CRYSTAL AND MOLECULAR STRUCTURE OF MU-CARBONYL-BIS-MU-DIPHENYLGERMANIUM-BIS(TRICARBONYLIRON), [GE(C6H5)2]2FE2(CO)7

The structural determination by single-crystal X-ray methods of μ-carbonyl-bis-μ-diphenylgermanium-bis(tricarbonyliron), [Ge(C6H5)2]2Fe2(CO)7, is described. The compound crystallizes in the triclinic space group P̅1 with a = 10.705 ± 0.004 Å, b = 10.916 ± 0.004 Å, c = 13.702 ± 0.005 Å, α = 103° 19′ ± 4′, β = 96° 39′ ± 4′, and γ = 101° 53′ ± 3′. There are two molecules per unit cell, calculated density 1.68 g cm-3. The density measured by flotation is 1.70 ± 0.02 g cm-3. A total of 1860 independent observations above background were collected by counter methods using crystal-monochromatized Mo Kα radiation. The structure was refined by least-squares methods to a conventional R factor of 4.9%. Hydrogen atoms were included and the phenyl groups were refined using the rigid-body approximation. The molecule has two tricarbonyliron groups linked by an iron-iron bond of 2.666 (3) Å which is bridged by two diphenylgermanium groups and a carbonyl group. The Fe-Ge distances are in the range 2.402-2.440 Å and the Fe-Fe bond subtends 66.8° at the germanium atoms. There are small deviations in the symmetry of the bridge system. The germanium ligands are slightly closer to one iron atom and the carbonyl group is displaced slightly toward the other. © 1969, American Chemical Society. All rights reserved.