Mixed-ligand terbium hydroxyaromatic carboxylates with o-phenanthroline: luminescence quenching at 300 and 77K

Photophysical studies of highly luminescent europium(III) and terbium(III) complexes functionalized with amino and mercapto groups

“…In order to verify that the deactivation channel is due to the energy transfer from the terbium(III) levels to the phen ligand levels the emission lifetime values were obtained at ∼298 K and ∼77 K ( Table 5). As one may see there is a two fold increase in the emission lifetime value of the [Tb(aba) 3 (phen)] complex at ∼77 K when compared with the value obtained at ∼298 K. The same tendency in emission lifetime values, at ∼298 K and ∼77 K, was found for complexes containing carboxylate and the phen ligands by Kuzmina and co-workers [33] and Zolin and co-workers [34].…”

Highly Luminescent, Water‐Soluble Lanthanide Fluorobenzoates: Syntheses, Structures and Photophysics, Part I: Lanthanide Pentafluorobenzoates

“…An example of a ligand with the same triplet‐state energy value (22 000 cm −1 ) that quenches terbium luminescence is o‐ phenanthroline 16a. Nevertheless, in the absence of vibrational quenching provided by anionic ligands it serves as an efficient sensitizer, such as in terbium mixed‐ligand chlorides or nitrates with o‐ phenanthroline 16b. The rather low quantum yield of δ‐Eu (PLQY=15 %; Table 3) can be caused by two possible reasons: 1) quenching by water molecules or 2) low efficiency of the energy transfer from the ligand to the Eu III ion, according to Equation (3): …”

“…We encompassed the scopeo fo ur search with fluorinated lanthanide aromatic carboxylates as an example of the latter approach.T his allows us to increaset he solubility of the complex due to enhanced intermolecular repulsion and to considerably reduce quenching through high-frequency CÀHv ibrations, which resultsi ne fficiency enhancement. [14,15,16] For instance, Roh and co-workers [17] observed a1 .5-fold increase in the NIR emission of erbium pentafluorobenzoateo ver erbium benzoate. Ye and co-workers [18] proved that fluorination of the organic ligand leads to an increase in the luminescence efficiency,w hich is reflected in the values of Judd-Ofelt parameters.…”

On the Structural Features of Substituted Lanthanide Benzoates

“…Among the mostly reported are NO 2 group, that dramatically quenches luminescence,, , and N 3 group was recently reported to be equally effective quencher . OH‐ and NH 2 groups are also known to quench lanthanide‐based luminescence …”