Nitrogen Enriched\nTroger’s Base Polymers\nof Intrinsic Microporosity for Heterogeneous Catalysis

Heterogeneous catalysis is significantly enhanced by\nthe use of\nhighly porous polymers with specific functionalities, such as basic\ngroups, which accelerate reaction rates. Polymers of intrinsic microporosity\n(PIMs) provide a unique platform for catalytic reactions owing to\ntheir high surface areas and customizable pore structures. We herein\nreport a series of Tröger’s base polymers (TB-PIMs)\nwith enhanced basicity, achieved through the incorporation of nitrogen-containing\ngroups into their repeat units, such as triazine and triphenylamine.\nThese polymers offer a perfect balance between the pore “swellability”,\nwhich allows the use of substrates of various dimensions, and the\nbasicity of their repeat units, which facilitates the use of reactants\nwith diverse acidity. The catalytic activity is evaluated through\nthe Knoevenagel condensation of benzaldehydes and various methylene\nspecies, conducted in the presence of ethanol as a green solvent and\nusing a 1:1 ratio of the two reagents. The results highlight a significant\nimprovement, with reactions reaching completion using just a 1% molar\nratio of catalysts and achieving a 3-fold enhancement over previous\nresults with 4-<i>tert</i>-butyl-benzaldehyde. Computational\nmodeling confirms that the enhanced basicity of the repeat units is\nattributable to the polymer design. Additionally, preliminary studies\nare undertaken to assess the kinetics of the catalyzed condensation\nreaction.