Formation and structure of [Ni3(µ3-S)(µ-SMe)3(SMe)3]2–, a cyclic trinuclear metal–sulphide–thiolate cluster with simple monofunctional thiolate ligands

Abstract

The reaction of NiCl₂ with Na(SMe) in acetonitril (molar ratio 1 : 4.4) gives the trinuclear cluster [Ni₃(µ₃-S)(µ-SMe)₃(SMe)₃]^2–(2) in 12% yield. It can be isolated as black crystals of [NMe₄]₂-[Ni₃(µ₃-S)(µ-SMe)₃(SMe)₃](3) in the presence of NMe₄Cl. The crystal and molecular structure of (3) has been determined from X-ray diffraction data. Crystals are cubic, space group P2₁3, with a= 13.801(4)Å and Z= 4. The structure was solved by direct methods and refined to R(R′)= 0.018 (0.014) on the basis of 1 029 observed reflections with l > 1.96σ(l). Anion (2) is the first example of a cyclic trinuclear metal–sulphide–thiolate complex which contains simple monofunctional ligands and thus is not stabilized by chelating thiolate groups. It consists of three Ni atoms, one triply bridging suphide ion, and six MeS^– ligands in two different co-ordination modes. The electronic spectrum is consistent with a diamagnetic d⁸ system. Structural changes related to the steric requirements of the ligands are discussed.