Silver Nanoparticle-Embedded Iron-Mediated Gel Matrix: Active Catalyst for CO₂ Fixation and A³ Coupling

Utilizing carbon dioxide (CO 2 ) as a primary C1 source and transforming it into valuable compounds offer a viable approach to tackle energy and environmental concerns. The incorporation of metal nanoparticles into template frameworks to create catalytic hybrid materials provides an ideal and promising approach for integrated CO 2 capture and conversion. Anchoring highly dispersed silver nanoparticles (AgNPs) on functional coordination polymer gels (CPGs) to create efficient heterogeneous catalysts for the carboxylative cyclization of propargyl alcohols with CO 2 is a fascinating but challenging prospect. Herein, a straightforward in situ reduction method is demonstrated to anchor well-dispersed AgNPs into triazine-based CPG (Fe_MG) scaffolds. A nitrogen-rich triazine moiety actively helps in nucleation and growth of Ag nanoparticles within the CPG network. Catalytic studies showed that the presence of Ag@Fe_MG allowed an excellent conversion (∼99%) of 2-methylbut-3-yn-2-ol to the corresponding alkylene cyclic carbonate within 24 h at room temperature. The as-synthesized catalyst not only aids in CO 2 chemical fixation but also facilitates a three-component coupling reaction that uses an aldehyde, a terminal alkyne, and a secondary amine to produce propargyl amines. The impressive functional group tolerance of different substrate scopes and reusability, as well as maintaining its activity without any significant decrease during cycles, dictate the efficiency of the Ag@Fe_MG catalyst. Therefore, our study demonstrates a judicious selection of templates to fabricate hybrid composites with silver nanoparticles, which serve as efficient heterogeneous catalysts for CO 2 fixation and multicomponent coupling reactions.