SYNTHESIS, CHARACTERIZATION, SPECTROSCOPIC AND PHOTOPHYSICAL STUDIES OF TERNARY COMPLEXES OF EU(III) WITH 3-AMINOPYRAZINE-2-CARBOXYLIC ACID (HL) AND HETEROBIARYL LIGANDS (2,2'-BIPYRIDINE AND 1,10-PHENANTHROLINE)

The synthesis and spectroscopic properties of mixed ligand complexes of Eu(III) with 3-aminopyrazine-2-carboxylic acid (HL) and two heterobiaryl ligands (2,2'-bipyridine and 1,10-phenanthroline) are described. These complexes were characterized by means of chemical analysis, IR, UV and luminescence spectra, 5D0 <-- F-7(0) selective excitation spectra and 5D0 excited state lifetimes. The complexes show strong ligand-centred absorption in the UV range, efficient energy transfer from the ligands and intense metal-centred emission in the visible range. The structures of the complexes in the solid state and in solution were deduced from spectroscopic and lifetime data. It was found that the complexes exist as different linkage isomers depending on the medium. The high quantum efficiencies indicate that these complexes can be used as light conversion molecular devices either in the solid state or in solution.