Photoactivated covalent metal–organic frameworks with dual functionalities for efficient colorimetric sensing and aerobic oxidation reaction

Abstract

Considering the intrinsic limitations of natural enzymes, the development of efficient, cost-effective artificial enzyme alternatives has become imperative. Covalent metal–organic frameworks (CMOFs), as a new type of open framework material with precise crystalline structures, clear metal catalytic sites, ordered pores and strong designability, can be considered as an ideal platform to develop efficient artificial enzyme materials. Here, we report two distinct enzyme-mimetic CMOFs, Tbpa-Ag₃ and Tbpa-Cu₃, which featured cyclic trinuclear metal clusters (Ag₃/Cu₃) as functional nodes respectively. Among the two CMOFs, Tbpa-Ag₃ achieved precise spatial integration of photoactive Tbpa ligands with catalytic Ag₃ clusters, establishing a more efficient electron transfer pathway that delivered superior oxidase-like activity under visible-light irradiation. Based on Tbpa-Ag₃, we engineered a biomarker detection platform for physiological antioxidants (L-cysteine and GSH) and a sustainable photocatalytic system for benzylamine oxidative coupling (yield >99%, 4 h), validating Tbpa-Ag₃'s dual functionality in analytical chemistry and green catalysis.