Water-soluble luminescent lanthanide complexes based on C6-DTTA-appended 5-aryl-2,2′-bipyridines

Abstract By using a number of synthetic approaches new lanthanide cations ligands based on 5-aryl-2,2′-bipyridines bearing diethylenetriamine tetracarboxylic acid (DTTA) residue at the C6-position of the pyridine moiety were synthesized. By using these ligands the water soluble lanthanide complexes (Ln = Eu, Tb, Sm, Dy) were prepared, and their photophysical properties were studied. For the europium complexes the luminescence quantum yields up to 12.8% and luminescence lifetime up to 1.09 ms were observed. For the terbium complexes of all the ligands a very weak luminescence with quantum yields not higher than 0.43% were observed. The influence of the nature of the bipyridine ligands on the photophysical properties of the lanthanide complexes was also discussed.