u2o5-film-preparation-via-uo2-deposition-direct-current-sputtering

U2O5 Film Preparation via UO2 Deposition by Direct Current Sputtering and Successive Oxidation and Reduction with Atomic Oxygen and Atomic Hydrogen

We describe a method to produce U2O5 films in situ using the Labstation, a modular machine developed at JRC Karlsruhe. The Labstation, an essential part ...

Directorate for Nuclear Safety and Security

The magnetic properties of the 5f(5) [tris-(tri-1-pyrazolylborato)-plutonium(III)] complex have been investigated by ac susceptibility measurements, showing it to be the first plutonium single-molecule magnet; its magnetic relaxation slows down with decreasing temperature through a thermally activated mechanism followed by a quantum tunnelling regime below 5 K.

A plutonium-based single-molecule magnet.

A dramatic difference in the ability of the reducing An(III) center in AnCp3 (An=U, Np, Pu; Cp=C5 H5 ) to oxo-bind and reduce the uranyl(VI) dication in the complex [(UO2 )(THF)(H2 L)] (L="Pacman" Schiff-base polypyrrolic macrocycle), is found and explained. These are the first selective functionalizations of the uranyl oxo by another actinide cation. At-first contradictory electronic structural data are explained by combining theory and experiment. Complete one-electron transfer from Cp3 U forms the U(IV) -uranyl(V) compound that behaves as a U(V) -localized single molecule magnet below 4 K. The extent of reduction by the Cp3 Np group upon oxo-coordination is much less, with a Np(III) -uranyl(VI) dative bond assigned. Solution NMR and NIR spectroscopy suggest Np(IV) U(V) but single-crystal X-ray diffraction and SQUID magnetometry suggest a Np(III) -U(VI) assignment. DFT-calculated Hirshfeld charge and spin density analyses suggest half an electron has transferred, and these explain the strongly shifted NMR spectra by spin density contributions at the hydrogen nuclei. The Pu(III) -U(VI) interaction is too weak to be observed in THF solvent, in agreement with calculated predictions.

Subtle Interactions and Electron Transfer between U(III) , Np(III) , or Pu(III) and Uranyl Mediated by the Oxo Group.

The reduction of U uranyl halides or amides with simple Ln or U salts forms highly symmetric, linear, oxo-bridged trinuclear U /Ln /U , Ln /U /Ln , and U /U /U complexes or linear Ln /U polymers depending on the stoichiometry and solvent. The reactions can be tuned to give the products of one- or two-electron uranyl reduction. The reactivity and magnetism of these compounds are discussed in the context of using a series of strongly oxo-coupled homo- and heterometallic poly(f-block) chains to better understand fundamental electronic structure in the f-block.

Article	Year
A plutonium-based single-molecule magnet. Chemical communications (Cambridge, England)\| PubMed ID: 24927255	2014
Subtle Interactions and Electron Transfer between U(III) , Np(III) , or Pu(III) and Uranyl Mediated by the Oxo Group. Angewandte Chemie (International ed. in English)\| PubMed ID: 27628291	2016
Axially Symmetric U-O-Ln- and U-O-U-Containing Molecules from the Control of Uranyl Reduction with Simple f-Block Halides. Angewandte Chemie (International ed. in English)\| PubMed ID: 28686336	2017

Roberto Caciuffo

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