Preparation and Fluorescence Properties of Tb(III) Complexes with Pyridine Dicarboxylic Acid Derivatives

Two novel ligands containing pyridine-2,6-dicarboxylic acid units, 2,6-bis[2-(2,6-dicarboxypyridin-4-yl)vinyl]pyridine (L(1)), 4-vinylpyridine-2,6-dicarboxylic acid (L(2)) and their complexes with Tb(III) have been designed, synthesized and characterized by elemental analysis, IR spectra and NMR. The fluorescence spectra of Tb(III) complexes in the solid state, in different solvents and at different pH value solutions were investigated. The results exhibit that the ligand with two pyridine-2,6-dicarboxylic acid units is better sensitizer to Tb(III) ion, compared with that with simple pyridine-2,6-dicarboxylic acid unit. The fluorescence intensities of the complexes are strongest in neutral solution and while the less the dipole moment of solvent molecule is, the stronger the fluorescence intensity is. Due to their excellent green-emmiter, they could be used as a candidate material in organic light-emitting devices.