Experimental and theoretical study of two novel thioperoxides: Methoxycarbonylsulfenyl acetate, CH3OC(O)SOC(O)CH3, and methoxycarbonylsulfenyl trifluoroacetate, CH3OC(O)SOC(O)CF3

Two novel thioperoxides, methoxycarbonylsulfenyl acetate, CH3OC(O)SOC(O)CH3, and methoxycarbonylsulfenyl trifluoroacetate, CH3OC(O)SOC(O)CF3 were generated through heterogeneous reactions and studied by photoelectron spectroscopy (PES) and quantum chemical calculations. The prevailing components in the gas phase may be the gauche (sp–sp–sp) conformers, which exhibit gauche conformation around the SO bond and the CO bonds syn to the SO bond. The torsional angle δCSOC of CH3OC(O)SOC(O)CH3 and CH3OC(O)SOC(O)CF3 are theoretically predicted to be 73.0° and 71.9° (MP2/6-311++G(d,p)), respectively. The first vertical ionization energies of CH3OC(O)SOC(O)CH3 and CH3OC(O)SOC(O)CF3 are determined to be 9.49 and 10.17 eV, respectively. According to the experimental results and theoretical analysis, the HOMOs of these two molecules both correspond to the electrons mainly localized on the sulfur 3p lone pair MOs.