Stable, crystalline, porous, covalent organic frameworks as a platform for chiral organocatalysts
Stable, crystalline, porous, covalent organic frameworks as a platform for chiral organocatalysts
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DOI：
10.1038/nchem.2352
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发表时间：
2015-11-01
期刊：
影响因子：
21.8
通讯作者：
Jiang, Donglin
中科院分区：
文献类型：
--
作者：
Xu, Hong;Gao, Jia;Jiang, Donglin
共价有机框架（COF）的周期性层和有序纳米通道使这些材料成为可行的开放式催化纳米反应器，但它们的低稳定性阻碍了它们的实际应用。在这里，我们报告的结晶多孔COF，对水，强酸和强碱是稳定的合成，我们证明了它的实用性作为一个材料平台的结构设计和功能开发。我们通过将甲氧基引入到其孔壁中以增强层间相互作用来赋予结晶和多孔的基于亚胺的COF稳定性。随后，我们将所得的非手性材料转化为两种不同的手性有机催化剂，保留了高结晶度和孔隙率，通过在其通道壁上附加手性中心和催化活性位点。由此制备的COFs联合收割机催化活性，对映选择性和可回收性，这在非均相有机催化中是有吸引力的，并且显示出在环境条件下促进水中不对称C-C键的形成。
The periodic layers and ordered nanochannels of covalent organic frameworks (COFs) make these materials viable open catalytic nanoreactors, but their low stability has precluded their practical implementation. Here we report the synthesis of a crystalline porous COF that is stable against water, strong acids and strong bases, and we demonstrate its utility as a material platform for structural design and functional development. We endowed a crystalline and porous imine-based COF with stability by incorporating methoxy groups into its pore walls to reinforce interlayer interactions. We subsequently converted the resulting achiral material into two distinct chiral organocatalysts, with the high crystallinity and porosity retained, by appending chiral centres and catalytically active sites on its channel walls. The COFs thus prepared combine catalytic activity, enantioselectivity and recyclability, which are attractive in heterogeneous organocatalysis, and were shown to promote asymmetric C-C bond formation in water under ambient conditions.