(Alkyl)(monocyclopentadienyl)niobium and -tantalum complexes in insertion processes

Alkyl high-valent early transition metal compounds are important organometallic species, particularly because their reactions with unsaturated molecules, such as carbon monoxide and organic isocyanides, are relevant to several industrial stoichiometric and catalytic processes. Recently, we have reported several studies concerning (alkyl)(monocyclopentadienyl) derivatives of group-5 metals, including both synthetic aspects and chemical behaviour in insertion reactions. This Microreview is an account of this work, covering syntheses, structure, spectroscopic, and reactivity details that have been reported by us together with the most significant contributions from other authors. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).