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Photoacidity of the 7‐Hydroxyflavylium Cation.
- Source :
- Photochemistry & Photobiology; Nov/Dec2019, Vol. 95 Issue 6, p1339-1344, 6p
- Publication Year :
- 2019
-
Abstract
- Theoretical descriptions of excited state proton transfer (ESPT) have had various degrees of success. This work presents a theoretical description of the photodissociation of the 7‐hydroxyflavylium cation (7‐HF), the fundamental chromophoric moiety of anthocyanin natural plant pigments. ESPT of 7‐HF is promoted by a significant shift of charge away from the OH group in the first singlet excited state, leading smoothly to the excited conjugate base and a protonated water cluster. Several factors contribute to the consistency of the results of the present study: (1) the theoretical approach (TD‐DFT with the B3‐LYP functional and def2‐TZVP basis set utilizing Grimme's D3 dispersion correction); (2) the modeling of the solvent effect combining hydrogen bonding of the photoacid to a cluster of discrete water molecules in a water‐like continuum solvent (COSMO); (3) the large S1‐S2 energy gap of flavylium cations; and (4) the electrostatics of the ESPT in which a proton is transferred from a cationic photoacid to water without Coulombic interaction between the proton and the conjugate base. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00318655
- Volume :
- 95
- Issue :
- 6
- Database :
- Complementary Index
- Journal :
- Photochemistry & Photobiology
- Publication Type :
- Academic Journal
- Accession number :
- 139824348
- Full Text :
- https://doi.org/10.1111/php.13139