He Shuanglin, Qing Yuhang, Zhang Ping, Xiong Ying, Wu Qianqian, Zhang Yaping, Chen Lin, Huang Fang, Li Fei
State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, 621010, Mianyang, P. R. China.
State Key Laboratory of Fine Chemicals, Dalian University of Technology, 116024, Dalian, P. R. China.
Angew Chem Int Ed Engl. 2023 May 8;62(20):e202216082. doi: 10.1002/anie.202216082. Epub 2023 Apr 5.
A series of manganese polypyridine complexes were prepared as CO reduction electrocatalysts. Among these catalysts, the intramolecular proton tunneling distance for metal hydride formation (PTD-MH) vary from 2.400 to 2.696 Å while the structural, energetic, and electronic factors remain essentially similar to each other. The experimental and theoretical results revealed that the selectivity of CO reduction reaction (CO RR) is dominated by the intramolecular PTD-MH within a difference of ca. 0.3 Å. Specifically, the catalyst functionalized with a pendent phenol group featuring a slightly longer PTD-MH favors the binding of proton to the [Mn-CO ] adduct rather than the Mn center and results in ca. 100 % selectivity for CO product. In contrast, decreasing the PTD-MH by attaching a dangling tertiary amine in the same catalyst skeleton facilitates the proton binding on the Mn center and switches the product from CO to HCOOH with a selectivity of 86 %.
制备了一系列锰多吡啶配合物作为CO还原电催化剂。在这些催化剂中，形成金属氢化物的分子内质子隧穿距离（PTD-MH）在2.400至2.696 Å之间变化，而结构、能量和电子因素彼此基本相似。实验和理论结果表明，CO还原反应（CO RR）的选择性在约0.3 Å的差异范围内由分子内PTD-MH主导。具体而言，用具有稍长PTD-MH的侧链酚基官能化的催化剂有利于质子与[Mn-CO]加合物而非Mn中心结合，并导致CO产物的选择性约为100%。相反，通过在相同催化剂骨架中连接一个悬空叔胺来降低PTD-MH，促进了质子在Mn中心上的结合，并将产物从CO切换为HCOOH，选择性为86%。
