Engineering single-atom active sites anchored covalent organic frameworks for efficient metallaphotoredox C-N cross-coupling reactions

Photoredox catalysis has become an indispensable solution for the synthesis of small organic molecules. However, the precise construction of single-atomic active sites not only determines the catalytic performance, but also avails the understanding of structure-activity relationship. Herein, we develop a facile approach to immobilize single-atom Ni sites anchored porous covalent organic framework (COF) by use of 4,40,400-(1,3,5-triazine-2,4,6-triyl)trianiline and 2,6-diformylpyridine (Ni SAS/TD-COF). Ni SAS/TDCOF catalyst achieves excellent catalytic performance in visible-light-driven catalytic carbon-nitrogen cross-coupling reaction between aryl bromides and amines under mild conditions. The reaction provides amine products in excellent yields (71%-97%) with a wide range of substrates, including aryl and heteroaryl bromides with electron-deficient, electron-rich and neutral groups. Notably, Ni SAS/TD-COF could be recovered from the reaction mixture, corresponding to the negligible loss of photoredox performance after several cycles. This work provides a promising opportunity upon rational design of single-atomic active sites on COFs and the fundamental insight of photoredox mechanism for sustainable organic transformation.(c) 2022 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

Automated summary

Photoredox catalysis has become an indispensable solution for the synthesis of small organic molecules. This study develops a facile approach to immobilize single-atom Ni sites anchored porous covalent organic framework (COF) for visible-light-driven catalytic carbon-nitrogen cross-coupling reactions. The catalyst exhibits excellent catalytic performance under mild conditions and can be recycled.