Highly Stable and Versatile Conjugated Microporous Polymer for Heterogeneous Catalytic Applications

Conjugated microporous polymers (CMPs) with highly ordered catalytic units have demonstrated potential in sustainable catalysis. A salen-based conjugated microporous polymer (CMP-Salen-Zn) was firstly synthesized by condensation polymerization of dialdehyde derivative of Salen-Zn and pyrrole. The resulting CMP-Salen-Zn with excellent thermal stability was fully accessed by a combination of spectroscopy techniques. The CMP-Salen-Zn exhibited a fair porosity with a Brunauer–Emmett–Teller (BET) surface area of up to 444.6 m2 g−1. The CMP-Salen-Zn also exhibited high CO2 uptakes with 59.5 mg g−1 at 273 K and 1 bar and an outstanding catalytic performance for cycloaddition of CO2 with epoxides. The catalytic systems feature atom economy, environmental friendliness, low catalyst loading and mild reaction conditions for the synthesis of a wide range of cyclic carbonates. Moreover, the catalytic system was found to be recycled up to eight times without significant loss of catalytic activity. The resulting CMP catalyst was also found to catalyze Knoevenagel condensation reaction between aromatic aldehyde and malononitrile in excellent conversion with environmentally friendly solvent. These results offered a promising strategy for screening the correlation between structural features and catalytic properties through the fine-tuning of active centers on CMP catalysts.Graphical Abstract