Herein we report a novel, ozone-based method for post-synthetic generation of mesoporosity in metalorganic frameworks (MOFs). By carefully selecting mixed-ligand Zr-fcu-MOFs based on organic ligand pairs in which one ligand has ozone-cleavable olefin bonds and the other ligand is ozoneresistant, we were able to selectively break the cleavable ligand via ozonolysis to trigger fusion of micropores into mesopores within the MOF framework. This solid-gas phase method is performed at room-temperature and, depending on the cleavable ligand used, the resultant ligand-fragments can be removed from the ozonated MOF by either washing or sublimation. Compared to the corresponding highly-microporous starting MOFs, the highly-mesoporous product MOFs exhibit radically distinct gas sorption properties. Herein we report application of our post-synthetic strategy to selectively and quantitatively cleave and remove the organic ligands in two multivariate (MTV) 23 Zr-fcu-MOFs (Figure 1), thereby affecting their adsorption performance in gas uptake. By controlling the ozone inert/active ratio of ligands in these MOFs, we were able to control the final number of defects in their structures.

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We describe solid-gas phase, single-crystal-to-single-crystal, postsynthetic modifications of a metal-organic framework (MOF). Using ozone, we quantitatively transformed the olefin groups of a UiO-66-type MOF into 1,2,4-trioxolane rings, which we then selectively converted into either aldehydes or carboxylic acids.

A Zr-based metal-organic framework (MOF) catalyst, Pt/Au@Pd@UIO-66, is assembled, where UIO-66 is Zr O (OH) (BDC) (BDC = 1,4-benzenedicarboxylate). The gold nanoparticles (NPs) act as the core for the epitaxial growth of Pd shells, and the core-shell monodispersed nanosphere Au@Pd is encapsulated into UIO-66 to control its morphology and impart nanoparticle functionality. The microporous nature of UIO-66 assists the adsorption of Pt NPs, which in turn enhances the interaction between NPs and UIO-66, favoring the formation of isolated and well-dispersed Pt NP active sites. This MOF exhibits high catalytic activity and CO product selectivity for the reverse-water-gas-shift reaction in a fixed-bed flow reactor.