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Cluster synthesis—XXIII. The synthesis, structure and bonding of Fe4(CO)10(μ-CO)(μ4-S)2

1989; Elsevier BV; Volume: 8; Issue: 15 Linguagem: Inglês

10.1016/s0277-5387(00)86409-8

1873-3719

Richard D. Adams, James E. Babin, Javier Estrada, Jin-Guu Wang, Michael B. Hall, Arthur A. Low,

Radiopharmaceutical Chemistry and Applications

The compound Fe4(CO)10(μ-CO)(μ4-S)2 (1) was synthesized in 38% yield by the UV induced decarbonylation of Fe(CO)5 in the presence of Fe3(CO)9(μ3-S)2. Compound 1 was characterized by a single-crystal X-ray diffraction analysis. Space group: Pccn, a = 6.603(1), b = 15.429(3), c = 17.292(4) Å, Z = 4. The structure was solved by direct methods and was refined (807 reflections) to the final values of the residuals R = 0.043 and Rw = 0.054. The molecule consists of a planar array of four iron atoms with a quadruply bridging sulphido ligand on each side of the plane. The shortest metal-metal bond, 2.489(3) Å, contains a bridging carbonyl ligand. Semi-bridging carbonyl ligands bridge the two adjacent metal-metal bonds, 2.532(2) Å. The longest metal-metal bond, 2.605(2) Å, has no carbonyl bridge. Compound 1 is unsaturated (by EAN rule) by the amount of two electrons. The two semi-bridged carbonyl-metal bonds in 1 are significantly shorter than those in the saturated cluster Fe2CO2(CO)11(μ4-S)2. A molecular orbital description which explains the differences in bonding between the two compounds is proposed.