Robust Zn(II)-Organic Framework for High Catalytic Activity on Cycloaddition of CO2 with Epoxides and Reversible Iodine Uptake

Increasingly serious natural disasters caused by excessive CO2 emission have given birth to a series of carbon-neutral technologies, among which the chemical transformation of CO2 catalyzed by metal–organic framework (MOF)-based catalysts has become a focus. Herein, the self-assembly of zinc(II) cation and designed flexible multifunctional ligand of 1,3-di(5,6-dicarboxylbenzimidazol-1-ylmethyl)benzene (H4DDBB) generated a highly robust microporous material of {[Zn(H2DDBB)]·2NMP}n (NUC-69) with 1D rectangle open channels (10.0 × 7.6 Å2). Because the inner wall of voids is densely functionalized by free −COOH groups, Nimidazole atoms, and tetra-coordinated open metal sites, activated NUC-69a exhibits high catalytic performance on the cycloaddition reactions of CO2 with epoxides under mild conditions with high turnover number and turnover frequency. In addition, NUC-69a can be used as an efficient iodine adsorbent with a maximum adsorption capacity of 0.94 g/g (4.26 I2 molecules per formulation unit) and 1.28 g/g (5.81 I2 molecules per formulation unit) in hexane solution and the volatilization phase. Hence, this work provides a productive insight into the design of multifunctional microporous MOFs by enhancing the types of active sites, which makes the developed materials a broader application prospect.