Stabilization and photochemical reactions of thiyl radicals in glassy matrices at 77 k

Abstract

The possibility of stabilization of thiyl radicals formed during the photolysis of thiol solutions at a wavelength λ = 253.7 nm in glassy matrices at 77 K was shown by means of electron spin resonance and UV spectroscopy. The main alternative process is the formation of adducts RSS(H)R (R  CH 3, C 2H 5, i-C 3H 7, tert-C 4H 9) in thiol self-associate. Stabilized alkyl-thiyl radicals are able to enter into photochemical reactions leading to C—C or C—H bond rupture in the position β to the sulphur atom. The ability of stabilized thiyl radicals to enter into photochemical reactions is suggested as the reason for their low concentrations in dilute thiol solutions in alcohol and hydrocarbon matrices subjected to photolysis at λ = 253.7 nm at 77 K.