On Nonequivalence of Rare-Earth Ion Positions in Mixed-Ligand Complexes with Acetylacetone and Unsaturated Organic Acids

Abstract

The luminescence spectra of Eu(III) complexes with diketones and acrylic and maleic acids are analyzed. The transitions are significantly broadened (by a factor of two or three) compared to the starting Eu(III) tris-acetylacetonate. This is explained by the presence of a large number of nonequivalent luminescence centers, originating from diverse (more than five types) modes of coordination of the carboxylic group of unsaturated acids to Eu(III) and by intermolecular association, leading to noncrystalline glasslike structures of the mixed complexes.