Talk:Mod:HAS1503
Cope Rearrangement
Presentation:
Data tabulated. Images generally good. Have numbered images and tables, and given them appropriate legends. However, could have shown animations – particularly for illustrating the imaginary frequencies for TS. File sharing would be useful, particular where things didn’t work as expected.
Results:
Anti and gauche conformations considered. Thorough thought to the contributing stabilising factors such as vdW interactions, MO orbitals etc. – v.good. It’s difficult to see why your results don’t correlate with those in the appendix without submission of files.
Anti 2 conformer – 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 – good. Included IR spectra and thermochemical data. Calculations at 0K?
Chair/boat TS- Results for chair good. Would’ve been useful to include files for boat optimization so could see what was going wrong. Were you optimizing to a minimum not TS? IRC calculations for chair good, considered different approaches. Could have calculated the activation energy for the chair, even without data for the boat.
Understanding:
Very good introduction to the topic no conclusion though. Steps taken generally clear. It’s a shame you didn’t use file-share, so we could see what went wrong with the calculations.
Diels Alder
Presentation:
Data tabulated. MOs presented well. Again, animations for the vibrational frequencies would be good.
Results:
HOMO and LUMO of cis-butadiene good – correct symmetries assigned. MOs for ethylene? Good explanation of HOMO/LUMO interactions. Would you expect the HOMO TS to be symmetric?
Analysis of C-C distances shows C-C distance of bond forming is less than twice the VdW radius of carbon, therefore suggests bond forming – good!
Limited results for the ‘Regioselectivity of the Diels alder reaction’ section.
Understanding:
Very good introduction again. HOMO/LUMO interactions and allowed/forbidden reactions well-understood. I am guessing you were running out of time towards the end, as it begins to feel rushed and is missing the last section.