Template?Mediated Control over Polymorphism in the Vapor?Assisted Formation of Zeolitic Imidazolate Framework Powders and Films

The landscape of possible polymorphs for some metal–organic frameworks (MOFs) can pose a challenge controlling the outcome their syntheses. Demonstrated here is use template to control in vapor-assisted formation zeolitic imidazolate framework (ZIF) powders and thin films. Introducing small amount either ethanol or dimethylformamide vapor during reaction between ZnO 4,5-dichloroimidazole results porous ZIF-71 phase, whereas other conditions lead dense ZIF-72 phase amorphous materials. Time-resolved situ small-angle X-ray scattering reveals that metastable be transformed into its polymorph. This transformation avoided through introduction vapor. porosity resulting ZIF films was studied by N2 Kr physisorption, as well positron annihilation lifetime spectroscopy. templating principle demonstrated members family well, including ZIF-7 series, ZIF-8_Cl, ZIF-8_Br.