Synthesis and Structure of Complexes of Np(V) Benzoate,o-Fluorobenzoate,and p-Fluorobenzoate with 1,10-Phenanthroline

Radiochemistry - The structures of three new Np(V) complexes [(NpO2)2(phen)2(C7H5O2)2] (I), [(NpO2)2(phen)2. (o-C7H4FO2)2] (II), and [(NpO2)2(phen)2(p-C7H4FO2)2] (III), where phen =...     

Synthesis of New Crystalline Pu(V) Compounds from Solutions: VI. Malonates Co(NH3)6[PuO2C3H2O4]2A · nH2O, A = HCOO, CH3COO, C2H5COO, and C3H3O4

New crystalline compounds of the general composition Co(NH₃)₆[PuO₂L]₂A · nH₂O, where L = CH₂(COO)₂ and A = HCOO, CH₃COO, C₂H₅COO, and HL, were prepared by adding a small excess of Co(NH₃) ₆ ³⁺ ions to freshly prepared neutral Pu(V) malonate solutions containing single-charged organic anions. The complexes are sparingly soluble in water and fairly stable when stored in air; they have a similar structure. Previously unknown double Np(V) malonates Co(NH₃)₆[NpO₂L]₂A · nH₂O, where A = HCOO, CH₃COO, and C₂H₅COO, isostructural with the corresponding Pu(V) compounds, were also prepared. The IR spectra of the new compounds were measured, and their behavior at heating was examined. __________ Translated from Radiokhimiya, Vol. 47, No. 5, 2005, pp. 423–426. Original Russian Text Copyright ? 2005 by Krot, Bessonov, Charushnikova, Grigor'ev, Makarenkov     

Synthesis of New Crystalline Pu(V) Compounds from Solutions: IV. Double Pu(V) Malonates of the Composition Co(NH3)6[PuO2C3H2O4]2A ? nH2O, A = NO3, ClO4, Cl, and Br

New crystalline compounds of the composition Co(NH₃)₆[PuO₂L]₂A ⋅ nH₂O, where L = C₃H₂O₄ and A = NO₃, ClO₄, Cl, and Br, were obtained by addition of a small excess of Co(NH₃) ₆ ³⁺ ions to freshly prepared neutral malonate solutions of Pu(V). They are fairly stable in storage in air and isostructural to the corresponding Np(V) compounds. Thermal behavior of the compounds synthesized was studied, and their IR spectra were measured.__________Translated from Radiokhimiya, Vol. 47, No. 3, 2005, pp. 224–227.Original Russian Text Copyright © 2005 by Krot, Bessonov, Charushnikova, Grigor’ev, Makarenkov.     

Absorption Spectra of Some Crystalline Np(V) Compounds in the Visible Range

The elecotronic absorption spectra in the range 500-750 nm were measured for crystalline Np(V) compounds with the pentagonal-bipyramidal [NpO₂OOCH·H₂O, NpO₂OOCCH₂OH·H₂O, (NpO₂)₂(DMSO)₇·(ClO₄)₂·3H₂O, NpO₂ClO₄·4H₂O], hexagonal-bipyramidal [KNpO₂CO₃, (NpO₂)₂(NO₃)₂·5H₂O], and tetragonal-bipyramidal [NpO₂(TPPO)₄ClO₄, Cs₃NpO₂Cl₄] ligand surrounding. The symmetry of the coordination polyhedra affects the symmetry of narrow absorption bands; however, the long-wave shift of the peak of hydrated NpO₂₊ ions at 617 nm, caused by cation-cation interaction, is considerably less pronounced than the shift of the band at 981 nm.     

Crystal structure of double acetates SrAnO<Subscript>2</Subscript>(OOCCH<Subscript>3</Subscript>)<Subscript>3</Subscript>·3H<Subscript>2</Subscript>O [An = Np(V), Pu(V)]

The crystal structure of isostructural Pu(V) and Np(V) acetates of the general composition SrAnO₂Ac₃ · 3H₂O (Ac = CH₃COO^?) was determined. The structures are based on complex anions [AnO₂Ac₃]^2? and Sr²⁺ cations combined into a three-dimensional framework with water molecules located in framework cavities. The An(V) atoms are characterized by the hexagonal-bipyramidal oxygen surrounding; the equatorial plane is formed by the O atoms of three acetate groups. The coordination surrounding of the Sr atom is a tetragonal antiprism formed by the O atoms of acetate ions and water molecules. The bond lengths within the coordination sphere decrease in passing from Np(V) to Pu(V): the average An=O and An-O bond lengths are 1.828(5) and 2.549(6) Å for Np and 1.811(4) and 2.530(4) Å for Pu, respectively.     

Coprecipitation of Transuranium Elements from Alkaline Solutions by the Method of Arising Agents: XXI. Coprecipitation of Pu(VI,V) and Np(VI,V) with Sodium Uranate

The conditions of recovery of sodium uranate in catalytic decomposition of peroxouranium(VI) ion in alkaline solutions were determined. Cu(II) was used as a catalyst. The capture of Pu(VI,V) and Np(VI,V) with the Na₂UO₄ precipitate was studied radiometrically. With increasing concentration of NaOH from 0.5 to 8 M the decontamination factor K _d decreases from 600 to 30 for Pu(VI,V) and from 200 to 10 for Np(VI,V).     

