Mechanistic determination using arrays of variable sized channel microband electrodes: The oxidation of 2,3,7,8-tetramethoxythianthrene in the presence of pyridine in acetonitrile solution

Journal article

2-Dimensional amperometry'' using arrays of gold channel microband electrodes is applied to the oxidation of 2,3,7,8-tetramethoxythianthrene (TMT) and to the characterization of the follow-up kinetics of the resulting radical cation with pyridine. In the absence of pyridine the reaction is consistent with an E mechanism and a value of 1.3 × 10-5 cm2s-1 is obtained for the diffusion coefficient of TMT. In the presence of pyridine the experimental results are consistent with a DISP2 mechanism where the values of the rate constant have a first order dependence on the concentration of pyridine. The following mechanism is proposed: TMT - 1e → TMT+• (i) TMT+• + py ⇌ [TMT/py]+• equilibration (ii) [TMT/py]+• + TMT+• → TMT + [TMT/py]2+ rate determining (iii) [TMT/py]2+ + py → [TMT/py2]2+ (iv) and a value of 5.8 × 104 M-2s-1 is found for the rate constant for the regeneration of TMT.

Authors: Prieto, F; Oyama, M; Coles, B; Alden, J; Compton, R

• Publication status: Published
• Journal: ELECTROANALYSIS
• Volume: 10
• Issue: 10
• Pages: 685-690
• Publication date: 1998-08-01
• DOI: 10.1002/(SICI)1521-4109(199808)10:10<685::AID-ELAN685>3.0.CO;2-B
• EISSN: 1521-4109
• ISSN: 1040-0397
• Language: English
• Keywords: two-dimensional amperometry; arrays of gold channel microband electrodes; 2,3,7,8-tetramethoxythianthrene; pyridine