Selenium-Bridged Clusters. Synthesis and Structural Characterization of the μ4-Se Twin Cluster [(μ-BuSe)Fe2(CO)6]2(μ4-Se)

The unusual tetranuclear cluster [(μ-BuSe)Fe 2 (CO) 6 ] 2 (μ 4 -Se) ( 1 ) has been obtained from the reaction of a monoanion, derived from Fe 2 (μ-Se 2 )(CO) 6 and n -BuLi, with 1,3-dibromopropane. Compound 1 has been characterized by IR and 1 H, 13 C, and 77 Se NMR spectroscopy. It has been structurally characterized by single-crystal X-ray diffraction methods. The structure consists of two [(μ-BuSe)Fe 2 (CO) 6 ] units bridged by a pseudotetrahedral Se atom.