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化学学报
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化学学报 ›› 2008, Vol. 66 ›› Issue (13): 1518-1522. 上一篇    下一篇

研究论文

Br＋活化甲烷C—H键反应机理的理论研究

余盛萍 颜 红 袁秀香 王 欣* 田安民   

  1. (四川大学化学学院 成都 610064)
  • 投稿日期:2007-11-17 修回日期:2008-01-24 发布日期:2008-07-14
  • 通讯作者: 王欣

Theoretical Study on Reaction Mechanism of the C—H Bond Activation of Methane by Br＋

YU, Sheng-Ping YAN, Hong YUAN, Xiu-Xiang WANG, Xin* TIAN, An-Min   

  1. An ab initio quantum chemical method and density functional theory have been used to study the reaction mechanism of the C—H bond activation of methane by Br＋. The geometries of the reactants, intermediates, transition states, and products were optimized at the B3LYP/6-311＋＋G(3df,3p) and MP2/6-311＋＋G(3df,3p) levels. The G2M(＋) method was used to obtain more accurate energies. The results show that the reaction undergoes three triplet endothermic pathways and two singlet exothermic reaction channels. The reaction is more likely to proceed through the singlet pathways. The mechanism proposed in the present work is in reasonable agreement with the known experimental facts. Our theoretical results indicate that the halogen cation, Br＋, may be a potential catalyst for C—H bond activation of methane.
  • Received:2007-11-17 Revised:2008-01-24 Published:2008-07-14
  • Contact: WANG, Xin

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化甲烷催化剂的可能性. 在B3LYP/6-311＋＋G(3df,3p)和MP2/6-311＋＋G(3df,3p)水平下优化了反应通道上各驻点(反应物、中间体、过渡态和产物)的几何构型. 在G2M(＋)水平下计算了各物种的能量. 研究结果表明: CH4与Br＋(3P)反应存在三条不同的吸热反应途径, 与Br＋(1D)反应存在二条不同的放热反应通道. 反应更易于通过单重态反应通道进行. 理论结果不仅较好地解释了实验事实, 还说明Br＋有可能成为一种活化甲烷的催化剂.

关键词: 从头算, 密度泛函理论, G2M(＋)方法, 甲烷C—H键活化, 反应机理

Ab initio quantum chemical method and density functional theory (DFT) have been used to study the reaction mechanism of the C-H bond activation of methane by Br+. The geometries of reactants, intermediates, transition states, and products were optimized at the B3LYP/6-311++G(3df,3p) and MP2/6-311++G(3df,3p) levels. The G2M(+) methods were used to obtain more accurate energies. The results show that the reaction undergoes via three triplet endothermic pathways and two singlet exothermic reaction channels. The reaction is more likely to proceed through the singlet pathways. The mechanism proposed in the present work is in reasonable agreement with the known experimental facts. Our theoretical results indicate that the halogen cation, Br+, may be a potential catalyst for C-H bond activation of methane.

Key words: ab initio, density functional theory, G2M(＋) method, C—H activation of methane, reaction mechanism