Enhanced Four‐Electron Oxygen Reduction Selectivity of Clamp‐Shaped Cobalt(II) Porphyrin(2.1.2.1) Complexes
Enhanced Four‐Electron Oxygen Reduction Selectivity of Clamp‐Shaped Cobalt(II) Porphyrin(2.1.2.1) Complexes
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钳形钴(II)卟啉(2.1.2.1)配合物增强的四电子氧还原选择性
DOI：
10.1002/anie.202218567
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Qiu Fengxian
中科院分区：
文献类型：
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作者：
Xue Songlin;Ryan Osterloh W.;Lv Xiaojuan;Liu Ningchao;Gao Yimei;Lei Haitao;Fang Yuanyuan;Sun Zhongti;Mei Peifeng;Kuzuhara Daiki;Aratani Naoki;Yamada Hiroko;Cao Rui;Kadish Karl M.;Qiu Fengxian
本文研究了大环两个位置上含Ph或F5Ph基团的两个CoIIPh(2.1.2.1)配合物的分子结构、电化学、光谱电化学和电催化氧还原反应(ORR)特性。单晶X射线分析表明，该化合物具有高度弯曲的非平面大环构象，形成了钳形的分子结构。循环伏安与UV/Vis光谱电化学相结合表明，第一次电子加成对应于大环中心的还原，而第一次氧化过程中观察到的光谱变化与金属中心的CoII/CoIII过程一致。 M-TBAP的第一次电子加成对应于大环中心的还原，而在第一次氧化过程中观察到的光谱变化与金属中心的CoII/CoIII过程一致。在0.1 M KOH中，钳形络合物对非均相ORR的活性表现出对4E−ORR途径的选择性，给出了H2O。对卟啉催化剂的密度泛函第一性原理计算表明，与2E−途径相比，4E−或R的过电势较低，这与实验数据一致。
The molecular structure, electrochemistry, spectroelectrochemistry and electrocatalytic oxygen reduction reaction (ORR) features of two CoIIporphyrin(2.1.2.1) complexes bearing Ph or F5Ph groups at the twomeso‐positions of the macrocycle are examined. Single crystal X‐ray analysis reveal a highly bent, nonplanar macrocyclic conformation of the complex resulting in clamp‐shaped molecular structures. Cyclic voltammetry paired with UV/Vis spectroelectrochemistry in PhCN/0.1 M TBAP suggest that the first electron addition corresponds to a macrocyclic‐centered reduction while spectral changes observed during the first oxidation are consistent with a metal‐centered CoII/CoIIIprocess. The activity of the clamp‐shaped complexes towards heterogeneous ORR in 0.1 M KOH show selectivity towards the 4e−ORR pathway giving H2O. DFT first‐principle calculations on the porphyrin catalyst indicates a lower overpotential for 4e−ORR as compared to the 2e−pathway, consistent with experimental data.