title: (dme)MCl3(NNPh2) (dme = dimethoxyethane; M = Nb, Ta): a versatile synthon for [Ta=NNPh2] hydrazido(2-) complexes.
abstract: Complexes (dme)TaCl(3)(NNPh(2)) (1) and (dme)NbCl(3)(NNPh(2)) (2) (dme =1,2-dimethoxyethane) were synthesized from MCl(5) and diphenylhydrazine via a Lewis-acid assisted dehydrohalogenation reaction. Monomeric 1 has been characterized by X-ray, IR, UV-vis, (1)H NMR, and (13)C NMR spectroscopy and contains a kappa(1)-bound hydrazido(2-) moiety. Unlike the corresponding imido derivatives, 1 is dark blue because of an LMCT that has been lowered in energy as a result of an N(alpha)-N(beta) antibonding interaction that raises the highest occupied molecular orbital (HOMO). Reaction of 1 with a variety of neutral, mono- and dianionic ligands generates the corresponding ligated complexes retaining the kappa(1)-bound [Ta-NNPh(2)] moiety.
authors.affiliation: Arnold and Mabel Beckman Laboratories of Chemical Synthesis, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Ian A
authors.initials: IA
authors.lastname: Tonks
authors.forename: John E
authors.initials: JE
authors.lastname: Bercaw