Five cage clusters that self-assemble in alkaline aqueous solution have been isolated and characterized. Each is built from uranyl hexagonal bipyramids with two or three equatorial edges occupied by peroxide, and three also contain phosphate tetrahedra. These clusters contain 30 uranyl polyhedra; 30 uranyl polyhedra and six pyrophosphate groups; 30 uranyl polyhedra, 12 pyrophosphate groups, and one phosphate tetrahedron; 42 uranyl polyhedra; and 40 uranyl polyhedra and three pyrophosphate groups. These clusters present complex topologies as well as a range of compositions, sizes, and charges. Two adopt fullerene topologies, and the others contain combinations of topological squares, pentagons, and hexagons. An analysis of possible topologies further indicates that higher-symmetry topologies are favored.

The synthesis and structural characterization of the compounds K[(UO(2))(2)(UO(4))(OH)(NO(3))(2)]H(2)O (1) and Ba[(UO(2))(4)(UO(4))(2)(OH)(2)(NO(3))(4)]H(2)O (2) have revealed that each contains sheets that are based upon the beta-U(3)O(8)-type topology and that these sheets are linked through low-valence interlayer cations. Consistent with other uranium(VI) compounds that have topologically identical sheets, one of the uranium(VI) sites exhibits a highly unusual (UO(4))(2-) tetraoxido core that is further coordinated by two bidentate (NO(3))(-) groups.

Uranium(VI) Tetraoxido Core Coordinated by Bidentate Nitrate. -The structures of (III) (orthorhombic, space group Pbca, Z = 8) and (V) (Pbca, Z = 4) are determined by single crystal XRD. Both compounds contain corrugated layers with β-U3O8 topology. Each sheet contains three U VI sites. Two of these sites are typical (UO2) 2+ uranyl ions, while the third U VI site exhibits a highly unusual (UO4) 2tetraoxido core that is further coordinated by two bidentate (NO 3 )groups. Adjacent layers are interconnected via the K + and Ba 2+ cations and through a hydrogen bonding network. -(UNRUH, D. K.; BARANAY, M.; BARANAY, M.; BURNS*, P. C.; Inorg. Chem. 49 (2010) 15, 6793-6795,

Crystals of Ba15 [(UO2)30(O2)30(OH)30] (I), (K,Li)42 [(UO2)42(O2)42(OH)42] (II), (K,Li)51 [(UO2)30(O2)30 (P2O7)12(PO4) (H2O)5] (III), (K,Li)48 [(UO2)42(O2)42(OH)36 (P2O7)3](H2O)92 (IV), and (K,Li)42 [(UO2)30(O2)39 (P2O7)6] (V) are obtained from aqueous alkaline solutions containing UO2(NO3)2 and H2O2.