Cobalt-based MOF nanoribbons with abundant O/N species for cycloaddition of carbon dioxide to epoxides.

Chemical fixation of CO with epoxides is an effective option to achieve sustainable synthesis of cyclic organic carbonates. Although metal-organic frameworks (MOFs) are promising catalysts for this reaction, their low stability in aqueous solutions makes this application infeasible. In an effort to overcome this limitation, cobalt-based metal-organic framework (Co(II)MOF) nanoribbons have been prepared by coordinating the Co(II) ions with a new ligand (CHNO) full of oxygen and nitrogen moieties. Strong chemical interactions occur between the adsorbed CO and oxygen/nitrogen atoms in this porous MOF structure. Co(II)-MOF nanoribbons with tetra-n-butylammonium bromide acted as cocatalysts with ∼97% yield of cyclic carbonate (reaction kinetic rate of 14.7 × 10 µmol g h) upon the cycloaddition of epichlorohydrin (ECH) to CO (>99% reaction selectivity under solvent-free reaction condition at 80 °C, 3 h and 1 MPa CO pressure). This work may open a new avenue for chemical fixation of CO by rational design of the components and morphology of MOF-based catalysts.