Hydroxo and Oxo Complexes of Platinum( II ) Stabilized by Phosphanes: Synthesis and Characterization − X‐ray Structures of cis ‐[L 2 Pt(μ‐OH)] 2 (NO 3 ) 2 (L = PMe 2 Ph, PMePh 2 ) and [{ cis ‐(PMe 2 Ph) 2 Pt} 3 (μ‐O) 2 ]Cl 2

The dinuclear hydroxo complexes cis ‐[L 2 Pt(μ‐OH)] 2 (NO 3 ) 2 (L = PMe 2 Ph and PMePh 2 ) have been characterized by single‐crystal X‐ray analysis, and their reactivity towards chloride ions has been investigated. Reaction of cis ‐[L 2 Pt(μ‐OH)] 2 X 2 (L = PMe 3 , PMe 2 Ph; X = NO 3 − , ClO 4 − ) with (NEt 4 )Cl·H 2 O or (AsPh 4 )Cl, in a 1:2 molar ratio, afforded a mixture of cis ‐[L 2 PtCl 2 ] and [{ cis ‐L 2 Pt} 3 (μ‐O) 2 ] 2+ in ca. equimolar amounts. The trinuclear oxo compounds, separated by fractional crystallization of the reaction mixtures, were fully characterized by spectroscopic techniques, and the derivative [{ cis ‐(PMe 2 Ph) 2 Pt} 3 (μ‐O) 2 ]Cl 2 was also characterized by X‐ray diffraction methods. Under the same experimental conditions, the structurally analogous hydroxo complex, stabilized by the less basic and more hindered PMePh 2 ligand, reacted with Cl − to give cis ‐[(PMePh 2 ) 2 PtCl 2 ] as the only isolable species. The 31 P NMR spectroscopic analysis of the reaction mixtures allowed the detection of a moderately stable product, which is most likely to be the neutral hydroxo complex cis ‐[L 2 PtCl(OH)]. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2002)