Syntheses, characterization and fluorescent properties of six novel lanthanide complexes with N,N-diphenyl-2-(quinolin-8-yloxy)acetamide

Six novel complexes of lanthanide nitrates (Ln = La, Sm, Eu, Gd, Tb, Dy) with a amide type ligand, N-methyl-N-phenyl-2-(quinolin-8-yloxy)acetamide (L) have been prepared and characterized by elemental analysis, conductivity measurements, IR and H-1 NMR spectra. The fluorescence properties of the complexes and the triplet state energy of the ligand were studied in detail. The result indicates that, the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III). In addition, the fluorescence intensities of the Eu(III) complex in different solutions(tetrahydrofuran, acetone and acetonitrile) are stronger than that in solid state. This is probably due to the solvate effect and the stoichiometry change of ligand with Eu(III) ion in solutions.