PUB - Publikationen an der Universität Bielefeld

A dinuclear ferric complex with the redox-active ligand (L(Cl2))(2-) (H(2)L(Cl2) = N,N'-dimethyl-bis(3,5-dichloro-2-hydroxybenzyl)-1,2-diaminoethane), was synthesized and characterized. The two iron(III) ions are six-coordinate in a distorted octahedral environment of the N(2)O(2)(Ph) donor set of one (L(Cl2))(2) and one amine and one phenolate donor of a second (L(Cl2))(2), which bridges the two complex halves. The relatively low-symmetric complex 1 crystallizes in the space group R (3) over bar. The crystal structure contains hexagonal, one-dimensional channels parallel to the c axis with diameters of similar to 13 angstrom. The absorption spectrum of 1 exhibits strong characteristic features of p(pi) -> d(pi*) ->, p(pi) -> d(sigma*), phenolate-to-metal CTs, and pi -> pi* ligand transitions. Electrochemical studies on 1 reveal the redox-activity of the coordinated ligand (L(Cl2))(2) by showing irreversible oxidative electron-transfer waves. The reductive electron transfers at negative potentials seem to originate from metal-centered processes. A detailed comparison to complexes with similar donor sets provides new insights into the electrochemical properties of these kinds of complexes. (C) 2011 Elsevier B.V. All rights reserved.