VIBRATIONAL ANALYSIS OF SUBSTITUTED ANILINES, ANISOLES AND ANISIDINES .1. VIBRATIONAL-SPECTRA AND NORMAL COORDINATE ANALYSIS OF SOME NITRO-COMPOUNDS

The Fourier transform infrared spectra of o-, m- and p-nitroanilines, o-, m- and p-nitroanisoles and 2-nitro-p-, 4-nitro-o- and 5-nitro-o-anisidines along with the Fourier transform far-infrared spectra of the nitroanilines, p-nitroanisole and the nitroanisidines were recorded. The Raman spectra of m- and p-nitroanilines, p-nitroanisole and nitroanisidines were also measured. A normal coordinate analysis was carried out for the in-plane vibrations of these molecules using a 63-parameter modified valence force field. The force constants were refined in an overlay least-squares technique employing 277 frequencies of the molecules. Unambiguously vibrational assignments were made using potential energy distributions and eigenvectors.