Electrochemically Induced Reversible and Irreversible Coupling of Triarylamines

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• 作者：Olena Yurchenko ; David Freytag ; Lisa zur Borg ; Rudolf Zentel ; J眉rgen Heinze ; Sabine Ludwigs
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：January 12, 2012
• 年：2012
• 卷：116
• 期：1
• 页码：30-39
• 全文大小：1077K
• 年卷期：v.116,no.1(January 12, 2012)
• ISSN：1520-5207

文摘

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 蟽-dimers. The 蟽-dimers become decomposed upon discharging at low potentials (E_pc = 鈭?.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.