Journal
JOURNAL OF PHYSICAL CHEMISTRY B
Volume 116, Issue 24, Pages 7154-7161Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jp3033337
Keywords
-
Categories
Funding
- Natural Science Foundation of China [20803091, 20933010]
- Fundamental Research Funds for the Central Universities (RUC) [10XNI007]
- Danish Research Council for Independent Research, Technology and Production Science [09-065906/FTP]
Ask authors/readers for more resources
In the reaction between trans-resveratrol (resveratrol) and the hydroxyl radical, kinetic product control leads to a short-lived hydroxyl radical adduct with an absorption maximum at 420 nm and a lifetime of 0.21 +/- 0.01 mu s (anaerobic acetonitrile at 25 degrees C) as shown by laser flash photolysis using N-hydroxypyridine-2(1H)-thione (N-HPT) as a photo-Fenton reagent. The transient spectra of the radical adduct are in agreement with density functional theory (DFT) calculations showing an absorption maximum at 442 or 422 nm for C2 and C6 hydroxyl adducts, respectively, and showing the lowest energy for the transition state leading to the C2 adduct compared to other radical products. From this initial product, the relative long-lived 4'-phenoxyl radical of resveratrol (tau = 9.9 +/- 0.9 mu s) with an absorption maximum at 390 nm is formed in a process with a time constant (tau = 0.21 +/- 0.01 mu s) similar to the decay constant for the C2 hydroxyl adduct (or a C2/C6 hydroxyl adduct mixture) and in agreement with thermodynamics identifying this product as the most stable resveratrol radical. The hydroxyl radical adduct to phenoxyl radical conversion with concomitant water dissociation has a rate constant of 5 x 10(6) s(-1) and may occur by intramolecular hydrogen atom transfer or by stepwise proton-assisted electron transfer. Photolysis of N-HPT also leads to a thiyl radical which adds to resveratrol in a parallel reaction forming a sulfur radical adduct with a lifetime of 0.28 +/- 0.04 mu s and an absorption maximum at 483 nm.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available