Bi Shuai, Zhang Zixing, Meng Fancheng, Wu Dongqing, Chen Jie-Sheng, Zhang Fan
School of Chemistry and Chemical Engineering; State Key Laboratory of Metal Matrix Composites; Shanghai Electrochemical Energy Devices Research Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
Angew Chem Int Ed Engl. 2022 Feb 1;61(6):e202111627. doi: 10.1002/anie.202111627. Epub 2021 Dec 17.
Embedding heteroatoms into the main backbones of polymeric materials has become an efficient tool for tailoring their structures and improving their properties. However, owing to comparatively harsh heteroatom-doping conditions, this has rarely been explored in covalent organic frameworks (COFs). Herein, upon aldol condensation of a trimethyl-substituted pyrylium salt with a tritopic aromatic aldehyde, a two-dimensional oxonium-embedded COF with vinylene linkages was achieved, which was further converted to a neutral pyridine-cored COF by in situ replacement of oxonium ions with nitrogen atoms under ammonia treatment. The two heteroatom-embedded COFs are conceptually isoelectronic with each other, featuring similar geometric structures but different electronic structures, rendering them capable of catalyzing the visible-light-promoted multi-component synthesis of tri-substituted pyridine derivatives with good recyclability.
将杂原子嵌入聚合物材料的主链已成为一种调整其结构和改善其性能的有效工具。然而，由于杂原子掺杂条件相对苛刻，在共价有机框架（COF）中很少对此进行探索。在此，通过三甲基取代的吡喃鎓盐与三官能团芳香醛的羟醛缩合反应，制备了一种具有亚乙烯基连接的二维嵌入氧鎓的COF，通过在氨处理下用氮原子原位取代氧鎓离子，该COF进一步转化为中性吡啶核COF。这两种嵌入杂原子的COF在概念上是等电子体，具有相似的几何结构但不同的电子结构，使其能够催化可见光促进的三取代吡啶衍生物的多组分合成，并且具有良好的可回收性。
