The Trifluoromethyl Sulfinyl and Oxathiyl Radicals

Two hitherto unreported sulfur-centered radicals CF3SO center dot and CF3OS center dot were generated in the gas phase through high-vacuum flash pyrolyses of sulfoxide CF3S(O)X (X=CF3, Cl, PhO) precursors. The CF3OS center dot molecule is the first experimental example that constitutes an oxathiyl radical. It was isolated and characterized by combining matrix-isolation IR and UV/Vis spectroscopy with quantum chemical computations up to the UCCSD(T)-F12/cc-pVTZ-F12 level of theory. Upon UV light irradiation (254 or 266nm), sulfinyl radical (CF3SO center dot) isomerizes to oxathiyl radical (CF3OS center dot) in cryogenic noble gas matrices (Ar and Ne). Natural population analyses at the BP86/def2-TZVPP//UCCSD(T)-F12/cc-pVTZ-F12 level suggest that the spin density in CF3OS center dot is mainly localized on the sulfur atom (0.86), whereas, in CF3SO center dot the spin density is almost equally distributed on the sulfur (0.55) and oxygen (0.43) atoms.