Structural and Dimensional Transformations between Covalent Organic Frameworks via Linker Exchange
Structural and Dimensional Transformations between Covalent Organic Frameworks via Linker Exchange
复制标题
通过连接子交换实现共价有机框架之间的结构和尺寸转换
DOI：
10.1021/acs.macromol.8b01814
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发表时间：
2019-02-12
期刊：
影响因子：
5.5
通讯作者：
Han, Bao-Hang
中科院分区：
文献类型：
--
作者：
Li, Zhen;Ding, Xuesong;Han, Bao-Hang
共价有机骨架材料是一类结构可控的多孔晶体材料，具有广泛的应用前景。然而，构建新的COF具有巨大的挑战，包括结构单元单体的设计和合成、反应溶剂体系的选择以及反应时间和温度的研究。在本文中，我们通过动态共价化学原理进行了三维（3D）COF（COF-300和COF-320）的结构转换以及从3D（COF-301）到2D（TPB-DHTP-COF）的尺寸转换，并通过FT-IR，H-1 NMR，PXRD和氮气吸附等温线测量证实了这些转换的成功实现。基于PXRD图谱和H-1 NMR谱的结果，成功地实现了COF-320向COF-300的转化，转化率高达89%。COF-320与COF-300相反方向转化后得到一种新的网络结构，它在一个骨架中含有两个醛结构单元联苯-4，4 '-二甲醛（BPDA）和乙醛（TA）。同时，还实现了COF-301-到-TPB-DHTP-COF的交换效率为78%的COF的尺寸转换。这些结果不仅揭示了COF到COF的3D到3D和3D到2D的转化，而且为构建难以一步合成的新型COF提供了新的途径。
Covalent organic frameworks (COFs) are porous crystalline materials with well-controlled structures and extensive potential applications. However, construction of new COFs has tremendous challenges including design and synthesis of building block monomers, selection of reaction solvent systems, and investigation of reaction time and temperature. Here, we performed the structural transformation in the three-dimensional (3D) COFs (COF-300 and COF-320) and dimensional transformation from 3D (COF-301) to 2D (TPB-DHTP-COF) via the dynamic covalent chemistry principle, and the successful realization of these exchanges was confirmed by FT-IR, H-1 NMR, PXRD, and nitrogen sorption isotherm measurements. Based on the results of PXRD patterns and H-1 NMR spectra, the COF-320-to-COF-300 transformation was successfully achieved, and an efficiency as high as 89% was attained. A new network structure rather than COF-320 was obtained after transformation in the opposite direction (from COF-300 to COF-320), which contains the two aldehyde building units biphenyl-4,4'-dicarbaldehyde (BPDA) and terephthaldehyde (TA) in one framework. Meanwhile, the dimensional transformation of COFs with 78% exchange efficiency for COF-301-to-TPB-DHTP-COF is also achieved. These results not only reveal the COF-to-COF transformation in 3D-to-3D and 3D-to-2D but also provide a new way for constructing new COFs that is difficult to synthesize in one step.