Overtone spectra of aniline derivatives

Abstract

Overtone spectra of 2-ethylaniline, N-methylaniline, N-ethylaniline, N,N-dimethylaniline and N,N-diethylaniline have been studied in 2500-15 000 cm-1 region. Vibrational frequency and anharmonicity constants for aryl/alkyl C-H stretch and N-H stretch vibrations have been determined. The effect of substitution of C2H5 group on the ortho position in the ring and CH3/C2H5 at the positions of the H-atom in NH2 group has been studied in these molecules. It is noted that the aryl C-H stretching frequency and the N-H stretching frequency is appreciably increased due to the replacement of H in NH2 group by CH3/C2H5. These experimental observations are well supported by theoretical calculations for charge density on N-atom using molecular orbital AM1 method. © 2003 Elsevier B.V. All rights reserved.