Ligand-Mediated Microenvironment in COFs Incorporating Ion-Pair Motifs and Atomically Dispersed Copper Sites for Cascade CO2 Conversion.

Precisely programming the local microenvironment of covalent organic frameworks (COFs) is critical for catalytic selectivity, but remains challenging, especially via de novo synthesis. Here, we present a rational ligand-effect-oriented microenvironment design for the de novo construction of multifunctional COFs that integrate N+/Br- ion-pairs and imine-anchored atomically dispersed copper sites. A key innovation lies in the precise control of the COFs microenvironment, enabling a seamless three-component cascade reaction of CO2 (1 bar), epoxides, and anilines to afford 2-oxazolidinones under mild and precious-metal-free conditions. The optimized catalyst, Cu@PD-iCOF, delivers up to 99% yield, exhibits broad functional-group compatibility, and retains >96% activity over nine cycles. This work shows that combining ion-pairs and single-atom sites reprograms the COFs microenvironment for efficient CO2 utilization.