Tris-µ-[bis(diphenylphosphino)methane]-diplatinum(<scp>0</scp>)

Abstract

The synthesis of [Pt2(µ-dppm)3][dppm = bis(diphenylphosphino)methane], either by the reduction of [PtCl2(dppm)] by Na[BH4] in aqueous ethanol, in the presence of 2 mol equivalents of dppm, or by a ligand displacement from [Pt(PPh3)4] by an excess of dppm, is described, and the complex was shown to have a ‘manxane’-type (bicyclo[3.3.3] undecane-type) structure in solution by multinuclear n.m.r. studies. This novel complex forms a bis(benzene) solvate whose crystal structure was determined by X-ray diffraction [space group I2, a= 22.539(4), b= 16.878(2), c= 20.641(2)Å, β= 109.82(1)°, Z= 4, R= 0.032 for 4 968 independent reflections with I > 3σ(I)]. The complex [Pt2(µ-dppm)3] has the same C3h structure in the solid state as in solution, and displays a trigonal planar co-ordination about each of the platinum atoms, which are separated by 3.023(1) A. Although it contains no formal metal–metal bond, it does exhibit a significant metal–metal interaction. Spectroscopic studies are consistent with the known complex [Pd2(µ-dppm)3] possessing the same structure.