Acid Effect on Photobase Properties of Curcumin
Autor: | Yuval Erez, Dan Huppert, Rinat Gepshtein, Tal Schwartz, Katherine Akulov, Ron Simkovitch |
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Rok vydání: | 2014 |
Předmět: | |
Zdroj: | The Journal of Physical Chemistry A. 118:2470-2479 |
ISSN: | 1520-5215 1089-5639 |
DOI: | 10.1021/jp501061p |
Popis: | Femtosecond UV-vis pump-probe spectroscopy was employed to study the acid effect on curcumin in the excited state. Curcumin in solutions of weak acids was found to be a photobase forming a protonated curcumin within a few tens of picoseconds from the time of excitation. The excited-state protonation reaction is also observed in the steady-state emission spectrum as a new red emission band with a maximum at 620 nm in the presence of weak acids. The transient pump-probe spectrum consists of four spectral bands, two emission bands, and two absorption bands. We assign a transient absorption band at ∼600 nm and an emission band at ∼540 nm to the neutral ROH form of curcumin. An absorption band at ∼500 nm and an emission band at 620 nm are assigned to the protonated ROH2(+) form of curcumin. |
Databáze: | OpenAIRE |
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