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

Journal article

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. © 1998 Elsevier Science S.A. All rights reserved.

Authors: Oyama, M; Marken, F; Webster, R; Cooper, J; Compton, R

• Publication status: Published
• Journal: JOURNAL OF ELECTROANALYTICAL CHEMISTRY
• Volume: 451
• Issue: 1-2
• Pages: 193-201
• Publication date: 1998-07-01
• DOI: 10.1016/S0022-0728(98)00084-9
• ISSN: 0022-0728
• Language: English
• Keywords: electrochemical reduction; 2,3-dichloro-5,6-dicyano-1,4-benzoquinone; Na+; acetonitrile solution; platinum electrodes