Molecular complexes. Part 11.—Some comments on electrostatic and steric effects in the formation of acrylonitrile + aromatic complexes

Abstract

The interactions between acrylonitrile and various alkylbenzenes have been studied by ¹H n.m.r. at several temperatures. The equilibrium quotients, K_x, and aromatic induced shifts, Δ_c, at a particular temperature, as well as ΔG°, ΔH° and ΔS° appear superficially to show an almost random variation with the degree of alkylation of the aromatic nucleus. However, the data have been rationalized in a quantitative fashion by considering that the reaction and complex parameters are governed by three factors. These are due to an intermolecular electrostatic effect and two steric features of the aromatic compounds due to the “blocking” and “trapping” effects of the alkyl substituents.