CO ₂ Valorization through Propargylic Activation Mediated by Silver Nanoparticles Functionalized Coordination Polymer Gel

The conversion of carbon dioxide (CO 2 ) into high-value-added chemicals represents a sustainable approach to carbon mitigation. The cyclization reaction of CO 2 with propargylic amine and propargylic alcohol to form oxazolidinones and α-alkylidene cyclic carbonates, respectively, serves as an atom-economic reaction. Silver nanoparticles (AgNPs) are highly effective alkyne activators owing to their unique electronic configuration. Immobilizing well-dispersed AgNPs within coordination polymer gels (CPGs) offers a robust platform for designing an efficient heterogeneous catalyst for the carboxylative cyclization of propargylic substrates with CO 2 . Herein, a zirconium CPG with a triazine core is created to facilitate the nucleation and development of silver nanoparticles on its surface. Catalytic investigation revealed that Ag_ZrCPG efficiently catalyzed the carboxylative cyclization of propargylic amine and alcohol with CO 2 under ambient conditions, achieving a conversion of 99%. Ag_ZrCPG, as a heterogeneous catalyst, demonstrated high catalytic performance even after being used for four catalytic cycles. NMR studies were performed to elucidate the mechanism, where Ag_ZrCPG and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) work synergistically to activate the amine/hydroxy groups of the substrate molecule and the C≡C bond. This work highlights AgNP-anchored soft coordination polymer gels as versatile platforms for heterogeneous CO 2 transformation chemistry.