Talk:Mod:catherinelu2

Introduction Very short general introduction. Be careful: Gaussview is a software that allows you to visualize the molecules, the molecular orbitals for example and to interact with Gaussian – Gaussian actually does the calculation not Gaussview.

Cope rearrangement Good introduction to this exercise. All conformers were successfully identified. Good discussion about their relative energy. Frequency calculation correctly interpreted. Good discussion about the different methods to optimize a TS. Chair and Boat structures successfully identified with the different methods proposed. IRC calculation successfully done and interpreted. Good conclusion about the preferred mechanism.

Diels-Alder How do the forming bonds compare to 2x the van der Waals radius. This indicates the two fragments are interacting at the TS, although the bond length is longer that the equilibrium bond distance of sp3-sp3 carbon suggesting it is not fully formed (corroborating that this is likely to be a TS without even looking at the imaginary mode). The reported activation energies seem on the large size, these are definitely TS-reactants (not TS-products)? “In the exo form, the oxygen π* orbitals are orientated upwards, away from the π* C=C orbitals, reducing the unfavourable repulsions and giving the endo product the lowest free energy.” By this reasoning the endo would be higher in energy. You show a diagram of secondary orbital overlap, but is there anything in your calculation that shows it? (http://pubs.acs.org/doi/abs/10.1021/ar0000152) Other references given.