Quantum chemical study of the autoxidation of ascorbate
Quantum chemical study of the autoxidation of ascorbate
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DOI：
10.1002/jcc.24408
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发表时间：
2016-07-30
影响因子：
3
通讯作者：
Cao, Xiaoyan
中科院分区：
文献类型：
--
作者：
Herrmann, Nils;Heinz, Norah;Cao, Xiaoyan
用量子化学第一性原理和从头算方法研究了抗坏血酸自氧化反应。在密度泛函理论水平上，采用梯度修正的BP86和混合B3LYP泛函，结合Def2-TZVP基组，计算了各反应的反应能和吉布斯能。用CC2、CCSD和CCSD(T)的单点计算结果对密度泛函理论数据进行了校正，结果与B3LYP值符合很好。根据Gibbs能量，抗坏血酸Asch(2)是水溶液中能量最低的物种，而单阴离子抗坏血酸Asch-在pH=7附近是最丰富的。Asc-被发现是自氧化和氧化过程的首选还原剂。结果还支持根据文献中提出的氧化还原循环机制，在金属催化下合成活性氧物种过氧化氢。(C)2016威利期刊公司。
Reactions involved in the autoxidation of ascorbate have been investigated with quantum chemical first-principles and ab initio methods. Reaction energies and Gibbs energies of the reactions were calculated at the density functional theory level applying the gradient-corrected BP86 and the hybrid B3LYP functionals together with def2-TZVP basis sets. Results of single-point CC2, CCSD, and CCSD(T) calculations were used for calibration of the density functional theory data and show excellent agreement with the B3LYP values. Based on the Gibbs energy ascorbic acid AscH(2) is found to be the energetically lowest species in aqueous solution, whereas the monoanion ascorbate AscH - is the most abundant one near pH=7. Asc 2- was found to be the preferred reducing agent for autoxidation and oxidation processes. The results also support a metal-catalyzed synthesis of the reactive oxygen species H2O2 according to a redox cycling mechanism proposed in literature. (c) 2016 Wiley Periodicals, Inc.