Zhang Yuanyuan, Zhang Xuan, Chen Zhijie, Otake Ken-Ichi, Peterson Gregory W, Chen Yongwei, Wang Xingjie, Redfern Louis R, Goswami Subhadip, Li Peng, Islamoglu Timur, Wang Bo, Farha Omar K
Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081, P.R. China.
Department of Chemistry and International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208-3113, USA.
ChemSusChem. 2020 Apr 7;13(7):1710-1714. doi: 10.1002/cssc.202000306. Epub 2020 Mar 5.
Flexible metal-organic frameworks (MOFs) are highly attractive porous crystalline materials presenting structural changes when exposed to external stimuli, the mechanism of which is often difficult to glean, owing to their complex and dynamic nature. Herein, a flexible interpenetrated Zr-MOF, NU-1401, composed of rare 4-connected Zr nodes and tetratopic naphthalenediimide (NDI)-based carboxylate linkers, was designed. The intra-framework pore opening deformation and inter-framework motions, when subjected to different solvent molecules, were investigated by single-crystal XRD. The distance and overlap angle between the stacked NDI pairs in the entangled structure could be finely tuned, and the interactions between NDI and solvent molecules led to solvochromism. Furthermore, the presence of electron-deficient NDI units in the linker and acid sites on the node of the interpenetrated porous structure offered high density of adsorption sites for ammonia molecules, resulting in high uptake at low pressures.
柔性金属有机框架材料（MOFs）是极具吸引力的多孔晶体材料，在受到外部刺激时会发生结构变化，由于其复杂且动态的性质，其作用机制往往难以探究。在此，设计了一种由罕见的四连接锆节点和基于萘二亚胺（NDI）的四齿羧酸盐连接体组成的柔性互穿锆基MOF材料NU-1401。通过单晶X射线衍射研究了该材料在不同溶剂分子作用下框架内的孔开口变形和框架间的运动。在缠结结构中堆叠的NDI对之间的距离和重叠角可以得到精细调节，并且NDI与溶剂分子之间的相互作用导致了溶剂致变色现象。此外，互穿多孔结构的连接体中缺电子的NDI单元和节点上的酸性位点为氨分子提供了高密度的吸附位点，从而在低压下实现了高吸附量。
