金属上甲胺C-N键断裂的系统密度泛函理论研究

A systematic density functional theory study of the C-N bond cleavage of methylamine on metals.

作者信息

Li Jun, Li Rui-Fang, Wang Gui-Chang

机构信息

Department of Chemistry, and the Center of Theoretical Chemistry Study, Nankai University, Tianjin 300071, People's Republic of China.

出版信息

J Phys Chem B. 2006 Jul 27;110(29):14300-3. doi: 10.1021/jp062975x.

DOI:10.1021/jp062975x

PMID:16854136

Abstract

The C-N bond cleavage for the relative large molecule of methylamine on Cu(1111), Ag(111), Au(111), Ni(111), Rh(111), Pd(111), Pt(111), and Mo(100) has been systemically studied using the DFT-GGA method; the reaction energy changes and the activation energies were obtained. The calculated results show that the activation energy of C-N bond cleavage decreases as the metal element goes up and to the left across the periodic table, which is in general agreement with the experimental observation. Moreover, it was found that the steric effect should be considered for the metals with high activity and small radius such as Ni, which is much different from the case for the small molecule decomposition in which the steric effect may be ignored. The linear relationships between the activation energies and electronic properties (d-band center) are presented. It is expected that such a rule can be used to predict the reactivity of metal for other dissociative adsorption systems.

摘要

采用密度泛函理论广义梯度近似（DFT-GGA）方法，对甲胺在Cu(1111)、Ag(111)、Au(111)、Ni(111)、Rh(111)、Pd(111)、Pt(111)和Mo(100)等相对大分子上的C-N键裂解进行了系统研究；获得了反应能量变化和活化能。计算结果表明，随着金属元素在元素周期表中向上和向左移动，C-N键裂解的活化能降低，这与实验观察结果基本一致。此外，发现对于活性高且半径小的金属（如Ni），应考虑空间效应，这与小分子分解中可忽略空间效应的情况有很大不同。给出了活化能与电子性质（d带中心）之间的线性关系。预计这样的规则可用于预测其他解离吸附体系中金属的反应活性。