Structure d'un complexe binucléaire du nitrate d'uranyle et du N,N-diméthyl-formamide: μ-peroxo-bis[bis(N,N-diméthyl-formamide)nitratodioxouranium(VI)], [(UO2)2(NO3)2O2(C3H7NO)4]

Charpin, P.; Folcher, G.; Lance, M.; Nierlich, Martine; Vigner, D.

doi:10.1107/s0108270185007533

Cited by 24 publications

(14 citation statements)

References 3 publications

(3 reference statements)

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“…The peroxo ligand most likely arose from oxidative addition of atmospheric dioxygen molecule to the UO 2 + intermediate through the above-mentioned catalytic oxidation of ethanol by the photo-excited *UO 2 2+ . A similar reaction was speculated in some of the former studies which also described incidental deposition of the uranyl-peroxo complexes [Charpin et al (1985); Doyle et al (1993); John et al (2004)].…”

Section: Data Collectionsupporting

confidence: 68%

“…For the structural chemistry of uranyl(VI)-peroxido complexes, see: Haegele & Boeyens (1977); Charpin et al (1985); Doyle et al (1993); Rose et al (1994); Thué ry et al (1999); de Aquino et al (2001); John et al (2004); Masci & Thué ry (2005); Zehnder et al (2005); Kubatko et al (2007); Ikeda et al (2007); Takao et al (2009); Vaska (1976).…”

Section: Related Literaturementioning

confidence: 99%

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μ-η²:η²-Peroxido-bis[nitratodioxidobis(pyrrolidin-2-one)uranium(VI)]

Kohara

Ikeda

2010

Acta Cryst E

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In the crystal structure of the title compound, [U2(NO3)2O4(O2)(C4H7NO)4], two UO2 2+ ions are connected by a μ-η2:η2-O2 unit. The O2 unit shows ‘side-on’ coordination to both U atoms. An inversion center is located at the midpoint of the O—O bond in the O2 unit, affording a centrosymmetrically expanded dimeric structure. The U—O(axial) bond lengths are 1.777 (4) Å and 1.784 (4) Å, indicating that the oxidation state of U is exclusively 6+, i.e., UO2 2+. Furthermore, the O—O distance is 1.492 (8) Å, which is typical of peroxide, O2 2–. The U atom is eight-coordinated in a hexagonal-bipyramidal geometry. The coordinating atoms of the nitrate and pyrrolidine-2-one ligands and the μ-η2:η2-O2 2– unit are located in the equatorial plane and form an irregular hexagon. An intermolecular hydrogen bond is found between N—H of the pyrrolidine-2-one ligand and the coordinating O of the same ligand in a neighboring complex. A second intermolecular hydrogen bond is found between the N—H of the other pyrrolidine-2-one ligand and one of the uranyl oxido atoms.

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Section: Data Collectionsupporting

confidence: 68%

Section: Related Literaturementioning

confidence: 99%

μ-η²:η²-Peroxido-bis[nitratodioxidobis(pyrrolidin-2-one)uranium(VI)]

Kohara

Ikeda

2010

Acta Cryst E

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“…Even if halogen anions are not encountered in U and Pu extraction processes, some papers describe complexes containing halogen anion instead of nitrates. 50 With nitrate counter ion, most reported structures contain short-chains ligands 28,27,29,51 or cyclic ligands [52][53][54][55][56] but a few structures with long-chain extractant molecules have also been reported. 51 cation is coordinated in the equatorial plane to two oxygen atoms from two monoamide ligands and two bidentate nitrates which ensure the charge compensation ( Figure 2).…”

