Coudert François-Xavier
Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris, 75005, Paris, France.
Chemphyschem. 2017 Oct 6;18(19):2732-2738. doi: 10.1002/cphc.201700463. Epub 2017 Aug 4.
Zeolitic imidazolate framework ZIF-8 displays flexibility of its structure by rotation of its imidazolate linker. This "swing effect" has been widely described in the literature, both experimentally and theoretically, as a bistable system where the linker oscillates between two structures: "open window" and "closed window". By using quantum chemistry calculations and first-principles molecular dynamics simulations, it is shown that the deformation upon adsorption is in fact continuous upon pore loading, with thermodynamics of packing effects being the reason behind stepped adsorption isotherms experimentally observed. Finally, we study a variant of ZIF-8 with a different linker, highlighting the influence of the linker and the balance of microscopic interactions on the framework's flexibility.
沸石咪唑酯骨架材料ZIF-8通过其咪唑酯连接体的旋转展现出结构的灵活性。这种“摆动效应”在文献中已有广泛的实验和理论描述，它是一个双稳态系统，其中连接体在两种结构之间振荡：“开放窗口”和“封闭窗口”。通过量子化学计算和第一性原理分子动力学模拟表明，吸附时的变形实际上在孔填充过程中是连续的，堆积效应的热力学是实验中观察到阶梯状吸附等温线背后的原因。最后，我们研究了一种具有不同连接体的ZIF-8变体，突出了连接体的影响以及微观相互作用的平衡对骨架灵活性的作用。
