Issue 13, 2022, Issue in Progress

Concentration-dependent HAT/ET mechanism of the reaction of phenols with 2,2-diphenyl-1-picrylhydrazyl (dpph˙) in methanol

Abstract

The reaction of a 2,2-diphenyl-1-picrylhydrazyl radical (dpph˙) with phenols carried out in alcohols is a frequently used assay for estimation of the antiradical activity of phenolic compounds. The rates of reactions of dpph˙ with five phenols (ArOH: unsubstituted phenol, 4-hydroxyacetophenone, two calix[4]resorcinarenes and baicalein) measured in methanol indicate the different kinetics of the process for very diluted phenols compared to their non-diluted solutions. This effect was explained as dependent on the ratio [ArO]/[ArOH] and for diluted ArOH corresponds to an increased contribution of much faster electron transfer (ET, ArO/dpph˙) over the Hydrogen Atom Transfer (HAT, ArOH/dpph˙). Simplified analysis of the reaction kinetics resulted in estimation of kET/kHAT ratios for each studied ArOH, and in calculation of the rate constants kET. Described results are cautionary examples of how the concentration of a phenol might change the reaction mechanism and the overall kinetics of the observed process.

Graphical abstract: Concentration-dependent HAT/ET mechanism of the reaction of phenols with 2,2-diphenyl-1-picrylhydrazyl (dpph˙) in methanol

Supplementary files

Article information

Article type
Paper
Submitted
16 Feb 2022
Accepted
01 Mar 2022
First published
15 Mar 2022
This article is Open Access
Creative Commons BY license

RSC Adv., 2022,12, 8131-8136

Concentration-dependent HAT/ET mechanism of the reaction of phenols with 2,2-diphenyl-1-picrylhydrazyl (dpph˙) in methanol

P. Przybylski, A. Konopko, P. Łętowski, K. Jodko-Piórecka and G. Litwinienko, RSC Adv., 2022, 12, 8131 DOI: 10.1039/D2RA01033J

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements