Department of Chemistry, University of California, 1 Shields Avenue, Davis, California 95616, United States.
Racah Institute of Physics, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel.
J Phys Chem Lett. 2021 Apr 1;12(12):3066-3073. doi: 10.1021/acs.jpclett.1c00406. Epub 2021 Mar 22.
Charged functional groups in the secondary coordination sphere (SCS) of a heterogeneous nanoparticle or homogeneous electrocatalyst are of growing interest due to enhancements in reactivity that derive from specific interactions that stabilize substrate binding or charged intermediates. At the same time, accurate benchmarking of electrocatalyst systems most often depends on the development of linear free-energy scaling relationships. However, the thermodynamic axis in those kinetic-thermodynamic correlations is most often obtained by a direct electrochemical measurement of the catalyst redox potential and might be influenced by electrostatic effects of a charged SCS. In this report, we systematically probe positive charges in a SCS and their electrostatic contributions to the electrocatalyst redox potential. A series of 11 iron carbonyl clusters modified with charged and uncharged ligands was probed, and a linear correlation between the ν absorption band energy and electrochemical redox potentials is observed except where the SCS is positively charged.
由于特定相互作用稳定了底物结合或带电中间体，从而提高了反应性，因此处于异相纳米粒子或均相电催化剂的次级配位域 (SCS) 中的带电官能团日益受到关注。与此同时，电催化剂体系的精确基准测试通常取决于线性自由能标度关系的发展。然而，在这些动力学-热力学相关关系中，热力学轴通常是通过直接电化学测量催化剂氧化还原电位获得的，并且可能受到带电 SCS 的静电效应的影响。在本报告中，我们系统地研究了 SCS 中的正电荷及其对电催化剂氧化还原电位的静电贡献。研究了一系列用带电和不带电配体修饰的 11 个铁羰基簇，观察到 ν 吸收带能量和电化学氧化还原电位之间存在线性相关，除非 SCS 带正电荷。
