The oxidation of dimethyl sulphide, trimethylamine, and trimethylphosphine by solvated copper(II) or thallium(III) hexafluorometallates in acetonitrile

Abstract

Dimethyl sulphide, trimethylamine, and trimethylphosphine are oxidized by solvated copper(II) hexafluorophosphate or solvated thallium(III) hexafluorouranate(V) in acetonitrile at room temperature. The reactions are all very similar and spectroscopic studies suggest that the oxidized products are the dinuclear, non-metal cations [Me2SSMe]+, [Me3NNMe2]+, and [Me3PPMe3]2+. The compound [Me3PPMe3][PF6]2 is obtained from the oxidation of PMe3 by diiodine in MeCN, followed by treatment with nitrosonium hexafluorophosphate. Coloured intermediates observed in the reactions of solvated CuII are formulated as redox-active cations [CuLx(NCMe)y]2+, L = SMe2, NMe3, or PMe3, and a generalized reaction scheme is proposed. Keywords: copper(II), thallium(III), acetonitrile, oxidation, fluorometallate.