Imidazolium-Functionalized UiO-66 Encapsulating Palladium Nanoparticles for Efficient Cyclization of Propargylamine...

Highly efficient and stable catalysts for carbon dioxide (CO₂) capture and conversion into value-added chemicals are critically needed. In this study, postmodification of UiO-66-MeIm with iodomethane via N-alkylation results in a roughened octahedral structure, yielding (I^-)BisMe-Im-UiO-66. A series of palladium nanoparticles (UiO-66-Pd-NPs) were subsequently synthesized through an ion exchange strategy with Na₂PdCl₄, followed by chemical reduction with NaBH₄. Comprehensive characterization of UiO-66-Pd-NPs was conducted using multiple analytical techniques, revealing PdNPs with an average size of 6.634 ± 1.510 nm. The catalyst demonstrated exceptional efficiency in the cyclization of CO₂ and propargylamine, achieving a yield of 100% in DMSO under mild conditions and ambient pressure with NaOAc as a weak base. No significant deactivation of catalytic performance was observed after the catalyst was reused three times. The synergistic effect of the imidazolium moiety and PdNPs facilitates the activation of both CO₂ and propargylamines, enabling the formation of 2-oxazolidinones.