Complexes with sulphur and selenium donor ligands. Part IV. Reaction of some bidentate phosphorus and arsenic donors with bis-(OO′-dimethyl phosphorodithioato)nickel(II), and the crystal structure of [1-(diphenylarsino)-2-(diphenylphosphino)ethane](O-methyl phosphoro-dithioato) nickel(II)–benzene (2/1)

Abstract

The reaction of Ni[S₂P(OMe)₂]₂ with Ph₂P·C₂H₄·AsPh₂ in benzene–dichloromethane gives [S₂PO(OMe)](Ph₂P·C₂H₄·AsPh₂)Ni,0·5C₆H₆. The crystal structure of this compound has been determined by Patterson and Fourier methods from three-dimensional X-ray photographic data. Crystals are monoclinic, space group P2₁/c, with a= 9·30(1),b= 17·37(1), c= 20·13(1)Å, β= 108·87(2)°, Z= 4. Refinement by least-squares methods gave a conventional R of 0·09 for 3852 independent non-zero reflections.

The nickel atom is co-ordinated in an approximately square-planar configuration of chromophore [NiS₂PAs], the sulphur donor being the novel ligand [S₂PO(OMe)]^2–. Features of the molecular geometry are discussed.

The same reaction is given by 1,2-bis(diphenylphosphino)ethane but not by the arsino-analogue, which instead gives a poorly characterised 1 :1 adduct with Ni[S₂P(OMe)₂]₂.