2194-09-4Relevant academic research and scientific papers
Hydrogen-Abstraction Reactivity of Excited-State Para-Substituted Benzyl Radicals in Solution at Room Temperature
Tokumura, Kunihiro,Ozaki, Tomomi,Itoh, Michiya
, p. 5999 - 6004 (1989)
In contrast to almost no H-abstraction reactivity of the ground-state para-substituted benzyl radicals (p-X-benzyls: X=CN, Cl, F, and OCH3) toward 1,4-cyclohexadiene (CHD), a significant fluorescence quenching by CHD in hexane at room temperature was conf
Electron Spin Resonance Studies. Part 71. Side-chain Oxidation Pathways in the Reactions of .OH and SO4-. with Some Phenyl-substituted Carboxylic Acids, their Anions, and Some related Compounds
Gilbert, Bruce C.,Scarratt, Cathryn J.,Thomas, C. Barry,Young, John
, p. 371 - 380 (2007/10/02)
A series of arene radical-cations has been generated in situ by the reactions of methylbenzene, phenylethanoic acid, and some derivatives and cyclic analogues with both SO4-. and .OH (the latter in acid solution).The results are interpreted in terms of a variety of subsequent rapid reactions including hydration, deprotonation (to give benzylic radicals), and fragmentation (decarboxylation: for a series of radical-zwitterions +.Ar(CH2)nCO2- (n=1-3) decarboxylation (k >/= 1E9 dm3 mol-1 s-1) appears to proceed via direct intramolecular elecron-transfer, though in some cases formation of a discrete ?-bonded intermediate cannot be ruled out.
Substituent Effects on Benzyl Radical ESR Hyperfine Coupling Constants. The ?α*Scale Based upon Spin Delocalization
Dust, Julian M.,Arnold, Donald R.
, p. 1221 - 1227 (2007/10/02)
The electron spin resonance spectra of 21 para- and meta-substituted benzyl radicals have been analyzed.A substituent constant, ?α*, has been defined from the benzylic α-hydrogen hyperfine coupling constant.The ?α* constant reflects the component of energy that may be attributed to spin delocalization in a substituted benzyl radical in comparison to the unsubstituted radical.For the derivatives studied, para substitution is stabilizing, except when fluorine is the substituent; meta substitution destabilizes the benzyl radical.A series of radical reactions is reexamined with an extended Hammett relation.The relative importance of spin delocalization vs. polar effects is assessed by the ratio of ρ* to ρ.The importance of choosing substituents for which ?a* and ? differ widely for such an assessment is emphasized.
