The nature of the effect of Gd(III) on fluorescence of Ln(III) chelates in water solutions
| Autor: | Valerii L Ermolaev, E. V. Krutineva, V. E. Lanin, E. B. Sveshnikova |
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| Rok vydání: | 2001 |
| Předmět: | |
| Zdroj: | Optics and Spectroscopy. 90:674-679 |
| ISSN: | 1562-6911 0030-400X |
| Popis: | The intensity of fluorescence of Eu(III) and Sm(III) ions sensitized by molecules of n-benzoyltrifluoroacetone and 1,10-phenanthroline introduced in a water solution in a ratio of 3: 1 is studied as a function of the ion concentration in the solution. The comparison of the fluorescence decay curves of Eu(III) and Sm(III) in D2O and H2O (pH≥7) solutions containing 10−4 M of n-Cl-BTFA and 3×10−5 M of 1,10-phen and the values of τfl of Sm(III) in themselves (51–90 μs) are indicative of an insignificant content of water molecules in the first coordination sphere of ions. The effect of other ions on I fl and τfl of Eu(III) ions is studied under these conditions. The intensity of fluorescence of Eu(III) in solutions of 10−4 M Cl-BTFA and 3×10−5 H 1,10-phen is found to increase by 1–2 orders of magnitude in the presence of Y(III) and Gd(III) ions, and the magnitude of this effect is unaffected by deoxygenation of the solution. The introduction of a third ion Nd(III) in the solution is shown to attenuate the influence of Gd(III) on I fl of Eu(III) for Nd(III) concentrations commensurable with the Eu(III) concentration in the solution. The strength of the influence of Gd(III) ions on I fl of Eu(III) is found to depend on the method of preparation of the solution. The analysis of the results obtained testifies that inhomogeneities consisting of chelates of lanthanide ions displaced from the water structure appear in water. The presence of these inhomogeneities results in efficient energy transfer from ligands of Gd(III) chelates to Eu(III) chelates, which is the reason for the increasing I fl of Eu(III). The possibility of using data on the enhancement of I fl of Eu(III) in the presence of Gd(III) and on the reduction of τfl of Eu(III) in the presence of Nd(III) for estimating dimensions and structures of displaced systems is discussed. |
| Databáze: | OpenAIRE |
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