摘要：

The complex di-μ-hydrido-icosacarbonyltriosmiumdirhenium(3Os-Os,2Os-Re), (μ-H)2Os3Re2(CO)20, previously prepared from Os3(CO)10(c-C8H14)2 and HRe(CO)5, has been studied by a complete three-dimensional single-crystal X-ray structural analysis. The complex crystallizes in the noncentrosymmetric monoclinic space group Cc with a = 9.2480 (16) , b = 23.010 (4) , c = 29.665 (5) , β = 104.589 (13)°, V = 6109.0 (17) 3, and ρ(calcd) = 3.273 g cm-3 for mol wt 1505.2 and Z = 8. Diffraction data were collected with a Syntex P21 diffractometer using an ω-scan collection mode; the structure was solved and refined to RF = 5.7% for those 2913 data with Fo > 2σ(Fo) and 4° < 2θ < 40° (Mo Kα radiation). All atoms other than the hydrogen atoms were located. The crystallographic asymmetric unit consists of two independent molecules of (μ-H)2Os3Re2(CO)20 which are related to each other by a local pseudo-inversion center at a general position in the unit cell. The two molecules have identical connectivities, and their bond lengths and bond angles are equivalent. The core of the molecule consists of a triangle of osmium atoms with the two rhenium atoms bonded in C3-related equatorial sites on two of the osmium atoms. Each rhenium atom bears five carbonyl groups, the osmium atoms which are linked to rhenium each bear three carbonyl groups, and the third osmium atom bears four carbonyl groups. The Os-Re bond lengths range from 2.942 (3) to 2.983 (3) ; Os-Os distances break down into two distinct groups-those believed to be bridged by single μ-hydride ligands, which range in length from 3.059 (3) to 3.084 (2) , and normal (nonbridged) Os-Os bonds, which have values of 2.876 (3) and 2.880 (3) .

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