Nitrogen-rich click-based porous organic polymers featuring flexible amine cores for catalytic CO2/epoxide cycloaddition

Abstract

CO2 utilization to produce value-added products such as cyclic carbonates especially under mild catalytic conditions is a promising strategy to reduce CO2 emissions to the environment. In this work nitrogen-rich click-based porous polymers (CPPs) were prepared from coupling of tripropargylamine and rigid diazido aromatic substrates featuring 1 4-phenylene (TB) 1 5-naphthalene (TN) and 4 4?-benzanilide (TBA) linkers in moderate to good yields (48�%) using Cu-catalyzed azide朼lkyne cycloaddition (CuAAC; TB-C TN-C TBA-C) and Huisgen cycloaddition (TB-H TN-H and TBA-H). The presence of the chelate tris(triazolylmethyl)amine ligands within the polymer s structure led to strong copper binding and consequently high copper loading ability of the CPPs. In addition high contents of Lewis basic N donors (21� wt% N) of TB-C TN-C TBA-C are most likely attributed to strong interactions between CO2 and CPPs and exceptionally high CO2 selectivity over N2 at 273 K based on gas sorption studies. The catalyst system TB-C/TBAB (TBAB = tetrabutylammonium bromide) promoted complete conversion of epoxides to cyclic carbonates under an atmospheric CO2 pressure after 24 h or 48 h at 100 ?C with the exception of the epichlorohydrin substrate where 42% selectivity was observed by 1H NMR spectroscopy. The TB-C/TBAB catalyst system could be reused for five catalytic runs without a loss in catalytic activities and any pre-activation processes. ? 2023 The Authors