Synthesis and structures of doubly bridged bis(cyclopentadienyl) tetracarbonyl diiron complexes

A series of doubly bridged bis(cyclopentadienyl) tetracarbonyl diiron complexes (7–13) have been synthesized by the reaction of the corresponding ligand (1–6) with Fe(CO)5 in refluxing xylene. It is unusual that the reaction of ligand (GeMe2)(GeMe2)(C5H4)2 (3) with Fe(CO)5 gave the complex (GeMe2)[(η5-C5H4)Fe(CO)]2(μ-CO)2 (10) as the main product which lost the GeMe2, only a small amount of the expected product (GeMe2)2[(η5-C5H3)Fe(CO)]2(μ-CO)2 (9) was obtained. The molecular structures of 9 and (SiMe2SiMe2)2[(η5-C5H3)Fe(CO)]2(μ-CO)2 (13) have been determined by X-ray diffraction.