Rep:Mod3:Ishouldnotbetrustedwithcomputers

The Cope Rearrangement Tutorial

Hexadiene

Hexadiene can adopt several conformations and all are not of the same energy. In this section, several conformations of hexadiene are modelled and optimised to assess their energies. One Particular conformation is further optimised and analysed to understand TO FINISH

Optimisation of different conformations of hexaniene

3-21G Optimisations

Conformation	Energy (a.u.)	Point group
Anti 1	-231.69260237	C2
Gauche 6	-231.68916020	C1
Anti 2	-231.69253528	Ci

Proof of competion of the optimisations

Anti 1

         Item               Value     Threshold  Converged?
 Maximum Force            0.000033     0.000450     YES
 RMS     Force            0.000006     0.000300     YES
 Maximum Displacement     0.000373     0.001800     YES
 RMS     Displacement     0.000081     0.001200     YES
 Predicted change in Energy=-3.986209D-09
 Optimization completed.
    -- Stationary point found.

Gauche 6

         Item               Value     Threshold  Converged?
 Maximum Force            0.000019     0.000450     YES
 RMS     Force            0.000003     0.000300     YES
 Maximum Displacement     0.000228     0.001800     YES
 RMS     Displacement     0.000077     0.001200     YES
 Predicted change in Energy=-3.556524D-09
 Optimization completed.
    -- Stationary point found.

Anti 2

         Item               Value     Threshold  Converged?
 Maximum Force            0.000060     0.000450     YES
 RMS     Force            0.000010     0.000300     YES
 Maximum Displacement     0.000565     0.001800     YES
 RMS     Displacement     0.000171     0.001200     YES
 Predicted change in Energy=-2.036691D-08
 Optimization completed.
    -- Stationary point found.

6-31G(d) Optimisation of Anti2

Optimisation level	Energy in a.u.	Point Group	Terminal C=C bond length in A	CH-CH2 bond length in A	middle CH2-C2 bond length in A
3-21G	-231.69253528	Ci	1.32	1.51	1.55
6-31G	-234.61173013	Ci	1.33	1.50	1.55

Anti 2

         Item               Value     Threshold  Converged?
 Maximum Force            0.000015     0.000450     YES
 RMS     Force            0.000006     0.000300     YES
 Maximum Displacement     0.000227     0.001800     YES
 RMS     Displacement     0.000083     0.001200     YES
 Predicted change in Energy=-1.557146D-08
 Optimization completed.
    -- Stationary point found. 

Frequency Analysis of Hexadiene in its anti 2 conformation

Low frequencies ---  -55.7193  -24.1625   -7.7453   -0.0006    0.0007    0.0011
 Low frequencies ---   40.8235   73.3254  122.9683