Study of the effect of ligands on the fluorescence properties of terbium ternary complexes

Four ternary complexes of Tb(III) were synthesized by introducing the first ligand (L1) (N-phenylanthranilic acid (N-HPA), α-furoic acid (FURA)) and the second ligand (L2) (1,10-phenanthroline (Phen), 2,2′-dipyridyl (Bipy)), respectively. These complexes were characterized by elemental analysis, infrared spectra, XRD, UV spectra and fluorescence spectra. The effect of L1 and L2 on the fluorescence properties of terbium complexes was discussed. It showed that all the complexes exhibited ligand-sensitized green emission. The fluorescent intensity increased in the sequence of Tb(FURA)3Bipy < Tb(N-PA)3Phen < Tb(FURA)3Phen < Tb(N-PA)3Bipy. It indicated that L1 affected fluorescence properties of the complexes differently when the corresponding L2 altered. Meanwhile, the influence of L2 on the luminescence properties of the complexes also depends on L1. The results showed that L1 and L2 affected each other and worked together as a whole. The matching of L1, L2 and Tb3+ ion is very important to the luminescence properties of Tb(III) ternary complexes.