15N–13C spin–spin coupling constants in some aniline derivatives

Abstract

Nitrogen–carbon spin–spin coupling constants in aniline-15N and some of its derivatives have been measured using 13C Fourier transform nmr spectroscopy. Observed values of 1J(15N,13C) in these aniline derivatives are dependent on the nature of the substituent as well as the solvent. Observed values of 1J(15N,13C) in the amino fragment of a number of amine derivatives are linearly related to the corresponding 1J(15N,H) values in these compounds. The 1J(15N,13C) values in these compounds also appear to be related to the N(s)—C(s) bond order. Comparison of observed 1J(15N,13C) values in a number of compounds with those calculated using INDO–MO theory indicate that 1J(15N,13C) in aniline and its derivatives is negative, that is, 1K(N,C) is positive. Observed and calculated 15N–13C spin–spin coupling constants over two and three bonds are also presented.