A reversible one-electron oxidation of tris(4-bromophenyl)amine (TBPA) in acetonitrile or 1-butyl-3-methylimidazoliumhexafluorophosphate [BMIm][PF6] media unambiguously generates the cation-radical (TBPA
+), and its reduced form is catalytically regenerated in a follow-up chemical reaction with benzyl alcohol in the presence of 2,6-lutidine. The electron-transfer kinetics for these transformations has been investigated by a detailed comparison of the results obtained in both media. The apparent standard heterogeneous rate constant
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for an interfacial single-electron transfer of the mediator in acetonitrile containing 0.1 M Et
4NClO
4 was estimated using cyclic voltammetry (CV) profiles within a wide range of sweep rates (20–1000 mV s
−1). The slightly higher
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value for the TBPA/TBPA
+ couple at a Pt electrode surface was found to be (2.1 ± 0.8) 10
−2 cm s
−1 compared to (1.4 ± 0.6) 10
−2 cm s
−1 at a glassy carbon (GC) surface.
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values estimated in [BMIm][PF6] are comparatively two orders of magnitude lower (6.6 ± 0.5 × 10
−4 cm s
−1 and 4.9 ± 0.4 × 10
−4 cm s
−1 at Pt and GC, respectively). It has been found that the second-order homogeneous rate constant for the oxidation of benzyl alcohol by TBPA
+ in acetonitrile (12.10 M
−1 s
−1) was estimated to be greater by one order of magnitude than that in ionic liquid [BMIm][PF6] (4.20 M
−1 s
−1). Similar experiments carried out for the oxidation of 2-chlorobenzyl alcohol, 4-
tert-butylcyclo hexanol and 4-methylcyclohexanol by the TBPA
+ showed no noticeable catalytic effect due to large potential difference of the mediator (
Ep/2 = 0.74 V vs. Fc/Fc
+), compared with those of the substrates.