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The controlled assembly of gold nanoparticles (AuNPs) with the size of quantum dots into predictable structures is extremely challenging as it requires the quantitatively and topologically precise placement of anisotropic domains on their small, approximately spherical surfaces. We herein address this problem by using polyoxometalate leaving groups to transform 2 nm diameter gold cores into reactive building blocks with hydrophilic and hydrophobic surface domains whose relative sizes can be precisely tuned to give dimers, clusters, and larger micelle-like organizations. Using cryo-TEM imaging and 1 H DOSY NMR spectroscopy, we then provide an unprecedented "solution-state" picture of how the micelle-like structures respond to hydrophobic guests by encapsulating them within 250 nm diameter vesicles whose walls are comprised of amphiphilic AuNP membranes. These findings provide a versatile new option for transforming very small AuNPs into precisely tailored building blocks for the rational design of functional water-soluble assemblies., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Polyoxometalate (POM) cluster anions are shown to serve as covalently coordinated ligands for anatase-TiO2 nanocrystals, giving isolable assemblies uniquely positioned between molecular macroanions and traditional colloidal nanoparticles. Na(+) salts of the water-soluble polyanionic structures are obtained by reacting amorphous TiO2 with the 1 nm lacunary ion, Na7 [α-XW11 O39 ] (X=P(5+) ), at 170 °C, after which an average of 55 α-PW11 O39 (7-) clusters are found as pentadentate ligands for Ti(IV) ions covalently linked to 6 nm single-crystal anatase cores. The attached POMs are reversible electron acceptors, the reduction potentials of which shift in a predictable fashion by changing the central heteroatom, X, directly influencing a model catalytic reaction. Just as POM cluster anions control the reactivities of metal centers in molecular complexes, directly coordinated POM ligands with tunable redox potentials now provide new options for rationally controlling the reactions of semiconductor nanocrystals., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)