Generation, Characterization, and Deprotonation of Phenol Radical Cations1

  1. Get@NRC: Generation, Characterization, and Deprotonation of Phenol Radical Cations1 (Opens in a new window)
DOIResolve DOI:
AuthorSearch for: ; Search for: ; Search for:
Journal titleJ. Phys. Chem. A
Journal of Physical Chemistry A
Pages88348839; # of pages: 6
AbstractA variety of methoxy- and methyl-substituted phenol radical cations have been generated and characterized by laser flash photolysis in solution under ambient conditions. The radical cations were generated by either photosensitized electron transfer using 1,4-dicyanonaphthalene with biphenyl as a cosensitizer in acetonitrile or by direct excitation of the phenol at 266 nm. The phenol radical cations have absorption maxima between 410 and 460 nm, with the exception of the 3,5-dimethoxyphenol which absorbs at 580 nm. The assignment of the observed transients to phenol radical cations is based on their spectral similarity to matrix spectra for the same species and to the corresponding methoxybenzene radical cations, as well as their characteristic reactivity. In the presence of small amounts of water the radical cations are not detected and the phenoxyl radical is the only observed transient in the photosensitized electron transfer. For those phenols for which authentic phenoxyl spectra are not available, the identity of the radical was confirmed by its generation by hydrogen abstraction by the tert-butoxyl radical. Although several of the phenols can be photoionized in either 1:1 aqueous ethanol or in acetonitrile, this is a less general route for the formation and characterization of the phenol radical cations. The rate constants for deprotonation of the phenol radical cations by water were measured and fall within the range (0.6-6) ? 108 M-1 s-1; the 2-methoxyphenol radical cation is more reactive than the 4-methoxy, consistent with a recent estimate of the pKa for these species.
Publication date
AffiliationNational Research Council Canada; NRC Steacie Institute for Molecular Sciences
Peer reviewedNo
NPARC number12338215
Export citationExport as RIS
Report a correctionReport a correction
Record identifiercaf919f3-37cd-4be2-900a-297854c69a49
Record created2009-09-10
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)