Novel Zinc Metal–Organic Framework for Catalytic CO2 Conversion to Cyclic Carbonates under Solvent-free and Mild Conditions

Abstract

Metal–organic frameworks (MOFs) exhibit wide applications in catalytic CO₂ conversion to high-value-added chemicals. In this work, we prepared a new MOF {Zn(Bibt)(nia^2–)}_n, namely Zn-BN, based on the self-assembly of 4,7-bis(1H-imidazol-1-yl) benzo-[2,1,3]thiadiazole (Bibt), 5-(1,8-naphthalimido)-isophthalic acid (H₂nia), and Zn(NO₃)₂·6H₂O under hydrothermal conditions. Zn-BN presents as a 4-connected porous framework with an {8⁶} point symbol, exhibiting good thermal and solvent stability as well as a broad range of pH durability. Then, Zn-BN is applied to catalyze the coupling reaction of CO₂ with various epoxides. The results show that Zn-BN can serve as a heterogeneous and efficient catalyst to promote the conversion of CO₂ to cyclic carbonates in yields of 48–98% at atmospheric CO₂ pressure, 60 °C temperature, and 18 h reaction time, which can be mainly attributed to the synergistic activation effect by Zn nodes in the framework and Br^– anions. Additionally, the Zn-BN can be reused up to 5 times, demonstrating good recyclability.