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Electronic Structure and Energy Transfer in Europium(III)–Ciprofloxacin Complexes: A Theoretical Studyстатья
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: 3 мая 2017 г.
- Авторы: Emelina Tatiana B., Freidzon Alexandra Ya, Bagaturyants Alexander A., Karasev Vladimir E.
- Журнал: The Journal of Physical Chemistry A: Molecules, Clusters, and Aerosols
- Том: 120
- Номер: 38
- Год издания: 2016
- Издательство: American Chemical Society
- Местоположение издательства: United States
- Первая страница: 7529
- Последняя страница: 7537
- DOI: 10.1021/acs.jpca.6b07258
- Аннотация: The structure and ligand-localized excited states of [Eu(cfqH)(cfq)(H2O)4]Cl2 (cfqH is ciprofloxacin) are studied by XMCQDPT2/CASSCF with full geometry optimization. The complex includes one anionic and one zwitterionic ligand. Two low-lying triplet states, both localized on the anionic ligand, are found. One of them has sufficient energy to transfer to the 5D1 sublevel of Eu3+, because its T−S0 vertical transition energy is equal (or very close) to the 7F0−5D1 Eu3+ excitation energy. The other triplet state has a very small S0−T1 gap, which favors fast nonradiative relaxation. Two other triplet states are localized on the zwitterionic ligand. One low-lying excited singlet state (S1) is localized on the anionic ligand; the other excited singlet is localized on the zwitterionic one. Spin−orbit coupling constants were calculated for the relaxed geometry of each state (ground state, two low-lying triplets, and one low-lying excited singlet) by spin−orbit configuration interaction (CI) with Pauli−Breit Hamiltonian. Large spin−orbit coupling constants between S1 and both triplets together with small energy gaps are indicative of fast intersystem crossing (ISC) from the excited singlet state to the triplet manifold. This ISC process is followed by energy transfer from the ligand-localized triplet states to the 5D1 sublevel of Eu3+. However, relatively large spin−orbit coupling constants between S0 and one of the triplet states together with the small T−S0 energy gap shows that this state can decay without transferring its energy to Eu3+. This mechanism is expected to be common for other Ln3+−fluoroquinolone complexes.
- Добавил в систему: Фрейдзон Александра Яковлевна