Density functional theory prediction of geometry and vibrational circular dichroism of bridged triarylamine helicenes

Ab initio calculations of conformational stabilities, IR absorption and vibrational circular dichroism spectra of four bridged triarylamine helicenes are reported, using DFT/B3LYP/6-31G(d, p) method. We find that the bridged triarylamine helicenes in M configuration are more stable than the helicenes in P-configuration (Scheme 1). The two atropisomers, M and P of the helicene 1 and 2 as well as the two diastereomers of the camphanate derivatives, 3 and 4, show no significant dissimilarities in the IR absorptions, but the VCD spectra of these molecules are the characteristic feature of the particular isomer and can be used for identification of absolute configuration of these chiral molecular systems, along with experimentally obtained VCD spectra.