) People (psychologists, ethnologists, historians, philosophers etc.) have for quite a while been discussing the difference between rationality and intelligence and how the two aren't the same.
I also seem to remember reading a quote on the internet that says that the idea of stupidity and intelligence being opposites is actually an invention of the 19th century bourgeoisie (I've got no idea if that's actually true, but it sounds very fancy!).

3) If you choose an answer to this question at random, what is the chance you will be correct? A) 25% B) 50% C) 60% D) 25%

<code>;)</code>

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T18:27:43Z

Rea12: /* Final thoughts */

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) 90% ==

nice use of references

"One example of atropisomerism is that encountered for the cycloctene molecule and another are the two conformers 5 & 6, a derivative from Taxol."

Grammar is a bit misleading here, maybe you can write something along the lines of:

"One well-known example of atropisomerism is that encountered for the cyclooctene molecule; another one, investigated in this report, is that of the two different taxol derivatives 5 & 6 (in Scheme 3)."

"... bridgehead olefins ARE preferred. These SHOWED remarkable ..."

"Table 5. HNMR raw data"

Very good work. But as we discussed, having the literature values tabulated would have been very helpful.

Also, we talked about being careful with "statistic" explanations. So, earlier defined "more ambiguous" and "less ambiguous" signals, but you average them all, regardless of your findings and without discussing the effect how different functional groups might lead to greater deviations. These are things that you really have to put into your discussion.

"HNMR simulations are far better (<0.1 ppm) than those for CNMR (5-6 ppm)."
We talked about that as well. Relatively speaking, a deviation of 5 out of 100ppm and 0.5 out of 10 would be very comparible.

These deviations are not very large, but they're acceptable.

"Hence, the average of the absolute deviation is a better representation of the deviation of the HNMR simulation."

Better than what? I'm not sure what you want to say here.

"This is unexpected since the twist up conformer is the highest energy conformation."
How would you explain that?
You put in a lot of work to lead up to that point in your discussion and you just end in saying, it is unexpected?

You should discuss potential reasons for that. And we talked about them all - be more critical on solvent effects, temperature and what they mean.

You mention them later on in the next paragraph, but from the placement within your report they seem very general and more like an afterthought. You should really embed them in your discussion directly and be more critical about what that means.

== Crystal structures(0.05) 95% ==

Good section!

"Table 9. Bond lengths"
Better use three digits for the values

Also, if you talk about "C8" etc., please refer to the picture this is shown in.
You should always aim at making it easy for your reader to navigate through your findings "at one glance". ;)

Very nice pictures on the different approach vectors!

== Epoxide NMR (0.05) 100% ==

"It would be expected that the proximity of the H7 proton to the epoxide function would deshield this proton further."

Yes and no, while this is generally true for aliphatic system, extended pi-systems - such as this benzene subunit - do have a lot of interaction going on thorugh the extended pi system.
It might be, that the epoxide deactivates the ring's meta-postion. There's many effects going on at the same time

It is also impossible to determine which atom is which in experiment, if you don't take the multiplicity into consideration (singlets, doublets, triplets...)

Good discussion of your findings.

== Optical Rotation and TS (0.35) 90% ==

A quick search on Reaxys showed Dihydronaphtalene oxide (39 deg - 140 deg) and Stilbene oxide (240 - 250deg). All in chloroform.

It is reasonably accurate, but your ignoring all the hints in the instructions.

Just because you find one agreement, doesn't mean that the method is accurate.

There's many literature references that disagree with your findings. Also, you need to discuss how exact the method is for values below/above 100deg. Effects of solvents, concentration temperature, to name a few.

Good intro on TS.

"The calculated ee values for the two substrates and catalysts are presented in table 15 above."

Please put "stilbene" in the table's caption!

Good effort on using the NCI here already, makes for a very nice discussion!

I'm missing the comparison to literature values, though!
You're saying it's in agreement with literature? Then please show the literature data and discuss how/why it's differing.

== QTAIM, NCI and product suggestion (0.10) 60% ==

You're missing the product suggestion.

== Final thoughts ==

In an almost, but not entirely unrelated response to your dedication:

1) I completely agree, a PhD degree is really not all that it's cracked up to be - that can refer to both the degree itself or the person carrying it.

2) People (psychologists, ethnologists, historians, philosophers etc.) have for quite a while been discussing the difference between rationality and intelligence and how the two aren't the same.
I also seem to remember reading a quote on the internet that says that the idea of stupidity and intelligence being opposites is actually an invention of the 19th century bourgeoisie (I've got no idea if that's actually true, but it sounds very fancy!).

3) If you choose an answer to this question at random, what is the chance you will be correct? A) 25% B) 50% C) 60% D) 25%

<code>;)</code>

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T18:26:33Z

Rea12: /* Final thoughts */

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) 90% ==

nice use of references

"One example of atropisomerism is that encountered for the cycloctene molecule and another are the two conformers 5 & 6, a derivative from Taxol."

Grammar is a bit misleading here, maybe you can write something along the lines of:

"One well-known example of atropisomerism is that encountered for the cyclooctene molecule; another one, investigated in this report, is that of the two different taxol derivatives 5 & 6 (in Scheme 3)."

"... bridgehead olefins ARE preferred. These SHOWED remarkable ..."

"Table 5. HNMR raw data"

Very good work. But as we discussed, having the literature values tabulated would have been very helpful.

Also, we talked about being careful with "statistic" explanations. So, earlier defined "more ambiguous" and "less ambiguous" signals, but you average them all, regardless of your findings and without discussing the effect how different functional groups might lead to greater deviations. These are things that you really have to put into your discussion.

