Synthesis and luminescent properties of novel pyrazolone rare earth complexes

A novel pyrazolone pyridine-containing ligand, 2,6-bis(1-phenyl-4-ethoxycarbonyl-5-pyrazolone-3-yl)pyridine (H2L) was designed and synthesized from pyridine-2,6-dicarboxylic acid (1), and its Eu(III) and Tb(III) complexes were prepared. The ligand and complexes were characterized in detail based on FT-IR spectra, 1H NMR, elemental analysis and thermal analysis, and the formula of Ln2L3·4H2O (Ln=Eu or Tb) of rare earth complexes was confirmed. The UV-vis absorption spectra and photoluminescence properties of the complexes were investigated, which showed that the Eu(III) and Tb(III) ions could be sensitized efficiently by the ligand (H2L) and emit the photoluminescence with high intensity, narrow half-peak width, and monochromic light. The results indicated that the complexes showed potential as excellent luminescent materials.