Influence of the nature of carboxylic acid on the luminescence and spectral properties of (carboxylato)bis(dibenzoylmethanato)europium(III) complexes

A series of (carboxylato)bis(dibenzoylmethanato)europium(III) complexes con taining anions of both saturated and unsaturated carboxylic acids were synt hesized to compare the luminescence and spectral properties of heteroligand Eu(III) complexes. (Carboxylato)bis(dibenzoylmethanato)europium(III) compl exes with unsaturated acid anions were synthesized for the first time. The compounds obtained were characterized using elemental analysis and luminesc ence and IR spectroscopy. These studies revealed two types of influence of the nature of an acid substituent on the luminescence spectra of (carboxyla to)bis(dibenzoylmethanato)europium(III) complexes. The anomalous Stark stru cture of the luminescence spectra of one group of compounds is attributed t o the charge transfer state at 77 K.