| Autor: |
Eli M. Espinoza, John A. Clark, Cassio Pacheco da. Silva, James B. Derr, Gustavo Thalmer de Medeiros Silva, Mimi K. Billones, Maryann Morales, Frank H. Quina, Valentine I. Vullev |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
|
| Zdroj: |
Journal of Photochemistry and Photobiology, Vol 10, Iss , Pp 100110- (2022) |
| Druh dokumentu: |
article |
| ISSN: |
2666-4690 |
| DOI: |
10.1016/j.jpap.2022.100110 |
| Popis: |
Pyranoflavylium cations are synthetic analogues of pyranoanthocyanin, colored pigments, formed from grape anthocyanins during the maturation of red wines. Studies of a series of monosubstituted pyranoflavylium cations, ranging from methoxy (PF+-OMe) to cyano (PF+-CN), have shown that they display fluorescence and form triplet states that sensitize singlet oxygen formation in acidified acetonitrile. In alcohol-water mixtures, they behave as photoacids, undergoing adiabatic excited state proton transfer (ESPT) to water on a picosecond timescale, as confirmed in this report by femtosecond pump-probe spectroscopy. In contrast, the corresponding dimethylamino substituted pyranoflavylium cation (PF+-NMe2) is virtually non-fluorescent under the same conditions and exhibits a long-wavelength absorption band that has been attributed to a charge-transfer (CT) transition. Indeed, pump-probe spectroscopy of PF+-NMe2 in acidified acetonitrile shows ultrafast ( |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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