Experimental and calculated vibrational and electronic circular dichroism spectra of 2-Br-hexahelicene.

The vibrational circular dichroism (VCD) and IR absorption spectra of the (-)-enantiomer of 2-Br-hexahelicene have been measured and interpreted by use of density functional theory (DFT) calculations. From time dependent DFT calculations we also interpret the electronic circular dichroism (ECD) spectra of 2-Br-hexahelicene. We compare the calculated IR, VCD and ECD spectra to the corresponding calculated data of hexahelicene and 2-aza-hexahelicene; for the last compound we also recorded the ECD spectra. Comparison with current literature allows an insight to be gained on the meaning and usefulness of some VCD features.