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Structures, luminescence and vibrational spectroscopy of europium and terbium nitro- and dinitro-substituted benzoates. Nitro groups as quenchers of Ln3+ luminescenceстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 марта 2017 г.
- Авторы: Tsaryuk V., Kudryashova V., Gawryszewska P., Szostak R., Vologzhanina A., Zhuravlev K., Klemenkova Z., Legendziewicz J., Zolin V.
- Журнал: Journal of Photochemistry and Photobiology A: Chemistry
- Том: 239
- Год издания: 2012
- Издательство: Elsevier BV
- Местоположение издательства: Netherlands
- Первая страница: 37
- Последняя страница: 46
- DOI: 10.1016/j.jphotochem.2012.04.022
- Аннотация: The nitro-substituted benzoates Ln(NBenz)3·nH2O, Ln(DNBenz)3·nH2O, Ln(NBenz)3·L·nH2O and Ln(DNBenz)3·L·nH2O (Ln = Eu, Tb; NBenz = 2- and 4-nitrobenzoate anions, DNBenz = 3,5- and 2,5-dinitrobenzoate anions; L = Phen and Bpy) were investigated by methods of luminescence and vibrational Raman and IR spectroscopy. The crystal structures of [Eu(4-NBenz)3·(H2O)2]·0.5H2O and [Eu2(4-NBenz)6·Bpy2·(H2O)2]·2H2O (1) were solved by X-ray diffraction methods. Known structural data for lanthanide nitrobenzoates are analyzed. The influence of NO2 groups located in different positions of benzene ring on the structure of Ln3+ coordination centre and on processes of the excitation energy transfer to Ln3+ ion was studied. The presence of electron-withdrawing nitro groups at aromatic ring of the ligand dramatically decreases Eu3+ and Tb3+ luminescence efficiencies. This fall amounts to factor ∼10^2 in comparison with europium and terbium benzoates. Low sensitization efficiency of Ln3+ luminescence in nitrobenzoates is caused by a dissipation of the excitation energy through the ligand View the MathML sourceSnπ* excited state corresponding to transition between the NO2 oxygen lone pairs orbital and the π* orbital of nitrobenzoate ligand. A low energy of the ligand View the MathML sourceTnπ* state in comparison with Tb3+5D4 state makes for a supplementary reduction of the sensitization of Tb3+ luminescence. In ternary compounds, an interligand energy transfer from the Phen or Bpy molecule to nitrobenzoate anion with following quenching due to the nitrobenzoate non-radiative relaxation is observed.
- Добавил в систему: Вологжанина Анна Владимировна