Supramolecular Assembly of Geometrically Unstable Hybrid Organic-Inorganic Uranyl Peroxide Cage Clusters and Their Transformations

An aromatic ligand was introduced into the synthesis of a uranyl peroxide polyoxometalate formulated as K-32(UO2)(19)(O-2)(26)(OH)(2)(C6H4P2O6)(4)center dot 65H(2)O that consists of a unique "open oyster" shaped structure (U-19) with intramolecular H-bonds. In the solid state, K-pi and pi-pi interactions as well as K-O bonds enable the formation of a supramolecular network between U-19 clusters. U-19 adopts an incomplete fullerene topology and was utilized as a precursor from which the geometrically favored U-24 structure was produced. A potassium-encapsulated U-24 structure was obtained upon heating the solution containing U-19.