Anion Stripping as a General Method to Create Cationic Porous Framework with Mobile Anions

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• 作者：Chengyu Mao ; Ryan A. Kudla ; Fan Zuo ; Xiang Zhao ; Leonard J. Mueller ; Xianhui Bu ; Pingyun Feng
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：May 28, 2014
• 年：2014
• 卷：136
• 期：21
• 页码：7579-7582
• 全文大小：294K
• 年卷期：v.136,no.21(May 28, 2014)
• ISSN：1520-5126

文摘

Metal鈥搊rganic frameworks (MOFs) with cationic frameworks and mobile anions have many applications from sensing, anion exchange and separation, to fast ion conductivity. Despite recent progress, the vast majority of MOFs have neutral frameworks. A common mechanism for the formation of neutral frameworks is the attachment of anionic species such as F^{鈥?/sup> or OH鈥?/sup> to the framework metal sites, neutralizing an otherwise cationic scaffolding. Here, we report a general method capable of converting such neutral frameworks directly into cationic ones with concurrent generation of mobile anions. Our method is based on the differential affinity between distinct metal ions with framework anionic species. Specifically, Al3+ is used to strip F鈥?/sup> anions away from framework Cr3+ sites, leading to cationic frameworks with mobile Cl鈥?/sup> anions. The subsequent anion exchange with OH鈥?/sup> further leads to a porous network with mobile OH鈥?/sup> anions. New materials prepared by anion stripping can undergo ion exchange with anionic organic dyes and also exhibit much improved ionic conductivity compared to the original unmodified MOFs.}