Structure of donor-acceptor complexes—I: Complexes of Lewis acids with amides

Abstract

Complexes of the Lewis acids, sulphur trioxide, antimony (V) chloride, tin (IV) chloride, titanium (IV) chloride and aluminium (III) chloride with formamide, acetamide, benzamide, acetanilide and benzanilide have been isolated. Their infra-red spectra and dipole moment in chloroform and conductances in molten state or in solution in nitrobenzene have been studied for elucidating their structure. It has been indicated by infra-red studies that the structure of amide is greatly influenced due to the coordination of the Lewis acid to the carbonyl oxygen of the amide and with strong Lewis acid, the carbonyl group loses its double bond character. Conductance of the complexes at low concentrations in nitrobenzene and their high dipole moments indicate the ionic nature of the complexes.