SYNTHESIS, CHARACTERIZATION, ELECTROCHEMICAL STUDIES AND CATECHOLASE ACTIVITY OF A NEW SERIES OF BINUCLEAR COPPER(II) COMPLEXES

New binucleating ligands L (L-, N'-R-bis(methyl-N-(2-pyridinyl)ketoace tamide) where R=ethylene, 1,3-propylene, o-phenylene were prepared by the condensation of 2 equivalents of methyl-N- (2-pyridinyl) ketoaceta mide with the diamines. The binuclear copper(II) complexes of the type [Cu2L]X-4 where X = ClO4- and [Cu2LX2]X-2 where X = Cl- and Br- were synthesised by refluxing the ligand with 2 equivalents of Cu(II) salts . Conductivity studies showed a 1.4 electrolyte for perchlorate comple xes and a 1:2 electrolyte for chloro and bromo complexes. Room tempera ture magnetic studies gave moment for the complexes in the range 1.08 to 1.45 B.M which are less than 1.73 B.M for d(9) system. This shows t hat there is antiferromagnetic coupling between the two copper centers . ESR spectra of the complexes show a broad band which is centered at 3300G and the g values obtained were in the range 2.09-2.14. Electroch emical studies show a quasireversible two electron reduction occuring at the negative potential in the range -0.25 to -0.70 V. The initial r ate constant for the oxidation of catechol to o-quinone by the complex es are in the range 1.504 x 10(-1) to 3.83 x 10(-1) min(-1). (C) 1998 Elsevier Science Ltd. All rights reserved.