Extending 2D covalent organic frameworks by inserting anthracene for promoted white-light-mediated photocatalysis

Abstract

Through the responsible manipulation of linkage chemistry on a molecular scale, the band gaps and electronic structures of two-dimensional covalent organic frameworks (2D COFs) can be finely tuned. Intrinsically, the incorporation of expanded conjugated moieties together with an enhancement of the donor–acceptor (D–A) effect through strategic structural engineering typically determines more favorable photochemical activities for polymers. However, understanding the functional underpinnings of these enhancements remains a significant challenge. In this work, we designed and synthesized a new anthracene-based COF (AND–TAPT) enhanced in its π-conjugation and D–A structure to boost photocatalytic performance. For comparison, an analogous phenyl COF (PDA–TAPT) was also manufactured. As expected, the introduction of anthracene moiety into 2D COFs significantly extended the visible light absorption range beyond 100 nm compared to PDA–TAPT and resulted in more efficient transfer and separation of photogenerated electron–hole pairs. Consequently, as a potent white light-activated catalyst, AND–TAPT achieved superior amine oxidative coupling, selective sulfide oxidation conversion, and selectivity (up to 99%), exemplifying the potential use of such anthracene-derived COFs in this field. This study provides an effective strategy for designing photocatalytic systems.