Crystal structure of U(VI) phthalate dihydrate [UO<Subscript>2</Subscript>(OOC)<Subscript>2</Subscript>C<Subscript>6</Subscript>H<Subscript>4</Subscript>•H<Subscript>2</Subscript>O]•H<Subscript>2</Subscript>O

Crystalline uranyl phthalate dihydrate was prepared by hydrothermal method, and its crystal structure was determined. The crystal structure consists of infinite chains [UO₂LH₂O]_n coupled in bands [(UO₂)₂L₂(H₂O)₂]_n [L = C₆H₄(COO)₂], between which water molecules of crystallization are located. The coordination polyhedron of uranium atoms is a pentagonal bipyramid with the equatorial plane formed by oxygen atoms of three phthalate ions and coordinated water molecule. The U-O bond length in the UO ₂ ²⁺ cations is 1.766 . The coordination capacity of the ligands is 4. Anions are bidentately coordinated to uranium atoms to form seven-membered rings. Being bridging ligands, phthalate ions combine the neighboring uranium atoms into chains through one carboxy group, and the chains into bands, through the other carboxy group.Translated from Radiokhimiya, Vol. 46, No. 6, 2004, pp. 513–515.Original Russian Text Copyright © 2004 by Charushnikova, Krot, Starikova.     

Synthesis of new crystalline Pu(V) compounds from solutions: I. Structure and characteristics of a double Pu(V) phthalate with [Co(NH<Subscript>3</Subscript>)<Subscript>6</Subscript>]<Superscript>3+</Superscript> in the outer sphere

The conditions of synthesis of Pu(V) phthalates by conversion of Pu(VI) into the pentavalent state with addition of H₂O₂ in the presence of excess of phthalate ions (L) were determined. Subsequent addition of [Co(NH₃)₆]Cl₃ allowed isolation of crystalline [Co(NH₃)₆][PuO₂L₂]2H₂O isostructural with [Co(NH₃)₆][NpO₂L₂]2H₂O studied previously. The thermal behavior and IR spectra of both compounds were studied.Translated from Radiokhimiya, Vol. 46, No. 6, 2004, pp. 516–520.Original Russian Text Copyright © 2004 by Krot, Bessonov, Grigorev, Charushnikova, Makarenkov.     

Crystal Structure of Double Np(V) Malonate with Co(NH3)6 3 + in the Outer Sphere, [Co(NH3)6][NpO2L]2HL (L = OOCCH2COO)

The single crystal X-ray analysis of [Co(NH₃)₆][NpO₂L]₂HL (L = OOCCH₂COO) was carried out [monoclinic system, a = 17.925(6), b = 7.736(4), c = 7.879(3) Å, = 103.65(3)°, space group C2/m]. The structure consists of infinite anionic chains [NpO₂L] _n ^n-, [Co(NH₃)]₆ ^{3 +} cations, and HL^- anions. The Np(V) atoms have hexagonal-bipyramidal oxygen surrounding. The coordination capacity of malonate ions is 6; two oxygen atoms (one of each carboxylate group) are bridging atoms between two Np atoms, owing to which the CPs of Np atoms share common equatorial edges to form infinite chains.     

Crystal Structure and Electronic Absorption Spectrum of Double Neptunium(V) Phthalate Co(NH3)6NpO2[(OOC)2C6H4]2·2H2O

Single crystals of Co(NH₃)₆NpO₂[(OOC)₂C₆H₄]₂·2H₂O were grown. The crystal structure of this compound [monoclinic cell: a = 7.748(2), b = 23.051(5), c = 14.608(3) Å, = 96.21(3)°, space group P2₁/c, Z = 4, V = 2593.7(9) ų, d _calc = 2.034 g cm^{- 3}, CAD4 automatic diffractometer, MoK , graphite monochromator, R ₁ = 0.041 for all 3567 reflections observed, wR ₂ = 0.1344 for all 4445 unique reflections, 325 refined parameters] was studied. The structure consists of infinite anionic chains {NpO₂[(OOC)₂C₆H₄]₂} _n ^{3 n -}, [Co(NH₃)₆]^{3 +} cations, and molecules of crystallization water. Neptunium(V) atom is in pentagonal-bipyramidal oxygen surrounding (CN 7); the neptunyl(V) group is linear and symmetrical; the Np = O bond lengths are 1.830(6) and 1.833(5)Å, the O = Np = O angle is 176.4(2)°. The equatorial plane of the bipyramid is formed by five oxygen atoms of phthalate anions. The Np-Oeq bond length correlates with the denticity of the phthalate anions. Two types of phthalate anions are localized in the structure. The first tridentate ligand is a bridge between Np(V) atoms in the chains. The second ligand is coordinated to Np in the bidentate fashion to form NpOCCCCO seven-membered chelate ring. The cation [Co(NH₃)₆]^{3 +} has an octahedral structure. The average Co-N distance in the octahedron is 1.961 Å the N-Co-N bond angles are close to 90°. Two water molecules along with [Co(NH₃)₆]^{3 +} cations are located between the anionic chains {NpO₂[(OOC)₂C₆H₄]₂} _n ^{3 n -}. The chains are additionally bonded along the Z-axis of the crystal by O_w-H···O hydrogen bonds.