Recent advances in the synthesis techniques for zeolitic imidazolate frameworks and their sensing applications

Zeolitic imidazolate frameworks (ZIFs) can be classified as metal–organic frameworks (MOFs) or metal-azolate frameworks (MAFs) with unique topologies. The presence of five membered heterocyclic ring structure in imidazole ring-based linkers facilitates their robust coordination with bridging metal nodes. This stable coordination imparts numerous advantageous properties (e.g., facile and reproducible crystallization, nanoscale processability, high loading capacities, and good biocompatibility) to ZIFs. Further, the technical advancements in the synthesis of porous coordination polymers have contributed to the diversification in the fabrication approaches needed for the ZIFs and to the characterization of their structural and functional attributes (e.g., ZIF-8 and ZIF-67). In light of this advancement in ZIF technologies, we describe the synthesis methods for the fabrication of ZIFs in relation to their resulting properties. This review also highlights the application of ZIF-based probes for sensing of a diverse array of targets (e.g., gas molecules, metabolites, pesticides, and metals). Further, a performance comparison between various ZIF-based sensing systems has been made for the listed target analytes in terms of various quality assurance (QA) criteria (e.g., sensor response and recovery time, limit of detection (LOD), specificity, and reproducibility). At last, the current challenges and future outlook for this research field are also discussed to help expand their real-world applications.