Studies on binuclear copper(II) complexes involving co-ordination of (quadridentate Schiff base)copper(II) with (tertiary diamine)copper(II)

Abstract

Dimeric copper(II) complexes of the type [Cu(L)Cu(A)][ClO₄]₂ have been prepared, where L = various quadridentate Schiff base ions derived by the condensation of salicylaldehyde or 2-hydroxyacetophenone with ethylenediamine or 1,3-propylenediamine and A = 2,2′-bipyridyl, 1,10-phenanthroline, or 2-(2′-pyridyl)benzimidazole. Magnetic moment values of the complexes are observed to be much lower than he spin-only value, due to antiferromagnetic interaction between the two Cu^II centres. [Cu(L)] and [Cu(A)]²⁺ seem to affect the ligand-field spectral band positions of each other when co-ordinated in the binuclear complexes [Cu(L)Cu(A)]²⁺. Ultraviolet spectral studies of these complexes have also been carried out which show that there is no significant interaction between the π orbitals of the two ligands through metal ion d orbitals. Infrared spectra show a shift of ν(C–O) bands to higher energy in the binuclear complexes indicating bridging through phenolic O^–.