Ion pair formation between the electrogenerated 2,3-dichloro-5,6-dicyano-1,4-benzoquinone dianion and the sodium ion at platinum surfaces

Munetaka Oyama, Frank Marken, Richard D. Webster, Jonathan A. Cooper, Richard G. Compton, Satoshi Okazaki

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Abstract

The electrochemical reduction at platinum electrodes of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in the presence of Na+ in acetonitrile solution was studied using various electrochemical measurements under conditions with significant mass transport, namely channel flow- and sono-voltammetries. In channel electrode voltammetry, the presence of Na+ was observed to change the voltammetric response from that of pure DDQ alone. In particular, at potentials corresponding, in the absence of Na+, to the two electron reduction step of DDQ, a spike-like increase and decrease of reductive current was observed on negative going potential scans after which the current returned to the level expected for a one-electron reduction. This behavior can be explained by the following reaction scheme with the formation of a passivated surface due to the adsorption of Na2+ DDQ2-. DDQ2-+Na+→Na+DDQ2- Na+DDQ2-→Na+DDQads2- Na+DDQads2-+Na+DDQ ads2-→Na2+ DDQads2-+DDQ2- This scheme was found to be consistent with independent sono-voltammetric data and with in situ electrochemical ESR measurements.

Original languageEnglish
Pages (from-to)193-201
Number of pages9
JournalJournal of Electroanalytical Chemistry
Volume451
Issue number1-2
DOIs
Publication statusPublished - 1 Jul 1998

Keywords

  • 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone
  • Acetonitrile solution
  • Electrochemical reduction
  • Na
  • Platinum electrodes

ASJC Scopus subject areas

  • Analytical Chemistry
  • Chemical Engineering(all)
  • Electrochemistry

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