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Chemistry and photochemistry of 2,6-bis(2-hydroxybenzilidene)cyclohexanone. An example of a compound following the anthocyanins network of chemical reactions.
- Source :
-
The journal of physical chemistry. A [J Phys Chem A] 2014 Aug 14; Vol. 118 (32), pp. 6208-15. Date of Electronic Publication: 2014 Aug 04. - Publication Year :
- 2014
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Abstract
- The kinetics and thermodynamics of the 2,6-bis(2-hydroxybenzilidene)cyclohexanone chemical reactions network was studied at different pH values using NMR, UV-vis, continuous irradiation, and flash photolysis. The chemical behavior of the system partially resembles anthocyanins and their analogue compounds. 2,6-Bis(2-hydroxybenzilidene)cyclohexanone exhibits a slow color change from yellow to red styrylflavylium under extreme acidic conditions. The rate constant for this process (5 × 10(-5) s(-1)) is pH independent and controlled by the cis-trans isomerization barrier. However, the interesting feature is the appearance of the colorless compound, 7,8-dihydro-6H-chromeno[3,2-d]xanthene, isolated from solutions of acid to neutral range, characterized by (1)H NMR and single crystal X-ray diffraction. Light absorption by 2,6-bis(2-hydroxybenzilidene)cyclohexanone solutions immediately after preparation exclusively results in cis-isomer as photoproduct, which via hemiketal formation yields (i) red styrylflavylium by dehydration under extremely acidic solutions (pH < 1) and (ii) colorless 7,8-dihydro-6H-chromeno[3,2-d]xanthene by cyclization in solutions of acid to neutral range.
Details
- Language :
- English
- ISSN :
- 1520-5215
- Volume :
- 118
- Issue :
- 32
- Database :
- MEDLINE
- Journal :
- The journal of physical chemistry. A
- Publication Type :
- Academic Journal
- Accession number :
- 25058169
- Full Text :
- https://doi.org/10.1021/jp505533b