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Talk:Mod:jd1910

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Introduction

Very good.

Cope rearrangement

Good introduction. Successful optimisations of the different conformers. “The energy is seen to be higher with the higher basis ­set.”: be careful with negative numbers, using DFT/6­31g method the energy is ­234.61 which is LOWER than ­-231.69. Good interpretation of the frequency calculation. Good presentation of the different methods used to optimise the TS. TS optimisations successful. Good interpretation of the IRC calculations and good conclusion about the preferred mechanism.

(DO CALCULATIONS AT 0 K...?)

Diels­Alder cycloaddition

The HOMO at the TS of ethene + buadiene is antisymmetric wrt the Cs plane. The fragment orbitals are of the same symmetry. What do the two lowest vibrational modes tell you about the curvature of the PES around the TS. Notice how the imaginary mode preserves symmetry while the lowest real mode breaks it, suggesting the reaction is concerted (as confirmed by the IRC). What do the matching symmetries of the two fragments indicate about the reactivity. Note the Woodward ­Hoffmann rule: "A ground ­state pericyclic change is symmetry­allowed when ..." https://en.wikipedia.org/wiki/Frontier_molecular_orbital_theory). Can you label the SOO interactions in the hypothetical diagrams in the computed MO diagrams? Extra discussion on this: <http://pubs.acs.org/doi/abs/10.1021/ar0000152>