Synthesis, characterization and gas phase conformational properties of chlorodifluoroacetylsulfenyl chloride, CF2ClC(O)SCl

Abstract

The simple chlorodifluoroacetylsulfenyl chloride species, CF2ClC(O)SCl, has been synthetized for the first time by the reaction between chlorodifluorothioacetic acid, CF2ClC(O)SH, and elemental chlorine. This sulfenyl carbonyl derivative has been exhaustively characterized by multinuclear (19F and 13C) NMR, FTIR, and FT-Raman spectroscopies. Conformational properties were investigated using gas-phase infrared and liquid Raman spectroscopy techniques, in combination with quantum chemical calculations at the B3LYP/6-311+G(3df) level of approximation. The coexistence of two forms, characterized by two orientations (gauche and syn) of the C-Cl single bond of the –CF2Cl group with respect to the C=O double bond, is confirmed in the gas phase. The synperiplanar (syn) conformation in the sulfenylcarbonyl chloride moiety is characterized by the C=O double bond and the S-Cl single bond adopting a mutual synperiplanar orientation. The lowest energy conformation is the gauche-syn, with the second anti-syn form higher in energy by around 1.0 kcal/mol.