An investigation into the structure and conformation of N-(4-bromophenyl)[15N]maleimide by 1H nuclear magnetic resonance spectroscopy of liquid crystalline solutions

Abstract

The set of dipolar couplings obtained by analysis of the ¹H n.m.r. spectrum of N-(4-bromophenyl)[¹⁵N]maleimide are used to investigate the conformation of the molecule. It is shown that the conformation derived previously from interproton dipolar couplings alone, and which has coplanar CN bonds, is incorrect. The dipolar couplings to ¹⁵N in addition to those between protons do show that inversion about nitrogen takes place, but cannot determine the minimum energy configuration of the molecule.