Talk:Mod:LBinfieldModule3

Introduction

No general introduction.

Cope rearrangement All conformers successfully optimised. Good comment about their relative energy. “I confirmed that all the vibrations were 'real' by ensuring that they were all positive” Why did you need to check that? What does it mean? Same comment about the transition state optimisations: how did you check they were TS? Did you run a frequency calculation and search for one imaginary frequency? Good interpretation of the IRC calculations. Good comparison with the experimental results and good conclusion about the preferred mechanism.

Diels-­Alder cycloaddition

How do the forming distances compare to 2x C vdW distance which indicates the limit at which the two electron clouds start interacting? The fact it is shorter than this but longer than the C­C equilibrium distance shows the structure is between reactant and product, i.e. a TS. The lowest real frequency is symmetry breaking, suggesting that this motion is uphill in energy (and would not occur).

Orbital images of maleic anhydride + cyclohexadiene should be rotated so that we can see the interfragment region more easily. Can you draw hypothetical diagrams to show the SOO interactions to see how they are present/absent in the computed MO diagrams? Extra discussion on this: <http://pubs.acs.org/doi/abs/10.1021/ar0000152>

Some explanations are unclear (what factors would make the calculation more accurate?) Also, bond lengths are at best only accurate to 3 decimal places.