Synthesis and X-ray characterization of the new pentanickel cluster cation [Ni5(μ5-S)(μ3-S)2(μ2-S)(μ-CH3COO)(PPh3)5]+

By reacting Ni(CH3COO)2·6H2O with H2S in the presence of PPh3, the new Ni/S cluster of formula [Ni5(μ5-S)(μ3-S)2(μ2-S)(μ-CH3COO)(PPh3)5]PF6·C7H8·0.5CH2Cl2 has been isolated and characterized by X-ray diffraction analysis. Crystal data: space group P21/c, a=15.774(4), b=21.235(7), c=29.288(7) Å, β=95.66(4)°. The inner core consists of a square pyramid of five nickel atoms, linked together by a bridging acetate and four variously bridging sulfur ligands. The 31P{1H} NMR spectra in dichloromethane solution are consistent with the above geometry.