"HNMR simulations are far better (<0.1 ppm) than those for CNMR (5-6 ppm)."
We talked about that as well. Relatively speaking, a deviation of 5 out of 100ppm and 0.5 out of 10 would be very comparible.

These deviations are not very large, but they're acceptable.

"Hence, the average of the absolute deviation is a better representation of the deviation of the HNMR simulation."

Better than what? I'm not sure what you want to say here.

"This is unexpected since the twist up conformer is the highest energy conformation."
How would you explain that?
You put in a lot of work to lead up to that point in your discussion and you just end in saying, it is unexpected?

You should discuss potential reasons for that. And we talked about them all - be more critical on solvent effects, temperature and what they mean.

You mention them later on in the next paragraph, but from the placement within your report they seem very general and more like an afterthought. You should really embed them in your discussion directly and be more critical about what that means.

== Crystal structures(0.05) 95% ==

Good section!

"Table 9. Bond lengths"
Better use three digits for the values

Also, if you talk about "C8" etc., please refer to the picture this is shown in.
You should always aim at making it easy for your reader to navigate through your findings "at one glance". ;)

Very nice pictures on the different approach vectors!

== Epoxide NMR (0.05) 100% ==

"It would be expected that the proximity of the H7 proton to the epoxide function would deshield this proton further."

Yes and no, while this is generally true for aliphatic system, extended pi-systems - such as this benzene subunit - do have a lot of interaction going on thorugh the extended pi system.
It might be, that the epoxide deactivates the ring's meta-postion. There's many effects going on at the same time

It is also impossible to determine which atom is which in experiment, if you don't take the multiplicity into consideration (singlets, doublets, triplets...)

Good discussion of your findings.

== Optical Rotation and TS (0.35) 90% ==

A quick search on Reaxys showed Dihydronaphtalene oxide (39 deg - 140 deg) and Stilbene oxide (240 - 250deg). All in chloroform.

It is reasonably accurate, but your ignoring all the hints in the instructions.

Just because you find one agreement, doesn't mean that the method is accurate.

There's many literature references that disagree with your findings. Also, you need to discuss how exact the method is for values below/above 100deg. Effects of solvents, concentration temperature, to name a few.

Good intro on TS.

"The calculated ee values for the two substrates and catalysts are presented in table 15 above."

Please put "stilbene" in the table's caption!

Good effort on using the NCI here already, makes for a very nice discussion!

I'm missing the comparison to literature values, though!
You're saying it's in agreement with literature? Then please show the literature data and discuss how/why it's differing.

== QTAIM, NCI and product suggestion (0.10) 60% ==

You're missing the product suggestion.

== Final thoughts ==

In an almost, but not entirely unrelated response to your dedication:

1) I completely agree, a PhD degree is really not all that it's cracked up to be - that can refer to both the degree itself or the person carrying it.

2) People (psychologists, ethnologists, historians, philosophers etc.) have for quite a while been discussing the difference between rationality and intelligence and how the two aren't the same.
I also seem to remember reading a quote on the internet that says that the idea of stupidity and intelligence being opposites is actually an invention of the 19th century bourgeoisie (I've got no idea if that's actually true, but it sounds very fancy!).

3) If you choose an answer to this question at random, what is the chance you will be correct? A) 25% B) 50% C) 60% D) 25%

';)'

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T15:48:40Z

Rea12:

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) 90% ==

nice use of references

"One example of atropisomerism is that encountered for the cycloctene molecule and another are the two conformers 5 & 6, a derivative from Taxol."

Grammar is a bit misleading here, maybe you can write something along the lines of:

"One well-known example of atropisomerism is that encountered for the cyclooctene molecule; another one, investigated in this report, is that of the two different taxol derivatives 5 & 6 (in Scheme 3)."

"... bridgehead olefins ARE preferred. These SHOWED remarkable ..."

"Table 5. HNMR raw data"

Very good work. But as we discussed, having the literature values tabulated would have been very helpful.

Also, we talked about being careful with "statistic" explanations. So, earlier defined "more ambiguous" and "less ambiguous" signals, but you average them all, regardless of your findings and without discussing the effect how different functional groups might lead to greater deviations. These are things that you really have to put into your discussion.

"HNMR simulations are far better (<0.1 ppm) than those for CNMR (5-6 ppm)."
We talked about that as well. Relatively speaking, a deviation of 5 out of 100ppm and 0.5 out of 10 would be very comparible.

These deviations are not very large, but they're acceptable.

"Hence, the average of the absolute deviation is a better representation of the deviation of the HNMR simulation."

Better than what? I'm not sure what you want to say here.

"This is unexpected since the twist up conformer is the highest energy conformation."
How would you explain that?
You put in a lot of work to lead up to that point in your discussion and you just end in saying, it is unexpected?

You should discuss potential reasons for that. And we talked about them all - be more critical on solvent effects, temperature and what they mean.

You mention them later on in the next paragraph, but from the placement within your report they seem very general and more like an afterthought. You should really embed them in your discussion directly and be more critical about what that means.

== Crystal structures(0.05) 95% ==

Good section!

"Table 9. Bond lengths"
Better use three digits for the values

Also, if you talk about "C8" etc., please refer to the picture this is shown in.
You should always aim at making it easy for your reader to navigate through your findings "at one glance". ;)

Very nice pictures on the different approach vectors!

== Epoxide NMR (0.05) 100% ==

"It would be expected that the proximity of the H7 proton to the epoxide function would deshield this proton further."

