Supramolecular Assembly of U(IV) Clusters and Superatoms

Superatoms are nanometer-sized molecules or particles that can form ordered lattices, mimicking their atomic counterparts. Hierarchical assembly of superatoms gives rise to emergent properties in superlattices of quantum-dots, p-block clusters, and fullerenes. Here, we introduce a family of uranium-oxysulfate cluster anions whose hierarchical assembly in water is controlled by two parameters; acidity and the countercation. In acid, larger Ln^III (Ln=La-Ho) link hexamer (U₆) oxoclusters into body-centered cubic frameworks, while smaller Ln^III (Ln=Er-Lu &Y) promote linking of fourteen U₆-clusters into hollow superclusters (U₈₄ superatoms). U₈₄ assembles into superlattices including cubic-closest packed, body-centered cubic, and interpenetrating networks, bridged by interstitial countercations, and U₆-clusters. Divalent transition metals (TM=Mn^II and Zn^II), with no added acid, charge-balance and promote the fusion of 10 U₆ and 10 U-monomers into a wheel–shaped cluster (U₇₀). Dissolution of U₇₀ in organic media reveals (by small-angle Xray scattering) that differing supramolecular assemblies are accessed, controlled by TM-linking of U₇₀-clusters.