Twenty-six nanoscale cage clusters built from uranyl polyhedra have been reported to self-assemble in aqueous solutions over a range of pH conditions [1]. All contain peroxide groups that bridge between uranyl polyhedra, and some contain additional linkages such as pyrophosphate and oxalate. The focus of the current study is the U24P12 cluster that consists of 24 uranyl hexagonal bipyramids and 12 pyrophosphate groups. We have optimized the synthesis of this cluster to obtain pure yields. Subsequently, we have examined the behavior of the cluster in solution using electrospray ionization mass spectroscopy and small angle X-ray scattering. These studies are emphasizing the persistence of this cluster under a variety of conditions, as well as their aggregation in solution. Such materials are of considerable interest because of potential applications in an advanced nuclear energy system, including in fuel recycling. Results to date show that the U24P12 cluster persists in aqueous solution for several days under a range of conditions, and can be induced to aggregate via addition of various counterions.

 

1. Burns, P.C. Mineralogical Magazine. 2011, 75, 1-25 Open Access on petercburns.com