Mechanistic Insight into the Gas-Phase Reactions of Methylamine with Ground State Co+(3F) and Ni+(2D)

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• 作者：Xiaoqing Lu ; Shuxian Wei ; Wenyue Guo ; Chi-Man Lawrence Wu
• 刊名：Journal of Physical Chemistry A
• 出版年：2010
• 出版时间：December 2, 2010
• 年：2010
• 卷：114
• 期：47
• 页码：12490-12497
• 全文大小：323K
• 年卷期：v.114,no.47(December 2, 2010)
• ISSN：1520-5215

文摘

The gas-phase reaction mechanisms of methylamine (MA) with the ground-state Co⁺(³F) and Ni⁺(²D) are theoretically investigated using density functional theory at both the B3LYP/6-311++G(d,p) and B3LYP/6-311++G(3df,2p) levels. The reactions for hydride abstraction and dehydrogenation are analyzed in terms of the topology of potential energy surfaces (PESs). Co⁺ and Ni⁺ perform similar roles along the isomerization processes to the final products. Hydride abstraction takes place via the key species of metal cation-methyl-H intermediate, followed by a charge transfer process before the direct dissociation of CH₂NH₂⁺···MH (M = Co, Ni). The enthalpies of reaction, stability of metal cation-methyl-H species, and competition between different channels account for the sequence of the hydride abstraction products: CoH < NiH < CuH. The most competitive dehydrogenation route occurs through a stepwise reaction, consisting of initial C−H activation, amino-H shift, and direct dissociation of the precursor CH₂NHM⁺···H₂. This theoretical work sheds new light on the experimental observations and provides fundamental understanding of the reaction mechanisms of amine prototype with late first-row transition metal cations.