Yes and no, while this is generally true for aliphatic system, extended pi-systems - such as this benzene subunit - do have a lot of interaction going on thorugh the extended pi system.
It might be, that the epoxide deactivates the ring's meta-postion. There's many effects going on at the same time

It is also impossible to determine which atom is which in experiment, if you don't take the multiplicity into consideration (singlets, doublets, triplets...)

Good discussion of your findings.

== Optical Rotation and TS (0.35) 90% ==

A quick search on Reaxys showed Dihydronaphtalene oxide (39 deg - 140 deg) and Stilbene oxide (240 - 250deg). All in chloroform.

It is reasonably accurate, but your ignoring all the hints in the instructions.

Just because you find one agreement, doesn't mean that the method is accurate.

There's many literature references that disagree with your findings. Also, you need to discuss how exact the method is for values below/above 100deg. Effects of solvents, concentration temperature, to name a few.

Good intro on TS.

"The calculated ee values for the two substrates and catalysts are presented in table 15 above."

Please put "stilbene" in the table's caption!

Good effort on using the NCI here already, makes for a very nice discussion!

I'm missing the comparison to literature values, though!
You're saying it's in agreement with literature? Then please show the literature data and discuss how/why it's differing.

== QTAIM, NCI and product suggestion (0.10) 60% ==

You're missing the product suggestion.

== Final thoughts ==

In a not entirely unrelated response to your dedication:

1) I completely agree, a PhD degree is really not all that it's cracked up to be - that can refer to both the degree itself or the person carrying it.

2) People (psychologists, ethnologists, historians, philosophers etc.) have for quite a while been discussing the difference between rationality and intelligence and how the two aren't the same.
I also seem to remember reading a quote on the internet that says that the idea of stupidity and intelligence being opposites is actually an invention of the 19th century bourgeoisie (I've got no idea if that's actually true, but it sounds very fancy!).

3) If you choose an answer to this question at random, what is the chance you will be correct? A) 25% B) 50% C) 60% D) 25%

;)

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T15:40:50Z

Rea12: /* Optical Rotation and TS (0.35) 92% */

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T15:39:22Z

Rea12: /* QTAIM and NCI (0.10) */

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) 90% ==

nice use of references

"One example of atropisomerism is that encountered for the cycloctene molecule and another are the two conformers 5 & 6, a derivative from Taxol."

Grammar is a bit misleading here, maybe you can write something along the lines of:

"One well-known example of atropisomerism is that encountered for the cyclooctene molecule; another one, investigated in this report, is that of the two different taxol derivatives 5 & 6 (in Scheme 3)."

"... bridgehead olefins ARE preferred. These SHOWED remarkable ..."

"Table 5. HNMR raw data"

Very good work. But as we discussed, having the literature values tabulated would have been very helpful.

Also, we talked about being careful with "statistic" explanations. So, earlier defined "more ambiguous" and "less ambiguous" signals, but you average them all, regardless of your findings and without discussing the effect how different functional groups might lead to greater deviations. These are things that you really have to put into your discussion.

"HNMR simulations are far better (<0.1 ppm) than those for CNMR (5-6 ppm)."
We talked about that as well. Relatively speaking, a deviation of 5 out of 100ppm and 0.5 out of 10 would be very comparible.

These deviations are not very large, but they're acceptable.

"Hence, the average of the absolute deviation is a better representation of the deviation of the HNMR simulation."

Better than what? I'm not sure what you want to say here.

"This is unexpected since the twist up conformer is the highest energy conformation."
How would you explain that?
You put in a lot of work to lead up to that point in your discussion and you just end in saying, it is unexpected?

You should discuss potential reasons for that. And we talked about them all - be more critical on solvent effects, temperature and what they mean.

You mention them later on in the next paragraph, but from the placement within your report they seem very general and more like an afterthought. You should really embed them in your discussion directly and be more critical about what that means.

== Crystal structures(0.05) 95% ==

Good section!

"Table 9. Bond lengths"
Better use three digits for the values

Also, if you talk about "C8" etc., please refer to the picture this is shown in.
You should always aim at making it easy for your reader to navigate through your findings "at one glance". ;)

Very nice pictures on the different approach vectors!

== Epoxide NMR (0.05) 100% ==

"It would be expected that the proximity of the H7 proton to the epoxide function would deshield this proton further."

Yes and no, while this is generally true for aliphatic system, extended pi-systems - such as this benzene subunit - do have a lot of interaction going on thorugh the extended pi system.
It might be, that the epoxide deactivates the ring's meta-postion. There's many effects going on at the same time

It is also impossible to determine which atom is which in experiment, if you don't take the multiplicity into consideration (singlets, doublets, triplets...)

Good discussion of your findings.

== Optical Rotation and TS (0.35) 92% ==

A quick search on Reaxys showed Dihydronaphtalene oxide (39 deg - 140 deg) and Stilbene oxide (240 - 250deg). All in chloroform.

It is reasonably accurate, but your ignoring all the hints in the instructions.

Just because you find one agreement, doesn't mean that the method is accurate.

There's many literature references that disagree with your findings. Also you need to discuss how exact the method is for values below/above 100deg. Effects of solvents, concentration temperature, to name a few.

Good intro on TS.

"The calculated ee values for the two substrates and catalysts are presented in table 15 above."

Please put "stilbene" in the table's caption!

Good effort on using the NCI here already, makes for a very nice discussion!

I'm missing the comparison to literature values, though!

