Coordination compounds of europium(III), terbium(III), dysprosium(III), samarium(III), and gadolinium(III) with 2-acetylbenzoic acid

Abstract

LnAcbenz3 · 3H2O complexes of Eu3+, Tb3+, Dy3+, Sm3+, and Gd3+ with 2-acetylbenzoic acid (HAcbenz) have been synthesized. The complexes have been studied by thermogravimetry and infrared and luminescence spectroscopy. According to IR spectroscopy data, the complexation of Acbenz− with lanthanide ions occurs due to the bidentate coordination of carboxyl groups. According to thermal analysis, the complexes are dehydrated at a temperature above 140°C, and their thermodestruction begins at a temperature above 250°C. From the luminescence spectra measured at 77 and 300 K, it has been established that the integral luminescence intensity of EuAcbenz3 · 3H2O and TbAcbenz3 ° 3H2O is, respectively, 10 and 19 times higher than for tris-benzoates of the same metals. TbAcbenz3 ° 3H2O, the most intensively luminescing complex, is recommended for use as a promising luminescent material.