Manipulation of the Reactivity of a Synthetic Anthocyanin Analogue in Aqueous Micellar Media
| Autor: | Paulo F. Moreira, António L. Maçanita, Adilson A. Freitas, Chang Yihwa, Marilene Bargas Rodrigues Alves, Frank H. Quina, João C. Lima, Carolina Vautier-Giongo |
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| Rok vydání: | 2002 |
| Předmět: |
Aqueous solution
Cationic polymerization Protonation Surfaces and Interfaces Condensed Matter Physics Micelle Medicinal chemistry chemistry.chemical_compound Deprotonation Reaction rate constant chemistry Electrochemistry Organic chemistry General Materials Science Sodium dodecyl sulfate Hydrate Spectroscopy |
| Zdroj: | Langmuir. 18:10109-10115 |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | The effects of anionic, cationic, and nonionic micelles on the dynamics of proton transfer in the ground and excited state of anthocyanins have been examined employing the 4-methyl-7-hydroxyflavylium ion (HMF) as a model compound. Unlike other anthocyanins and anthocyanin analogues, HMF does not hydrate in water, allowing study of the acid−base (AH+/A) equilibrium in the absence of competing hydration or tautomerism reactions. Anionic sodium dodecyl sulfate (SDS) micelles are found to stabilize the acid form of HMF, AH+, relative to A, while both cationic hexadecyltrimethylammonium chloride and nonionic Triton X-100 and Brij 35 micelles stabilize A more than AH+. Stabilization in SDS is reflected in the decrease of the deprotonation rate constant (ca. 40-fold relative to water), while destabilization in cationic and nonionic micelles is evidenced by a decrease in the protonation rate of A. Surprisingly, HMF is no longer resistant to hydration in cationic and nonionic micelles. Thus, one can manipulate the... |
| Databáze: | OpenAIRE |
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