Utility of Silver Nanoparticles Embedded Covalent Organic Frameworks as Recyclable Catalysts for the Sustainable Synthesis of Cyclic Carbamates and 2-Oxazolidinones via Atmospheric Cyclizative CO 2 Capture

The present work introduces the favorable synthesis of porous functionalized nanomaterials with excellent surface area, porosity, and high CO 2 capture ability to facilitate cyclizative reactions by incorporating the CO 2 molecule into highly reactive organic moieties. We have attempted to fulfill the target by the decoration of Ag NPs over the exterior surfaces of covalent organic frameworks (COFs) TpPa-1 and TpTta to achieve Ag@TpPa-1 and Ag@TpTta nanomaterials with an absolutely ordered structure. Characterizations of the nanocatalysts (Ag@TpPa-1 and Ag@TpTta) have been performed by field emission scanning electron microscopy, thermogravimetric tools, N 2 adsorption/desorption, transmission electron microscopy, Fourier transform infrared spectroscopy, UV–vis, and powder X-ray diffraction analysis. These Ag NPs architectured porous COFs described excellent performance for the benign synthesis of cyclic carbamates from unsaturated amines in the presence of N-iodosuccinimide (NIS) and several 2-oxazolidinone derivatives from propargylamine derivatives via cyclizative atmospheric CO 2 capture under solvent-free and alkali-free conditions (sustainable approach). The microporous material Ag@TpTta revealed most excellent catalytic performance than Ag@TpPa-1during production of cyclic carbamates and oxazolidinones which indicates that the selection of Ag NPs decorated COFs with the excellent surface area has a contributory effect on carboxylative cyclization reaction. Density functional theory studies furnished important information to establish the detailed mechanism of silver (0) catalyzed CO 2 incorporation into unsaturated amine. These COFs enriched with N centers can interact with the Ag NPs at their outer exterior surfaces very tightly. These two nanocatalysts exhibited magnificent recycling efficiencies for the generation of cyclic carbamates and 2-oxazolidinones with almost zero silver leaching from the exterior part of the catalyst.