CESIUM DIMETHYLTETRACHLOROPLATINATE, A COMPLEX OF DIMETHYLPLATINUM(IV) - SYNTHESIS AND SOME REDUCTIVE ELIMINATION-REACTIONS INVOLVING THE MONOMETHYLPLATINUM(II) COMPLEX AS AN INTERMEDIATE

The reduction of Pt(IV) complexes followed by the oxidative addition o f dimethyl sulfate to Pt(II) affords Cs(2)PtMe(2)Cl(4), a complex of d imethylplatinum(IV). On treatment with such nucleophiles as Cl-, Br-, I-, and PtCl42- in aqueous solutions at 368 K this complex undergoes r eductive elimination to give MeX and Pt(II)Me as a transient species. The latter is further converted to methane upon protolysis, whereas in the presence of an oxidant (Na2PtCl6) it gives rise to the Pt(IV)Me s pecies. The kinetics of decomposition of Cs(2)PtMe(2)Cl(4) in aqueous HCl-KCl systems (2 M or 3 M in Cl-; [Pt(IV)Me(2)]<<[Cl-]) were studied . The reaction takes place as an S(N)2 attack of X(-) on the carbon at om of a methyl group located with the trans position with respect to t he aqua-ligand of the [PtMe(2)Cl(3)(H2O)](-) complex.