Catalytic Reduction of O2 by Pyrazine Derivatives
Catalytic Reduction of O2 by Pyrazine Derivatives
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DOI：
10.1021/jp036024k
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发表时间：
2004-02
影响因子：
2.9
通讯作者：
Rong Wang;T. Okajima;F. Kitamura;S. Kawauchi;N. Matsumoto;T. Thiemann;S. Mataka*;T. Ohsaka
中科院分区：
文献类型：
--
作者：
Rong Wang;T. Okajima;F. Kitamura;S. Kawauchi;N. Matsumoto;T. Thiemann;S. Mataka*;T. Ohsaka
用循环伏安法、旋转圆盘伏安法和MOPAC PM5分子轨道计算方法研究了2，3，5，6-四甲基吡嗪、2，3-二甲基喹恶啉、2，3-二苯基喹恶啉和吩嗪四种吡嗪类化合物对分子氧的催化还原反应。在强酸性溶液(pH≈1)中，吡嗪类化合物连续发生两次单电子还原反应。因此，可以比较在酸性溶液中衍生物的单电子还原形式(自由基)和两电子还原形式对O2的反应活性。理论计算表明，在该溶液中，所有氧化还原形式的衍生物都被质子化为阳离子，并且除吩嗪外，所有还原形式都与O2反应。用旋转圆盘伏安法估算了还原形式与O2二级反应的速率常数(K1)。结果表明，Log(K1)与单波电势(e1/2)呈线性关系.
The catalytic reduction of molecular oxygen (O2) by four kinds of pyrazine derivatives2,3,5,6-tetramethylpyrazine, 2,3-dimethylquinoxaline, 2,3-diphenylquinoxaline, and phenazinehas been studied by cyclic and rotating disk voltammetry and molecular orbital calculations using the MOPAC PM5 method. In sufficiently acidic solution (pH ≈ 1), the pyrazine derivatives underwent two successive one-electron reductions. Therefore, it was possible to compare the reactivity of both one-electron reduced forms (the radicals) and two-electron reduced forms of the derivatives toward O2 in this acidic solution. Theoretical calculations showed that all of the redox forms of the derivatives are protonated to be cations in this solution and that all of the reduced forms, except for that of phenazine, react with O2. The rate constants (k1) of the second-order reactions of the reduced forms with O2 were estimated by rotating disk voltammetry. A linear relationship between log(k1) and the half-wave potential (E1/2) of the one-...