The conformation of some nitro-polycyclic aromatic hydrocarbons

Abstract

The Raman spectra of some nitro-polycyclic aromatic hydrocarbons, including 2-nitroanthracene, 7-nitrobenz[a]anthracene, 6-nitrochrysene, 1-nitropyrene, 6-nitrobenzo[a]pyrene, and 6-nitro-7,8,9,10-tetrahydrobenzo[a]pyrene, have been recorded in the frequency region 1100–1700cm−1. The stretching vibrational modes for the nitro group in each of these compounds were assigned based on group frequencies, the measured infrared and Raman spectra, the relative spectral intensities, and the Raman depolarization data. From the measured Raman depolarization data, the orientation of the nitro-substituent with respect to polycyclic aromatic hydrocarbon was determined for each of these compounds except 6-nitro-7,8,9,10-tetrahydrobenzo[a]pyrene. The results were correlated with the direct-acting mutagenicity of the nitro compounds according to the hypothesis suggested by P.P. Fu and his co-workers.