A Cu-salen-based conjugated microporous polymer catalyst for N-formylation of CO₂ under mild conditions

A heterogeneous salen-based conjugated microporous polymer catalyst (CMP@Cu-salen) is prepared by a one-pot method for N-formylation of amines with CO₂. The uniformly dispersed Cu-salen site and porous structure facilitates the enrichment of CO₂ and transfer of substrates and the transformation. Our CMP@Cu-salen shows excellent catalytic performance (conversion: 99%, selectivity: 90%) for formylation of N-methylaniline under mild conditions (0.1 MPa, 40 °C), outperforming most existing heterogeneous catalysts. Additionally, it retains high catalytic activity even after three consecutive cycles. This work provides insight into the potential value of CMP@Cu-salen in CO₂ conversion.