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

Reaction of the activated cluster [Os-3(CO)(10)(NCMe)(2)] with [PhHgS(C5H4N)] afforded two new Os-Hg clusters cis-[Os(CO)(4){Os-3(CO)(10)(mu-eta(2)-SC5H4N)(mu-Hg)}(2)] 1 and [{Os-3(CO)(10)(mu-eta(2)-SC5H4N)}(2)(mu(4)-Hg)] 2 in 25 and 30% yields, respectively. Cluster 1 consists of two {Os-3(CO)(10)(mu-eta(2)-SC5H4N)(mu-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 [Ru-3(CO)(10)(NCMe)(2)] produced the cluster compound cis-[Ru(CO)(4){Ru-3(CO)(9)(mu-eta(3)-SC5H4N)(mu-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 mu-eta(3) fashion. Treatment of [Os-3(CO)(10)(NCMe)(2)] with [PhHg(mbt)] (Hmbt=2-mercaptobenzothiazole) afforded [{Os-3(CO)(10)(mu-eta(2)-mbt)}(2)(mu(4)-Hg)] 4 (35%) and [Os-3(CO)(10)(mu-eta(2)-mbt)(mu-eta(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 Os-3 triangle having one edge spanned by both [mu-eta(2)-mbt] and [mu-eta(2)-Hg(mbt)] moieties. The reaction of [Os5C(CO)(15)] and [Ru-3(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)(mu-eta(2)-SPh)}(2)(mu(4)-Hg)] 6 (26%) and [{Os5C(CO)(14)(mu-eta(2)-L')}(2)(mu(4)-Hg)] 7 (34%) and [Ru-2(CO)(4)Ph{mu-eta(2)-C(O)Ph}(mu(2)-S)(mu-eta(2)-L')] 8 (15%), [Ru-2(CO)(4){C(O)Ph}{mu-eta(2)-C(O)Ph}(mu(2)-S)(mu-eta(2)-L')] 9 (15%) and [{Ru(CO)(2)Ph}(2)(mu-eta(2)-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 mu-eta(2)-SPh in 6 and mu-eta(2)-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.