d-Orbital Reconstructions Forced by Double Bow-Shaped Deformations and Second Coordination Sphere Effects of Cu(II) Heme Analogs in HER.
d-Orbital Reconstructions Forced by Double Bow-Shaped Deformations and Second Coordination Sphere Effects of Cu(II) Heme Analogs in HER.
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DOI：
10.1002/chem.202103892
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发表时间：
2022-01
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影响因子：
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通讯作者：
Qiuhua Liu;Wanjie Ren;Siwei Zhang;Yang Huang;Di-Ping Chen;W. Zeng;Zaichun Zhou;Lin He;W. Guo;Jianfeng Li
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作者：
Qiuhua Liu;Wanjie Ren;Siwei Zhang;Yang Huang;Di-Ping Chen;W. Zeng;Zaichun Zhou;Lin He;W. Guo;Jianfeng Li
血红素蛋白的几何构型和电子构型对其活性均有影响。在这项工作中，我们设计并合成了一系列的四个铜（II）卟啉配合物（4-，3-，2-和1-铜），其中的分子构象调制的逐步缩短带在同一卟啉侧（顺-邻），得到双弓形骨架。单晶结构表明，条带逐渐增加鞍形变形和偏离的金属中心，这是根据两个，不寻常的d-轨道重建的两个不同的基态，所揭示的4 K EPR和DFT计算。在电催化析氢反应（HER）的研究中，1-Cu，具有最短的条带，表现出最明显的活性提高。第二配位球（SCS）效应所产生的双弓状结构和强大的鞍形卟啉核心1-铜被发现在催化过程中的质子捕获的关键作用。该研究为通过调控配体的几何构型来提高血红素类似物的催化性能提供了一种新的策略。
Both geometric architecture and electronic configurations of heme proteins contribute to its activity. In this work we designed and synthesized a series of four copper(II) porphyrin complexes (4-, 3-, 2- and 1-Cu) where the molecular conformations are modulated by a pair of stepwise shortened straps on the same porphyrin side (cis-ortho) to give double bow-shaped skeletons. Single crystal structures demonstrate that the straps gradually increase the saddle deformation and the deviation of the metal centers, which is in accordance with two, unusual d-orbital reconstructions of two different ground states, as revealed by 4 K EPR and DFT calculations. In the study of the electrocatalytic hydrogen evolution reaction (HER), 1-Cu, with the shortest straps, showed the most apparent improvement of activity. Second coordination sphere (SCS) effects created by the double bow-shaped architecture and the strong saddle porphyrin core in 1-Cu are found to play key roles in proton trapping during the catalytic process. The work contributes a novel strategy to improve the catalytic performance of heme analogs through ligand geometric modulation.