Luminescence Properties of Inert Lanthanide Ion Doped Europium Complexes with 2-Pyrazinecarboxylic Acid and Butanedioic Acid

Nine europium complexes with 2-pyrazinecarboxylic acid (Hpyca) and butanedioic acid (HBDA) were synthesized and characterized by elemental, IR, EDTA titration, ICP, and TG-DSC analyses. The results show that the complexes have the compositions of Eu(Pyca)(BDA)center dot 2H(2)O, Eu0.7Gd0.3(Pyca)(BDA)center dot 2H(2)O, Eu0.6La0.4(pyca)(BDA)center dot 3H(2)O, Eu0.5La0.5(pyca)(BDA)center dot 4H(2)O, Eu0.7Y0.3(Pyca)(BDA)center dot 3H(2)O, Eu0.6Y0.4 (Pyca)(BDA)center dot 2H(2)O, Eu0.5Y0.5(Pyca)(BDA)center dot 3H(2)O, Eu0.7Gd0.3(Pyca)(BDA)center dot 2H(2)O and Eu0.5Gd0.5(Pyca)(BDA)center dot 2H(2)O. IR spectra indicate that lanthanide ions coordinate with the carboxylic oxygen atoms and nitrogen atoms of Hpyca and oxygen atoms of HBDA. Luminescence spectra show that the introduction of La3+, Y3+ or Gd3+ in the complexes does not change the luminescence peak position, but remarkably increases luminescent intensity of the europium complexes. The quantum yields of the complexes doped with inert lanthanide ions (La3+, Y3+ or Gd3+) are higher than that of the undoped europium complex. Furthermore, doping the inert lanthanide ions in right proportion can increase the luminescence lifetimes of complexes. Those complexes are of strong luminescence, low cost and practical value.