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Publication 576
J. Am.
Chem. Soc., 125 (48), 14801 -14806, 2003
DOI: 10.1021/ja0374574 S0002-7863(03)07457-2 |
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The Standard Redox Potential of the Phenyl Radical/Anion Couple
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Claude
P. Andrieux and JeanPinson
Contribution from the Laboratoire d'Electrochimie
Moléculaire, Université de Paris 7 - Denis Diderot,
Case Courrier 7107, 2 place Jussieu, 75251 Paris Cedex 05, France.
E-mail: andrieux@paris7.jussieu.fr;
jean.pinson@laposte.net
The voltammogram of aryldiazonium tetrafluoroborates in acetonitrile
(ACN), at low concentration, shows a first one-electron wave followed
at a more negative potential by a small second wave; this last one corresponds
to the reduction of the radical formed at the level of the first wave.
Simulation of the voltammogram permits one to determine the standard
redox potential of the radical/anion couple E° (Ph /Ph-)
= 0.05 V/SCE and the reduction mechanism of the diazonium cation. An
electron transfer concerted with the cleavage of the C-N bond furnishes
the aryl radical; this radical undergoes two competitive reactions: reduction
at the electrode and H-atom transfer. |
