ZIF

ZIF stands for zeolitic imidazolate framework, a class of metal–organic frameworks (MOFs) characterized by metal ions, typically Zn2+ (often also Co2+), coordinated to imidazolate ligands. The imidazolate bridges mimic the Si–O–Si angles of zeolites, producing zeolite-like topologies within a crystalline, porous framework.

Structure and tunability: ZIFs feature rigid, porous networks with high surface areas and tunable pore sizes, governed by metal identity and linker choice. Among the most studied is ZIF-8, Zn(mim)2, which combines a large internal cavity with a small pore window, enabling selective adsorption. The chemistry allows substitution of metals (e.g., Co) and functionalized imidazolates to adjust pore environment, stability, and catalytic activity.

Synthesis and stability: ZIFs are typically prepared by solvothermal or hydrothermal synthesis from metal salts and imidazolate or substituted imidazolate linkers, sometimes using modulators to control crystallinity and defect concentration. They often display high thermal stability compared to many MOFs, and chemical stability is variable, generally robust in non-aqueous settings with organic solvents; hydrolytic stability depends on metal and linker.

Applications: Gas storage and separation (hydrogen, carbon dioxide, hydrocarbon mixtures), catalysis (as heterogeneous catalysts or supports), and drug delivery with gated release under specific conditions. ZIFs are also explored for sensing and water purification.