Synthesis and luminescent properties of complexes of Eu(III) with 2-thienyltrifluoroacetonate, terephthalic acid and phenanthroline

Abstract

This work reports the synthesis and luminescent properties of complexes of europium(III) with 2-thienyltrifluoroacetonate (HTTA), terephthalic acid (TPA) and phenanthroline (Phen), in the solid state. The new complexes were characterized by elemental analysis, infrared (IR) spectroscopy, scanning electronic microscopy (SEM) and thermal stability analysis. Both binuclear complex Eu 2(TPA)(TTA) 4Phen 2 and polynuclear complex Eu(TPA)(TTA)Phen present better thermal stability than the mononuclear complex Eu(TTA) 3Phen does. The formation of the binuclear/polynuclear structure of the complexes appears to be responsible for the enhancement of the thermal stability. The emission spectra show narrow emission bands that arise from the 5D 0→ 7F J ( J=0–4) transition of the Eu 3+ ion. The spectral data of the complexes Eu(TPA)(TTA)Phen and Eu 2(TPA)(TTA) 4Phen 2 present only one sharp peak in the region of the 5D 0→ 7F 0 transition indicating that only one Eu 3+ ion species is present in each sample. In addition, the luminescence decay curves of the complexes Eu(TPA)(TTA)Phen and Eu 2(TPA)(TTA) 4Phen 2 fit a single-exponential decay law. The values of quantum efficiencies of the emitting 5D 0 level for the complexes Eu(TPA)(TTA)Phen and Eu 2(TPA)(TTA) 4Phen 2 are 29% and 28%, respectively.