Implementing Mesoporosity in Zeolitic Imidazolate Frameworks through Clip-Off Chemistry in Heterometallic Iron-Zinc ZIF-8

Bond breaking has emerged as a new tool to postsynthetically modify the pore structure in metal-organic frameworks since it allows us to obtain pore environments in structures that are inaccessible by other techniques. Here, we extend the concept of clip-off chemistry to archetypical ZIF-8, taking advantage of the different stabilities of the bonds between imidazolate and Zn and Fe metal atoms in heterometallic Fe-Zn-ZIF-8. We demonstrate that Fe centers can be removed selectively without affecting the backbone of the structure that is supported by the Zn atoms. This allows us to create mesopores within the highly stable ZIF-8 structure. The strategy presented, combined with control of the amount of iron centers incorporated into the structure, permits porosity engineering of ZIF materials and opens a new avenue for designing novel hierarchical porous frameworks.

Automated summary

Bond breaking is a new tool for postsynthetically modifying the pore structure in metal-organic frameworks. In this study, the concept of clip-off chemistry is extended to ZIF-8, and the different stabilities of bonds between imidazolate and Zn and Fe metal atoms in heterometallic Fe-Zn-ZIF-8 are utilized. It is demonstrated that Fe centers can be selectively removed without affecting the backbone structure supported by Zn atoms. This strategy allows for the creation of mesopores within the highly stable ZIF-8 structure and opens up new possibilities for designing novel hierarchical porous frameworks.