Cluster fragmentation and facile cleavage of phenyl groups from the SnPh3 ligand in reactions of Os3(CO)11(SnPh3)(μ-H) with CO and HSnPh3

Two new cluster complexes, Os-3(CO)(12)(Ph)(mu(3)-SnPh), 8 (35% yield), and Os-4(CO) 16(mu(4)-Sn), 9 (10% yield), were formed when the complex Os-3(CO)(11)(SnPh3)(mu-H), 6, was heated to reflux in toluene solvent under a CO atmosphere. Compound 8 was transformed to 9 in 28% yield when a solution in octane solvent was heated to reflux under a CO atmosphere. Biphenyl was a coproduct in this reaction. Compound 8 contains three osmium atoms with a triply bridging SnPh group. The triosmium cluster has opened and there is only one Os-Os bond between the three osmium atoms. Compound 9 contains two Os-2(CO) 8 groups held together by a central quadruply bridging tin atom, giving an overall bow-tie structure for the five metal atoms. Two other new compounds, Os-2(CO)(6)(mu-SnPh2)(2)(SnPh3)(2), 10, and HOs(CO)(4)(SnPh3), 11, were formed in 51% and 20% yields, respectively, from the reaction of 6 with HSnPh3. Compound 10 contains only two osmium atoms linked by an Os-Os bond and two bridging SnPh2 ligands. Each osmium atom also contains one terminal SnPh3 ligand. Compound 11 contains only one osmium atom. It has one SnPh3 ligand and a hydrido ligand in cis position in the six-coordinate pseudo-octahedral complex. All four new compounds were characterized by single-crystal X-ray diffraction analysis.