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Free Radical Scavenging Reactions of Tetrahydroxyquinone: A Pulse Radiolysis Study
Author(s) -
Joshi Ravi
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600030
Subject(s) - chemistry , radiolysis , radical , photochemistry , radical disproportionation , radical substitution , hydroxyl radical , redox , semiquinone , radical ion , free radical reaction , reaction rate constant , radical nucleophilic aromatic substitution , inorganic chemistry , disproportionation , ion , kinetics , organic chemistry , catalysis , nucleophilic aromatic substitution , quantum mechanics , nucleophilic substitution , physics
Free radical induced redox reaction kinetics and mechanism of tetrahydroxy‐1,4‐benzoquinone (THQ) has been studied using pulse radiolysis technique. THQ efficiently scavenged hydrated electron, superoxide radical anion, ethanol radical, hydroxyl radical, azidyl radical, thiocyanate radical anion, sulfate radical anion, haloperoxyl radical, lipid peroxyl radical, tryptophanyl radical and tyrosyl radical. Transient absorption spectra of THQ semiquinone radical anion, THQ radical cation and THQ radical produced with these free radicals and rate constants for these reactions have been studied. A probable mechanism of free radical induced redox reactions of THQ has been proposed. Reaction of THQ with free radicals and cyclic voltammetry measurements suggest its oxidation potentials at 0.81 V and 0.94 V vs NHE. To the best of our knowledge, free radical reactions of THQ have been reported for the first time.