Three-Dimensional Covalent Thiazolo[5,4-d]thiazole Frameworks with sur-a Topology for Coupling Photoactivation of...

Developing new topological three-dimensional (3D) covalent organic framework (COF) structures with strong electron donor-acceptor (D-A) properties represents a promising approach for harvesting high-performance photocatalysts. In this study, we developed two unprecedented 3D COFs with sur-a topology by [3 + 2 + 4]-c strategy. The formation of sur-a topological structures relies on an elongated [3 + 2]-c tetrahedral thiazolo[5,4-d]thiazole (DTZ)-based building block (DTZ-CHO) with lower C₂-symmetry. This unit is formed by inserting linear asymmetric DTZ subunit (2-c vertex) between two 3-c vertices. The incorporation of strong DTZ-pyrene/vinyl electron D-A structures efficiently promote exciton separation and charge transfer during photocatalysis, thereby demonstrating high-efficiency coupling photoactivation performance toward oxygen and biomass. It delivers a hydrogen peroxide photosynthesis rate of ∼12 092 µmol g^-1 h^-1 based on four-step direct Yeager-type oxygen photoreduction mechanism on DTZ active centers, pairing with efficient 5-hydroxymethylfurfural photooxidation (∼10 264 µmol g^-1 h^-1). This work highlights the potential of topologically unique 3D COFs with robust D-A structures as high-efficiency photocatalysts for artificial photosynthesis.