Zhang Jinjin, Tang Mingjie, Yang Siyuan, Li Hongqing, Cheng Guangbin, Tang Yongxing, Liu Ming
Department of Chemistry, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, P.R. China.
School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, 210094, P.R. China.
Angew Chem Int Ed Engl. 2025 May 26;64(22):e202501187. doi: 10.1002/anie.202501187. Epub 2025 Mar 27.
The cyclo-pentazolate anion (cyclo-N ) has garnered significant attention as an all-nitrogen, five-membered-ring ion with a high energy state and unique aromaticity. Typically, the free cyclo-N anion is a highly unstable species, and its stabilization relies on strong interactions, such as a hydrogen bonding network or metal coordination. However, these interactions often compromise the independence of the anion, thus diminishing its aromaticity. Herein, we present a molecular trap designed to encapsulate and isolate cyclo-N through collective weak interactions. This approach utilizes a pre-positioned ion to subsequently displace the cyclo-N anion into the cage cavity, addressing the challenge posed by the absence of strong-interaction-driven binding. This setup preserves the aromaticity of the anion to a significant extent, as predicted by computational studies. More importantly, the decomposition of free cyclo-N within the microenvironment was directly recorded for the first time using single-crystal X-ray diffraction analysis.
环戊唑酸根阴离子（环 - N⁻）作为一种具有高能量状态和独特芳香性的全氮五元环离子，已引起了广泛关注。通常，游离的环 - N⁻ 阴离子是一种高度不稳定的物种，其稳定性依赖于强相互作用，如氢键网络或金属配位。然而，这些相互作用常常会损害阴离子的独立性，从而降低其芳香性。在此，我们展示了一种分子陷阱，旨在通过集体弱相互作用来封装和隔离环 - N⁻。这种方法利用预先定位的离子，随后将环 - N⁻ 阴离子置换到笼状空腔中，解决了缺乏强相互作用驱动的结合所带来的挑战。如计算研究所预测的那样，这种设置在很大程度上保留了阴离子的芳香性。更重要的是，首次使用单晶X射线衍射分析直接记录了微环境中游离环 - N⁻ 的分解情况。
