Efficient Oxidative Cycloreversion Reaction of Photochromic Dithiazolythiazole

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• 作者：Takuya Nakashima ; Yoshiyuki Kajiki ; Sayo Fukumoto ; Maki Taguchi ; Satoshi Nagao ; Shun Hirota ; Tsuyoshi Kawai
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：December 5, 2012
• 年：2012
• 卷：134
• 期：48
• 页码：19877-19883
• 全文大小：379K
• 年卷期：v.134,no.48(December 5, 2012)
• ISSN：1520-5126

文摘

Electrochemical response of photochromic tearylenes was surveyed by means of cyclic voltammetry, DFT calculations, and spectroelectrochemistry. 4,5-Bis(2-phenyl-5-methylthiazolyl)-2-phenylthiazole was found to show electrochemical oxidative ring-cycloreversion reaction. The net current efficiency of the cycloreversion reaction under constant potential electrolysis was as high as 900%, which is ascribed to an electrochemical local-cell mechanism and a chain reaction mechanism. Electron transfer stopped-flow study using a chemical oxidant successfully identified radical cation intermediates of both closed- and open-ring isomers, involved in the oxidative cycloreversion process. The significantly long-lived radical cation of open-ring isomer with the lifetime of 33 s takes part in the indirect electron transfer process from the neutral closed-ring isomer to the radical cation of open-ring isomer in the chain reaction manner.