A DFT Exploration of Efficient Catalysts Based on Metal‐Salen Monomers for the Cycloaddition Reaction of CO2 to Propylene Oxide

Using quantum chemistry calculations, we explored the interactions between non-rare earth metal-salophen complex (M-Salen) monomers and propylene oxide (PO) and explored the catalytic mechanisms for the cycloaddition reaction of CO2 to epoxides by the M-Salen monomers. Our theoretical results demonstrated that a larger binding energy for M-Salen interacting with PO results in a lower apparent barrier height for the cycloaddition reaction. The Cr-III-Salen monomer possessed the lowest apparent barrier, while the Al-III-Salen monomer showed the highest barrier along the reaction pathway, which are consistent with experimental results. In addition, a low apparent barrier was found for the Sc-III-Salen monomer, suggesting another potential conjugated microporous polymer catalyst for CO2 conversion.