Chain Compounds Based on Tetranuclear Basic Copper(II) Carboxylate Clusters and Quadruple Zwitterionic Linkers: Structures and Magnetic Properties

Two Cu II complexes with the new zwitterionic ligand 1-carboxymethylpyridinio-3-benzoate (L), (Cu 4 L 4 (OH) z] (ClO 4 ) 2 · 8H 2 O (1) and [Cu 4 L 4 (OH) 2 ]Cl 2 ·8H 2 O (2), have been synthesized and characterized crystallographically and magnetically. The two compounds contain isostructural chains, in which the anionic basic copper(II) carboxylate clusters [Cu 4 (μ 3 -OH) 2 (RCOO) 8 ] 2- are quadruply interlinked by cationic organic spacers. Magnetic analyses using a tetranuclear model indicate that antiferromagnetic interactions between neighboring copper(II) ions are operative through the double hydroxo bridges and the mixed hydroxo/carboxylato bridges.