== QTAIM, NCI and product suggestion (0.10) 60% ==

You're missing the product suggestion.

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T15:37:09Z

Rea12: /* Optical Rotation and TS (0.35) */

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) 90% ==

nice use of references

"One example of atropisomerism is that encountered for the cycloctene molecule and another are the two conformers 5 & 6, a derivative from Taxol."

Grammar is a bit misleading here, maybe you can write something along the lines of:

"One well-known example of atropisomerism is that encountered for the cyclooctene molecule; another one, investigated in this report, is that of the two different taxol derivatives 5 & 6 (in Scheme 3)."

"... bridgehead olefins ARE preferred. These SHOWED remarkable ..."

"Table 5. HNMR raw data"

Very good work. But as we discussed, having the literature values tabulated would have been very helpful.

Also, we talked about being careful with "statistic" explanations. So, earlier defined "more ambiguous" and "less ambiguous" signals, but you average them all, regardless of your findings and without discussing the effect how different functional groups might lead to greater deviations. These are things that you really have to put into your discussion.

"HNMR simulations are far better (<0.1 ppm) than those for CNMR (5-6 ppm)."
We talked about that as well. Relatively speaking, a deviation of 5 out of 100ppm and 0.5 out of 10 would be very comparible.

These deviations are not very large, but they're acceptable.

"Hence, the average of the absolute deviation is a better representation of the deviation of the HNMR simulation."

Better than what? I'm not sure what you want to say here.

"This is unexpected since the twist up conformer is the highest energy conformation."
How would you explain that?
You put in a lot of work to lead up to that point in your discussion and you just end in saying, it is unexpected?

You should discuss potential reasons for that. And we talked about them all - be more critical on solvent effects, temperature and what they mean.

You mention them later on in the next paragraph, but from the placement within your report they seem very general and more like an afterthought. You should really embed them in your discussion directly and be more critical about what that means.

== Crystal structures(0.05) 95% ==

Good section!

"Table 9. Bond lengths"
Better use three digits for the values

Also, if you talk about "C8" etc., please refer to the picture this is shown in.
You should always aim at making it easy for your reader to navigate through your findings "at one glance". ;)

Very nice pictures on the different approach vectors!

== Epoxide NMR (0.05) 100% ==

"It would be expected that the proximity of the H7 proton to the epoxide function would deshield this proton further."

Yes and no, while this is generally true for aliphatic system, extended pi-systems - such as this benzene subunit - do have a lot of interaction going on thorugh the extended pi system.
It might be, that the epoxide deactivates the ring's meta-postion. There's many effects going on at the same time

It is also impossible to determine which atom is which in experiment, if you don't take the multiplicity into consideration (singlets, doublets, triplets...)

Good discussion of your findings.

== Optical Rotation and TS (0.35) 92% ==

A quick search on Reaxys showed Dihydronaphtalene oxide (39 deg - 140 deg) and Stilbene oxide (240 - 250deg). All in chloroform.

It is reasonably accurate, but your ignoring all the hints in the instructions.

Just because you find one agreement, doesn't mean that the method is accurate.

There's many literature references that disagree with your findings. Also you need to discuss how exact the method is for values below/above 100deg. Effects of solvents, concentration temperature, to name a few.

Good intro on TS.

"The calculated ee values for the two substrates and catalysts are presented in table 15 above."

Please put "stilbene" in the table's caption!

Good effort on using the NCI here already, makes for a very nice discussion!

I'm missing the comparison to literature values, though!

== QTAIM and NCI (0.10) ==

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T15:15:34Z

Rea12: /* Epoxide NMR (0.05) 100% */

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T15:11:24Z

Rea12: /* Epoxide NMR (0.05) 100% */

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) 90% ==

nice use of references

"One example of atropisomerism is that encountered for the cycloctene molecule and another are the two conformers 5 & 6, a derivative from Taxol."

Grammar is a bit misleading here, maybe you can write something along the lines of:

"One well-known example of atropisomerism is that encountered for the cyclooctene molecule; another one, investigated in this report, is that of the two different taxol derivatives 5 & 6 (in Scheme 3)."

"... bridgehead olefins ARE preferred. These SHOWED remarkable ..."

"Table 5. HNMR raw data"

Very good work. But as we discussed, having the literature values tabulated would have been very helpful.

Also, we talked about being careful with "statistic" explanations. So, earlier defined "more ambiguous" and "less ambiguous" signals, but you average them all, regardless of your findings and without discussing the effect how different functional groups might lead to greater deviations. These are things that you really have to put into your discussion.

"HNMR simulations are far better (<0.1 ppm) than those for CNMR (5-6 ppm)."
We talked about that as well. Relatively speaking, a deviation of 5 out of 100ppm and 0.5 out of 10 would be very comparible.

These deviations are not very large, but they're acceptable.

"Hence, the average of the absolute deviation is a better representation of the deviation of the HNMR simulation."

Better than what? I'm not sure what you want to say here.

"This is unexpected since the twist up conformer is the highest energy conformation."
How would you explain that?
You put in a lot of work to lead up to that point in your discussion and you just end in saying, it is unexpected?

You should discuss potential reasons for that. And we talked about them all - be more critical on solvent effects, temperature and what they mean.

You mention them later on in the next paragraph, but from the placement within your report they seem very general and more like an afterthought. You should really embed them in your discussion directly and be more critical about what that means.

== Crystal structures(0.05) 95% ==

Good section!

