Modeling the Oxidative Degradation of Azo Dyes: A Density Functional Theory Study
Modeling the Oxidative Degradation of Azo Dyes: A Density Functional Theory Study
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模拟偶氮染料的氧化降解：密度泛函理论研究
DOI：
10.1021/jp026287z
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
R. Klein
中科院分区：
文献类型：
--
作者：
A. S. Özen;V. Aviyente;R. Klein
在本文中，我们表明，使用DFT方法，反应性指数，和电子密度拓扑结构，偶氮染料的氧化降解发生通过以下羟基自由基加成到发色团的N-N键的断裂。两个实验提出的反应途径，涉及C-N或N-N键的断裂，结构已经在B3 LYP/6- 31 G（d）水平上优化;能量进一步使用B3 LYP/6-311+G（d，p）//B3 LYP/6- 31 G（d）水平上的单点计算进行了改进。势能面（PES）进行了比较，这两种机制，以确定哪种机制是积极更有利的。反应性指数和电子密度拓扑计算证实了PES的结果。详细的电子密度等值线绘图允许电子分布的精确可视化，即，它的拓扑结构，对于过渡状态。通过自洽反应场（SCRF）理论计算，考虑了介质介电常数的影响。
In this paper, we show, using DFT methods, reactivity indices, and electron density topology, that oxidative degradation of azo dyes occurs through the cleavage of the N−N bond following hydroxyl radical addition to the chromophore. Structures for both experimentally proposed reaction pathways, involving either cleavage of the C−N or N−N bonds, have been optimized at the B3LYP/6-31G(d) level of theory; the energies were further refined using single point calculations at the B3LYP/6-311+G(d,p)//B3LYP/6-31G(d) level. Potential energy surfaces (PES) have been compared for the two mechanisms to determine which mechanism is energetically more favorable. Reactivity indices and electron density topology calculations confirmed the findings of the PES. Detailed electron density contour mapping allowed accurate visualization of the electron distribution, i.e., its topology, for the transition states. The effect of the medium dielectric constant was allowed for via self-consistent reaction field (SCRF) theory calcul...