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

The reaction of Re-2(CO)(8)(mu-SnPh2)(2) (1) with NaOMe in methanol in the presence of (Bu4NBr)-N-n yielded the salt [NBu4n][Re-2(CO)(8){mu-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 Re-2(CO)(8)[mu-C(H)C(H)Bu-n](mu-H) with Ph3GeH and H2O in heptane solvent yielded the complex Re-2(CO)(8)[mu-Ph2GeO-(H)GePh2](mu-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 [NBu4n][OH] to give the salt [NBu4n][Re-2(CO)(8)(mu-Ph2GeOGePh2)(mu-H)] ([NBu4n]center dot 5). The three new compounds were characterized by IR, H-1 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).