Bimetallic osmium-tin complexes: Stannylene and hydrostannylene clusters upon addition of Ph3SnH to unsaturated triosmium clusters [(μ-H)2Os3(CO)8(μ-diphosphine)] (diphosphine = dppm, dppf)

• Reactions of Ph3SnH with the unsaturated triosmium clusters [(μ-H)2Os3(CO)8(μ-diphosphine)].
• Synthesis of bimetallic Os–Sn clusters containing stannylene and hydrostannylene ligands.
• Cluster mediated Sn–H and Sn–C bond activation.

Products of the addition of Ph3SnH to the unsaturated triosmium clusters [(μ-H)2Os3(CO)8(μ-dppm)] (1) and [(μ-H)2Os3(CO)8(μ-dppf)] (2) are highly dependent on the nature of the diphosphine. With the rigid bis(diphenylphosphino)methane (dppm), the stannylene complex [H2Os3(CO)7(μ-SnPh2)2(μ-dppm)] (3) is the major cluster product (35% yield), resulting from both Sn–H and Sn–C bond activation, while two previously reported triphenyltin complexes, [(μ-H)2Os3(CO)8(SnPh3)2(μ-dppm)] (4) (10% yield) and [(μ-H)2Os3(CO)8(SnPh3){μ-Ph2PCH2P(Ph)C6H4}] (5) (11% yield) also result. Biphenyl is also a co-product of this reaction and it is postulated to be formed concomitantly with 3. A similar reaction with the highly flexible 1,1′-bis(diphenylphosphino)ferrocene (dppf) complex leads to the formation of four tin-containing complexes: two previously reported compounds [HOs(CO)4(SnPh3)] (6) (8% yield) and [Os2(CO)6(SnPh3)2(μ-SnPh2)2] (8) (5% yield), and the new triphenyltin and hydrostannylene clusters [H(μ-H)2Os3(CO)8(SnPh3)(μ-dppf)] (10) (22% yield) and [(μ-H)Os2(CO)4(SnPh3)2(μ-HSnPh2)(μ-dppf)] (9) (12% yield) respectively, together with the dihydroxy cluster [Os3(CO)8(μ-OH)2(μ-dppf)] (7). Two of these new clusters have been characterized by X-ray crystallography. Cluster 3 consists of a central Os3 triangle with two stannylene groups, each bridging one Os–Os edge, a dppm ligand that bridges the third Os-Os edge, and two terminal hydride ligands. Cluster 10 consists of an Os3 triangle with a terminal SnPh3 group, one terminal and two bridging hydride ligands, and a bridging dppf ligand. The new compounds 3, 7, 9, and 10 have been investigated by electronic structure calculations, and the computed ground-state structures are discussed relative to the X-ray crystallographic structures.

New bimetallic osmium-tin clusters have been synthesized from the high temperature reactions between Ph3SnH and the unsaturated triosmium clusters [(μ-H)2Os3(CO)8(μ-diphosphine)] (diphosphine = dppm, dppf).Figure optionsDownload as PowerPoint slide