Wu Guohua, Stewart Hamish, Liu Zeyu, Wang Yongcheng, Stace Anthony J
Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang, 212018, China,
J Am Soc Mass Spectrom. 2015 Aug;26(8):1382-7. doi: 10.1007/s13361-015-1165-3. Epub 2015 May 20.
We present an experimental study of methane activation by pyridine cation and its substituents in the gas phase. Mass spectrometric experiments in an ion trap demonstrate that pyridine cation and some of its substituent cations are able to react with methane. The deuterated methane experiment has confirmed that the hydrogen atom in the ionic product of reaction does come from methane. The collected information about kinetic isotope effects has been used to distinguish the nature of the bond activation as a hydrogen abstraction. Furthermore, experimental results demonstrated that the substituent groups on the pyridine ring can crucially influence their reactivity in methane bond activation processes. Density functional calculation (DFT) was employed to study the electronic structures of the complex and reaction mechanism of CH4+C5H5N(+). The calculations confirmed the hypothesis from the experimental observation, namely, the reaction is rapid with no energy barrier.
我们展示了一项关于吡啶阳离子及其取代基在气相中活化甲烷的实验研究。在离子阱中进行的质谱实验表明，吡啶阳离子及其一些取代阳离子能够与甲烷发生反应。氘代甲烷实验证实，反应离子产物中的氢原子确实来自甲烷。收集到的关于动力学同位素效应的信息已被用于区分作为氢提取的键活化的性质。此外，实验结果表明，吡啶环上的取代基对其在甲烷键活化过程中的反应活性有至关重要的影响。采用密度泛函理论（DFT）计算研究了CH4 + C5H5N(+) 配合物的电子结构和反应机理。计算结果证实了实验观察得出的假设，即该反应迅速且无能量势垒。
