COMPLEXES WITH MACROCYCLIC LIGANDS, .1. DINUCLEAR COPPER(II) COMPLEXES WITH A TOTALLY PI-CONJUGATED MACROCYCLE OF SCHIFF-BASE TYPE - SYNTHESES, STRUCTURES, ELECTROCHEMICAL, AND MAGNETOCHEMICAL PROPERTIES

The dinuclear copper(II) complexes 6, 7, and 8 of three novel macrocyclic ligands were synthesized by the Schiff base condensation of 2 equiv. of 1,2-phenylenediamine and 2,6-diformylphenol in the presence of 2 equiv. of copper(II) perchlorate and were characterized by X-ray structure analyses, electrochemical investigations (DCV), and variable-temperature magnetic susceptibility measurements. Complex 6 exists in two different solvated crystalline forms. The copper(II) ions in all three complexes are octahedrally coordinated with long axial distances to solvent molecules or perchlorate ions. The copper ions in 6 (in solvate a) are only five-coordinate and square-pyramidal. The (CuCuII)-Cu-II complexes were reduced in successive, quasi-reversible, one-electron steps. The antiferromagnetic exchange interactions were determined. Upon dissolution in acetonitrile complex 8 decomposed to form [Cu(MeCN)(4)](ClO4-)-Cl-+ and the benzimidazolium perchlorate 9 (X-ray structure determination).