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 K32(UO2)19(O2)26(OH)2­(C6H4P2O6)4·65H2O that consists of a unique “open oyster” shaped structure (U19) with intramolecular H-bonds. In the solid state, K−π and π–π interactions as well as K–O bonds enable the formation of a supramolecular network between U19 clusters. U19 adopts an incomplete fullerene topology and was utilized as a precursor from which the geometrically favored U24 structure was produced. A potassium-encapsulated U24 structure was obtained upon heating the solution containing U19.