A complex core-shell cluster consisting of 68 uranyl peroxo polyhedra, 16 nitrate groups, and ~44 K(+) and Na(+) cations was obtained by self-assembly in alkaline aqueous solution under ambient conditions. Crystals formed after a month and were characterized. The cluster, designated as {U(1)⊂U(28)⊂U(40R)}, contains a fullerene-topology cage built from 28 uranyl polyhedra. A ring consisting of 40 uranyl polyhedra linked into five-membered rings and 16 nitrate groups surrounds this cage cluster. Topological pentagons in the cage and ring are aligned, and their corresponding rings of uranyl bipyramids are linked through K(+) cations located between the two shells. A partially occupied U site is located at the center of the cluster. Time-resolved small-angle X-ray scattering and electrospray ionization mass spectrometry demonstrated that the U(28) cage cluster formed in solution within an hour, whereas the U(40R) shell formed around the cage cluster after more than several days.
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http://dx.doi.org/10.1021/ja210163b | DOI Listing |
ACS Omega
September 2024
Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee, New South Wales 2232, Australia.
The synthesis of two zinc-bearing uranium oxide hydrate (UOH) materials has been achieved, and their crystal structures, obtained via single-crystal X-ray diffraction using synchrotron radiation, and additional structural and spectroscopic properties are reported herein. Although both structures incorporate Zn cations, the two differ significantly. The compound Zn(OH)(HO)[(UO)UO(HO)] (), forming a framework-type structure in the 1̅ space group, was composed of β-UO layers pillared by uranyl polyhedra, with the Zn cations incorporated within the framework channels.
View Article and Find Full Text PDFInorg Chem
December 2023
Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India.
Herein, we report the uranyl sensitization of Sm emissions in uranium-codoped LiBO:Sm phosphor. The uranyl speciation in codoped [Sm, U] LTB samples was determined by synchrotron-based extended X-ray absorption fine structure (EXAFS) spectroscopy that revealed two coordination shells for U(VI) ions with bond distances of U-O (∼1.81 Å) and U-O (∼2.
View Article and Find Full Text PDFSci Rep
August 2023
Department of Materials Science and Engineering, University of Sheffield, Sheffield, UK.
ThTiO derived compounds with the brannerite structure were designed, synthesised, and characterised with the aim of stabilising incorporation of U or U, at dilute concentration. Appropriate charge compensation was targeted by co-substitution of Gd, Ca, Al, or Cr, on the Th or Ti site. U L edge X-ray Absorption Near Edge Spectroscopy (XANES) and High Energy Resolution Fluorescence Detected U M edge XANES evidenced U as the major oxidation state in all compounds, with a minor fraction of U (2-13%).
View Article and Find Full Text PDFFront Chem
March 2023
Institute of Energy and Climate Research (IEK-9), Forschungszentrum Jülich GmbH, Jülich, Germany.
The study of phase formation in the U-Te-O systems with mono and divalent cations under high-temperature high-pressure (HT/HP) conditions has resulted in four new inorganic compounds: K [(UO) (TeO)], Mg [(UO) (TeO)], Sr [(UO) (TeO)] and Sr [(UO) (TeO)]. Tellurium occurs as Te, Te, and Te in these phases which demonstrate the high chemical flexibility of the system. Uranium VI) adopts a variety of coordinations, namely, UO in K [(UO) (TeO), UO in Mg [(UO) (TeO)] and Sr [(UO) (TeO)], and UO in Sr [(UO) (TeO)].
View Article and Find Full Text PDFDalton Trans
November 2021
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, China.
Ultrathin nanosheets of luminescent metal-organic frameworks or coordination polymers have been widely used for sensing ions, solvents and biomolecules but, as far as we are aware, not yet used for temperature sensing. Herein we report two luminescent uranyl phosphonates based on 2-(phosphonomethyl)benzoic acid (2-pmbH), namely (UO)(2-pmbH) (1) and (HO)[(UO)(2-pmb)(2-pmbH)] (2). The former has a supramolecular layer structure, composed of chains of corner-sharing {UO} octahedra and {POC} tetrahedra which are connected by hydrogen bonds between phosphonate and carboxylic groups.
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