"Table 9. Bond lengths"
Better use three digits for the values

Also, if you talk about "C8" etc., please refer to the picture this is shown in.
You should always aim at making it easy for your reader to navigate through your findings "at one glance". ;)

Very nice pictures on the different approach vectors!

== Epoxide NMR (0.05) 100% ==

"It would be expected that the proximity of the H7 proton to the epoxide function would deshield this proton further."

Yes and no, while this is generally true for aliphatic system, extended pi-systems - such as this benzene subunit - do have a lot of interaction going on thorugh the extended pi system.
It might be, that the epoxide deactivates the ring's meta-postion. There's many effects going on at the same time

It is also impossible to determine which atom is which in experiment, if you don't take the multiplicity into consideration (singlets, doublets, triplets...)

Good discussion of your findings.

"However, such molecular interactions are not included in the solvent model, neither are temperature or pressure effects. '''All of these affect the final result.'''"

This is a good example for me to give you a general note on how to improve your discussion.

- You present your findings and explain the findings and you show that the computation is differen from the experiment, which is good.

- Then you explain what possible reasons for the differences are. Good.

Now, however, you need to link that to your findings. You could for examples

== Optical Rotation and TS (0.35) ==

== QTAIM and NCI (0.10) ==

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T15:10:57Z

Rea12: /* Epoxide NMR (0.05) */

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) 90% ==

nice use of references

"One example of atropisomerism is that encountered for the cycloctene molecule and another are the two conformers 5 & 6, a derivative from Taxol."

Grammar is a bit misleading here, maybe you can write something along the lines of:

"One well-known example of atropisomerism is that encountered for the cyclooctene molecule; another one, investigated in this report, is that of the two different taxol derivatives 5 & 6 (in Scheme 3)."

"... bridgehead olefins ARE preferred. These SHOWED remarkable ..."

"Table 5. HNMR raw data"

Very good work. But as we discussed, having the literature values tabulated would have been very helpful.

Also, we talked about being careful with "statistic" explanations. So, earlier defined "more ambiguous" and "less ambiguous" signals, but you average them all, regardless of your findings and without discussing the effect how different functional groups might lead to greater deviations. These are things that you really have to put into your discussion.

"HNMR simulations are far better (<0.1 ppm) than those for CNMR (5-6 ppm)."
We talked about that as well. Relatively speaking, a deviation of 5 out of 100ppm and 0.5 out of 10 would be very comparible.

These deviations are not very large, but they're acceptable.

"Hence, the average of the absolute deviation is a better representation of the deviation of the HNMR simulation."

Better than what? I'm not sure what you want to say here.

"This is unexpected since the twist up conformer is the highest energy conformation."
How would you explain that?
You put in a lot of work to lead up to that point in your discussion and you just end in saying, it is unexpected?

You should discuss potential reasons for that. And we talked about them all - be more critical on solvent effects, temperature and what they mean.

You mention them later on in the next paragraph, but from the placement within your report they seem very general and more like an afterthought. You should really embed them in your discussion directly and be more critical about what that means.

== Crystal structures(0.05) 95% ==

Good section!

"Table 9. Bond lengths"
Better use three digits for the values

Also, if you talk about "C8" etc., please refer to the picture this is shown in.
You should always aim at making it easy for your reader to navigate through your findings "at one glance". ;)

Very nice pictures on the different approach vectors!

== Epoxide NMR (0.05) 100% ==

"It would be expected that the proximity of the H7 proton to the epoxide function would deshield this proton further."

Yes and no, while this is generally true for aliphatic system, extended pi-systems - such as this benzene subunit - do have a lot of interaction going on thorugh the extended pi system.
It might be, that the epoxide deactivates the ring's meta-postion. There's many effects going on at the same time

It is also impossible to determine which atom is which in experiment, if you don't take the multiplicity into consideration (singlets, doublets, triplets...)

Good discussion of your findings.

"However, such molecular interactions are not included in the solvent model, neither are temperature or pressure effects. 'All of these affect the final result.'"

This is a good example for me to give you a general note on how to improve your discussion.

- You present your findings and explain the findings and you show that the computation is differen from the experiment, which is good.

- Then you explain what possible reasons for the differences are. Good.

Now, however, you need to link that to your findings. You could for examples

== Optical Rotation and TS (0.35) ==

== QTAIM and NCI (0.10) ==

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T15:00:32Z

Rea12: /* Crystal structures(0.05) */

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T15:00:15Z

Rea12: /* Crystal structures(0.05) */

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T14:52:25Z

Rea12: /* Atropisomerism of Taxol (0.25) 90% */

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T14:49:27Z

Rea12: /* Atropisomerism of Taxol (0.25) */

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T14:21:43Z

Rea12:

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) ==

nice use of references

"One example of atropisomerism is that encountered for the cycloctene molecule and another are the two conformers 5 & 6, a derivative from Taxol."

Grammar is a bit misleading here, maybe you can write something along the lines of:

"One well-known example of atropisomerism is that encountered for the cyclooctene molecule; another one, investigated in this report, is that of the two different taxol derivatives 5 & 6 (in Scheme 3)."

== Crystal structures(0.05) ==

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM and NCI (0.10) ==

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T14:15:42Z

Rea12: /* Taxol (0.25) */

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Atropisomerism of Taxol (0.25) ==

== Crstal structures(0.05) ==

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM and NCI (0.10) ==

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T14:15:27Z

Rea12: /* Cyclopentadiene (0.20) */

= Comments =

== Cyclopentadiene (0.20) 105% ==

Very nice introduction!

Good and nice-to-read discussion!

