LUMINESCENT PROPERTIES OF COMPLEX COMPOUNDS OF EUROPEUM(III), GADOLI-NIUM(III), AND TERBIUM(III) WITH ALKYLOXYBENZOIC ACIDS

Abstract

The luminescent properties of complex compounds of europium(III), gadolinium(III), and terbium(III) with dodecyl-, 4-octadecyloxybenzoic acids have been studied. According to the phosphorescence spectra of the gadolinium(III) complexes measured at 77 K, the energies of the excited triplet states of the anions of the used acids (T₁) were determined. Based on the luminescence mechanism, it was established that intramolecular energy transfer from the organic ligand to the lanthanide ion is effective for the europium(III) complexes. To increase the luminescence intensity of the terbium(III) complex compounds, compounds of the composition LnL₃Phen were obtained, where Phen is 1,10-phenanthroline. Using experimental spectra, an increase in the integrated luminescence intensity of the Tb³⁺ ion compared to TbL₃ was shown.