Novel 3D Nitrogen-Rich Metal Organic Framework for Highly Efficient CO2 Adsorption and Catalytic Conversion to Cyclic Carbonates under Ambient Temperature

A novel Lewis acid–base bifunctional Zn(II)-based MOF-Zn-1 [Zn2L2MA·2DMF] (MA = melamine, H2L = 2,5-thiophenedicarboxylic acid), with abundant micropores and free -NH2 groups was facilely assembled by incorporating zinc(II) ion with nitrogen-rich melamine and 2,5-thiophenedicarboxylic acid ligands. The constructed MOF-Zn-1 presented an excellent affinity toward CO2 molecules due to the Lewis-base property together with abundant micropores. The Zn active sites could be used for epoxide activation. The acid–base synergistic effects facilitated CO2 conversion into cyclic carbonates under ambient temperature using the porous MOF-Zn-1 as a heterogeneous catalyst. Moreover, the MOF-Zn-1 exhibited satisfied stability and versatility, and it was easy to recycle with no obvious decrease of catalytic activity. Then the feasible synergistic mechanism of MOF-Zn-1/Bu4NBr catalysts for CO2 conversion was proposed.