Growth of ionic polymers on ZIFs to construct core-shell hybrid materials via coordination interactions for catalytic CO₂ conversion

A sustainable and practical method has been developed for synthesizing ZIF-ionic polymer core-shell hybrid materials. This one-pot, two-step process employs imidazole, zinc nitrate, DABCO (1,4-diazabicyclo[2.2.2]octane), and 1,3,5-tris(bromomethyl)benzene in ethanol, yielding high efficiency. In this approach, DABCO facilitates ZIF formation by deprotonating imidazole and subsequently reacts with 1,3,5-tris(bromomethyl)benzene to generate a poly-DABCO salt that coats the ZIF surface via coordination interactions. The resulting hybrid materials, which exhibit dual Lewis acid and base functionalities, demonstrate exceptional activity and stability in catalyzing CO₂ conversion into cyclic carbonates. Interestingly, the catalyst also exhibits high activity in the synthesis of bis(cyclic carbonate) from diepoxide, which subsequently reacts with diamines to form non-isocyanate polyurethanes. A proposed reaction mechanism, combining experimental findings and density functional theory (DFT) calculations, highlights the critical roles of zinc and the ionic polymer in achieving high catalytic performance. Specifically, zinc and ionic polymer are identified as key contributors to epoxide activation and ring-opening processes. This study not only deepens the understanding of ZIF-polymer hybrid materials but also establishes a strong foundation for future advancements in their design, research, and applications. • A novel coordination-driven strategy was developed to grow ionic polymers on ZIFs, forming core–shell hybrid materials. • The synthetic approach is facile, scalable, and environmentally benign. • The ZIF–ionic polymer core–shell hybrids exhibit dual Lewis acid–base functionalities. • The core–shell hybrids demonstrate a synergistic effect in the cycloaddition of CO₂ with epoxides to form cyclic carbonates.