Binuclear dimethylplatinum (II) complexes each containing monodentate phosphine ligands and a bridging diphosphine ligand X(PPh2)2, X = CH2 or NH. Molecular structure of cis,cis-[Me2(pyPh2P)Pt(μ-Ph2PNHPPh2)Pt(PPh2py) Me2] · 2CH2Cl2

Displacement of the labile bridging SMe2 ligand in the organodiplatinum(II) complexes cis,cis-[Me2Pt(μ-SMe2){μ-X(PPh2)2}PtMe2], in which X(PPh2)2 is either bis(diphenylphosphino)amine [dppa (X = NH)], 1a, or bis(diphenylphosphino)methane [dppm (X = CH2)], 1b, with 2 equiv of some monodentate phosphine ligands, L, gave a series of organodiplatinum(II) complexes with general formula cis,cis-[Me2LPt(μ-dppa)PtLMe2][L = PPh3, 2a, PPh2py(2-diphenylphosphinopyridine, PN), 3a, or P(O-iPr)3, 4a] or cis,cis-[Me2LPt(μ-dppm)PtLMe2][L = PPh3, 2b, PN, 3b, or P(O-iPr)3, 4b] in good yields. In these complexes the two metallic centers are held together by only one bridging diphosphine ligand with no metal–metal bond. When L is PPh2Me or PPhMe2, the diplatinum(II) complexes are split to the corresponding monomers, [PtMe2{X(PPh2)2}] and cis-[PtMe2L2]. No reaction was observed when L is pyridine or SMe2. The complexes were fully characterized using multinuclear NMR (1H, 13C, 31P and 195Pt) methods, and the structure of cis,cis-[Me2(pyPh2P)Pt(μ-Ph2PNHPPh2)Pt(PPh2py)Me2] · 2CH2Cl2, 3a, has been determined crystallographically.