Talk:Mod:pikachu
Cope Rearrangement
Presentation:
Data clearly tabulated. Jmol used appropriately. Animations of vibrational frequencies for TS would assist report. Good use of file-sharing.
Results:
A number of anti and gauche conformers considered. Noted gauche 1 as the lowest energy conformer; however visualisation and comparison of its energy with the appendix suggests it is in fact gauche 3. However the fact it is lowest in energy is explained very well with use of vdW interactions, MOs (diagrams v.useful) and hyperconjugation.
Reoptimised a number of isomers using B3LYP. This included reoptimising anti2 (as asked in the script), however you’ve named it anti 3! Note, you cannot compare energies between different methods (HF and DFT) - they’re calculated on different energy scales! Differences in geometry well considered. Frequency analysis for anti 3 (actually anti 2) carried out, inc. IR spectra and thermochemical data for 0K and 298K – v. good!
Chair/Boat: Results v. good. Have additionally investigated optimising the boat TS using QST3 – great! IRC carried out for chair and boat. Activation energies calculated for chair and boat for both levels of theory. Results at 298K?
Understanding:
Very good introduction and conclusion (particularly justifying why the chair TS is lower in energy). Steps taken clearly stated, and reasons why explained. Good understanding of levels of theory, methods, keywords etc. Only slight confusion is the difference of naming in the report to the appendix.
Diels Alder
Presentation:
Same as above.
Results:
MOs of reactants good, and correct symmetries assigned. Good understanding of HOMO/LUMO interactions in TS. Are images muddled for the TS? As the assigned symmetry for the HOMO is symmetric, but the assigned diagram for this is anti-symmetric . Correctly noted C-C bond forming distance is < 2 x vdW radius of C, therefore implying the bond is forming.
Endo/exo: Correctly noted endo is lower in energy. Considered why this is so using steric reasoning and the secondary orbital overlap effect . Has looked to see if this effect is apparent in their results – v.thorough. Additionally have carried out IRC calculations as further work.
Understanding:
Very good introduction and conclusion. Excellent explanation of HOMO/LUMO interactions and allowed/forbidden reactions. Good use of (and comparison to) primary literature throughout. Suggested improvements to the study, such as using a higher level of theory, are provided.