Li Gen, Du Zelin, Wu Chao, Liu Yawei, Xu Yan, Lavendomme Roy, Liang Shihang, Gao En-Qing, Zhang Dawei
State Key Laboratory of Petroleum Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.
Department of Computer Science, Durham University, Durham, UK.
Nat Commun. 2025 Jan 9;16(1):546. doi: 10.1038/s41467-025-55893-z.
Intensified host-guest electronic interplay within stable metal-organic cages (MOCs) presents great opportunities for applications in stimuli response and photocatalysis. Zr-MOCs represent a type of robust discrete hosts for such a design, but their host-guest chemistry in solution is hampered by the limited solubility. Here, by using pyridinium-derived cationic ligands with tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (BAr) as solubilizing counteranions, we report the preparation of soluble Zr-MOCs of different shapes (1-4) that are otherwise inaccessible through a conventional method. Enforced arrangement of the multiple electron-deficient pyridinium groups into one cage (1) leads to magnified positive electrostatic field and electron-accepting strength in favor of hosting electron-donating anions, including halides and tetraarylborates. The strong charge-transfer (CT) interactions activate guest-to-host photoinduced electron transfer (PET), leading to pronounced and regulable photochromisms. Both ground-state and radical structures of host and host-guest complexes have been unambiguously characterized by X-ray crystallography. The CT-enhanced PET also enables the use of 1 as an efficient photocatalyst for aerobic oxidation of tetraarylborates into biaryls and phenols. This work presents the solution assembly of soluble Zr-MOCs from cationic ligands with the assistance of solubilizing anions and highlights the great potential of harnessing host-guest CT for boosting PET-based functions and applications.
稳定的金属有机笼（MOCs）内增强的主客体电子相互作用为刺激响应和光催化应用提供了巨大机遇。锆基金属有机笼（Zr-MOCs）是这种设计中一类坚固的离散主体，但它们在溶液中的主客体化学受到有限溶解度的阻碍。在此，通过使用吡啶鎓衍生的阳离子配体与四（3,5-双（三氟甲基）苯基）硼酸根（BAr）作为增溶抗衡阴离子，我们报道了制备不同形状（1 - 4）的可溶性Zr-MOCs，而这些通过传统方法是无法获得的。将多个缺电子吡啶鎓基团强制排列在一个笼中（1）会导致正静电场和电子接受强度放大，有利于容纳给电子阴离子，包括卤化物和四芳基硼酸盐。强烈的电荷转移（CT）相互作用激活了客体到主体的光致电子转移（PET），导致明显且可调节的光致变色现象。主体以及主客体配合物的基态和自由基结构均已通过X射线晶体学明确表征。CT增强的PET还使1能够作为一种高效的光催化剂，用于将四芳基硼酸盐有氧氧化为联芳基和酚类。这项工作展示了在增溶阴离子的辅助下，由阳离子配体进行可溶性Zr-MOCs的溶液组装，并突出了利用主客体CT来增强基于PET的功能和应用的巨大潜力。
