Synthesis and structural characterisation of ruthenium and osmium carbonyl clusters containing organomercurials

Abstract

Reaction of the activated cluster [Os3(CO)10(NCMe)2] with [PhHgS(C5H4N)] afforded two new Os-Hg clusters cis-[Os(CO)4{Os3(CO)10(μ-η 2-SC5H4N)(μ-Hg)}2] 1 and [{Os3(CO)10(μ-η2-SC5H 4N)}2(μ4-Hg)] 2 in 25 and 30% yields, respectively. Cluster 1 consists of two {Os3(CO)10(μ-η2-SC5H 4N)(μ-Hg)} subunits bonded to a central Os(CO)4 moiety in a cis configuration. Cluster 2 comprises two skewed Os-Hg metal butterflies sharing a common wingtip Hg atom. Treatment of the same organomercurial with [Ru3(CO)10(NCMe)2] produced the cluster compound cis-[Ru(CO)4{Ru3(CO)9(μ-η 3-SC5H4N)(μ-Hg)}2] 3 (48%). This has a metal skeleton similar to that of 2 with the {S(C5H4N)} ligand moiety bonding to the ruthenium atoms in a μ-η3 fashion. Treatment of [Os3(CO)10(NCMe)2] with [PhHg(mbt)] (Hmbt = 2-mercaptobenzothiazole) afforded [{Os3(CO)10(μ-η2-mbt)} 2(μ4-Hg)] 4 (35%) and [Os3(CO)10(μ-η2-mbt)(μ-η 2-Hg(mbt)] 5 (20%). Cluster 4 is very similar to 2, but the S(C5H4N) ligand is replaced by the mbt ligand, while 5 consists of an Os3 triangle having one edge spanned by both [μ-η2-mbt] and [μ-η2-Hg(mbt)] moieties. The reaction of [Os5C(CO)15] and [Ru3(CO)12] with another class of organomercurial (diphenylthiocarbazono)phenylmercury reagent [PhHgL′] [L′ = SC(N=NPh)(=NNHPh)] containing a N=N functionality under thermal conditions produced [{Os5C(CO)14(μ-η2-SPh)} 2(μ4-Hg)] 6 (26%) and [{Os5C(CO)14(μ-η2-L′)} 2(μ4-Hg)] 7 (34%) and [Ru2(CO)4Ph{μ-η2-C(O)Ph}(μ 2-S)(μ-η2-L′)] 8 (15%), [Ru2(CO)4(C(O)Ph) {μ-η2-C(O)Ph}(μ2-S)(μ-η 2-L′)] 9 (15%) and [{Ru(CO)2Ph}2(μ-η2-L′)] 10 (45%), respectively. In clusters 6 and 7, two {Os5C(CO)14} subunits linked by a common wingtip mercury atom, are bonded with both μ-η2-SPh in 6 and μ-η2-L′ in 7. However, in the case of complexes 8, 9 and 10, only binuclear ruthenium carbonyl complexes formed instead of the expected formation of mixed-metal clusters. Complexes 1-10 result from the cleavage of both Hg-C and Hg-S bonds in the parent organomercury species. All these complexes have been fully characterized by both spectroscopic and crystallographic techniques.