Related Experiment Video
Updated: Jun 21, 2026
![[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
Published on: May 21, 2019
Accurate oxidation potentials of benzene and biphenyl derivatives via electron-transfer equilibria and transient
Paul B Merkel1, Pu Luo, Joseph P Dinnocenzo
1Department of Chemistry and the Center for Photoinduced Charge Transfer, University of Rochester, Rochester, New York 14627-0216, USA. pmerkel@rochester.rr.com
Abstract:
Nanosecond transient absorption methods were used to determine accurate oxidation potentials (E(ox)) in acetonitrile for benzene and a number of its alkyl-substituted derivatives. E(ox) values were obtained from a combination of equilibrium electron-transfer measurements and electron-transfer kinetics of radical cations produced from pairs of benzene and biphenyl derivatives, with one member of the pair acting as a reference. Using a redox-ladder approach, thermodynamic oxidation potentials were determined for 21 benzene and biphenyl derivatives. Of particular interest, E(ox) values of 2.48 +/- 0.03 and 2.26 +/- 0.02 V vs SCE were obtained for benzene and toluene, respectively. Because of a significant increase in solvent stabilization of the radical cations with decreasing alkyl substitution, the difference between ionization and oxidation potentials of benzene is approximately 0.5 eV larger than that of hexamethylbenzene. Oxidation potentials of the biphenyl derivatives show an excellent correlation with substituent sigma+ values, which allows E(ox) predictions for other biphenyl derivatives. Significant dimer radical cation formation was observed in several cases and equilibrium constants for dimerization were determined. Methodologies are described for determining accurate electron-transfer equilibrium constants even when dimer radical cations are formed. Additional equilibrium measurements in trifluoroacetic acid, methylene chloride, and ethyl acetate demonstrated that solvation differences can substantially alter and even reverse relative E(ox) values.
More Related Videos
11:44Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
Published on: October 18, 2018
05:34Efficient Synthesis of Polyfunctionalized Benzenes in Water via Persulfate-promoted Benzannulation of α,β-Unsaturated Compounds and Alkynes
Published on: December 16, 2019
Related Concept Videos
Reactions at the Benzylic Position: Oxidation and Reduction
Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
NMR Spectroscopy of Benzene Derivatives
Electrophilic Aromatic Substitution: Chlorination and Bromination of Benzene
Structure of Benzene: Kekulé Model
He proposed that benzene has a cyclic structure of six carbon atoms attached to one hydrogen atom each, with three alternating pi bonds.
Electrophilic Aromatic Substitution: Sulfonation of Benzene