THE PHOTO-EC MECHANISM - REDUCTION OF TERT-BUTYL BROMIDE BY EXCITED-STATE TETRACHLOROBENZOQUINONE RADICAL-ANION

Journal article

The mediated reduction of t-butyl bromide by the photochemically excited radical anion of tetrachlorobenzoquinone (TCBQ) is studied in acetonitrile solution using the channel electrode. The reduction of TCBQ in the dark is a reversible one-electron process which forms the corresponding stable radical anion. Upon photoexcitation of the radical anion in the presence of t-butyl bromide, photocurrents are observed and the electrode process is shown to have the characteristics of an EC′ mechanism: TCBQ ⇌ TCBQ.-, TCBQ.- →hv TCBQ.-* TCBQ.-* + ButBr → TCBQ + ButBr.-, ButBr.- → products. The value of the effective rate constant (rate = keff[TCBQ.-][ButBr]) for the electron transfer between the radical anion and t-butyl bromide has been evaluated from analysis of the limiting current/flow rate behaviour at the channel electrode. keff was found to be 1315 ± 50 dm3 mol-1 s-1, at a light intensity of 0.120 W cm-2.

Authors: Compton, R; Eklund, J; Fisher, A; Waller, A

• Publication status: Published
• Journal: JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS
• Volume: 86
• Issue: 17
• Pages: 2951-2953
• Publication date: 1990-09-07
• DOI: 10.1039/ft9908602951
• EISSN: 1364-5455
• ISSN: 0956-5000
• Language: English