Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
J Am Chem Soc. 2017 Sep 20;139(37):12911-12914. doi: 10.1021/jacs.7b06913. Epub 2017 Sep 7.
Covalent organic frameworks (COFs) are crystalline, permanently porous, two-dimensional or three-dimensional polymers with tunable topology and functionality. COFs linked with imines or β-ketoenamines are more chemically stable than their boron-linked counterparts, making them more promising for a broad range of applications, including energy storage devices, proton-conductive membranes, and catalyst supports. We report a general and scalable method for synthesizing imine- and β-ketoenamine-linked COFs based on the formal transimination of N-aryl benzophenone imines. These substrates are often the synthetic precursors of traditional polyfunctional aryl amine monomers and are more stable, soluble, and easy to handle and purify. The imine- and β-ketoenamine-linked COFs obtained from this approach show excellent materials quality, as characterized by X-ray diffraction and surface area analysis. The most optimized COF exhibited a Brunauer-Emmett-Teller surface area (>2600 m/g) very close to its theoretical value (2830 m/g). This method is amenable to both conventional solvothermal conditions and microwave heating, providing similar or even improved materials quality with shorter reaction times. The high materials quality, scalability, and availability of benzophenone imine monomers are all attractive features of this approach.
共价有机骨架（COFs）是结晶的、永久多孔的二维或三维聚合物，具有可调拓扑和功能。与亚胺或β-酮亚胺相连的 COFs 比硼键合的 COFs 具有更高的化学稳定性，因此更有希望应用于广泛的领域，包括储能装置、质子传导膜和催化剂载体。我们报道了一种基于 N-芳基二苯甲酮亚胺的形式反胺化反应来合成亚胺和β-酮亚胺连接的 COFs 的通用和可扩展方法。这些底物通常是传统多功能芳基胺单体的合成前体，它们更稳定、更易溶解、更易于处理和纯化。通过这种方法得到的亚胺和β-酮亚胺连接的 COFs 表现出优异的材料质量，这可以通过 X 射线衍射和比表面积分析来表征。最优化的 COF 的 Brunauer-Emmett-Teller 比表面积（>2600 m/g）非常接近其理论值（2830 m/g）。该方法既适用于传统的溶剂热条件，也适用于微波加热，即使在较短的反应时间内，也能提供相似甚至更好的材料质量。该方法具有高材料质量、可扩展性和苯甲酮亚胺单体的可用性，这些都是该方法吸引人的特点。
