Su Jian, Yuan Shuai, Cheng Yi-Xun, Yang Zhi-Mei, Zuo Jing-Lin
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University Nanjing 210023 P. R. China
Chem Sci. 2021 Oct 11;12(42):14254-14259. doi: 10.1039/d1sc03962h. eCollection 2021 Nov 3.
Controlled synthesis of hydrogen-bonded organic frameworks (HOFs) remains challenging, because the self-assembly of ligands is not only directed by weak hydrogen bonds, but also affected by other competing van der Waals forces. Herein, we demonstrate the coordination-bond-directed synthesis of HOFs using a preformed metal-organic framework (MOF) as the template. A MOF (Cu-TTFTB) based on two-coordinated Cu centers and tetrathiafulvalene-tetrabenzoate (TTFTB) ligands was initially synthesized. Cu-TTFTB was subsequently oxidized to the intermediate (Cu-TTFTB) and hydrated to the HOF product (TTFTB-HOF). Single-crystal-to-single-crystal (SC-SC) transformation was realized throughout the MOF-to-HOF transformation so that the evolution of structures was directly observed by single-crystal X-ray diffraction. The oxidation and hydration of the Cu center are critical to breaking the Cu-carboxylate bonds, while the synergic corbelled S⋯S and π⋯π interactions in the framework ensured stability of materials during post-synthetic modification. This work not only provided a strategy to guide the design and discovery of new HOFs, but also linked the research of MOFs and HOFs.
氢键有机框架（HOFs）的可控合成仍然具有挑战性，因为配体的自组装不仅受弱氢键的导向，还受到其他竞争性范德华力的影响。在此，我们展示了以预先形成的金属有机框架（MOF）为模板，通过配位键导向合成HOFs。首先合成了一种基于二配位铜中心和四硫富瓦烯四苯甲酸酯（TTFTB）配体的MOF（Cu-TTFTB）。随后，Cu-TTFTB被氧化为中间体（Cu-TTFTB）并水合为HOF产物（TTFTB-HOF）。在整个MOF到HOF的转变过程中实现了单晶到单晶（SC-SC）转变，从而通过单晶X射线衍射直接观察到结构的演变。铜中心的氧化和水合对于打破铜-羧酸酯键至关重要，而框架中协同的堆叠S⋯S和π⋯π相互作用确保了材料在合成后修饰过程中的稳定性。这项工作不仅提供了一种指导新HOFs设计和发现的策略，还将MOFs和HOFs的研究联系起来。
