Rapid Conversion of CO<sub>2</sub> Using Propargylic Amines by a Silver Nanoparticle-Loaded Triazole-Based Porous Organic Polymer
Aniket Sahoo, Arkaprabha Giri, Muhammad Delwar Hussain, Shilpi Jaiswal, Abhijit Patra
Abstract
Selective sequestration of atmospheric CO 2 and its use as precursors for various value-added products are in growing demand. However, the high activation energy of CO 2 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 CO 2 fixation. The highly porous structure ( S BET ∼ 804 m 2 g –1 ) of TT-POP with CO 2 -philic functionalities facilitates selective CO 2 uptake. Further, TT-POP is postsynthetically modified by in situ formation of silver nanoparticles to fabricate a heterogeneous catalyst, Ag@TT-POP ( S BET ∼ 589 m 2 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 CO 2 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 CO 2 -philicity for rapid CO 2 conversion. The mechanistic aspects of the CO 2 insertion and cyclization of propargylic amines have been proposed through 1 H 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 CO 2 -philic and highly robust metal nanoparticle-loaded POP for the scalable and rapid conversion of CO 2 using propargylic amines.