Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, P. R. China.
ChemSusChem. 2021 Apr 22;14(8):1835-1839. doi: 10.1002/cssc.202100182. Epub 2021 Mar 10.
The effect of the coordination sphere around metal centers on the oxygen reduction reaction (ORR) activity of transition metal macrocyclic complexes is still unclear. Here, the aromaticity/antiaromaticity effect of macrocycles on ORR activity was investigated based on TM norcorrole (TM=Mn, Fe, Co, Ni), TM porphycene, and TM porphyrin by first-principle calculations. It was found that the complexes with weaker aromatic macrocycles exhibited a stronger adsorption strength while the complexes with antiaromatic macrocycles showed further enhanced adsorption strengths. Further investigations indicated that the variation in the adsorption strengths of catalysts was attributed to the different redox activities of macrocycles with different aromaticities. Such difference in redox activities of macrocycles was reflected in the activities of metal centers via d-π conjugation, which acted as a bridge between π-electrons on macrocycles and active d-electrons on metal centers. This work deepens the understanding of the role of macrocycles in oxygen electroreduction.
金属中心配位环境对过渡金属大环配合物氧还原反应（ORR）活性的影响尚不清楚。本工作基于 TM 诺咯啉（TM=Mn、Fe、Co、Ni）、TM 卟吩和 TM 卟啉，通过第一性原理计算研究了大环的芳香性/反芳香性效应对 ORR 活性的影响。结果表明，具有较弱芳香大环的配合物表现出更强的吸附强度，而具有反芳香大环的配合物则表现出进一步增强的吸附强度。进一步的研究表明，催化剂吸附强度的变化归因于不同芳香性大环的氧化还原活性不同。这种大环氧化还原活性的差异通过 d-π 共轭反映在金属中心的活性上，d-π 共轭充当了大环π电子和金属中心活性 d 电子之间的桥梁。这项工作加深了对大环在氧电还原中作用的理解。
