PUB - Publikationen an der Universität Bielefeld

The synthesis and crystal structures of two new tetranuclear complexes are described: [{L(g-OH)Cu-2}(mu-fum){Cu-2(mu-OH)L}]1(ClO4)(2) (1) and [{L(mu-OH)Cu-2}(mu-IN)(2){Cu-2(mu-OH)L}](ClO4)(2).2C(2)H(5)OH.0.5H(2)O (2). The two complexes have been obtained through self-assembly processes involving a binuclear copper(II) complex, [L(mu-OH)Cu-2](ClO4)(2) (L stands for a compartmental end-off ligand, 2,6-bis[N-2-pyridylethyl)formimidoyl]-phenolato), and exo-dentate ligands (the fumarate anion, fum(2-), and the isonicotinato anion, IN-). The crystal structure of 1 consists of centrosymmetric tetranuclear cationic species, which result by connecting two binuclear units with one dicarboxylato linker. Each carboxylato group forms a third bridge between the copper(II) ions within the binuclear moiety (syn -syn bridging mode). The closest (CuCu)-Cu-... distances in tetramer are 2.930(1) and 9.313(3) Angstrom. Compound 2 contains cationic [Cu-4] rectangles, with the short edges constructed from the preexisting [L-OH and Aphenoxo groups [3.062(1) Angstrom], and the long ones constructed from the isonicotinato linkers [9.352(1) Angstrom]. In both compounds the copper(II) ions are pentacoordinated with a square-pyramidal stereochemistry. (C) 2003 Elsevier Science Ltd. All rights reserved.