Ding Kun, Zhuang Bo, Deng Bo-Wen, Li Zhi-Long, Lu Hai-Feng, Zhang Zhi-Xu, Fu Da-Wei
Ordered Matter Science Research Center College of Chemistry and Chemical Engineering, Southeast University, 211189, Nanjing, P. R. China.
Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, 321019, Jinhua, P. R. China.
Chemistry. 2024 Oct 11;30(57):e202402119. doi: 10.1002/chem.202402119. Epub 2024 Sep 24.
The lone pair electrons in the electronic structure of molecules have been a prominent research focus in chemistry for more than a century. Stable s lone pair electrons significantly influence material properties, including thermoelectric properties, nonlinear optical properties, ferroelectricity, and electro(photo)catalysis. While major advances have been achieved in understanding the influence of lone pair electrons on material characteristics, research on this effect in organic-inorganic hybrid materials is in its initial stage. In this work, we successfully obtained a novel organic-inorganic hybrid multifunctional material incorporating Ge with 4s lone pair electrons, (MeHDabco)[GeBr]-HO (MeHDabco=N-methyl-1,4-diazabicyclo[2.2.2]octane) (1). Driven by the stereochemically active lone pair electrons on the Ge, 1 crystallizes in the noncentrosymmetric space group P2 at room temperature and exhibits good second harmonic generation (SHG) responses. Interestingly, 1 also shows electrocatalytic activity for the hydrogen evolution reaction (HER) due to the existence of lone pair electrons on Ge cations. The electrochemical experiment combined with the density functional theory (DFT) calculations revealed that the lone pair electrons act as both an active site for proton adsorption and facilitate the ionization of water. This work not only emphasizes the important role of lone pair electrons in material properties and functions but also provides new insight for designing novel Ge-based multifunctional hybrid materials.
分子电子结构中的孤对电子在化学领域已成为一个突出的研究焦点长达一个多世纪。稳定的s孤对电子显著影响材料性能，包括热电性能、非线性光学性能、铁电性以及电（光）催化性能。虽然在理解孤对电子对材料特性的影响方面已取得重大进展，但关于其在有机-无机杂化材料中的研究仍处于初始阶段。在这项工作中，我们成功获得了一种新型的有机-无机杂化多功能材料，其包含具有4s孤对电子的Ge，即(MeHDabco)[GeBr]·H₂O（MeHDabco = N-甲基-1,4-二氮杂双环[2.2.2]辛烷）(1)。受Ge上立体化学活性孤对电子的驱动，1在室温下结晶于非中心对称空间群P2，并表现出良好的二次谐波产生（SHG）响应。有趣的是，由于Ge阳离子上存在孤对电子，1对析氢反应（HER）也表现出电催化活性。电化学实验结合密度泛函理论（DFT）计算表明，孤对电子既是质子吸附的活性位点，又促进了水的电离。这项工作不仅强调了孤对电子在材料性能和功能中的重要作用，还为设计新型基于Ge的多功能杂化材料提供了新的见解。
