Fluorescence properties of mixed-ligand europium carboxylates

Synthesis, Structure, and Luminescence of Mixed-Ligand Lanthanide Trifluoroacetates

“…The energies of singlet states are estimated using the onsets of the absorption edges observed in the reflectance spectra given in Figure a. Following this approach, the first excited singlet of tfa may be located at ≈42100 cm –1 (S 1 ), in good agreement with previous spectroscopic studies of lanthanide trifluoroacetates. − ,, In the case of 4-cpno, the first two excited singlets of 4-cpno appear to be located at 27954 cm –1 (S 1 , n → π*) and 36325 cm –1 (S 2 , π → π*); both values are in excellent agreement with those previously reported for pyridine N -oxide. − The positions of the lowest-lying triplet states (T 1 ) are estimated using the highest-energy edge of the emission bands observed in the phosphorescence spectra shown in Figure b. The spectrum of Gd­(tfa) 3 (H 2 O) 3 exhibits two peaks at 23320 and 21858 cm –1 .…”

“…This strategy is commonly used in the design and synthesis of mono- and polynuclear luminescent lanthanide complexes . Following this approach, mixed-ligand lanthanide trifluoroacetates featuring 2,2′-bipyridine, ,− 1,10-phenanthroline, ,, diphenylguanidine, tris­[3-(2′-pyridyl)­pyrazolyl]­borate, triphenylphosphine oxide, and hexamethylphosphotriamide have been synthesized. Unfortunately, these studies did not report luminescence quantum yields and sensitization efficiencies.…”