Influence of Configurational Isomerism of Pyridine π Bridge in Donor-π Bridge-Acceptor Type Covalent Triazine Frameworks on The Photocatalytic Performance.

Covalent triazine frameworks (CTFs) involving a donor-π bridge-acceptor (D-π-A) structure are considered one of the most promising photocatalytic materials, in which the π bridge is known to play an important role in influencing the photocatalytic performance. So far, much effort has been directed at the designing of the different π bridge structure to facilitate the photo-induced charge separation. However, the orientation of the π bridge units (configurational isomerism) has not been considered. In this paper, a pair of pyridine-bridged D-π-A type CTFs, named TFA-P1-CTF and TFA-P2-CTF, were designed to investigate how the orientation of the π bridge would influence their performance in the photocatalytic oxidation of olefins into carbonyl compounds. Interestingly, due to the superior charge separation capability, TFA-P2-CTF was found to be able to catalyze the reaction more efficiently than TFA-P1-CTF. Our study eventually provided a guide for the design of D-π-A type CTFs as high-performance photocatalytic materials via tuning the configurational isomerism of the π bridge unit for use in chemical transformations.