Mechanistic Insight into Hydrogen-Bond-Controlled Crystallinity and Adsorption Property of Covalent Organic Frameworks from Flexible Building Blocks
Mechanistic Insight into Hydrogen-Bond-Controlled Crystallinity and Adsorption Property of Covalent Organic Frameworks from Flexible Building Blocks
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柔性结构单元对氢键控制的共价有机框架的结晶度和吸附性能的机理洞察
DOI：
10.1021/acs.chemmater.7b05121
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发表时间：
2018-04-10
影响因子：
8.6
通讯作者：
Li, Shoujian
中科院分区：
文献类型：
--
作者：
Guo, Xinghua;Tian, Yin;Li, Shoujian
共价有机骨架(COF)结晶度的有效控制和与结晶度相关的性能优化一直被认为是一个巨大的挑战。承载柔性砌块(FBB)的COF通常具有更大的晶格尺寸和更广泛的单体来源，这可能赋予它们前所未有的应用价值。在这里，我们报道了从不同层内氢键含量的FBB定向合成一系列二维(2D)COF。氢键对结晶度和吸附性能的影响研究表明，碳纤维的部分结构被氢键相互作用“锁定”，从而提高了其微观有序度和结晶度。因此，通过控制COF中氢键的含量可以有效地实现结晶度的调节。令人印象深刻的是，所制备的COF对挥发性碘表现出良好的可逆吸附性能，吸附容量高达543wt%，远远高于所有已报道的吸附剂，尽管吸附容量的变化趋势与它们的结晶度相反。本研究为高/适当结晶度的COF和超大容量碘吸附剂的设计和构造提供了一般性的指导。
The effective control of crystallinity of covalent organic frameworks (COFs) and the optimization of their performances related to the crystallinity have been considered as big challenges. COFs bearing flexible building blocks (FBBs) generally own larger lattice sizes and broader monomer sources, which may endow them with unprecedented application values. Herein, we report the oriented synthesis of a series of two-dimensional (2D) COFs from FBBs with different content of intralayer hydrogen bonds. Studies of H-bonding effects on the crystallinity and adsorption properties indicate that partial structure of the COFs is "locked" by the H-bonding interaction, which consequently improves their microscopic order degree and crystallinity. Thus, the regulation of crystallinity can be effectively realized by controlling the content of hydrogen bonds in COFs. Impressively, the as-prepared COFs show excellent and reversible adsorption performance for volatile iodine with capacities up to 543 wt %, much higher than all previously reported adsorbents, although the variation tendency of adsorption capacities is opposite to their crystallinity. This study provides a general guidance for the design and construction of highly/appropriately crystalline COFs and ultrahigh-capacity iodine adsorbents.