Cluster Fragmentation and Facile Cleavage of Phenyl Groups from the SnPh3Ligand in Reactions of Os3(CO)11(SnPh3)(μ-H) with CO and HSnPh3

Two new cluster complexes, Os 3 (CO) 12 (Ph)(μ 3 -SnPh), 8 (35% yield), and Os 4 (CO) 16 (μ 4 -Sn), 9 (10% yield), were formed when the complex Os 3 (CO) 11 (SnPh 3 )(μ-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 (μ-SnPh 2 ) 2 (SnPh 3 ) 2, 10, and HOs(CO) 4 (SnPh 3 ), 11, were formed in 51% and 20% yields, respectively, from the reaction of 6 with HSnPh 3 . Compound 10 contains only two osmium atoms linked by an Os−Os bond and two bridging SnPh 2 ligands. Each osmium atom also contains one terminal SnPh 3 ligand. Compound 11 contains only one osmium atom. It has one SnPh 3 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.