Bifunctional Cyclopentadienyl Ligands in Organotransition Metal Chemistry

Abstract

The coordination chemistry of cyclopentadienyl ligands that contain an additional coordination site appended to the ring-periphery by a covalent bridge Z, C₅R₄−Z-X or C₅R₄−Z-L, is outlined. When transition metals are coordinated both to the cyclopentadienyl group C₅R₄ and the pendent donor site X or L (X = CH₂ NR′, O; L = HC[dbnd]CH₂ NR₂′, PR₂′, OR′, SR′), the resulting complexes possess distinct properties due to the chelate effect. In such complexes the coordination sphere is defined by the nature of the bridge Z and the coordinating groups X and L and a series of metallacyclic complexes becomes available of which the chemistry is different from that of their non-bridged analogs.