Novel HBD-Containing Zn (dobdc) (datz) as efficiently heterogeneous catalyst for CO₂ chemical conversion under mild conditions

A novel Zn-based metal–organic framework Zn (dobdc) (datz) [Zn₂(H₂dobdc) (datz)₂·1.5DMF] with plentiful hydrogen bond donors (HBD) groups was facilely synthesized from mixed ligands. The dual activation of metal Zn sites and HBD groups for epoxides by forming Zn–O adduct and hydrogen bonds facilitated the ring-opening of epoxide substrate, which is critical for the subsequent CO₂ fixation. Also, the existence of micropores and N-rich units in Zn (dobdc) (datz) afforded affinity towards CO₂, which is beneficial to further improvement on catalytic CO₂ conversion performance. Satisfactorily, Zn (dobdc) (datz)/Bu₄NBr system was proved efficient heterogeneous catalyst for the CO₂ cycloaddition with epoxides, and 98% propylene carbonate yield was obtained under mild conditions (80 °C, 1.5 MPa and solvent-free). In addition, Zn (dobdc) (datz)/Bu₄NBr exhibited remarkable versatility to different epoxides and could be completely recycled over six runs with high catalytic activity. The highly stable, easily recycle and solvent-free Zn-based MOF reported here displays eco-friendly and efficient performance to CO₂ conversion.