Lu Meng, Zhang Shuai-Bing, Li Run-Han, Dong Long-Zhang, Yang Ming-Yi, Huang Pei, Liu Yu-Fei, Li Ze-Hui, Zhang Han, Zhang Mi, Li Shun-Li, Lan Ya-Qian
Guangdong Provincial Key Laboratory of Carbon Dioxide Resource Utilization, School of Chemistry, South China Normal University, Guangzhou 510006, P.R. China.
School of Chemistry and Environment Engineering, Changchun University of Science and Technology, Changchun 130022, P.R. China.
J Am Chem Soc. 2024 Sep 18;146(37):25832-25840. doi: 10.1021/jacs.4c08951. Epub 2024 Sep 4.
The connectivity (valency) of building blocks for constructing 3D covalent organic frameworks (COFs) has long been limited to 4, 6, 8, and 12. Developing a higher connectivity remains a great challenge in the field of COF structural design. Herein, this work reports a hierarchical expansion strategy for making 16-connected building blocks to construct 3D COFs with sqc topology. The [16 + 2] construction achieved by condensation between a 16-connected carbazolyl dicyanobenzene-based building block (CzTPN) and linear diamino linkers (BD or Bpy) affords two 3D COFs (named CzBD COF and CzBpy COF). Furthermore, attributed to the well-organized donor-acceptor (D-A) heterojunction, the Ni chelated CzBpy COF (Ni@CzBpy COF) exhibits excellent performance for photoredox/Ni dual catalytic C(sp)-C(sp) cross-coupling of alkyltrifluoroborates with aryl halides, achieving a maximum 98% conversion and 94% yield for various substrates. This work developed the first case of high-connectivity COFs bearing 16-connected units, which is the highest connectivity reported until now, and achieved efficient photocatalysis applications, thus greatly enriching the possibilities of COFs.
用于构建三维共价有机框架（COF）的结构单元的连接性（价态）长期以来一直局限于4、6、8和12。开发更高的连接性仍然是COF结构设计领域的巨大挑战。在此，这项工作报道了一种用于制备具有16连接结构单元以构建具有sqc拓扑结构的三维COF的分级扩展策略。通过基于咔唑基二氰基苯的16连接结构单元（CzTPN）与线性二氨基连接体（BD或Bpy）之间的缩合实现的[16 + 2]构建提供了两种三维COF（命名为CzBD COF和CzBpy COF）。此外，由于有序的供体-受体（D-A）异质结，镍螯合的CzBpy COF（Ni@CzBpy COF）在光氧化还原/镍双催化烷基三氟硼酸盐与芳基卤化物的C(sp)-C(sp)交叉偶联反应中表现出优异的性能，各种底物的转化率最高可达98%，产率可达94%。这项工作开发了首例带有16连接单元的高连接性COF，这是迄今为止报道的最高连接性，并实现了高效的光催化应用，从而极大地丰富了COF的可能性。
