Song Jianbo, Pallach Roman, Frentzel-Beyme Louis, Kolodzeiski Pascal, Kieslich Gregor, Vervoorts Pia, Hobday Claire L, Henke Sebastian
Anorganische Materialchemie, Fakultät für Chemie & Chemische Biologie, Technische Universität Dortmund, Otto-Hahn-Straße 6, 44227, Dortmund, Germany.
Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching, Germany.
Angew Chem Int Ed Engl. 2022 May 16;61(21):e202117565. doi: 10.1002/anie.202117565. Epub 2022 Mar 24.
The high-pressure behaviour of flexible zeolitic imidazolate frameworks (ZIFs) of the ZIF-62 family with the chemical composition M(im) (bim) is presented (M =Zn , Co ; im =imidazolate; bim =benzimidazolate, 0.02≤x≤0.37). High-pressure powder X-ray diffraction shows that the materials contract reversibly from an open pore (op) to a closed pore (cp) phase under a hydrostatic pressure of up to 4000 bar. Sequentially increasing the bim fraction (x) reinforces the framework, leading to an increased threshold pressure for the op-to-cp phase transition, while the total volume contraction across the transition decreases. Most importantly, the typical discontinuous op-to-cp transition (first order) changes to an unusual continuous transition (second order) for x≥0.35. This allows finetuning of the void volume and the pore size of the material continuously by adjusting the pressure, thus opening new possibilities for MOFs in pressure-switchable devices, membranes, and actuators.
本文介绍了具有化学式M(im) (bim)的ZIF-62家族柔性沸石咪唑酯骨架（ZIFs）的高压行为（M = Zn、Co；im = 咪唑酯；bim = 苯并咪唑酯，0.02≤x≤0.37）。高压粉末X射线衍射表明，在高达4000巴的静水压力下，材料从开孔（op）相到闭孔（cp）相发生可逆收缩。依次增加bim的比例（x）会增强骨架结构，导致op到cp相变的阈值压力增加，而整个相变过程中的总体积收缩减小。最重要的是，对于x≥0.35，典型的不连续op到cp转变（一级）变为不寻常的连续转变（二级）。这使得通过调节压力可以连续微调材料的空隙体积和孔径，从而为金属有机框架材料在压力可切换装置、膜和致动器方面开辟了新的可能性。
