Dialkyl sulphoxides as starting materials for the preparation of alkyl-transition-metal complexes. Formation of penta-aquamethylchromium(III) and pentacyanomethylcobaltate(III) salts, and the reduction of methyl radicals by vanadium(II)

Abstract

The penta-aquamethylchromium(III) ion is formed in high yield from the chromium(II)–hydrogen peroxide–dimethyl sulphoxide system in aqueous solution. The methyl-deuteriated analogue has been prepared by the corresponding reaction with [²H₆]dimethyl sulphoxide. The secondary kinetic deuterium isotope effect for the acid-catalysed aquation has been measured. The analogous ‘Fenton reagents’ with pentacyanocobaltate(II) and with vanadium(II) yield the pentacyanomethylcobaltate(III) ion and methane, respectively.