Co-crystallization of K⁺ and Li⁺ ions with γ-cyclodextrin (γ-CD) has been shown to substitute the K⁺ ion sites partially by Li⁺ ions, while retaining the structural integrity and accessible porosity of CD-MOF-1 (MOF, metal–organic framework). A series of experiments, in which the K⁺/Li⁺ ratio was varied with respect to that of γ-CD, have been conducted in order to achieve the highest possible proportion of Li⁺ ions in the framework. Attempts to obtain a CD-MOF containing only Li⁺ ions resulted in nonporous materials. The structural occupancy on the part of the Li⁺ ions in the new CD-MOF has been confirmed by single-crystal X-ray analysis by determining the vacancies of K⁺-ion sites and accounting for the cation/γ-CD ratio in CD-MOF-1. The proportion of Li⁺ ions has also been confirmed by elemental analysis, whereas powder X-ray diffraction has established the stability of the extended framework. This noninvasive synthetic approach to generating mixed-metal CD-MOFs is a promising method for obtaining porous framework unattainable de novo. Furthermore, the CO₂ and H₂ capture capacities of the Li⁺-ion-substituted CD-MOF have been shown to exceed the highest sorption capacities reported so far for CD-MOFs.

中文翻译：

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Li ⁺离子对环糊精金属有机骨架中K ^+位点的无创替代

已证明K ⁺和Li ⁺离子与γ-环糊精（γ-CD）的共结晶可以部分地用Li ⁺离子取代K ⁺离子位点，同时保留CD-MOF-1的结构完整性和可达到的孔隙度（ MOF，金属有机框架）。为了实现框架中Li ⁺离子的最大可能比例，已进行了一系列实验，其中K ⁺ / Li ⁺比例相对于γ-CD有所不同。试图获得仅包含Li ⁺离子的CD-MOF会导致产生无孔材料。Li ⁺部分的结构性占用通过确定K ⁺离子位点的空位并考虑CD-MOF-1中的阳离子/γ-CD比，已通过单晶X射线分析确认了新CD-MOF中的离子。Li ⁺离子的比例也已通过元素分析得到证实，而粉末X射线衍射已确定了扩展骨架的稳定性。这种生成混合金属CD-MOF的非侵入性合成方法是一种获得无法从头获得的多孔骨架的有前途的方法。此外，业已证明，Li ⁺离子取代的CD-MOF的CO ₂和H ₂捕获能力超过了迄今为止报道的CD-MOF的最高吸附能力。