Visible-Light-Driven C–S Coupling Reaction Using Covalent Organic Framework Films

Abstract

A visible-light-driven C–S cross-coupling reaction using covalent organic frameworks (COFs) as heterogeneous photocatalysts is reported. Three β-keto-enamine-linked COFs, TpAzo, TpDPP, and TpBDMe2, were synthesized and systematically evaluated. Among them, TpAzo exhibited superior photocatalytic activity due to its high surface area (1725 m2 g–1), low band gap (1.78 eV), and efficient charge separation. To enhance the reusability and accessibility, a thin-film morphology of TpAzo COF was developed, which facilitated catalyst recovery and sustained performance over multiple cycles. The optimized protocol enabled the arylation of thiols with a wide range of aryl halides, including iodides, bromides, chlorides, tosylates, and mesylates, delivering the corresponding thioethers in good to excellent yields (55–94%) under ambient conditions. This study highlights the potential of COF-based photocatalysts for sustainable C–S bond formation and broadens their application in organic synthesis. © 2026 American Chemical Society