Synthesis and Infrared and Fluorescence Spectra of Europium and Terbium Complexes with a Novel Bis-Schiff Base Ligand Derived from 2,6-Diaminopyridine and Indole-2-carbaldehyde

A new bis-Schiff base ligand 2,6-bis[(indol-2-ylmethylene)amino]pyridine, and its complexes with europium and terbium were synthesized. The complexes were characterized by elemental analysis, infrared spectra, and conductivity. The europium and terbium ions were found to coordinate to the C=N nitrogen atoms, pyridine nitrogen atoms, and indole nitrogen atoms. The fluorescence properties of these complexes in DMSO, DMSO/CH 3 OH, and CH 3 OH were studied. Under the excitation of UV light, these complexes exhibit characteristic fluorescence of europium and terbium ions. The solvent factors influencing the fluorescence intensity are discussed.