Abstract

Copper(II) quelates with Schiff bases derived from ethylenediamine, 1R,2R-(+)- or 1S,2S-(-)-1,2-diphenylethylenediamine and 5-X-salicylaldehyde (X=OCH 3, H, Br, NO 2) have been synthesized and characterized by elemental analysis and IR and UV-visible spectroscopies. The ORD and CD spectra of the chiral ligands and their related complexes have also been measured. The absorption and CD spectra of the metal complexes in the visible region are consistent with near square planar coordination geometries. Trends in absorption spectra over the series of complexes can be correlated with electronic effects of the substituents at position 5 of the salicylaldehyde. The sign patterns of the CD spectra in both UV and visible regions suggest the prevalence of ? and ? conformations for the chelate ring in the complexes of Schiff bases derived, respectively, from R,R- and S,S-diamines. Specific features of the CD spectra of the metal complexes are discussed in terms of the exciton chirality method.