‡School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States.
§Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405, United States.
J Am Chem Soc. 2015 Apr 1;137(12):4191-7. doi: 10.1021/jacs.5b00803. Epub 2015 Mar 23.
Nanoporous zeolitic imidazolate frameworks (ZIFs) form structural topologies equivalent to zeolites. ZIFs containing only one type of imidazole linker show separation capability for limited molecular pairs. We show that the effective pore size, hydrophilicity, and organophilicity of ZIFs can be continuously and drastically tuned using mixed-linker ZIFs containing two types of linkers, allowing their use as a more general molecular separation platform. We illustrate this remarkable behavior by adsorption and diffusion measurements of hydrocarbons, alcohols, and water in mixed-linker ZIF-8(x)-90(100-x) materials with a large range of crystal sizes (338 nm to 120 μm), using volumetric, gravimetric, and PFG-NMR methods. NMR, powder FT-Raman, and micro-Raman spectroscopy unambiguously confirm the mixed-linker nature of individual ZIF crystals. Variation of the mixed-linker composition parameter (x) allows continuous control of n-butane, i-butane, butanol, and isobutanol diffusivities over 2-3 orders of magnitude and control of water and alcohol adsorption especially at low activities.
纳米多孔沸石咪唑酯骨架（ZIFs）形成与沸石相当的结构拓扑。仅含有一种咪唑连接体的 ZIF 对有限的分子对具有分离能力。我们表明，使用含有两种类型连接体的混合连接体 ZIF，可以连续且剧烈地调节 ZIF 的有效孔径、亲水性和亲脂性，从而使其成为更通用的分子分离平台。我们通过使用体积法、重量法和 PFG-NMR 方法，在具有大晶体尺寸（338nm 至 120μm）的混合连接体 ZIF-8(x)-90(100-x)材料中，对碳氢化合物、醇和水的吸附和扩散测量，说明了这种显著的行为。NMR、粉末 FT-Raman 和微拉曼光谱明确证实了单个 ZIF 晶体的混合连接体性质。混合连接体组成参数（x）的变化允许 n-丁烷、i-丁烷、正丁醇和异丁醇扩散系数在 2-3 个数量级连续控制，并特别在低活度下控制水和醇的吸附。
Zotero 插件