== Taxol (0.25) ==

== Crstal structures(0.05) ==

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM and NCI (0.10) ==

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T13:30:49Z

Rea12:

= Comments =

== Cyclopentadiene (0.20) ==

== Taxol (0.25) ==

== Crstal structures(0.05) ==

== Epoxide NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM and NCI (0.10) ==

Talk:Mod:Monty Hall is the root of all evil

2015-03-15T13:26:59Z

Rea12: Created page with "= Comments = == Cyclopentadiene (0.20) == == Taxol (0.25) == == Epoxide (0.05) == == NMR (0.05) == == Optical Rotation and TS (0.35) == == QTAIM and NCI (0.10) =="

= Comments =

== Cyclopentadiene (0.20) ==

== Taxol (0.25) ==

== Epoxide (0.05) ==

== NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

== QTAIM and NCI (0.10) ==

Talk:Mod:organictg1412

2015-03-03T11:28:46Z

Rea12: /* final note */

= Comments =

== Cyclopentadiene (0.20) ==

Good intro.

"The Exo product is lower in energy, and is the thermodynamic product. Ie, height of the transition state barrier is not a determining factor in its formation."

punctuation...

"Dimer 1 energies"

Try to label your tables and graphs with exo and endo, in addition to just dimer 1/2.

"and closer to the desired 109.5 of sp3, so is less unstable"

minor typo

good explanation

== Taxol (0.25) ==

Good explanation of atropisomerism

"It is fairly deshielded due to the anisotropy of double bonds[CITATION NEEDED]-"

Yes, a simple model explains that. The electron density is in the pi orbitals, which are further away than the sigma orbitals, and additionally the electron density for pi-bonds is located between two atoms - rather than located on the atoms themselves. Therefore an "sp2 proton" has less electron density than an "sp3 proton". Draw it out to get a better understanding.

"However, the match with literature (1.38, the most deshielded value for methyl proton sets in literature) is poor. the remaining two sets of methyl proton shifts are in somewhat acceptable agreement with literature"

Yeah, it's mainly conformation that's to blame.

"Calculated values are in very good agreement to literature values."
Calculated values are in very good agreement WITH literature values.

"Another factor which will provide different results is the solvent choice."
That's correct.

Another big effect is the specific solvent interaction. Choosing a solvent in your calculation is an approximation that doesn't take solvent-molecule into account - e.g. how proton-oxygen interaction changes the electronic properties of your molecule.

"Carbon 11 is bonded to an oxygen atom, so gibes the largest chemical shift. This value is around 10ppm lower than the reported value for the shift. Once again, these discrepancies can be blamed on use of different solvent in the simulation, incorrect basis set approximation and sensitivity in geometry."

Actually no - you're trying to make your life too easy by giving a number of reasons without discussing them in some more detail.
The deviation here is actually easy to explain - that's due to the "heavy" atom effect not being taken in to account.

Along the same line, you completely ignored the info given in the toolbox:
https://wiki.ch.ic.ac.uk/wiki/index.php?title=Mod:toolbox#Analyzing_the_NMR_Chemical_Shift_calculation.5B5.5D.2C.5B6.5D

"From the simulated 1H NMRs above, it seems that 1H NMRs are most sensitive to changes in chemical shifts since the calculated differences vary dramatically from literature values."

dramatically is a very unscientific term.

"Literature values could not be found for twist boat conformation. However, given that the energies between this twist boat and the chair for isomer 18 are very close in energy, I would expect.."

No use of personal pronouns please ("I").

"This supports the idea that they are fluctional in ambient conditions, and we are expected to observe both at equilibrium. "
That's a very good discussion. Nicely done!

"Since this isomer has two conformers which are readily fluctuating, the reported literature values for this isomer may contain peaks which are undefined as a result of an overlap of two NMRs, for each conformer. "

To be nit-picking here, the resulting NMR would not exactly be an overlap of two spectra - because the conformers would not in actuality exist. The spectra would rather be the result of a molecule that undergoes constant conformational change between two theoretical extremes, i.e. two fixed conformational structures.

That is pretty the same that you said, yes - with an important difference: An "overlap of two spectra" is something that is okay to say when talking in a discussion because everyone will know what you mean. But for a report you need to pay a bit more attention to describing things in an exact manner.

== Epoxide (0.05) ==
Nice graphics.

Good explanation on the Shi catalyst.

For the Jacobsen you could have gone into a bit more detail e.g. in how you know that there is repulsive force between the tertiary butyl groups.

Otherwise good section.

== NMR (0.05) ==
good.

== Optical Rotation and TS (0.35) ==

OR:
Please tabulate the data you find for OR. It's difficult to compare the different values reading them from the text. The value of "7.54%" is not very meaningful, especially if you find that by modelling the molecule twice you introduce an error of ~1%. Try using absolute differences instead.

A quick search by reaxys showed that the reported ORs lie between 90° and 140°, so the literature you use is just one among many and it might be sheer coincidence that thee values agree reasonably well.

You also could have discussed the exactness of the calculation in a bit more detail, i.e. values of alpha below/above 100° (see Toolbox)

Overall a bit more discussion on the optical rotation would have been nice. You put a lot of effort into this, but the discussion doesn't always reflect this, I'm afraid.

Transition state: again please tabulate your data.

And it's good that you mention the formulas you used, but it's really difficult to read them.
Try putting them into a text box or at least into a separate line.

== QTAIM and NCI (0.10) ==
Very good.

