Synthesis, fluorescence properties of Eu(III) complexes with novel carbazole functionalized β-diketone ligand

A novel carbazole functionalized β-diketone, methyl 6-(9-ethylcarbazole-3-yl)-oxoacetyl-2-pyridinecarboxylate (MEP), and its corresponding binary Eu(III) complexes Eu(MEP) 3 ·2H 2 O and ternary complex Eu(MEP) 3 Phen with 1,10-Phenanthroline (Phen) were prepared. The ligand was characterized based on elemental analysis, FT-IR, and 1 H NMR, and the complexes were characterized with elemental analysis, FT-IR and thermogravimetric and differential thermal analysis (TG-DTA). The investigation of fluorescence properties of the complexes Eu(MEP) 3 ·2H 2 O and Eu(MEP) 3 Phen showed that the Eu(III) ion could be sensitized efficiently by the ligand to some extent, in particular, in the ternary system, the secondary ligand Phen acting as a light-harvesting center was involved in the highly efficient energy transfer process, and the emission was stronger than the binary complex. In addition, the introduction of the carbazole moiety enlarged the π-conjugated system of the ligand and enhanced the luminescent intensity of the complexes.