Conformation of diaryl sulphides with intramolecular sulphur(II)—oxygen interaction: an X-ray study of methyl 2-(4-nitrophenylthio)benzoate and 2-diazoacethyl-4′-nitrodiphenyl sulphide

Abstract

The molecular structures of methyl 2-(4-nitrophenylthio)benzoate and 2-diazoacetyl-4′-nitrodiphenyl sulphide have been determined by X-ray diffraction. The skew conformation observed for the ester is favourable to the formation of a sulphur(II)—oxygen(carbonyl) close contact, but unfavourable to sulphur(II)—aryl(nitro) conjugation, as shown by S(II)⋯O (2.701 Å) and S(II)⋯C ar(nitro) (1.780 Å) distances. For the diazo compound exhibiting a distorted twist conformation S(II)…O (2.778 Å) and S(II)C ar(nitro) (1.765 Å) were measured. In the latter case, the extremely long CO distance (1.234 Å) and the very low ν(CO) frequency (1600 cm −1) may be due to both the enolate structure of the COCHN 2 group, and the donor—acceptor interaction between carbonyl—oxygen and sulphur(II) atoms. NoS(II)⋯C −C (diazomethyl) close contact was observed.