A highly augmented, (12,3)-connected Zr-MOF containing hydrated coordination sites for the catalytic transformation of gaseous CO2 to cyclic carbonates

Abstract

A porous Zr-based MOF, [Zr₆(BTEB)₄(μ₃-O)₄(μ₃-OH)₄(H₂O)₄], which contains partially hydrated, 12-connected {Zr₆} nodes and extended carboxylate ligands (BTEB³⁻), was synthesized and physicochemically characterised. The resulting (12,3)-connected, 3D framework adopts an uncommon llj topology with a large, solvent accessible void volume of ca. 79% of the unit cell volume. The porous structure facilitates the uptake of N₂ and activated samples give rise to BET surface areas of >1000 m² g⁻¹. Furthermore, the porosity and accessibility of Lewis acidic Zr(IV) sites promote the catalytic transformation of gaseous CO₂ to cyclic carbonates via cycloaddition reactions using epoxide reactants, whereby solvated MOFs exhibit higher catalytic performance than thermally treated samples.