COMPLEXES WITH MACROCYCLIC LIGANDS, .1. D INUCLEAR 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 macrocyc lic ligands were synthesized by the Schiff base condensation of 2 equi v. of 1,2-phenylenediamine and 2,6-diformylphenol in the presence of 2 equiv. of copper(II) perchlorate and were characterized by X-ray stru cture analyses, electrochemical investigations (DCV), and variable-tem perature magnetic susceptibility measurements. Complex 6 exists in two different solvated crystalline forms. The copper(II) ions in all thre e complexes are octahedrally coordinated with long axial distances to solvent molecules or perchlorate ions. The copper ions in 6 (in solvat e 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. Up on dissolution in acetonitrile complex 8 decomposed to form [Cu(MeCN)( 4)](ClO4-)-Cl-+ and the benzimidazolium perchlorate 9 (X-ray structure determination).