Di- and tri-nuclear nickel(<scp>II</scp>) complexes with bridging thiolato groups. Crystal structure of [NBu₄]₂[Ni₃(C₆F₅)₄(µ-SEt)₄]

Abstract

The hydroxo complex [NBu4]2[Ni2(C6F5)4(µ– OH)2] reacts with H2S or a thiol at room temperature in methanol to give the binuclear complexes [NBu4]2[Ni2(C6F5)4(µ– SR)2](R = H, Me, Et, Pri, Ph or C6H4Me-p). The trinuclear complex [NBu4]2[Ni3(C6F5)4(µ– SEt)4] has been obtained by reaction of an excess of EtSH with the same hydroxo complex in refluxing methanol. The µ–azolato-µ-thiolato complexes [NBu4]2[Ni2(C6F5)4(µ– L)(µ– SR)](HL = pyrazole or 1,2,4-triazole; R = H, Ph or C6H4Me-p) can be prepared either by treating the µ-hydroxo–µ-azolato complexes [NBu4]2[Ni2(C6F5)4(µ– OH)(µ– L)] with H2S or a thiol (1:1 molar ratio) or [NBu4]2[Ni2(C6F5)4(µ– OH)2] with the corresponding thiol and azole (1:1:1 molar ratio). Analytical (C, H, N, S), conductance and spectrroscopic (IR, 1H and 19F NMR) data have been used for structural assignments. An X-ray crystal structure determination of [NBu4]2[Ni3(C6F5)4(µ– SEt)4] has established the trinuclear nature of the anion. The structure has been solved and refined to R= 0.052 and R′= 0.062 based on 3398 observed reflections. The Ni atoms are four-co-ordinated and show approximate square-planar arrangements. The bridge conformation could be determined by S ⋯ S repulsions.