Preparation and fluorescent properties of europium (III) complexes with β-diketone ligand and 2,2-dipyridine or 1,10-phenanthroline

Synthesis and spectroscopic behavior of highly luminescent trinuclear europium complexes with tris-β-diketone ligand

“…The results indicated these trinuclear europium complexes presented the higher luminescence quantum efficiency, especially complexes C2 (g = 46.5%) and C3 (g = 47.4%), which was in agreement with the results from their luminescence emission intensity. From these results, the trinuclear europium complexes C2 and C3 have much longer lifetime values and much higher quantum efficiency as compared to their corresponding dibenzoylmethane (DBM) mononuclear europium complexes, such as Eu(DBM) 3 ÁPhen (s = 0.503 ms, g = 31.3%) [22], Eu(4-methoxy-DBM) 3 ÁBipy (s = 0.25 ms, g = 25.2%) [10], Eu(alkoxy-DBM) 3 ÁBipy (s = 0.24 ms, g = 20-23%) [23], which due to the effect of two additional europium (III) ion lumophors in trinuclear complexes. Therefore, the introduction of ligands with multiple binding sites in europium complexes could effectively improve the luminescent properties of europium complexes.…”

“…Consequently, many europium complexes with the high absorption coefficient ligands, especially b-diketone ligands, have been designed and synthesized [6][7][8]. Recently, we also reported some new europium complexes with b-diketone ligands and investigated their photoluminescence properties [9,10].…”

Synthesis, photoluminescent features and intramolecular energy transfer mechanism of europium (III) complexes with fluorinate β-diketone ligand and auxiliary ligands

“…The proton signal of enolic -OH at 15.01 ppm and keto -CH 2 protons peak at 4.22 ppm are missing from complexes spectra indicating that the enolic -OH involved in coordination. The enolic -CH proton of ligand exhibits a singlet at 6.35 ppm which is shifted to upfield at 3.20-2.80 ppm in complexes, signifying the paramagnetism of lanthanide ion [21]. The multiplet of benzene protons in ligand is moved toward higher field in the spectra of complexes.…”

Preparation and photoluminescence of some europium (III) ternary complexes with β-diketone and nitrogen heterocyclic ligands

“…However, the absorption and emission cross section of europium complexes is small because of the forbiddance for its 4f-4f electronic transitions. To improve their luminescence intensity, many europium complexes have been reported in recent years [9][10][11]. In most cases, the luminescent europium complexes contain a europium ion and its organic ligand as a photosensitizer.…”