DINUCLEAR AND TRINUCLEAR NICKEL(II) COMPLEXES WITH BRIDGING THIOLATO GROUPS - CRYSTAL-STRUCTURE OF [NBU4]2[NI3(C6F5)4-(MU-SET)4]

The hydroxo complex [NBu4]2[Ni2(CF5)4(mu-OH)2] reacts with H2S or a th iol at room temperature in methanol to give the binuclear complexes [N Bu4]2[Ni2(C6F5)4(mu-SR)2] (R = H, Me, Et, Pr(i), Ph or C6H4Me-p). The trinuclear complex [NBu4]2[Ni3(CF5)4(mu-SEt)4] has been obtained by re action of an excess of EtSH with the same hydroxo complex in refluxing methanol. The mu-azolato-mu-thiolato complexes [NBu4]2[Ni2(C6F5)4(mu- L)(mu-SR)] (HL = pyrazole or 1,2,4-triazole; R = H, Ph or C6H4Me-p) ca n be prepared either by treating the mu-hydroxo-mu-azolato complexes [ NBu4]2[Ni2(C6F5)4(mu-OH)(mu-L)] with H2S or a thiol (1:1 molar ratio) or [NBu4]2[Ni2(C6F5)4(mu-OH)2] with the corresponding thiol and azole (1:1:1 molar ratio). Analytical (C, H, N, S), conductance and spectros copic (IR, H-1 and F-19 NMR) data have been used for structural assign ments. An X-ray crystal structure determination of [NBu4]2[Ni3(C6F5)4( mu-SEt)4] has established the trinuclear nature of the anion. The stru cture has been solved and refined to R=0.052 and R' = 0.062 based on 3 398 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.