A spectroscopic study of some organic free radicals

Abstract

Several organic compounds which contain an unsaturated carbon-sulphur bond and amino or hydrazino groups have been x-irradiated at room temperature and at 105°K. Electron spin resonance has been used to identify the radical products of irradiation. The unsaturated carbon-sulphur bond is found to be resistant to irradiation damage, which generally occurs at another site in the molecule. In thiosemicarbazide and related compounds the major products of irradiation are nitrogen-centred π radicals and the structure of one such radical has been fully determined. In sodium diethydithiocarbamate, which has a delocalised Π-electron system the ionic products of irradiation are stabler and the radical cation has been characterised. Upon irradiation at room temperature however, the molecule undergoes structural deformation and the extended π-structure is destroyed. Mechanisms for the radiation damage which explain the observed products have been discussed.