Fluorescence and picosecond induced absorption from the lowest singlet excited states of quercetin in solutions and polymer films
| العنوان: | Fluorescence and picosecond induced absorption from the lowest singlet excited states of quercetin in solutions and polymer films |
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| المؤلفون: | Tamara F. Raichenok, S. L. Bondarev, O. V. Buganov, V. N. Knyukshto, Sergei A. Tikhomirov |
| المصدر: | Optics and Spectroscopy. 122:452-461 |
| بيانات النشر: | Pleiades Publishing Ltd, 2017. |
| سنة النشر: | 2017 |
| مصطلحات موضوعية: | Materials science, Absorption spectroscopy, 02 engineering and technology, Buffer solution, 010402 general chemistry, 021001 nanoscience & nanotechnology, Photochemistry, Internal conversion (chemistry), 01 natural sciences, Fluorescence, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, chemistry, Excited state, Singlet state, 0210 nano-technology, Absorption (electromagnetic radiation), Luminescence |
| الوصف: | The spectroscopic and photophysical properties of the biologically important plant antioxidant quercetin in organic solvents, polymer films of polyvinyl alcohol, and a buffer solution at pH 7.0 are studied by stationary luminescence and femtosecond laser spectroscopy at room temperature and 77 K. The large magnitude of the dipole moment of the quercetin molecule in the excited Franck–Condon state μeFC= 52.8 C m indicates the dipolar nature of quercetin in this excited state. The transient induced absorption spectra S1→Sn in all solvents are characterized by a short-wave band at λabsmax = 460 nm with exponential decay times in the range of 10.0–20.0 ps. In the entire spectral range at times of >100 ps, no residual induced absorption was observed that could be attributed to the triplet–triplet transitions Т1 → Тk in quercetin. In polar solvents, two-band fluorescence was also recorded at room temperature, which is due to the luminescence of the initial enol form of quercetin (~415 nm) and its keto form with a transferred proton (550 nm). The short-wave band is absent in nonpolar 2-methyltetrahydrofuran (2-MTHF). The spectra of fluorescence and fluorescence excitation exhibit a low dependence on the wavelength of excitation and detection, which may be related to the solvation and conformational changes in the quercetin molecule. Decreasing the temperature of a glassy-like freezing quercetin solution in ethanol and 2-MTHF to 77 K leads to a strong increase in the intensity (by a factor of ~100) of both bands. The energy circuits for the proton transfer process are proposed depending on the polarity of the medium. The main channel for the exchange of electronic excitation energy in the quercetin molecule at room temperature is the internal conversion S1 ⇝ S0, induced by the state with a proton transfer. |
| تدمد: | 1562-6911 0030-400X |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::e9d3a9c9d74d1ab16ca0a573db1c2c9e https://doi.org/10.1134/s0030400x17030031 |
| حقوق: | CLOSED |
| رقم الأكسشن: | edsair.doi...........e9d3a9c9d74d1ab16ca0a573db1c2c9e |
| قاعدة البيانات: | OpenAIRE |
Find this article in full text from Springer Verlag. | تدمد: | 15626911 0030400X |
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