Exponential growth in the field of covalent–organic frameworks (COFs) is emanating from the direct correlation between designing principles and desired properties. The comparison of catalytic activity between single-pore and dual-pore COFs is of importance to establish structure–function relationship. Herein, the synthesis of imine-linked dual-pore [(BPyDC)]_x%-ETTA COFs (x = 0%, 25%, 50%, 75%, 100%) with controllable bipyridine content is fulfilled by three-component condensation of 4,4′,4″,4′″-(ethene-1,1,2,2-tetrayl)tetraaniline (ETTA), 4,4′-biphenyldialdehyde, and 2,2′-bipyridyl-5,5′-dialdehyde in different stoichiometric ratio. The strong coordination of bipyridine moieties of [(BPyDC)]_x%-ETTA COFs with palladium imparts efficient catalytic active sites for selective functionalization of sp² CH bond to CX (X = Br, Cl) or CO bonds in good yield. To broaden the scope of regioselective CH functionalization, a wide range of electronically and sterically substituted substrates under optimized catalytic condition are investigated. A comparison of the catalytic activity of palladium decorated dual-pore frameworks with single-pore imine-linked Pd(II) @ Py-2,2′-BPyDC framework is undertaken. The finding of this work provides a sporadic example of chelation-assisted CH functionalization and disclosed an in-depth comparison of the relationship between superior catalytic activity and core properties of rationally designed imine linked frameworks.

中文翻译：

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单孔与双孔基于联吡啶的共价有机框架：洞察选择性 C 的多相催化活性？H 功能化

共价有机框架 (COF) 领域的指数增长源于设计原则和所需特性之间的直接相关性。单孔和双孔COFs催化活性的比较对于建立结构-功能关系很重要。在此， 联吡啶含量可控的亚胺连接双孔[(BPyDC)] _{x %} -ETTA COFs ( x = 0%, 25%, 50%, 75%, 100%)的合成是通过三组分缩合实现的4,4',4",4'"-(乙烯-1,1,2,2-四基)四苯胺 (ETTA)、4,4'-联苯二醛和 2,2'-联吡啶-5,5' -不同化学计量比的二醛。[(BPyDC)] _{x %}的联吡啶部分的强配位-ETTA COFs 与钯赋予有效的催化活性位点，用于 sp ² C  H 键选择性功能化为C  X (X = Br, Cl) 或 C  O 键，收率良好。为了拓宽区域选择性 C  H 功能化的范围，研究了在优化催化条件下的各种电子和空间取代底物。进行了钯装饰的双孔框架与单孔亚胺连接的 Pd(II)@Py-2,2'-BPyDC 框架的催化活性的比较。这项工作的发现提供了螯合辅助 C 的零星例子H 官能化并揭示了对合理设计的亚胺连接框架的优异催化活性与核心性能之间关系的深入比较。