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 excessiveCO(2) emission have given birth to a series of carbon-neutraltechnologies,among which the chemical transformation of CO2 catalyzedby metal-organic framework (MOF)-based catalysts has becomea focus. Herein, the self-assembly of zinc(II) cation and designedflexible multifunctional ligand of 1,3-di(5,6-dicarboxylbenzimidazol-1-ylmethyl)benzene(H4DDBB) generated a highly robust microporous materialof {[Zn(H2DDBB)]center dot 2NMP}( n ) (NUC-69) with 1D rectangle open channels (10.0 x7.6 angstrom(2)). Because the inner wall of voids is denselyfunctionalized by free -COOH groups, N-imidazole atoms,and tetra-coordinated open metal sites, activated NUC-69a exhibits high catalytic performance on the cycloaddition reactionsof CO2 with epoxides under mild conditions with high turnovernumber and turnover frequency. In addition, NUC-69a canbe used as an efficient iodine adsorbent with a maximum adsorptioncapacity of 0.94 g/g (4.26 I-2 molecules per formulationunit) and 1.28 g/g (5.81 I-2 molecules per formulation unit)in hexane solution and the volatilization phase. Hence, this workprovides a productive insight into the design of multifunctional microporousMOFs by enhancing the types of active sites, which makes the developedmaterials a broader application prospect. A highly robust microporous materialof {[Zn(H2DDBB)]center dot 2NMP}( n ) (NUC-69) with 1D rectangle open channels displays highcatalytic performanceon the cycloaddition reactions of CO2 with epoxides andexcellent adsorption capacity for iodine (I-2).