== final note ==

Try to write more scientifically. Do not use personal pronouns ("I") or words that are not emotionally neutral - such as "dramatically", "extremely" etc. What you define as "extreme" vs what someone else defines as "extreme" might be a difference like day and night. In the end, the definition of such words comes down to personal preference and/or personal experiences, and either is inappropriate in a scientific text and should be avoided.

You also have quite a few left-overs like "[INSERT DIAGRAM]" in your text. That doesn't really matter too much, but it does show you have not proof-read your text sufficiently.

Altogether it's a good report but you do need to work on certain details.

Talk:RG1712

2015-03-03T11:26:15Z

Rea12: /* Comments */

= Comments =

== Cyclopentadiene (0.20) ==

Good intro.

"Each program possesses its own distinctive energy scale and so in order to ensure consistency the same program must be used for all calculations."

nice!

"Energies of Molecules 1 and 2 " "exo, endo"

Please try to be consistent with your labels in graphs and tables. Use one label - or both.

== Taxol (0.25) ==

Nice section.

Why didn't you discuss the angles for the hyperstable olefins a bit more? What do those values mean? How are they different between Olefine and alkane? Why/how do they influence the total energy?

Nice extra effort on analysing the different conformations for molecule 17 and 18!

Table 12 - very nice discussion!

"One point of note however is the difference in the shift of atom number 26, the alkene proton, on going from the chair to the twist-boat conformation. The proton is more deshielded when the molecule lies in the chair conformation. An examination of the structure would seem to suggest that this is due to the differing number of van der Waals interactions between conformers. "

good!

== Epoxide (0.05) ==

Very detailed discussion of the crystal structures. Very nice!

== NMR (0.05) ==

== Optical Rotation and TS (0.35) ==

Good section!

"Enantiomeric Excess Calculations - Conclusions"
nice.

== QTAIM and NCI (0.10) ==

Talk:Mod:organictg1412

2015-03-03T11:25:41Z

Rea12: /* Comments */

= Comments =

== Cyclopentadiene (0.20) ==

Good intro.

"The Exo product is lower in energy, and is the thermodynamic product. Ie, height of the transition state barrier is not a determining factor in its formation."

punctuation...

"Dimer 1 energies"

Try to label your tables and graphs with exo and endo, in addition to just dimer 1/2.

"and closer to the desired 109.5 of sp3, so is less unstable"

minor typo

good explanation

== Taxol (0.25) ==

Good explanation of atropisomerism

"It is fairly deshielded due to the anisotropy of double bonds[CITATION NEEDED]-"

Yes, a simple model explains that. The electron density is in the pi orbitals, which are further away than the sigma orbitals, and additionally the electron density for pi-bonds is located between two atoms - rather than located on the atoms themselves. Therefore an "sp2 proton" has less electron density than an "sp3 proton". Draw it out to get a better understanding.

"However, the match with literature (1.38, the most deshielded value for methyl proton sets in literature) is poor. the remaining two sets of methyl proton shifts are in somewhat acceptable agreement with literature"

Yeah, it's mainly conformation that's to blame.

"Calculated values are in very good agreement to literature values."
Calculated values are in very good agreement WITH literature values.

"Another factor which will provide different results is the solvent choice."
That's correct.

Another big effect is the specific solvent interaction. Choosing a solvent in your calculation is an approximation that doesn't take solvent-molecule into account - e.g. how proton-oxygen interaction changes the electronic properties of your molecule.

"Carbon 11 is bonded to an oxygen atom, so gibes the largest chemical shift. This value is around 10ppm lower than the reported value for the shift. Once again, these discrepancies can be blamed on use of different solvent in the simulation, incorrect basis set approximation and sensitivity in geometry."

Actually no - you're trying to make your life too easy by giving a number of reasons without discussing them in some more detail.
The deviation here is actually easy to explain - that's due to the "heavy" atom effect not being taken in to account.

Along the same line, you completely ignored the info given in the toolbox:
https://wiki.ch.ic.ac.uk/wiki/index.php?title=Mod:toolbox#Analyzing_the_NMR_Chemical_Shift_calculation.5B5.5D.2C.5B6.5D

"From the simulated 1H NMRs above, it seems that 1H NMRs are most sensitive to changes in chemical shifts since the calculated differences vary dramatically from literature values."

dramatically is a very unscientific term.

"Literature values could not be found for twist boat conformation. However, given that the energies between this twist boat and the chair for isomer 18 are very close in energy, I would expect.."

No use of personal pronouns please ("I").

"This supports the idea that they are fluctional in ambient conditions, and we are expected to observe both at equilibrium. "
That's a very good discussion. Nicely done!

"Since this isomer has two conformers which are readily fluctuating, the reported literature values for this isomer may contain peaks which are undefined as a result of an overlap of two NMRs, for each conformer. "

To be nit-picking here, the resulting NMR would not exactly be an overlap of two spectra - because the conformers would not in actuality exist. The spectra would rather be the result of a molecule that undergoes constant conformational change between two theoretical extremes, i.e. two fixed conformational structures.

That is pretty the same that you said, yes - with an important difference: An "overlap of two spectra" is something that is okay to say when talking in a discussion because everyone will know what you mean. But for a report you need to pay a bit more attention to describing things in an exact manner.

== Epoxide (0.05) ==
Nice graphics.

Good explanation on the Shi catalyst.

For the Jacobsen you could have gone into a bit more detail e.g. in how you know that there is repulsive force between the tertiary butyl groups.

Otherwise good section.

== NMR (0.05) ==
good.

