Matrix Photochemistry of the Chlorocarbonyl Sulfenyl Compounds ClC(O)SY, with Y = Cl or CH3

Abstract

The photochemistries of the molecules ClC(O)SCl and ClC(O)SCH3 (in both their normal and perdeuterated forms) isolated in solid Ar or N2 matrixes at 15 K have been investigated. On the basis of evidence of the IR spectra of the matrixes, the products of irradiation with broad-band UV−visible light (200 ≤ λ ≤ 800 nm) were identified, thereby revealing quite different photochemical behaviors for the two molecules. ClC(O)SCl is subject to multichannel changes that include interconversion of the syn and anti rotamers, photodecomposition to give CO and SCl2, formation of the hitherto unknown radical ClC(O)S•, and subsequent decomposition of this radical to give either the ClCO• radical or the OCS molecule. By contrast, ClC(O)SCH3 decomposes in two steps, the first consisting of fragmentation to CO and ClSCH3, and the second entailing detachment of a hydrogen atom from the methyl group of ClSCH3 with the formation of the molecular complex H2CS···HCl. The IR spectra of both the ClC(O)S• radical and H2CS···HCl have been interpreted with reference to the spectra predicted by ab initio and density functional theory methods.