Experimental and theoretical studies on bis(chlorocarbonyl)trisulfane, ClC(O)SSSC(O)Cl

Bis(chlorocarbonyl)trisulfane, ClC(O)SSSC(O)Cl, was prepared by the reaction of (CH3)2CHOC(S)SC(S)OCH(CH3)2 and SO2Cl2 at 65°C. The compound was characterized and identified by vibrational spectroscopy, GC–MS, matrix isolation and photochemical studies as well as by quantum chemical calculations. Matrix photochemical studies and vibrational spectra were interpreted in terms of the presence of three forms with syn-gauche-gauche-syn (I), syn-(−)gauche-gauche-syn (II), and syn-gauche-gauche-anti (III) conformations. The syn and anti conformations correspond to the orientation of each CO group with respect to the adjacent SS bond, while the gauche form refers to the conformation around each of the SS bond. This result is in agreement with quantum chemical calculations which predict structures II and III to be higher in energy than conformer I by about 1.51/0.98 and 2.52/2.84kcal/mol for the B3LYP/MP2 approximations in combination with the 6-31+G* basis set. An assignment of the liquid IR and Raman spectra is proposed for ClC(O)SSSC(O)Cl, as well as the possible mechanisms of the photolysis in Ar and N2 matrices. The presence of ClC(O)SSCl as a photochemical product opens the possibility of further investigations for this family.