== Optical Rotation and TS (0.35) ==

OR:
Please tabulate the data you find for OR. It's difficult to compare the different values reading them from the text. The value of "7.54%" is not very meaningful, especially if you find that by modelling the molecule twice you introduce an error of ~1%. Try using absolute differences instead.

A quick search by reaxys showed that the reported ORs lie between 90° and 140°, so the literature you use is just one among many and it might be sheer coincidence that thee values agree reasonably well.

You also could have discussed the exactness of the calculation in a bit more detail, i.e. values of alpha below/above 100° (see Toolbox)

Overall a bit more discussion on the optical rotation would have been nice. You put a lot of effort into this, but the discussion doesn't always reflect this, I'm afraid.

Transition state: again please tabulate your data.

And it's good that you mention the formulas you used, but it's really difficult to read them.
Try putting them into a text box or at least into a separate line.

== QTAIM and NCI (0.10) ==
Very good.

== final note ==

Try to write more scientifically. Do not use personal pronouns ("I") or words that are not emotionally neutral - such as "dramatically", "extremely" etc. What you define as "extreme" vs what someone else defines as "extreme" might be a difference like day and night. In the end, the definition of such words comes down to personal preferences and personal experiences, and either is inappropriate in a scientific text and should be avoided.

You also have a few left-overs like "[INSERT DIAGRAM]" in your text. That doesn't really matter too much, but it implies you may not have proof-read your text sufficiently. ;)

Altogether that's a well-done report but you need to pay some more attention to detail.

Talk:RG1712

2015-03-03T11:23:46Z

Rea12: /* Comments */

= Comments =

== Cyclopentadiene (0.20) 100% ==

Good intro.

"Each program possesses its own distinctive energy scale and so in order to ensure consistency the same program must be used for all calculations."

nice!

"Energies of Molecules 1 and 2 " "exo, endo"

Please try to be consistent with your labels in graphs and tables. Use one label - or both.

== Taxol (0.25) 99% ==

Nice section.

Why didn't you discuss the angles for the hyperstable olefins a bit more? What do those values mean? How are they different between Olefine and alkane? Why/how do they influence the total energy?

Nice extra effort on analysing the different conformations for molecule 17 and 18!

Table 12 - very nice discussion!

"One point of note however is the difference in the shift of atom number 26, the alkene proton, on going from the chair to the twist-boat conformation. The proton is more deshielded when the molecule lies in the chair conformation. An examination of the structure would seem to suggest that this is due to the differing number of van der Waals interactions between conformers. "

good!

== Epoxide (0.05) 100% ==

Very detailed discussion of the crystal structures. Very nice!

== NMR (0.05) 100 % ==

== Optical Rotation and TS (0.35) 100% ==

Good section!

"Enantiomeric Excess Calculations - Conclusions"
nice.

== QTAIM and NCI (0.10) 100% ==

Talk:RG1712

2015-03-03T11:22:21Z

Rea12: /* Optical Rotation and TS (0.35) */

= Comments =

== Cyclopentadiene (0.20) 100% ==

Good intro.

"Each program possesses its own distinctive energy scale and so in order to ensure consistency the same program must be used for all calculations."

nice!

"Energies of Molecules 1 and 2 " "exo, endo"

Please try to be consistent with your labels in graphs and tables. Use one label - or both.

== Taxol (0.25) 99% ==

Nice section.

Why didn't you discuss the angles for the hyperstable olefins a bit more? What do those values mean? How are they different between Olefine and alkane? Why/how do they influence the total energy?

Nice extra effort on analysing the different conformations for molecule 17 and 18!

Table 12 - very nice discussion!

"One point of note however is the difference in the shift of atom number 26, the alkene proton, on going from the chair to the twist-boat conformation. The proton is more deshielded when the molecule lies in the chair conformation. An examination of the structure would seem to suggest that this is due to the differing number of van der Waals interactions between conformers. "

good!

== Epoxide (0.05) 100% ==

Very detailed discussion of the crystal structures. Very nice!

== NMR (0.05) 100 % ==

== Optical Rotation and TS (0.35) ==

Good section!

"Enantiomeric Excess Calculations - Conclusions"
nice.

== QTAIM and NCI (0.10) ==

Talk:RG1712

2015-03-03T11:22:07Z

Rea12: /* Epoxide (0.05) 100% */

Talk:RG1712

2015-03-03T11:21:42Z

Rea12: /* NMR (0.05) */

= Comments =

== Cyclopentadiene (0.20) 100% ==

Good intro.

"Each program possesses its own distinctive energy scale and so in order to ensure consistency the same program must be used for all calculations."

nice!

"Energies of Molecules 1 and 2 " "exo, endo"

Please try to be consistent with your labels in graphs and tables. Use one label - or both.

== Taxol (0.25) 99% ==

Nice section.

Why didn't you discuss the angles for the hyperstable olefins a bit more? What do those values mean? How are they different between Olefine and alkane? Why/how do they influence the total energy?

Nice extra effort on analysing the different conformations for molecule 17 and 18!

Table 12 - very nice discussion!

"One point of note however is the difference in the shift of atom number 26, the alkene proton, on going from the chair to the twist-boat conformation. The proton is more deshielded when the molecule lies in the chair conformation. An examination of the structure would seem to suggest that this is due to the differing number of van der Waals interactions between conformers. "

good!

== Epoxide (0.05) 100% ==

Very detailed discussion of the crystal structures. Very nice!

"Enantiomeric Excess Calculations - Conclusions"
Excellent section.

== NMR (0.05) 100 % ==

== Optical Rotation and TS (0.35) ==

== QTAIM and NCI (0.10) ==