Monovalent copper complexes of N-aryl-pyridine-2-aldimine. Synthesis, characterization and structure

A direct synthetic route, based on silver(I) assisted metal exchange reaction, to cationic bis-ligand complexes of copper(I) involving N-aryl-pyridine-2-aldimines (L, 1) has been studied. These complexes are obtained as their perchlorates, [Cu(L)(2)]ClO4 (2). They have been characterized 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 independent molecules in the asymmetric unit. The ligand L(2) coordinates in a bidentate manner providing a highly distorted tetrahedral geometry about copper. The complexes show highly resolved symmetrical H-1 NMR spectra. Intense MLCT absorptions are observed in the visible range. In methanol 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