Synthesis and electrochemical studies of octahedral nickel β-diketonate complexes
作者:Phimphaka Harding、David J. Harding、Wasinee Phonsri、Saowanit Saithong、Hirihattaya Phetmung
DOI:10.1016/j.ica.2008.03.014
日期:2009.1
The reaction of [Ni(tmhd)(2)] and [Ni(dbm)(2)] with N-donor chelating ligands in dichloromethane and acetone, respectively, yields the complexes [Ni(tmhd)(2)(L-L)] (L-L = 2,2'-bpy 1, phen 2 and dmae 3) and [Ni(dbm)(2)(L-L)] (L-L = 2,2'-bpy 4, phen 5, dmae 6). UV-Vis spectroscopy shows very strong bands in the UV region consistent with ligand centred pi -> pi* transitions. The electrochemical studies of 1-6 reveal oxidation to Ni(III). The [Ni(tmhd)(2)(L-L)] 1-3 are more easily oxidized by ca. 300 mV and are quasi-reversible whereas for the [Ni(dbm)(2)(L-L)] series only complex 6 shows significant reversibility. X-ray crystallographic studies have been conducted in the case of [ Ni( dbm) 2( phen)] 5 and [Ni(dbm)(2)(dmae)] 6 . The structures both show that the nickel metal centre is octahedral with an O4N2 coordination environment. In the structures the beta-diketonate ligands exhibit a cis-arrangement, with the metal displaced out of the planar chelate ring. (c) 2008 Elsevier B.V. All rights reserved.