5-COORDINATE NICKEL(II) XANTHATE DERIVATIVES WITH TRIPHOS - CRYSTAL-STRUCTURE OF TRIS(O-CYCLOHEXYLDITHIOCARBONATO)NICKELATE(II) OF NYLPHOSPHINE-O-CYCLOHEXYLDITHIOCARBONATONICKEL(II)

Five-coordinate complexes, [Ni(S(2)COR)(TRIPHOS)]X (R = cyclo-C6H11, X = Cl, PF6, [Ni(S2COC6H11)(3)]; R = Et, X = PF6, [Ni(S(2)COEt)(3)]), h ave been obtained by the reaction of O-alkyldithiocarbonato complexes, [Ni(S(2)COR)(2)], with bis(2-diphenylphosphinoethyl)phenylphosphine ( TRIPHOS). The structure of [Ni(S2COC6H11) (TRIPHOS)][Ni(S2COC6H11)(3)] was determined by X-ray crystallography. The compound contains a five -coordinate cation and a hexa-coordinate anion. The geometry about the nickel atom in the [Ni(S2COC6H11) (TRIPHOS)](+) is distorted trigonal bipyramidal with the axial positions occupied by one sulfur atom of t he bidentate O-cyclohexyldithiocarbonate and the central phosphorus at om of the TRIPHOS. In the [Ni(S2COC6H11)(3)](-) anion, the nickel atom is bonded to six sulfur atoms of three O-cyclohexyldithiocarbonate li gands. Formation of the dithiocarbonato complexes in the reactions of [Ni(S(2)COEt)(2)] with TRIPHOS has also been observed.