Use molecule (4) as a model of the trans conformation of the chromophore found in rhodopsin. In this model, the methyl group bound to the nitrogen atom of the protonated Schiff ’s base replaces the protein.

(a) Using molecular modelling software and the computational method of your instructor’s choice, calculate the energy separation between the HOMO and LUMO of (4).

(b) Repeat the calculation for the 11-cis form of (4).

(c) Based on your results from parts (a) and (b), do you expect the experimental frequency for the π*←π visible absorption of the trans form of (4) to be higher or lower than that for the 11-cis form of (4)?

Transcribed Image Text:

4 C₁1 I-Z+