Tri-Coordinated PdNP Architecture for Simultaneous Capture, Activation, and Catalytic Conversion of Dilute CO2 via Multisite Synergy†

Abstract

Palladium nanoparticles (PdNPs) are valuable for their unique properties, but their catalytic applications are frequently limited by the balance between the reactivity and coordination modes. Herein, we present a universal strategy for preparing ultrafine PdNPs (1c‒4c, 1.6‒2.9 nm) with multiple active sites through three-coordination modes involving acetylglucose (AcGlu), N-heterocyclic olefin (NHO), and π bonds from AcGlu-MeIm-Pd (1b‒4b). PdNP 3c demonstrates superior performance in carboxylative‒cyclization‒cross‒coupling tri-component reactions involving dilute CO2 (15%), propargylic amines, and aryl iodides, achieving the highest turnover frequency of 600 h-1 while maintaining activity over 7 cycles. Mechanistic insights via in situ‒NMR reveal that the multiple active sites simultaneous activation of all substrates, forming AcGlu‒CO2 philes and NHO‒CO2 adducts. Notably, this is the first PdNP that enables the simultaneous capture, activation, and catalytic conversion of in situ‒activated dilute CO2, propargylic amine, and aryl iodide, potentially paving the way for new highly reactive transition metal NPs and novel nanomaterials.