Structure Elucidation of 6-t-Butyl-6-phenylpentathiane Monoxides by X-ray Crystallography and DFT Calculations

Abstract

Abstract 6-t-Butyl-6-phenylpentathiane was oxidized with trifluoroperacetic acid (CF3CO3H) or dimethyldioxirane (DMD) at -20 °C. Oxidation with CF3CO3H yielded pentathiane 3-oxide as the main product, whereas that of DMD gave 1- and 3-oxides. The structures of 1- and 3-oxides were finally determined by X-ray crystallographic analysis. DFT calculations of the NMR chemical shifts were performed on the chair and twist forms of the pentathiane and sixteen isomers of the monoxides with the GIAO method at the B3LYP/6-31G* level. The calculated chemical shifts were verified to be in practical agreement with the experimental data of the pentathiane and the isolated 1- and 3-oxides.