Cocatalyst‐Free Conversion of CO₂ to Cyclic Carbonates Using a Postsynthetically Modified Trifunctional Cu‐MOF

Abstract Carbon capture and conversion (CCC) into value‐added products offers a dual benefit of mitigating CO₂ emissions while generating industrially relevant chemicals. The cycloaddition of CO₂ with epoxides to form cyclic carbonates is among the most efficient and sustainable approaches within the CCU framework. Herein, we report a postsynthetically modified Cu(II)‐based metal–organic framework (MOF), [Cu(II)‐IP‐Tz] + Br − ( C*) , as a fully heterogeneous catalyst for this transformation. The parent MOF [(DMF)Cu(II)‐IP‐NH₂] ( C ), synthesized from Cu(II) salt and 5‐aminoisophthalic acid (IP‐NH 2 ), was functionalized with 5‐aminotetrazole (Tz‐NH 2 ) moieties and subsequently quaternized with C 2 H 5 Br to introduce Br⁻ anion. The resulting material ( C* ) combines Lewis acidic Cu(II) sites, Lewis basic amino groups, and nucleophilic Br⁻, enabling efficient catalysis under solvent‐free and cocatalyst‐free conditions at ambient CO₂ pressure. C* not only exhibits a higher CO₂ conversion of 85.4% with styrene oxide but also shows enhanced CO₂ adsorption capacity (0.68 mmol g⁻¹) compared to the unmodified MOF (conversion: 20.4%, CO 2 adsorption capacity: 0.19 mmol g⁻¹). Moreover, the catalyst demonstrates a broad substrate scope across various epoxides, underscoring its potential for practical CO₂ fixation. This study emphasizes the significance of targeted postsynthetic modifications in transforming MOFs into complete heterogeneous catalysts with enhanced functionality and markedly improved performance for sustainable CO₂ fixation.