Methyl-group motions and potential in t-butyl cyanide

Abstract

The motions and potential function for the methyl groups in t-butyl cyanide have been studied using neutron scattering measurements. Torsional frequencies, reorientation frequencies and thermodynamic data are consistent with a three-fold potential with barrier height ca. 18 kJ mol^–1. This means that, contrary to the conclusions of a number of n.m.r. studies of such systems, the methyl-group reorientations are much slower than, and are decoupled from, the whole-molecule reorientations about the three-fold axis.