Molecular complexes. Part I. Proton magnetic resonance studies of complexes of nitroform with benzene and with some methylbenzenes

Abstract

Equilibrium constants for the formation of complexes of nitroform with benzene and with some methylbenzenes are determined from the nitroform proton resonance shifts and their dependence on the concentration of the aromatic in nitroform–aromatic–cyclohexane systems. The difference in proton shielding in the free and complexed nitroform is determined and used to calculate the separation of the nitroform hydrogen and the plane of the aromatic ring in each complex. The values obtained compare favourably with those estimated from hydrogen and aromatic Van der Waals radii.