Exploring the Performance Improvement for CO 2 Chemical Fixation in Zn/ZnMg-MOFs.

A new 3D zinc-based metal-organic framework {[Zn 7 L 2 (DMF) 3 (H 2 O)(OH) 2 ]·5DMF} n ( 1 ) (H 6 L = 5,5',5″-(methylsilanetriyl) triisophthalic acid) was constructed with an organosilicon-based linker, where H 6 L is a tetrahedral structure furnished with rich -COO - chelating sites for Zn(II) immobilization. Compound 1 exhibited two types of irregular one-dimensional channels and a three-dimensional skeleton with large specific surface area, making it a promising catalytic platform. Moreover, by incorporation of the second metal ion into the inorganic node of framework 1 , isomorphic bimetallic MOF ZnMg- 1 was successfully synthesized. ZnMg- 1 demonstrated enhanced catalytic activity compared to 1 under identical conditions. Contrast experiments and theoretical calculations indicate that bimetallic active sites play a facilitating role in the chemical fixation of epoxides and CO 2 . It indicated that efficient chemical fixation of CO 2 to cyclic carbonates was obtained over isomorphic MOF catalysts 1 and ZnMg- 1 .