Organoplatinum(II) complexes with phosphite ligands

The phosphite complexes cis-[PtMe2L(SMe2)] in which L = P(OiPr)3, 1a, or L = P(OPh)3, 1b, were synthesized by the reaction of cis,cis-[Me2Pt(μ-SMe2)2PtMe2] with 2 equiv. of L. If 4 equiv. of L was used the bis-phosphite complexes cis-[PtMe2L2] in which L = P(OiPr)3, 2a, or L = P(OPh)3, 2b, were obtained. The reaction of cis-[Pt(p-MeC6H4)2(SMe2)2] with 2 equiv. of L gave the aryl bis-phosphite complexes cis-[Pt(p-MeC6H4)2L2] in which L = P(OiPr)3, 2a′, or L = P(OPh)3, 2b′. Use of 1 equiv. of L in the latter reaction gave the bis-phosphite complex along with the starting complex in a 1:1 ratio. The complexes failed to react with MeI. The reaction of cis,cis-[Me2Pt(μ-SMe2)2PtMe2] with 2 equiv. of the phosphine PPh3 gave cis-[PtMe2(PPh3)2] and cis-[PtMe2(PPh3)(SMe2)] along with unreacted starting material. Reaction of cis-[PtMe2L(SMe2)], 1a and 1b with the bidentate phosphine ligand bis(diphenylphosphino)methane, dppm = Ph2PCH2PPh2, gave [PtMe2(dppm)], 8, along with cis-[PtMe2L2], 2. The reaction of cis-[PtMe2L(SMe2)] with 1/2 equiv. of the bidentate N-donor ligand NN = 4,4′-bipyridine yielded the binuclear complexes [PtMe2L(μ-NN)PtMe2L] in which L = P(OiPr)3, 3a, or L = P(OPh)3, 3b. The complexes were fully characterized using multinuclear NMR (1H, 13C, 31P, and 195Pt) spectroscopy.