(Alkyl) platinum(II) intermediates in CH activation by platinum complexes in aqueous solution

Abstract

Generation of [PtMeCl 3] 2−, the putative first intermediate in activation of methane by Pt II/Pt IV, is achieved by reduction of Na 2[PtMeCl 5] in THF with cobaltocene. The monomethyl dianion is obtained, not in pure form but combined with [PtMe 2Cl 2] 2− and [PtCl 4] 2− as the mixed cobalticenium salt. [PtMeCl 3] 2− reacts with water to liberate CH 4; in an acidic aqueous solution of [PtCl 6] 2−, it undergoes competitive protonolysis and oxidation to [PtMeCl 5] 2−. The relevance of this chemistry to alkane activation by platinum in aqueous solution is discussed.