Density Functional Theory Studies of Thermal Activation of Methane by MH (M = Ru, Rh, and Pd)

作者：Li Wenqiang; Geng Zhiyuan^*; Wang Yongcheng; Yan Penji; Zhang Xu; Wang Zheng; Liu Fengxia

来源：Journal of Physical Chemistry A, 2009, 113(9): 1807-1812.

DOI：10.1021/jp808830c

The dehydrogenation reaction mechanisms of methane catalyzed by a ligated transition metal MH (M = Ru, Rh, and Pd) have been investigated theoretically. Activation of methane by MH complexes is proposed to proceed in a one-step manner via one transition state: MH CH4 -> MH CH4 -> [TS] -> (MCH3 )H-2 -> MCH3 H-2. Both high-spin and low-spin potential energy surfaces are characterized in detail. Our calculations indicate that the ground-states species have low electron spin and a dominant 4d(n) configuration for RuH , RhH , and PdH , and the whole reaction proceeds on the ground-states potential energy surfaces with a spin-allowed manner. The MH (M = Ru, Rh, and Pd) complexes are expected from the general energy profiles of the reaction pathways to efficiently convert methane to metal methyl, thus RuH , RhH , and PdH are likely to be excellent mediators for the activity of methane. In the reactions of MH with methane, the H-2 elimination from the dihydrogen complex is quite facile without barriers. The exothermicities of the reactions are close for Ru, Rh, and Pd: 11.1, 1.2, and 5.2 kcal/mol, respectively.

• 出版日期2009-3-5
• 单位西北师范大学