It remains an intriguing challenge to convert CO₂ into valuable chemicals under atmosphere conditions by porous heterogeneous catalysts. Ionic metal-organic frameworks (iMOFs) have not only permanent porosity and tunable structures but also programmable components, which make them have the potential applications in capture and conversion of CO₂.

Recently, the research group led by Prof. CAO Rong from Fujian Institute of Research on the Structure of Matter (FJIRSM) of the Chinese Academy of Sciences (CAS) reported a series of functional iMOFs focused on the chemical fixation of CO₂ into cyclic carbonates. These targeted porous materials have been successfully created based on the theory of ‘Inorganic-organic sites synergistic catalysis’.

For the first time, a microporous cationic imidazolium functionalized Zr-MOF, (I^-)Me-UiO-66, was synthesized via reticular chemistry and post-synthetic modification. (I^-)Me-UiO-66, containing Brønsted acid sites and nucleophilic iodine ions, could effectively convert various epoxides into cyclic carbonates without the use of co-catalyst under 1 bar CO₂ condition (Chem. Sci.).

Later, an ionic multivariate MOF, containing both the zinc porphyrin and imidazolium bromide, was obtained by tandem post-synthetic modification method. This MOF showed more superior performance than other iMTV-MOFs herein in the conversion of allyl glycidyl ether (AGE) into corresponding cyclic carbonates under 1 bar CO₂ conditions. This work has provided a feasible approach for the preparation of ionic metalloporphyrin based MOF materials (Inorg. Chem. ).

Recently, a mesoporous cationic Cr-MOF denoted FJI-C10 containing imidazolium moieties, Lewis acidic Cr³⁺ sites and free halogens, was constructed by a topology-guided synthesis. Compared with neutral MIL-101, FJI-C10 exhibited enhanced CO₂ adsorption ability (20.2 wt%, 273 K, 1 bar). On the other hand, FJI-C10 could convert various epoxides into cyclic carbonates without the use of co-catalyst under atmospheric pressure (Chem.Commun. Inside Cover).

Based on this, those porous heterogeneous catalytic systems for chemical fixation of CO₂ into cyclic carbonates have been systematically reviewed in Coord. Chem. Rev.