Effect of ligand exchange on the one-electron oxidation process of alkoxo or phenoxo bridged binuclear copper(II) complexes.

The authors report on the influence of methanol/methoxide on the structure and the mono-electronic oxidn. process of two different dicopper(II,II) complexes: a binuclear $μ$-alkoxo $μ$-acetato dicopper(II,II) complex obtained with a tetraamide-contg. ligand (1) or a new unsym. $μ$-phenoxo, $μ$-hydroxo dicopper(II,II) complex based on a ligand bearing one bis(2-pyridylmethyl)aminomethyl arm (BPA) and one thiosemicarbazone (2). Structural data obtained from x-ray diffraction anal. showed that, in the case of complex 2, bridging hydroxide was replaced by a methoxide bound in a bridging mode (2-OMe). Concerning complex 1, redox properties were studied by electrochem. and rationalized using theor. calcns. The authors' studies indicate that (i) the acetate bridge of 1 is decoordinated from the copper ions after mono-oxidn. (ii) in presence of methoxide, acetate is released and a complex with two pendant oxygen ligands (one methoxide and one solvent, 1-OMe-DMF) is a plausible structure although bridging methoxide cannot be excluded. In the case of 2 the anodic potentials are not influenced by the nature of the bridge (hydroxo in 2 or methoxy in 2-OMe). Finally, the computed redox potentials using DFT calcns. are in good agreement with the exptl. ones and indicates that in the case of the complexes derived from 1, oxidn. is copper-centered therefore leading to Cu(II)Cu(III) species although oxidn. is ligand-centered in the case of 2 and 2-OMe. [on SciFinder(R)]

Références

Titre
Effect of ligand exchange on the one-electron oxidation process of alkoxo or phenoxo bridged binuclear copper(II) complexes.
Type de publication
Article de revue
Année de publication
2017
Revue
Inorganica Chim. Acta
Volume
481
Pagination
113-119
ISSN
0020-1693
Soumis le 12 avril 2018