Preparation of tertiary arsine sulphides. Crystal and molecular structures of the adduct of AsMePh2S and P(NMe2)3O

Abstract

Several tertiary arsine sulphides have been prepared by the action of sulphur on tertiary arsines in C₆H₄Cl₂-o at high temperature. AsPh₃ and AsMePh₂ react with S₂Cl₂ to produce AsPh₃Cl₂ and AsMePh₂Cl₂, respectively, and no tertiary arsine sulphide, contrary to an earlier report. The reversible transfer of sulphur from AsPh₃S to AsMePh₂ occurs readily in solution. Methyldiphenylarsine sulphide, a liquid at room temperature, forms a 1 : 1 crystalline adduct with P(NMe₂)₃O. The structure of the adduct has been determined from 1 913 independent diffractomer data and refined to a final R factor of 0.050. The crystals are orthorhombic, space group Pbca with a= 11.866(3), b= 17.134(7), c= 22.657(2)Å, and Z= 8. There were no interactions between the two components other than normal van der Waals forces. Bond lengths and angles appeared normal with As–S 2.069(3), As–C(methyl) 1.932(10), As–C(phenyl) 1.947(average), P–O 1.461(7), and P–N 1.649 Å(average).