Synthesis and structure of the mercaptodithiotrinickel complex [Ni3(µ3-S)2(SH)(PEt3)5]BPh4

Abstract

Reaction of H₂S and PEt₃ with [Ni(C₂H₄)(PPh₃)₂] gives the mercaptodithiotrinickel complex [Ni₃(µ₃-S)₂(SH)(PEt₃)₅]BPh₄, whose molecular structure has been established by three-dimensional X-ray data collected by the counter method. The crystals are triclinic, space group P, with a= 17.461(8), b= 17.048(7), c= 11.112(6)Å, α= 99.21(7), β= 90.76(8), γ= 102.57(7)°, and Z= 2. Full-matrix least-squares refinement converged at the conventional R factor of 0.070 for 2 990 observed reflections. The cation consists of a triangle of nickel atoms capped above and below by two triply bridging sulphur atoms. Moreover, Ni(1) and Ni(2) are co-ordinated by two triethylphosphine ligands and Ni(3) by a triethylphosphine and by a mercapto-group. The average Ni–Ni distance of 2.93(5)Å is indicative of no significant direct metal–metal interaction so that the geometry may be described as three square-planar d⁸ moieties sharing two bridging ligands. An X-ray photoelectron spectroscopic characterisation of the electronic structure of the title compound is presented.