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Updated: May 26, 2026

Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyl(tropone)iron
Published on: August 12, 2019
Electrochemically induced reversible and irreversible coupling of triarylamines
Olena Yurchenko1, David Freytag, Lisa zur Borg
1Freiburg Institute for Advanced Studies & Institut für Makromolekulare Chemie, Universität Freiburg, Freiburg, Germany.
Abstract:
The electrochemical coupling and dimerization behavior of the low molecular compounds triphenylamine (TPA) and 9-phenylcarbazole (PHC) in comparison to tri-p-tolylamine (p-TTA) with para-blocked methyl groups has been investigated in detail. In contrast to the unsubstituted radical cations of TPA and PHC, the radical cations of p-TTA are stable in the radical cation state and do not undergo any further coupling reactions. However, we found that the dicationic state of p-TTA does undergo two different competitive reaction pathways: (1) an irreversible intramolecular coupling reaction which leads to phenylcarbazole moieties and (2) a reversible intermolecular dimerization leading to charged σ-dimers. The σ-dimers become decomposed upon discharging at low potentials (E(pc) = -0.97 V vs Fc/Fc(+)) so that the starting monomer p-TTA is partially regenerated. In particular, the reversible dimerization reaction has not been described in literature so far. Polymeric systems containing para-methyl blocked triarylamines in the side chain exhibit similar coupling behavior upon electrochemical doping.
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