Stereochemie der Metall-Metall-Bindung: Darstellung und Struktur von Co2(CO)4C5H5P(CH3)2 / Stereochemistry of the Metal-Metal Bond: Preparation and Structure of Co2(CO)4C5H5P(CH3)2

The title complex 4 was prepared from η-C3H5Co(CO)3 and η-C5H5(CO)Co-P(CH3)2H. It completes the series of PR2-and AsR2-bridged homodinuclear complexes C2(CO)7C5H5-As(CH3)2, Mn2(CO)6C5H5As(CH3)2, and Fe2(CO)5C5H5P(CH3)2. Its crystal structure analysis reveals the systematic variation of the ligand distribution along the series which depends only on the number of ligands present and not on given coordination geometries. The metal-metal bond length in 4 is mainly determined by the stereochemical require-ments of the bridging phosphido ligand.