Luminescence of dipicolinic complexes of lanthanide ions

Autor: Valerii L Ermolaev, B. M. Bolotin, T. A. Shakhverdov, V. E. Lanin, R. U. Safina, P. A. Shakhverdov, E. B. Sveshnikova
Rok vydání: 2003
Předmět:
Zdroj: Optics and Spectroscopy. 95:898-907
ISSN: 1562-6911
0030-400X
Popis: The luminescence decay times τlum of the complexes of the ions Tb(III), Eu(III), Sm(III), Dy(III), and Yb(III) with dipicolinic acid (DPA) dissolved in protonated and deuterated water, methanol, and dimethyl sulfoxide are measured. The values of τlum for crystals H3[Ln(DPA)3]·nH2O and their aqueous solutions coincide, which points to the identity of the environment in the nearest spheres of an ion in both cases. A comparison of τlum of solutions of the complexes in H2O and D2O, as well as in CH3OH, CH3OD, CD3OD, DMSO-h 6, and DMSO-d 6 shows that the molecular groups in the second and third spheres of an ion, exhibiting high-frequency vibrations, have a noticeable effect on the rate constants of nonradiative transitions k nr in the ion. From this comparison, some inferences on the structure of the solvate shell of the Ln(DPA) 3 3− complexes in the solvents used are made. The contributions to k nr of Eu(III), Tb(III), Sm(III), Dy(III), Nd(III), and Yb(III) made by OH and CH groups located at different distances from the ion are estimated. It is demonstrated that the dependence of k nr on the distance to the OH and CH groups is steeper for the Eu(III) and Tb(III) ions than for the remaining ions.
Databáze: OpenAIRE