Esr studies on the free radical intermediates in the photoreduction of duroquinone in alcohol solutions.
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概要
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ESR measurements during photolysis of duroquinone (DQ) solutions in ethanol and 2-propanol have revealed the generation of both durosemiquinone anion (DQ<SUP>−</SUP>) and durosemiquinone radicals (DQH·). Correspondingly, alkoxyl radicals have been detected from the photolyzed solutions by the spin trapping-ESR technique, though the quantum yield of their formation is very low (10<SUP>−3</SUP> for the ethanol solution). Main conclusions deduced from the present work are (1) that DQ<SUP>\newdot</SUP> is generated through the one-electron reduction of DQ by α-hydroxyalkyl radical and through the photodissociation of (DQ-DQH<SUB>2</SUB>) complex, and (2) that DQH· is generated through the hydrogen abstraction of <SUP>3</SUP>DQ<SUP>*</SUP> either from solvent alcohols or from photoproduct durohydroquinone (DQH<SUB>2</SUB>). The one-electron reduction in alcohol solution previously reported for <I>p</I>-benzoquinone is a minor pathway of chemical quenching of <SUP>3</SUP>DQ<SUP>*</SUP>. The quantum yield of the DQH<SUB>2</SUB> formation in an early period of photolysis of a dilute DQ in methanol, ethanol, and 2-propanol has been observed to be 0.12, 0.23, and 0.36 respectively. These values are discussed in terms of the mechanism of the quinone photorecduction.
- 公益社団法人 日本化学会の論文
著者
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Yoshida Hiroshi
Faculty Of Math Kyushu Univ.
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Noda Shoji
Faculty of Engineering, Hokkaido University
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Doba Takahisa
Faculty of Engineering, Hokkaido University
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Sanehira Kiyoshi
Faculty of Engineering, Hokkaido University
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Yoshida Hiroshi
Faculty of Engineering, Hokkaido University
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