Controlled synthesis of hierarchical zeolitic imidazolate framework-GIS (ZIF-GIS) architectures

Abstract

We report the first example of the preparation of an ordered hierarchical zeolitic imidazolate framework nest architecture (denoted as ZIF-GIS). ZIF-GIS (Zn(eIm)_0.65(dmbIm)_1.35) is a novel compound with GIS topology and has been synthesized by using complementary ligands of 2-ethylimidazole (eIm) and 5,6-dimethylbenzimidazole (dmbIm) in several solution systems. ZIF-GIS which exhibits hierarchical and nest architectures was obtained by a solvothermal approach based on the mixed solvent of aqueous ammonia (NH₃·H₂O) and methanol (CH₃OH). The apple-like hierarchical ZIF-GIS architectures with diameters of about 2–3 μm are built from numerous nanoplates with a thickness of about 20–40 nm. The results demonstrated that the formation of ordered hierarchical and nest architectures could be ascribed to the cooperation of NH₃·H₂O and CH₃OH. This synthesis strategy in a mixed solvent might be extended to other systems for the synthesis of hierarchical ZIF or MOF architectures.