Hybrid Uranium–Transition-Metal Oxide Cage Clusters

Abstract

Transition-metal based polyoxometalate clusters have been known for decades, whereas those built from uranyl peroxide polyhedra have more recently emerged as a family of complex clusters. Here we report the synthesis and structures of six nanoscale uranyl peroxide cage clusters that contain either tungstate or molybdate polyhedra as part of the cage, as well as phosphate tetrahedra. These transition-metal-uranium hybrid clusters exhibit unique polyhedral connectivities and topologies that include 6-, 7-, 8-, 10-, and 12-membered rings of uranyl polyhedra and uranyl ions coordinated by bidentate peroxide in both trans and cis configurations. The transition-metal polyhedra appear to stabilize unusual units built of uranyl polyhedra, rather than templating their formation.

Counterion-Controlled Formation of an Octanuclear Uranyl Cage with cis-1,2-Cyclohexanedicarboxylate Ligands

“…Anal. calcd for C11H17NO7U: C, 25 Crystallography. Crystallographic data were collected at 150(2) K on a Nonius Kappa-CCD area-detector diffractometer using graphite-monochromated Mo Kα radiation (λ = 0.71073 Å).…”

Trends and new directions in the crystal chemistry of actinide oxo-clusters incorporated in polyoxometalates

“…100 Later, an alternative approach was successfully performed by using Keggin type phospho-polyoxometalates (instead of [WO 4 ] 2tungstate precursors), associated to uranyl and hydrogen peroxide at pH around 6. Six hybrid uraniumtransition metals-peroxo cage clusters were isolated: the uranyl-peroxo polyhedra interact with monomers of tungstate or molybdate (depending on the precursor used) in which uranium-transition metal nuclearity goes from {U VI 101 For all the molecules, the uranyl centers adopt the typical coordination environment with hexagonal bipyramid geometry. Here, the originality of this geometry consists in the fact that two peroxo ligands on the uranyl groups are in a trans-arrangement which is relatively rare in the uranyl peroxo cage family.…”

Cavity Formation in Uranyl Ion Complexes with Kemp’s Tricarboxylate: Grooved Diperiodic Nets and Polynuclear Cages

“…In recent years, several examples of uranyl-based cage-like species have been reported, the most remarkable by every measure being the series obtained with bridging peroxide anions [1][2][3][4][5] and the very large, quasi-spherical assemblies containing p-carboxylatocalixarenes as ligands. 6 Although carboxylate ligands are commonly used in the synthesis of uranyl ion complexes and in particular of coordination polymers and frameworks, [7][8][9][10][11] they have given only about a dozen of cage-like polynuclear uranyl ion complexes, all of them of moderate size.…”