Section: Dbba Solid-state Structuresmentioning

confidence: 99%

Structures of Plutonium(IV) and Uranium(VI) with N,N-Dialkyl Amides from Crystallography, X-ray Absorption Spectra, and Theoretical Calculations

et al. 2016

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The structures of plutonium(IV) and uranium(VI) ions with a series of N,N-dialkyl amides ligands with linear and branched alkyl chains were elucidated from single-crystal X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS), and theoretical calculations. In the field of nuclear fuel reprocessing, N,N-dialkyl amides are alternative organic ligands to achieve the separation of uranium(VI) and plutonium(IV) from highly concentrated nitric acid solution. EXAFS analysis combined with XRD shows that the coordination structure of U(VI) is identical in the solution and in the solid state and is independent of the alkyl chain: two amide ligands and four bidentate nitrate ions coordinate the uranyl ion. With linear alkyl chain amides, Pu(IV) also adopt identical structures in the solid state and in solution with two amides and four bidentate nitrate ions. With branched alkyl chain amides, the coordination structure of Pu(IV) was more difficult to establish unambiguously from EXAFS. Density functional theory (DFT) calculations were consequently performed on a series of structures with different coordination modes. Structural parameters and Debye-Waller factors derived from the DFT calculations were used to compute EXAFS spectra without using fitting parameters. By using this methodology, it was possible to show that the branched alkyl chain amides form partly outer-sphere complexes with protonated ligands hydrogen bonded to nitrate ions.

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“…In the absence of added H 2 O 2 or significant α activity, the formation of multiple uranyl peroxide species has been demonstrated via photochemical mechanisms induced by sunlight. − Two different photochemical mechanisms have been presented. In the first, the uranyl ion is excited by incident light (*UO 2 2+ ), reduced to UO 2 + via H-abstraction or electron transfer, and then reoxidized by atmospheric oxygen to regenerate UO 2 2+ , producing H 2 O 2 in the process (eq ).…”

mentioning

confidence: 99%

Evidence of a Nonphotochemical Mechanism for the Solid-State Formation of Uranyl Peroxide

et al. 2018

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We have demonstrated the solid-state formation of a uranyl peroxide (UP) species from hydrated uranyl fluoride via a uranyl hydroxide intermediate, the first observation of a UP species formed in a solid-state reaction. Water vapor pressure is shown to be a driving factor of both the loss of fluorine and the subsequent formation of peroxo units. We have ruled out a photochemical mechanism for formation of the UP species by demonstrating that the same reaction occurs in the dark. A radiolytic mechanism is unlikely because of the low radioactivity of the sample material, suggesting the existence of a novel UP formation mechanism.

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Structure d'un complexe binucléaire du nitrate d'uranyle et du N,N-diméthyl-formamide: μ-peroxo-bis[bis(N,N-diméthyl-formamide)nitratodioxouranium(VI)], [(UO2)2(NO3)2O2(C3H7NO)4]

Cited by 24 publications

References 3 publications

μ-η²:η²-Peroxido-bis[nitratodioxidobis(pyrrolidin-2-one)uranium(VI)]

μ-η²:η²-Peroxido-bis[nitratodioxidobis(pyrrolidin-2-one)uranium(VI)]

Structures of Plutonium(IV) and Uranium(VI) with N,N-Dialkyl Amides from Crystallography, X-ray Absorption Spectra, and Theoretical Calculations

Evidence of a Nonphotochemical Mechanism for the Solid-State Formation of Uranyl Peroxide

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Structure d'un complexe binucléaire du nitrate d'uranyle et du N,N-diméthyl-formamide: μ-peroxo-bis[bis(N,N-diméthyl-formamide)nitratodioxouranium(VI)], [(UO2)2(NO3)2O2(C3H7NO)4]

Cited by 24 publications

References 3 publications

μ-η2:η2-Peroxido-bis[nitratodioxidobis(pyrrolidin-2-one)uranium(VI)]

μ-η2:η2-Peroxido-bis[nitratodioxidobis(pyrrolidin-2-one)uranium(VI)]

Structures of Plutonium(IV) and Uranium(VI) with N,N-Dialkyl Amides from Crystallography, X-ray Absorption Spectra, and Theoretical Calculations

Evidence of a Nonphotochemical Mechanism for the Solid-State Formation of Uranyl Peroxide

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μ-η²:η²-Peroxido-bis[nitratodioxidobis(pyrrolidin-2-one)uranium(VI)]

μ-η²:η²-Peroxido-bis[nitratodioxidobis(pyrrolidin-2-one)uranium(VI)]