Synthesis, Characterization, and Photophysical Properties of Dinuclear Eu(III) and Tb (III) Complexes Based on β-diketonate with Triphenylamine and Pyridine Moieties

Abstract

A novel β-diketonate ligand with triphenylamine and pyridyl moieties and its corresponding dinuclear Eu(III) and Tb(III) complexes using 1,10-phenanthroline as the second ligand were prepared and characterized by elemental analysis, IR spectra, UV-Vis spectra, 1H NMR, and ESI-MS. The thermogravimetric analysis show the Eu(III) and Tb(III) complexes have good thermal stabilities with decomposition temperatures 361 and 358 °C respectively. The photoluminescence spectra indicate that the ligand has excellent antenna effect to sensitize the lanthanide ions while using quinine sulfate solution as reference sample, the quantum efficiency of the Eu(III) and Tb(III) complexes are 0.267 and 0.281 in the CHCl3 solution at room temperature, respectively. The phosphorescence spectrum was determined using the ligand's gadolinium complex Gd2L3·4H2O and the results show that the triplet state energy levels of the ligand in the complexes is higher than that of the lowest excited level of Eu3+ (5D0), Tb3+ (5D4) respectively, which indicates a ligand-sensitized luminescence photoluminescence mechanism of the Eu(III) and Tb(III) complexes. They may be provided with potential applications in organic electroluminescent materials.