Lewis Acid Transition-Metal-Catalyzed Hydrogen Activation: Structures, Mechanisms, and Reactivities
Lewis Acid Transition-Metal-Catalyzed Hydrogen Activation: Structures, Mechanisms, and Reactivities
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路易斯酸过渡金属催化氢活化：结构、机制和反应性
DOI：
10.1002/chem.201903193
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Ke Zhuofeng
中科院分区：
文献类型：
--
作者：
Li Yinwu;Liu Jiahao;Huang Xiao;Qu Ling-Bo;Zhao Cunyuan;Langer Robert;Ke Zhuofeng
As a new type of bifunctional catalyst, the Lewis acid transition‐metal (LA‐TM) catalysts have been widely applied for hydrogen activation. This study presents a mechanistic framework to understand the LA‐TM‐catalyzed H2activation through DFT studies. Themer(trans)‐homolytic cleavage, thefac(cis)‐homolytic cleavage, the synergetic heterolytic cleavage, and the dissociative heterolytic cleavage should be taken as general mechanisms for the field of LA‐TM catalysis. Four typical LA‐TM catalysts, the Z‐type κ4‐L3B‐Rh complex tri(azaindolyl)borane‐Rh, the X‐type κ3‐L2B‐Co complex bis‐phosphino‐boryl (PBP)‐Co, the η2‐BC‐type κ3‐L2B‐Pd complex diphosphine‐borane (DPB)‐Pd, and the Z‐type κ2‐LB‐Pt complex (boryl)iminomethane (BIM)‐Pt are selected as representative models to systematically illustrate their mechanistic features and explore the influencing factors on mechanistic variations. Our results indicate that the tri(azaindolyl)borane‐Rh catalyst favors the synergetic heterolytic mechanism; the PBP‐Co catalyst prefers themer(trans)‐homolytic mechanism; the DPB‐Pd catalyst operates through thefac(cis)‐homolytic mechanism, whereas the BIM‐Pt catalyst tends to undergo the dissociative heterolytic mechanism. The mechanistic variations are determined by the coordination geometry, the LA‐TM bonding nature, the electronic structure of the TM center, and the flexibility or steric effect of the LA ligands. The presented mechanistic framework should provide helpful guidelines for LA‐TM catalyst design and reaction developments.
