A Copper Nanoparticle-Anchored Reusable Zr(IV) MOF Catalyst for Efficient Atmospheric CO ₂ Fixation into Biologically Active Heterocycles and Multicomponent Coupling Reaction

Due to high agglomeration resistance, embedding of metal nanoparticles (NPs) in metal–organic frameworks (MOFs) has garnered a lot of interest in the catalysis community. A Zr(IV)-based metal–organic framework (MOF) named Cu NPs@1′ was synthesized by incorporating copper nanoparticles (Cu NPs) using a straightforward one-step in situ solvothermal approach. Immobilizing Cu NPs into Zr(IV)-MOF significantly improves its stability, providing a promising platform for the development of high-performance heterogeneous catalysts with enhanced catalytic efficiency. Various characterization techniques were employed to analyze the crystalline nature and morphology of Cu NPs@1′ and the incorporation of Cu NPs in the framework structure. Compound Cu NPs@1′ displayed high specific surface area (1068 m 2 g –1 ) and CO 2 adsorption capacity (34 cm 3 g –1 at 1 bar and 0 °C). Owing to its high porosity and strong affinity for CO 2, the catalytic efficiency of Cu NPs@1′ was evaluated in the CO 2 fixation reaction with N -propargylbenzylamines to achieve pharmaceutically active 2-oxazolidinones and a three-component coupling reaction involving an aldehyde, an alkyne, and an amine to produce propargylamines. Both the reactions afforded high conversion percentages under optimized reaction conditions, which showed strong effectiveness of Cu NPs in promoting catalytic reactions. This is the first report of a Cu NP-anchored MOF for efficiently catalyzing the three-component coupling reaction. The solid MOF catalyst maintained its activity for both reactions across three successive cycles without any alteration in its crystallinity and morphology. Furthermore, the catalyst demonstrated broad substrate compatibility under the optimized reaction conditions. Based on the obtained results, plausible mechanisms for the three-component coupling and CO 2 fixation reaction into biological heterocycles were proposed. Therefore, these findings emphasize the potential of the copper nanoparticle-immobilized MOF to serve as a sustainable catalyst for CO 2 valorization and multicomponent coupling for synthesizing various value-added chemicals including pharmaceutical heterocycles.