Molecular solids of actinide hexacyanoferrate: Structure and bonding

The hexacyanometallate family is well known in transition metal chemistry because the remarkable electronic delocalization along the metal-cyano-metal bond can be tuned in order to design systems that undergo a reversible and controlled change of their physical properties. We have been working for few years on the description of the molecular and electronic structure of materials formed with [Fe(CN)6]n- building blocks and actinide ions (An = Th, U, Np, Pu, Am) and have compared these new materials to those obtained with lanthanide cations at oxidation state +III. In order to evaluate the influence of the actinide coordination polyhedron on the three- dimensional molecular structure, both atomic number and formal oxidation state have been varied : oxidation states +III, +IV. EXAFS at both iron K edge and actinide LIII edge is the dedicated structural probe to obtain structural information on these systems. Data at both edges have been combined to obtain a three-dimensional model. In addition, qualitative electronic information has been gathered with two spectroscopic tools : UV-Near IR spectrophotometry and low energy XANES data that can probe each atom of the structural unit : Fe, C, N and An. Coupling these spectroscopic tools to theoretical calculations will lead in the future to a better description of bonding in these molecular solids. Of primary interest is the actinide cation ability to form ionic – covalent bonding as 5f orbitals are being filled by modification of oxidation state and/or atomic number

Synthesis of Bimetallic Uranium and Neptunium Complexes of a Binucleating Macrocycle and Determination of the Solid-State Structure by Magnetic Analysis

Syntheses of the bimetallic uranium(III) and neptunium(III) complexes [(UI)2(L)], [(NpI)2(L)], and [{U(BH4)}2(L)] of the Schiff-base pyrrole macrocycles L are described. In the absence of single-crystal structural data, fitting of the variable-temperature solid-state magnetic data allows the prediction of polymeric structures for these compounds in the solid state.JRC.E.6-Actinides researc

Crystal Structures of Molecular Adducts between Uranyl Nitrate and 2,2 6,2-Terpyridine or 2,2-Bipyridyl

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Aquatris(nitrato-2O,O')(2,2'6,2'-terpyridine)praseodymium(III) acetone solvate

International audienceThe Pr atom in the title complex, [Pr(NO3)(3)(C15H11N3)-(H2O)] (.) C3H6O, is ten-coordinated and the arrangement can be described as a distorted bicapped square antiprism

An X-ray absorption near edge spectroscopy study of trace amount technetium implanted in apatite

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Double photoexcitation involving 2p and 4f electrons in L-3-edge x-ray absorption spectra of protactinium

The L3-edge x-ray absorption spectrum of Pa(V) fluoride in aqueous solution show clear evidence for the double photoexcitation involving 2p and 4f electrons. A comparison with the [2p4f] double-electron excitations observed in the L3-edge x-ray absorption spectra of other actinides (thorium, uranium, neptunium, plutonium, and americium) indicates a monotonic increase in the excitation energy. The sharp edgelike structure of the multielectron excitation reveals the origin of a shake-up channel