Polyoxometalate clusters based on transition metals are structurally diverse and have been intensely investigated. Normally, they are synthesized in one-pot reactions. However, the details of their self-assembly mechanisms in reactions remain poorly understood. In this study, we investigated the formation processes of a uranium-peroxide cluster {U1?U28?U40R} with a core-shell structure using time-resolved small-angle X-ray scattering (SAXS) and electrospary ionization mass spectrometry (ESI-MS) techniques. The 'core' of {U1?U28?U40R} is a cage cluster built from 28 uranyl polyhedra. A partially occupied U site is at its center. The 'shell' is a ring consisting of 40 uranyl polyhedra linked into five-membered rings and 16 nitrate groups. Topological pentagons in the cage and ring are aligned, and their corresponding rings of uranyl bipyramids are linked through K cations. Both SAXS and ESI-MS results demonstrate that the cage cluster forms in solution within an hour, whereas the ring forms after more than several days.

Time-resolved self-assembly of a Fullerene-topology core-shell cluster containing 68 uranyl polyhedra

243rd National Meeting (2012)

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