Synthesizing New Hybrid Zeolitic Imidazolate Frameworks by Controlled Demolition and Reconstruction

A synthesis method to obtain new zeolite imidazolate framework (ZIF) materials that are otherwise difficult to synthesize by known techniques such as direct crystallization or solvent-assisted linker exchange, is demonstrated. Treatment of an easily synthesized “template” ZIF (such as ZIF-8) with an acid gas (humid SO₂) allows controlled demolition of metal-linker coordination bonds, while preserving overall crystal topology. The partially demolished crystals are then reconstructed into highly crystalline mixed-linker ZIFs with unique characteristics by insertion of different linkers that displace the damaged linkers. One illustration shows the synthesis of a series of mixed-linker ZIFs containing benzimidazole linkers that show entirely different gate-opening and diffusion characteristics from ZIFs of the same composition prepared by direct crystallization. Also shown is the synthesis of new mixed-linker SOD-topology ZIFs containing bulky halobenzimidazole and alkylbenzimidazole linkers, which are very difficult to synthesize by other methods. The present method is seen to considerably reduce thermodynamic or kinetic barriers for replacement and insertion of linkers into ZIF topologies.