eesti teaduste
akadeemia kirjastus
SINCE 1952
Proceeding cover
of the estonian academy of sciences
ISSN 1736-7530 (Electronic)
ISSN 1736-6046 (Print)
Impact Factor (2022): 0.9
Study of thermal and optical properties of dibenzoylmethane Eu(III) organic complexes; pp. 493–500

Ilze Malina, Nikolajs Juhnevics, Valdis Kampars

Two Europium(III) organic complexes (ternary complex Eu(DBM)3(PHEN) and tetrakis complex [Eu(DBM)4]N(Et)4, where DBM is dibenzoylmethane and PHEN is 1,10-phenantroline) were synthesized and their structures proven with 1H-NMR spectroscopy, elemental analysis, FT-IR and mass spectroscopy. Their photophysical properties have been investigated in solution, solid-state and in poly-N-vinylcarbazole (PVK) films varying complex composition from 1 to 15 wt%. Both complexes exhibit intense UV light absorption and bright red-light emission with maximum wave length at 612 nm. It was shown that tetrakis complex in solution, solid-state and PVK films have enhanced photoluminescence properties compared to ternary complex due to four DBM molecules in Eu3+ coordination sphere, which leads to more effective excited energy transfer to Eu3+ ion. In THF solutions both complexes are characterized with low photoluminescence quantum yields (4% and 6%), in PVK films – moderate quantum yields (14–48%), but in solid state with high quantum yields (56% and 75%). Thermal properties for pure complexes and their PVK films were studied with thermogravimetric analysis. Both complexes exhibit high thermal degradation temperatures of 304 °C for ternary and 267 °C for tetrakis complex, but their PVK films show even higher degradation temperature (over 370 °C).


   1. Binnemans, K. Lanthanide-Based Luminescent Hybrid Materials. Chem. Rev., 2009, 109, 4283–4374.

   2. Singh, A. K., Singh, S. K., Mishra, H., Prakash, R., and Rai, S. B. Structural, Thermal, and Fluorescence Properties of Eu(DBM)3PhenxComplex Doped in PMMA. J. Phys. Chem. B, 2010, 114, 13042–13051.

   3. Liang, H., Xie, F., Liu, M., Jin, Z., Luo, F., and Zhang, Z. Luminescence studies of europium chelates with increasing benzene ring substituents ligand-doped polymer. Spectrochim. Acta, Part A, 2008, 71, 588–591.

   4. Ma, D.-G., Wang, D.-K., Hong, Z.-Y., Zhao, X.-J., Jing, X.-B., Song, F., et. al. Bright red electroluminescent devices based on a soluble lanthanide complex Eu(DBM)3(phen). Chin. J.Chem., 1998, 16(1), 1–6.

   5. Santos, G., Fonseca, F. J., and Andrade, A. M. The dependence of OLED external efficiency on the mass concentration of europium(III) dispersed in PVK. ECS Trans., 2011, 39(1), 475–480.

   6. Mech, A., Karbowiak, M., Görller-Walrand, C., and Van Deun, R. The luminescence properties of three tetrakis dibenzoyl­methaneeuropium(III) complexes with different counter ions. J. Alloys Compd., 2008, 451, 215–219.

   7. Malba, C. M., Enrichi, F., Facchina, M., Demitric, N., Plaisier, J. R., Natile, M. M., Selva, M., Riello, P., Perosa, A., and Benedetti, A. Phosphonium-based tetrakis dibenzoylmethane Eu(III) and Sm(III) complexes: synthesis, crystal structure and photoluminescence properties in a weakly coordinating phosphonium ionic liquid. RSC Adv., 2015, 5, 60898–60907.

   8. Zhou, D., Huang, C., Yaong, G., Bai, J., and Li, T. Luminescent europium-dibenzoylmethane complexes and their Langmuir–Blodgett films, J. Alloys Compd.,1996, 235, 156–162.

   9. Zawadiak, J. and Mrzyczek, M. Influence of substituent on UV absorption and keto–enol tautomerism equilibrium of dibenzoylmethane derivatives. Spectrochim. Acta Part A Mol. Biomol. Spectrosc., 2012, 96, 815–819.

10. Wang, D., Zheng, C., Fan, L., Zheng, J., and Wei, X. Preparation and fluorescent properties of europium(III) complexes with b-diketone ligand and 1,10-phenantroline. Synth. Met., 2012, 162, 2063–2068.

11. Biju, S., Xu, L.-J., Sun, C.-Z., and Chen, Z.-N. White OLEDs based on a novel EuIII-tetrakis-b-diketonate doped into 4,4’-N,N’-dicarbazlebiphenyl as emitting material. J. Mater. Chem. C, 2015, 3, 5775–5782.

12. Biju, S., Freire, R. O., Eom, Y. K., Scopelliti, R., Bunzli, J.-C.G., and Kim, H. K. A EuIII tetrakis (b-diketonate) dimeric complex: photophysical properties, structural elucidation by sparkle/AM1 calculations, and doping into PMMA films and nanowires. Inorg. Chem., 2014, 53, 84078417.

13. Li, W., Yan, P., Hou, G., Li, H., and Li, G. Efficient red emission from PMMA films doped with 5,6-DTFI europium(III) complexes: synthesis, structure and photophysical properties. Dalton Trans., 2013, 42, 1153711547.

14. Ma, Q., Zheng, Y., Armaroli, N., Bolognesi, M., and Accorsi, G. Synthesis and photoluminescence properties of asymmetrical europium(III) complexes involving carbazole, phenanthroline and bathophenanthroline units. Inorg. Chem. Acta, 2009, 362, 3181–3186.

15.  Yu, G., Liu, Y., Wu, X., and Zhu, D. Soluble europium complexes for light-emitting diodes. Chem. Mater., 2000, 12, 2537–2541.

16. Deichmann, V. A. F., Novo, J. B. M., Cirpan, A., Karasz, F. E., and Akcelrud, L. Photo- and electroluminescent behaviour of Eu3+ ions in blends with poly(vinyl-carbazole). J. Braz. Chem. Soc., 2007, 18(2), 330336.

17. Raj, D. B. A., Francis, B., Reddy, M. L. P., Butorac, R. R., Lynch, V. M., and Cowley, A. H. Highly luminescent poly(methyl methacrylate)-incorporated europium complex supported by a carbazole-based fluorinated β-diketonate ligand and a 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene oxide co-ligand. Inorg. Chem., 2010, 49, 9055–9063.

18. Forster, P. L., Parra, D. F., Lugao, A. B., Kai, J., and Brito, H. F. Highly luminescent polycaprolactone films doped with diaquatris (thenoyltrifluoroacetonate) europium(III) complex. J. Lumin., 2015, 167, 85–90.


Back to Issue