Oxidation of a Dinuclear Platinum(II) Complex with Hydrogen Peroxide

The oxidation of a dinuclear Pt(II) complex with hydrogen peroxide is described. The dinuclear complex ion [cis-Pt^II-(¹⁵NH₂CH₂CH₃)₂(μ-OH)]₂²⁺undergoes oxidation in aqueous H₂O₂to produce dinuclear Pt(IV) ions of the type [cis-Pt^IV-(¹⁵NH₂CH₂CH₃)₂(OH)₂(μ-OH)]₂²⁺. Following the reaction by using¹⁹⁵Pt NMR spectroscopy and isolation of the major product pOi revealed that oxidation primarily yields a D_2h-symmetry dinuclear compound having a four-membered [formula omitted] ring. However, the fact that the reaction also yields lower symmetry dinuclear Pt(IV) compounds possessing this ring indicates that the oxidation, at least in part, proceeds through an “open-ring” intermediate that allows isomerization to occur. The^l95Pt NMR chemical shifts and ¹J(¹⁹⁵Pt-¹⁵N) values, the latter measured by using both¹⁹⁵Pt and¹⁵N NMR spectroscopies, were used to examine the effects of the four-membered ring and the various ligands on the electronic properties of the platinum ion.