Chemical and structural stability of zirconium-based metal-organic frameworks with large three-dimensional pores by linker engineering

The synthesis of metal–organic frameworks with large three-dimensional channels that are permanently porous and chemically stable offers new opportunities in areas such as catalysis and separation. Two linkers (L1=4,4′,4′′,4′′′-([1,1′-biphenyl]-3,3′,5,5′-tetrayltetrakis(ethyne-2,1-diyl)) tetrabenzoic acid, L2=4,4′,4′′,4′′′-(pyrene-1,3,6,8-tetrayltetrakis(ethyne-2,1-diyl))tetrabenzoic acid) were used that have equivalent connectivity and dimensions but quite distinct torsional flexibility. With these, a solid solution material, [Zr₆O₄(OH)₄(L1)_2.6(L2)_0.4]⋅(solvent)_x, was formed that has three-dimensional crystalline permanent porosity with a surface area of over 4000 m² g⁻¹ that persists after immersion in water. These properties are not accessible for the isostructural phases made from the separate single linkers.