2D sp(2) Carbon-Conjugated Porphyrin Covalent Organic Framework for Cooperative Photocatalysis with TEMPO

摘要

2D covalent organic frameworks (COFs) are receiving ongoing attention in semiconductor photocatalysis. Herein, we present a photocatalytic selective chemical transformation by combining sp(2) carbon-conjugated porphyrin-based covalent organic framework (Por-sp(2)c-COF) photocatalysis with TEMPO catalysis illuminated by 623 nm red light-emitting diodes (LEDs). Highly selective conversion of amines into imines was swiftly afforded in minutes. Specifically, the pi-conjugation of porphyrin linker leads to extensive absorption of red light; the sp(2) -C=C- double bonds linkage ensures the stability of Por-sp(2)c-COF under high concentrations of amine. Most importantly, we found that crystalline framework of Por-sp(2)c-COF is pivotal for cooperative photocatalysis with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO). This work foreshadows that the outstanding hallmarks of COFs, particularly crystallinity, could be exploited to address energy and environmental challenges by cooperative photocatalysis.