Vibrational spectra and normal mode calculations of p‐toluidine and p‐nitrotoluene molecules

Abstract

Raman and infrared spectroscopic studies of p-toluidine and p-nitrotoluene molecules have been performed. In normal mode calculations, the force field has been constructed by the local interaction approximation.

Vibrational spectra of substituted toluenes – 4-amino-3-bromotoluene and 5-amino-2-bromotoluene

“…Similar spectral investigations on isomers of toluidine, bromotoluene, and bromoaniline were reported by earlier workers (1,(4)(5)(6)(7). The vibrational spectra of certain isomers of aminofluorotoluene (8, 9) and aminochlorotoluene (10) were already reported while those of aminobromotoluene were, so far, not reported and analysed.…”

“…Primary aromatic amines absorb strongly in the region 1250-1340 cm-', due to stretching of the phenyl carbon-nitrogen bond ( 13). The medium intense absorption at 1270 cm-' (1266 cm-') in A is taken to represent the C-NH, stretching mode in conformity with a similar vibration reported at 1278 cm-' in aniline (I), 1265 cm-', 1265 cm-', 1273 cm-' in bromoanilines (7), 1275 cm-', 1260 cm-', 1289 cm-' in dibromoanilines (14), 1273 cm-' in p-toluidine (4) and also in a number of other substituted anilines (1). In B, where the two "light" substituents NH, and CH3 are vibrating out-of-phase in the meta position, the C-X stretching vibration, mode 76, corresponding to one of the substituents will be observed below 1000 cm-' ( I , 1 I).…”