Rapid Conversion of CO2 Using Propargylic Amines by a Silver Nanoparticle-Loaded Triazole-Based Porous Organic Polymer

Selective sequestration of atmospheric CO2 and its use as precursors for various value-added products are in growing demand. However, the high activation energy of CO2 poses a limitation on its usage as an effective reagent for chemical conversion. Herein, we have fabricated a triazole- and triazine-based porous organic polymer, TT-POP, through alkyne–azide click polymerization that offers a recyclable heterogeneous platform and anchors the active metal nanoparticle for catalytic CO2 fixation. The highly porous structure (SBET ∼ 804 m2 g–1) of TT-POP with CO2-philic functionalities facilitates selective CO2 uptake. Further, TT-POP is postsynthetically modified by in situ formation of silver nanoparticles to fabricate a heterogeneous catalyst, Ag@TT-POP (SBET ∼ 589 m2 g–1), for 99% of conversion of 0.5 mmol of terminal propargylic amine and internal propargylic amine within 15 min to their respective oxazolidinone derivatives under ambient conditions (50 °C). Further, computational studies and CO2 temperature-programmed desorption (TPD) analysis suggest the impact of the nitrogen centers as well as Ag nanoparticles present in Ag@TT-POP, leading to enhanced CO2-philicity for rapid CO2 conversion. The mechanistic aspects of the CO2 insertion and cyclization of propargylic amines have been proposed through 1H NMR studies at different time intervals. In addition, Ag@TT-POP demonstrated high catalytic activity for bulk-scale catalysis (7 mmol, ∼1 g) as well as in flue gas conditions. The present study provides a detailed understanding of the development of CO2-philic and highly robust metal nanoparticle-loaded POP for the scalable and rapid conversion of CO2 using propargylic amines.