A cooperative pathway for water activation using a bimetallic Pt 0 -Cu I system.

A mixture of the platinum(0) complex [Pt(Pt Bu3 )2 ] and tetrakis(acetonitrile)copper(i) hexafluorophosphate in acetone activated a water molecule and gave the hydride platinum(ii) complex [PtH(CH3 CN)(Pt Bu3 )2 ]PF6 , 1, and the hydroxide Cu(i) species. The crystal structure of complex 1 was determined by X-ray crystallography, indicating a distorted square planar geometry around the platinum center. Although three possible mechanisms are proposed for this transformation, monitoring of the reaction using NMR spectroscopy at low temperature reveals that a cooperative pathway involving formation of a Pt0 -CuI dative bond complex is the most probable pathway. The hydride platinum complex 1 is stable in acidic and neutral conditions but undergoes intramolecular C-H activation in the presence of pyridine. Monitoring of the reaction using1 H and31 P NMR spectroscopy shows that a cyclometalation reaction of one of the phosphine ligands is followed by displacement of a second phosphine ligand by pyridine to give the cyclometalated platinum(ii) complex, [Pt(κ2 PC -Pt Bu2 CMe2 CH2 )(py)2 ], 4. The structure of 4 in solution and solid state phases was determined using NMR spectroscopy and X-ray crystallography, respectively.