DIRECT ELECTROCHEMICAL SYNTHESIS AND CRYSTALLOGRAPHIC CHARACTERIZATION OF METAL DIPHENYLPHOSPHIDO AND DIPHENYLTHIOPHOSPHINATO COMPOUNDS, AND SOME DERIVATIVES

The electrochemical oxidation of a number of metals in acetonitrile solutions of PPh2H gives rise to M(PPh2)n compounds (M = Co, Zn or Cd, n = 2; M = Cu, Ag or Au, n = 1). With anodic nickel the product is Ni(PPh2).PPh2H. In the presence of elemental sulphur such oxidation reactions yield [M(S2PPh2)2] (M = Co, Zn or Cd). The electrochemical processes involved have been identified. The crystal structure of the addition compound [Cu4(PPh2)4(dppm)2].4MeCN 1 [dppm = bis(diphenylphosphino)methane] has been determined by X-ray crystallography, which reveals a Cu4P4 ring, capped by Cu2PCP'2 rings. Crystal parameters: triclinic, space group P1BAR, a = 14.719(4), b = 13.649(5), c = 17.112(5) angstrom, alpha = 112.40(3), beta = 106.22(2), gamma = 115.39(2)-degrees and Z = 1; R = 0.0632 for 3622 observed reflections [/ greater-than-or-equal-to 3-sigma-(/)]. The compound Ni(PPh2).PPh2H is oxidized by elemental oxygen, sulphur or selenium to give [Ni(E2PPh2)2] (E = O, S or Se), and also reacts with PhNCS to yield [Ni{PPh2(SCNPh)}2],2. Crystal parameters: triclinic, space group P1BAR, a = 8.950(6), b = 9.745(4), c = 10.366(7) angstrom,alpha = 112.28(4), beta = 99.09(5), gamma = 90.88(4)-degrees and Z = 1. Disorder prevented this structure from being refined beyond R = 0.1612, but the essential features of the square-planar NiS2P2 core were identified. The crystal parameters of [Ni(O2PPh2)2(HO2PPh2)2(MeCN)2] 3 are monoclinic, space group P2(1)/c, a = 12.420(5), b = 9.737(7), c = 20.729(16) angstrom, beta = 100.29(5)-degrees and Z = 2. The nickel atom is co-ordinated by two monodentate Ph2PO(O)- ligands and two monodentate Ph2P(O)OH ligands which are hydrogen-bonded to their anionic analogues, and by two MeCN molecules, to give a NiO2O'2N2 core.