The mechanism of hydrogen abstraction by high valence transition metal oxo compounds

作     者：Gang Fu Ruming Yuan Huilin Wan Xin Xu 

作者机构：Department of Chemistry State Key Laboratory for Physical Chemistry of Solid Surfaces College of Chemistry & Chemical Engineering Xiamen University Department of Chemistry MOE Laboratory for Computational Physical Science Shanghai Key Laboratory of Molecular Catalysis and Innovative MaterialsFudan University 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2016年第25卷第6期

页      面：1045-1050页

核心收录：

学科分类：0820[工学-石油与天然气工程] 0808[工学-电气工程] 07[理学] 070304[理学-物理化学(含∶化学物理)] 0817[工学-化学工程与技术] 0807[工学-动力工程及工程热物理] 0827[工学-核科学与技术] 0703[理学-化学] 

基　　金：financial support from the National Nature Science Foundation of China (21133004,21373167,21573178) the Fundamental Research Funds for the Central Universities (20720160046) the Program for Innovative Research Team in Chinese Universities (IRT_14R31) 

主　　题：C-H bond activation Polanyi relationship Oxygen radical Valence bond state correlation diagram DFT calculation 

摘      要：We present here a systematic theoretical study to explore the underlying mechanisms of the H abstraction reaction from methane. Various abstracting agents have been modeled, using oxygen radicals and a set of high valence metal oxo compounds. Our calculations demonstrate that although H abstraction from CH3-H by metal oxoes can be satisfactorily fitted into the Polanyi correlation on the basis of oxygen radicals, the mechanisms behind are significantly different. The frontier orbital analyses show that there are three electrons and three active orbitals (3e, 3o) involved in H abstraction by oxygen radicals; whereas an additional orbital of pi(M-O)* is involved in H abstraction by M = O, resulting in a (4e, 4o) interaction. In terms of valence bond state correlation diagram, we find that H abstraction by a metal oxo may benefit from the contribution of ionic resonance structures, which could compensate the penalty of opening the M-O pbond. We believe that these findings can help to design more effective catalysts for the activation of light alkanes. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B. V. and Science Press. All rights reserved.