Engineering Photocatalytic Porous Organic Materials for Directing Redox vs Energy Transfer Processes

Two organic materials containing phenanthroline and triazine fragments but connected in different ways are presented. The imine‐based material Phen‐Tz‐COF preferentially shows photocatalytic activity through an energy transfer pathway as observed for olefin photoisomerization. However, an analogous covalent triazine framework (Phen‐CTF) behaves as a powerful photoredox catalyst able to activate C‐X (X=Br,Cl) bonds. The analysis of this phenomenon by means of theoretical calculations enable the rationalization of the different photocatalytic behaviour observed. Phen‐CTF behaves as a donor‐acceptor material resulting in efficient charge separation upon excitation while the imine groups present in Phen‐Tz‐COF hamper charge separation contributing to the rapid recombination between electrons and holes. This justifies a better activation via electron transfer in Phen‐CTF and via energy transfer in Phen‐Tz‐COF. This article is protected by copyright. All rights reserved.