Synthesis and Structures of Oxo-Bridged Distannyl- and Digermyldirhenium Complexes

The reaction of Re2(CO)8(μ-SnPh2)2 (1) with NaOMe in methanol in the presence of Bu n 4NBr yielded the salt [NBu n 4][Re2(CO)8{μ-Ph2SnO(Me)SnPh2}] (3). The anion of 3 contains a Ph2SnO(Me)SnPh2 ligand formed by the addition of a [OMe]- group to the two bridging SnPh2 groups in 1. The bidentate ligand bridges the two Re(CO)4 groups that are joined by a Re−Re single bond. The reaction of Re2(CO)8[μ-C(H)C(H)Bu n ](μ-H) with Ph3GeH and H2O in heptane solvent yielded the complex Re2(CO)8[μ-Ph2GeO(H)GePh2](μ-H) (4). The structure of 4 consists of two Re(CO)4 units bridged by a Ph2GeO(H)GePh2 ligand and a hydrido ligand that bridges the Re−Re bond. Compound 4 was deprotonated at the OH group by treatment with [NBu n 4][OH] to give the salt [NBu n 4][Re2(CO)8(μ-Ph2GeOGePh2)(μ-H)] ([NBu n 4]·5). The three new compounds were characterized by IR, 1H NMR, and single-crystal X-ray diffraction analyses. The electronic structures of 4 and 5 were probed by computations employing density functional theory (ADF 2004.01, PW91).