Porphyrin-based Vinylene-linked 3D Covalent Organic Framework with Unprecedented cya Topology for Photocatalytic H₂O₂...

Designing and realizing new topologies represent one of the most important ways toward developing new structures and functionalities for molecule-based frameworks including SOFs, MOFs, and COFs. Herein, Aldol condensation between 5,10,15,20-tetrayl(tetrakis(([1,1':3',1''-terphenyl]-4,4''-dicarbaldehyde)))-porphyrin (TTEP) and 2,4,6-trimethyl-1,3,5-triazine (TMT) affords the vinylene-linked 3D covalent organic framework Por-COF-cya. Powder X-ray diffraction (PXRD) in combination with structural simulation reveals its high crystalline structure with an unprecedented cya topology in the molecule-based frameworks reported thus far. Por-COF-cya displayed polycrystallinity and possessed high permanent porosity. Especially, the incorporation of light-harvesting porphyrin unit and vinylene linkages in Por-COF-cya enables a conjugation effect within the framework, endowing it with a photocatalytic H₂O₂ production rate of 2209 μmol g^-1h^-1 in pure aqueous solution under visible-light irradiation (λ >420 nm). Inclusion of the guest molecules TTF into the pores of Por-COF-cya results in a donor-acceptor system TTF@Por-COF-cya, enhancing the photocatalytic activity with H₂O₂ production rate of 6994 μmol g^-1h^-1. This work paves a new way for the development of new topological functional molecule-based frameworks toward diverse application potentials.