Synthesis and X-ray crystal structure of the asymmetric trinuclear complex [Ni3(µ3-S)2(H2O)(PPh3)5][PF6]2

Abstract

By reaction of H₂S and PPh₃ with [Ni(H₂O)₆]²⁺ the trinuclear complex cation [Ni₃(µ₃-S)₂(H₂O)(PPh₃)₅]²⁺ is formed. The molecular structure of [Ni₃(µ₃-S)₂(H₂O)(PPh₃)₅][PF₆]₂ was determined from three-dimensional X-ray data collected by counter methods. The crystals are monoclinic, space group Pn, with a= 24.235(14), b= 13.892(8), c= 14.141 (8)Å, β= 91.45(7)°, and Z= 2. The inner core of the cation consists of a triangle of nickel atoms capped above and below by two triply bridging sulphur atoms. Two nickel atoms are co-ordinated by two triphenylphosphine ligands, whereas the third is linked to a triphenylphosphine and to one water molecule. The mean value of the nickel–nickel bond distances, 2.95(5)Å, seems to exclude any direct metal–metal interaction; the geometry may be therefore described as three square-planar nickel(II) moieties sharing two triply bridging sulphur ligands.