Reversible Postsynthetic Modification in a Metal-Organic Framework

Postsynthetic modification (PSM) of metal-organic frameworks (MOFs) provides access to functional materials and advanced porous solid engineering. Herein, we report the reversible PSM of a multivariate isoreticular MOF by applying dynamic furan-maleimide Diels-Alder (DA) chemistry. The key step involves incorporating a furan group into the MOF via "click" PSM, which can then undergo repeated cycles of modification and de-modification with maleimides. The structural integrity, crystallinity, and porosity of the furan-appended MOF remained intact even after three consecutive PSM/de-modification cycles using three different functionalized maleimides. In this work, reversible covalent postsynthetic modification (PSM) is demonstrated in a multivariate metal-organic framework (MTV-MOF) using thermoreversible furan-maleimide Diels-Alder chemistry. The MOF was modified with a pendant furan functional group that was then capable of undergoing repeated cycles of PSM and de-modification with different functionalized maleimides. Reversible PSM was achieved with complete retention of structural integrity, crystallinity, and porosity of the MOF.image