Crystal and molecular structures of transition metal complexes with N- and C-bonded diazoalkane ligands

The review covers structural and physicochemical studies on diazoalkanes N-coordinated to transition metals and encompasses all collected crystal structures. Our goal is to provide a classification of the complexes based on the metal, ranging from early to late transition metals, the nuclearity of the complex (mono, dinuclear, dusters), the electronic configuration of the metal (d(0) to d(10)) and the bonding mode of the diazoalkanes. Interestingly, the variety of structures may be rationalized within the valence bond formalism, the reactions being essentially oxidative addition of diazoalkane on the metal complexes giving hydrazonido (-2-ligand). C-coordinated diazoalkyl complexes are still restricted to a few metals and a few diazosubstituents and their chemistry is not well developed. (C) 1998 Elsevier Science S.A. All rights reserved.