MONOVALENT COPPER-COMPLEXES OF N-ARYL-PYRIDINE-2-ALDIMINE - SYNTHESIS, CHARACTERIZATION AND STRUCTURE

A direct synthetic route, based on silver(I) assisted metal exchange r eaction, to cationic bis-ligand complexes of copper(I) involving N-ary l-pyridine-2-aldimines (L, 1) has been studied. These complexes are ob tained as their perchlorates, [Cu(L)(2)]ClO4 (2). They have been chara cterized with the help of spectroscopy and X-ray crystallography. The X-ray structure of [Cu(L(2))(2)]ClO4, where L(2) is N-p-tolyl-pyridine -2-aldimine is reported. There are two crystallographically independen t molecules in the asymmetric unit. The ligand L(2) coordinates in a b identate manner providing a highly distorted tetrahedral geometry abou t copper. The complexes show highly resolved symmetrical H-1 NMR spect ra. Intense MLCT absorptions are observed in the visible range. In met hanol the CuL(2)(2+)/CuL(2)(+) couple has E(1/2) ca, 0.35 V vs SCE at 298 K. The moderately high positive potential is brought about by the distortion in the geometry of CuL(2)(2+). Copyright (C) 1996 Elsevier Science Ltd