Abnormal Association between Metal−Organic Cages and Counterions Regulated by the Hydration Shells
Abnormal Association between Metal−Organic Cages and Counterions Regulated by the Hydration Shells
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金属有机笼与水合壳调节的反离子之间的异常关联
DOI：
10.1002/chem.202104332
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Liu, Tianbo
中科院分区：
文献类型：
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作者：
Yang, Yuqing;Raee, Ehsan;Liu, Tianbo
在水介质中观察到阳离子金属−有机笼(MOCs)与外部反阴离子结合亲和力的独特趋势。与许多大分子离子类似，两个结构相似但电荷数目不同的MOC通过反离子介导的吸引自组装成中空球形单层黑莓型结构。动态和静态光散射和等温滴定热法测量证实了低电荷MOCs和反离子之间的相互作用比高电荷MOCs更强，从而导致更大的组装尺寸。剂量核磁共振测量表明，高电荷MOC的厚水化壳具有重要意义，抑制了MOC与反离子的结合，削弱了它们之间的相互作用。研究表明，与MOCs的电荷密度相比，水化壳层对离子对的形成起着更大的作用。
A unique trend in the binding affinity between cationic metal−organic cages (MOCs) and external counteranions in aqueous media was observed. Similar to many macroions, two MOCs, sharing similar structures but carrying different number of charges, self‐assembled into hollow spherical single‐layered blackberry‐type structures through counterion‐mediated attraction. Dynamic and static light scattering and isothermal titration calorimetry measurements confirm the stronger interactions among less charged MOCs and counteranions than that of highly charged MOCs, leading to larger assembly sizes. DOSY NMR measurements suggest the significance of thick hydration shells of highly charged MOCs, inhibiting the MOC‐counterion binding and weakening the interaction between them. This study demonstrates that the greater role played by hydration shell on ion‐pair formation comparing with charge density of MOCs.