Triazine‐Carbazole‐Based Covalent Organic Frameworks as Efficient Heterogeneous Photocatalysts for the Oxidation of N‐aryltetrahydroisoquinolines

Abstract

AbstractCovalent organic frameworks (COFs) have attracted growing interests as new material platform for a range of applications. In this study, a triazine‐carbazole‐based covalent organic framework (COF‐TCZ) was designed as highly porous material with conjugated donor‐acceptor networks, and feasibly synthesized by the Schiff condensation of 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tr ianiline (TAPB) and 9‐(4‐formylphenyl)‐9H‐carbazole‐3,6‐dicarbaldehyde (CZTA) under the solvothermal condition. Considering the effect of linkage, the imine‐linked COF‐TCZ was further oxidized to obtain an amide‐linked covalent organic framework (COF‐TCZ‐O). The as‐synthesized COFs show high crystallinity, good thermal and chemical stability, and excellent photoactive properties. Two π‐conjugated triazine‐carbazole‐based COFs with tunable linkages are beneficial for light‐harvesting capacity and charge separation efficiency, which are empolyed as photocatalysts for the oxidation reaction of N‐aryltetrahydroisoquinoline. The COFs catalyst systems exhibit the outstanding photocatalytic performance with high conversion, photostability and recyclability. Photoelectrochemical tests were employed to examine the behavior of photogenerated charge carriers in photo‐illumination system. The control experiments provide further insights into the nature of photocatalysis. In addition, the current research also provided a valuable approach for developing photofunctional COFs to meet challenge in achieving the great potential of COFs materials in organic conversion.