15773-12-3Relevant academic research and scientific papers
Oxidation of phenols employing polyoxometalates as biomimetic models of the activity of phenoloxidase enzymes
Galli, Carlo,Gentili, Patrizia,Nunes Pontes, Ana Sofia,Gamelas, Jose A. F.,Evtuguin, Dmitry V.
, p. 1461 - 1467 (2007)
A kinetic study of the oxidation of substituted phenols with either vanadium(v) polyoxotungstate, [α-SiVVW11O 40]5- (viz. SiW11V), or manganese(iii) polyoxotungstate, [α-SiMnIIIW11/su
Hydrogen atom abstraction kinetics from intramolecularly hydrogen bonded ubiquinol-0 and other (poly)methoxy phenols
De Heer, Martine I.,Mulder, Peter,Korth, Hans-Gert,Ingold, Keith U.,Lusztyk, Janusz
, p. 2355 - 2360 (2000)
The effect of methoxy substitution on the abstraction of the phenolic hydrogen atom involved in intramolecular hydrogen bonding by tert-butoxyl and cumyloxyl radicals has been investigated by laser flash photolysis. Also transition state calculations for
Kinetic and thermodynamic parameters for the equilibrium reactions of phenols with the dpph. radical
Foti, Mario C.,Daquino, Carmelo
, p. 3252 - 3254 (2006)
The kinetics and energetics of the reversible reaction of phenols with the dpph. radical have been studied; steric shielding of the divalent N by the o-NO2 in dpph. seems to be the main cause of the entropic barriers of this reaction. The Royal Society of Chemistry 2006.
Absolute rate constants for some intermolecular reactions of α-aminoalkylperoxyl radicals. Comparison with alkylperoxyls
Lalevee, Jacques,Allonas, Xavier,Fouassier, Jean-Pierre,Ingold
, p. 6489 - 6496 (2008/12/22)
(Graph Presented) Seven α-aminoalkylperoxyl radicals have been generated by 355 nm laser flash photolysis (LFP) of oxygen-saturated di-tert-butyl peroxide containing mono-, di-, and trialkylamines and a dialkylarylamine. All these peroxyls possess absorptions in the near-UV (strongest for the trialkylamine-derived peroxyls) which permits direct monitoring of the kinetics of their reactions with many substrates. The measured rate constants for hydrogen atom abstraction from some phenols and oxygen atom transfer to triphenylphosphine demonstrated that all seven α- aminoalkylperoxyls have similar reactivities toward each specific substrate. More importantly, a comparison with literature data for alkylperoxyls shows that α-aminoalkylperoxyls and these alkylperoxyls have essentially the same reactivities. The combination of LFP and alkylamines provides a quick, reliable method for determining absolute rate constants for alkylperoxyl radical reactions, an otherwise laborious task.
Effect of Solvation on the Bond Dissociation Energies of Phenolic Antioxidants
Pedrielli, Pamela,Pedulli, Gian Franco
, p. 509 - 512 (2007/10/03)
The effect of solvent on the bond dissociation energies (BDEs) of the oxygen-hydrogen bond in substituted phenolic antioxidants has been investigated by means of an EPR technique.On changing the solvent from benzene to tert-butanol the BDE's were found to increase by ca. 2.2 kcal/mol for phenols without ortho substituents, by ca. 1 kcal/mol for 2,6-dimethyl substituted phenols while in 2,6-di-tert-butyl phenols they seem to be substantially unaffected.This behaviour has been interpreted by admitting that the BDE increase observed in tert-butanol is essentially due to the solvation of the hydroxylic hydrogen which stabilises the phenol, leaving the energy of the phenoxyl radical unaltered.Thus, solvation effects are expected to be large with unhindered phenols and relatively unimportant in phenols containing bulky substituents in the proximity of the OH group.
Antioxidation Mechanisms of Uric Acid
Simic, Michael G.,Jovanovic, Slobodan V.
, p. 5778 - 5782 (2007/10/02)
One-electron oxidation of uric acid generates the urate radical, which was studied in aqueous solution by pulse radiolysis and oxygen-uptake measurements.Acid-base properties of the uric acid radical were determined, i.e., pKa1 = 3.1 +/- 0.1 and pKa2 = 9.5 +/- 0.1.The reaction of the radical with oxygen was too slow to be measured, k 3 mol-1 s-1.The one-electron-redox potential vs NHE, E7 = 0.59 V, was derived from the pH dependence of the redox potential, which was fitted trough the values measured at pH 7 and 8.9 and those previously at pH 13.Rapid reactions of uric acid with oxidizing species and peroxy radicals were indicative of uric acid as a possible water-soluble physiological antioxidant.Rapid reaction of uric acid with the guanyl radical indicates that uric acid may also act as a repair agent of oxidative damage to DNA bases.
