Bridging phenyl ligands. Unsaturated mercury-triosmium carbonyl cluster complexes containing bridging phenyl ligands

Abstract

The gold phosphine group in the complex Os3(CO)10(μ-η1-Ph)(μ-AuPPh3), 1 can be replaced by mercury halide groups by reactions with mercury halides. The reaction of 1 with HgI2 yielded the new compound [Os3(CO)10(μ-η1-Ph)(μ-HgI)]4, 2 in 19% yield. The reaction of 1 with HgCl2 yielded the new compound Os4(CO)13(μ-η1-Ph)(μ-Cl)3, 3 in 18% yield. When heated to reflux in cyclohexane solvent, compound 2 was converted into the compound [Os3(CO)9(μ3-C6H4)(μ-H)(μ3-Hg)]2Os(CO)4, 4 in 11% yield. All new compounds were characterized by single-crystal X-ray diffraction analyses. Compound 2 is a tetramer of the unit “Os3(CO)10(μ-η1-Ph)(μ-HgI)” that is held together by a cubane-like Hg4I4 core having D2 symmetry. Each triosmium cluster is formally electronically unsaturated and contains one edge-bridging phenyl ligand. Compound 3 contains a Os3(CO)10(μ-η1-Ph)(μ-Hg) cluster, but in this case the Hg atom bridges to an additional Os(CO)3 group via three bridging chloride ligands. Compound 4 contains two Os3(CO)9(μ3-C6H4)(μ-H)(μ3-Hg) clusters that are linked by a bridging Os(CO)4 group. Each Os3 cluster in 4 contains a triply bridging C6H4 benzyne ligand and one bridging hydrido ligand.