AgNPs supported over porous organic polymers for the fixation of CO2 on propargyl alcohols and amines under solvent free conditions

Abstract

Designing efficient catalysts for the chemical fixation of CO2 on reactive organics under mild conditions is very challenging from the perspectives of green and sustainable chemistry. Here we report a triazinetriamine-based porous organic polymer (TzTa-POP) and immobilized silver nanoparticles at its surface to fabricate a metal nanoparticle embedded catalyst AgNPs@TzTa-POP. The characterizations of AgNPs@TzTa-POP have been carried out by using FTIR, PXRD, TGA, SEM, EDAX, TEM, N2 sorption and XPS analyses. The catalytic activity of Ag-NPs@TzTa-POP was evaluated in the carboxylative cyclization (intramolecular nucleophilic) of propargyl alcohols by using CO2 as a reactant to obtain α-alkylidene cyclic carbonates. The desired α-alkylidene cyclic carbonates with high selectivity (>99%) and significantly high yield (87–98%) were achieved via atmospheric fixation of CO2 at room temperature under easily operative reaction conditions. Furthermore, Ag-NPs@TzTa-POP showed excellent catalytic activity in the three component coupling reaction involving CO2, aromatic/aliphatic amine and aliphatic/aromatic halide for the synthesis of value added organic carbamates. High isolated yield (∼87–95%) of the desired carabamate product was obtained using 1 atm CO2 pressure under mild reaction conditions at room temperature. The catalyst sustains its activity for five consecutive reaction cycles for both the reactions. Post catalytic characterizations of AgNPs@TzTa-POP after five reaction cycles were carried out to figure out any materialistic changes in the metal nanoparticle embedded porous organic polymer.