Ionothermal Synthesis of Imide-Linked Covalent Organic Frameworks
Ionothermal Synthesis of Imide-Linked Covalent Organic Frameworks
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DOI：
10.1002/anie.202007372
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发表时间：
2020-08-11
影响因子：
16.6
通讯作者：
Lotsch, Bettina, V
中科院分区：
文献类型：
--
作者：
Maschita, Johannes;Banerjee, Tanmay;Lotsch, Bettina, V
共价有机骨架（COFs）是一类被广泛研究的多孔材料，其与其他多孔聚合物的区别在于其结晶度和高度的模块化，使得能够实现广泛的应用。COF最常见的合成溶剂热，这通常是一个耗时的过程，并限于溶解性良好的前体分子。聚酰亚胺连接的COF（PI-COF）的合成由于在溶剂热条件下闭环反应的不良可逆性而进一步复杂化。在此，我们报道了在氯化锌和低共熔盐混合物中离子交换法合成结晶和多孔PI-COFs。该合成不需要可溶性前体，并且与标准溶剂热合成方法相比，反应时间显著减少。除了将合成应用于先前报道的酰亚胺COF之外，还合成了一种新的基于二萘嵌苯的COF，其不能通过经典的溶剂热路线获得。原位高温XRPD分析提示形成作为结晶中间体的双金属-盐加合物，其然后彼此反应以形成COF。
Covalent organic frameworks (COFs) are an extensively studied class of porous materials, which distinguish themselves from other porous polymers in their crystallinity and high degree of modularity, enabling a wide range of applications. COFs are most commonly synthesized solvothermally, which is often a time-consuming process and restricted to well-soluble precursor molecules. Synthesis of polyimide-linked COFs (PI-COFs) is further complicated by the poor reversibility of the ring-closing reaction under solvothermal conditions. Herein, we report the ionothermal synthesis of crystalline and porous PI-COFs in zinc chloride and eutectic salt mixtures. This synthesis does not require soluble precursors and the reaction time is significantly reduced as compared to standard solvothermal synthesis methods. In addition to applying the synthesis to previously reported imide COFs, a new perylene-based COF was also synthesized, which could not be obtained by the classical solvothermal route. In situ high-temperature XRPD analysis hints to the formation of precursor-salt adducts as crystalline intermediates, which then react with each other to form the COF.