Catalytic performance of MOFs containing trinuclear lanthanides clusters in the cycladdition reaction of CO2 and epoxide

Abstract

With the rapid development of global industrialization, global warming and ocean acidification caused by the accumulation of greenhouse gases (such as CO2) have attracted widespread attention. It is of great significance to use microporous metal-organic frameworks (MOFs) to adsorb carbon dioxide and further convert it into valuable chemical products. Herein, two kinds of isomorphic (MOFs): {[Ln3(deta)2(DMF)2(COOH)·2H2O]·DMF·H2O}n (LnDy(1), Tb(2), DMF = N-N-dimethyl formamide) based on 4-(3,5-dicarboxyphenoxy)phthalic acid (H4deta) ligands were successfully synthesized by the solvothermal synthesis method. Interestingly, MOFs 1–2 is based on a trinuclear Dy/Tb unit connected to six adjacent trinuclear Dy/Tb units via a (deta)4- ligand, extending to a 3D microporous network structure. MOFs 1–2 not only has good thermal stability, chemical stability and excellent water resistance, but also has abundant active sites of Lewis acid due to the fact that the metal center of MOFs 1–2 is lanthanides metal. The results show that MOFs 1–2 has a good catalytic activity for the chemical fixation of carbon dioxide with epoxides under moderate conditions. Moreover, they can be recycled at least 5 times without affecting their activity, showing excellent chemical stability and reusability. In addition, the reaction mechanism of CO2 cycloaddition to PO catalyzed by MOF 1–2 was also discussed.