Bis(η-cyclopentadienyl)-molybdenum and -tungsten imido complexes: X-ray structures of [Mo(η-C5H5)2(NBut)] and [Mo(η-C5H4Me)2(NBut)Me]I

Abstract

The pseudo-trigonal bis(η-cyclopentadienyl)-molybdenum and -tungsten imido complexes [M(η-C₅H₄R)(η-C₅H₄R′)(NBu^t)](M = Mo or W; R = R′= Me or H, R′= Prⁱ R = H) are reported together with the ring-slipped indenyl analogue [Mo(η-C₅H₄Prⁱ)(η³-C₉H₇)(NBu^t)] and the metal-methylated salts [Mo(η-C₅H₄Me)₂(NBu^t)Me]X (X = I or BF₄); the X-ray structures of [Mo(η-C₅H₅)₂(NBu^t)] and [Mo(η-C₅H₄Me)₂(NBu^t)Me]BF₄ suggest that the NBu^t ligand acts as a strong π-donor to the metal centre; photoelectron studies identify an unusually low ionization-energy band largely localized on the ligands.