Investigation of Metal Binding Sites on Soil Fulvic Acid Using Eu(III) Luminescence Spectroscopy

Investigation of Coordinational Properties of Europium(III) Complexes with Picolinic Acid Using Eu(III) Excitation Spectroscopy

“…This shift is considered to be due to a nephelauxetic effect, reflecting an increase in the metal-ligand bond covalency or a decrease in effective nuclear charge on the metal ion upon complexation. Some authors have reported that the coordination of one carboxylate group in cases of acetic and benzoic acids causes a shift of 0.25 nm to a longer wavelength (7,11). In our case, picolinic acid, the shift for the first three peaks can be explained well in terms of coordination by carboxylate groups, but the shift for the remaining three can not.…”

“…Can these three peaks correspond to 1:4, 1:5, and 1:6 complexes, respectively? We might find the answer from the experimental results obtained using acetic, benzoic, nicotinic, and isonicotinic acids (7,8). In those Eu(III) systems the maximum number of peaks was found to be 3, thereby reflecting that the species possibly present in the solution are limited only up to 1:3 complexes.…”

Laser-induced fluorescence study on the interaction of Eu(III) with polycarboxylates

“…Since humic substances can form metal complexes through carboxylate groups, synthetic polycarboxylic acids were often employed as polyetectrotyte analogues of humic substances. [5][6][7] On the other hand, the structural information on the interaction between the metal ion and humic acid or synthetic polycarboxylate is still limited. Laser-induced fluorescence spectroscopy (LIF) applied to Eu(III) aqueous species provides lots of information on local structure around Eu(III); in particular, the emission lifetime informs us of the number of water molecules in the first coordination sphere of Eu(III), noted as NH20 hereinafter.…”

3,4,5-Trisbenzyloxy benzoic acid as a new photo-sensitizer for Tb3+ion

“…Contrary to the above, Ana de BettencourtDias and Subha Viswanathan [7] observed quantum yields around 1% and 3% for Eu 3+ and Tb 3+ containing nitrobenzoate complexes in methanolic solutions. Due to their ecological importance, aromatic carboxylic acids have been widely studied as sensitizers for lanthanide ions [8]. Investigating the relationship between the structures of organic ligands and the energy levels of lanthanide ions will give scope for designing highly luminescent terbium organic complexes.…”