Alexander M Fedosseev

Four new Np(V) dicyanoguanidinate complexes with neutral N-donor ligands were synthesized and structurally characterized: [(NpO 2 )(Bipy)(C(NH 2 )(NCN) 2 )(H 2 O)]·2H 2 O ( 1 ), [(NpO 2 )(Phen)(C(NH 2 )(NCN) 2 )(H 2 O)]·2H 2 O ( 2 ), [(NpO 2 )(TPTZ)(C(NH 2 )(NCN) 2 )]·3H 2 O ( 3 ) and [(NpO 2 )( i Pr-BTP)(C(NH 2 )(NCN) 2 )(H 2 O)] ( 4 ). Dicyanogua...

Interaction of U(VI) and Np(VI) with quinaldic acid in the presence of various inorganic (nitrate, chloride, bromide, perrhenate, selenate, sulfate) or organic (dipicolinic acid) counter-ions allowed obtaining a series of complexes where quinaldic acid presents in the zwitterionic form. In all compounds, except one complex, quinaldic acid acts as a...

The solution, containing 2 M NaOH and 4.8 mM Pu(VI) mainly in ionic-dispersed phase, becomes dark blue during 2–3 min under ozonation. The absorption spectrum of the solution in the visible range coincides with the well-known absorption spectrum of Pu(VII). The addition in Pu(VII) solution of the aliquot of Pu(VI) solution reduces the absorbance of...

https://doi.org/10.1016/j.jorganchem.2021.122146 Highlights • A new method for obtaining halogen-free polymer clusters of Tc is proposed. • Low molecular weight fragments of Tc-containing clusters were detected using MALDI. • A mechanism for the formation of polymer Tc-containing clusters is proposed.

A process of phosphorylation for a mercerized cotton kersey fabric was investigated. After wet oxidation, the phosphorus content in each sample was determined by spectrophotometric analysis. The range was 0.179 to 0.950 mmol g–1. A significant decrease in the tensile strength of samples resulted from an increase of phosphoric acid concentration in...

Acetates of actinides and their fission products were essential for the development of radiochemical industries using acetate precipitation technology. Despite this, the literature describes only the synthesis of species containing technetium in the oxidation state +3 and higher. New synthetic routes for the preparation of technetium +2.5 carboxyla...

H7O3]4[Tc20O68] ⋅ 4H2O [1] was prepared from an aqueous Tc2O7 solution concentrated over anhydrous H2SO4. [Tc20O68]⁴⁻ is the first polyanionic species to be reported for Tc. The unit cell contains one centrosymmetric [Tc20O68]⁴⁻ polyanion as well as hydronium ions and water molecules. The core of the structure consists of four Tc(V)O6 octahedra tha...

The inclusion of monopyridinecarboxylic acids into the structures of uranyl halides results in the formation of unexpected structural units. Molecules of picolinic and nicotinic acids acting as bridging ligands favor the formation of unprecedented dinuclear units in two uranyl bromide complexes, which comprise two metal centers in different, tetrag...

New uranyl coordination polymers have been synthesized in the presence of organic cations using phthalic acid as a linker. X-ray analysis of single crystals has shown that compounds with protonated imidazole, and 2-methylimidazole exhibit 2D layered structures. The complex (HIm)2[(UO2)3{C6H4(COO)2}4]·2H2O contains two crystallographically unique ur...

A series of new dimethyl-sulfoxide-containing pertechnetates and perrhenates of tetravalent U, Np, and Pu were synthesized and structurally characterized by the X-ray diffractometry. In all the synthesized compounds, the actinide atoms were coordinated by eight DMSO molecules with or without an extra XO4- anion in the coordination sphere. This resu...

Behavior of UVI, NpVI and PuVI in water‐acetonitrile solutions was studied spectrophotometrically with the successive addition of the polar organic ligands (dimethyl sulfoxide or hexamethylphosphoric triamide) and the NCS– ion. The detected spectral effects – changes in the absorption intensity, bathochromic shifts in the absorption bands, the abse...

The possibility of XeO3 photo-activation in KHCO3 + K2CO3 solutions at room temperature to oxidize AmIII was studied.

A new U(VI) complex with methanesulfonic acid was obtained [UO 2 (OH)(CH 3 SO 3 )]. Its crystal structure was determined using X-ray single crystal diffractometry. The compound crystallizes in P2 1 /n space group. Main crystallographic data: a = 8.6825(6) Å, b = 8.0551(6) Å, c = 8.9298(7) Å, β = 102.162(1)˚, V = 610.52(8) Å ³ , Z = 4. Compound has...

Americium citrate, (NH4)2{Co(NH3)6}2[Am3(Citr)4(OH)(H2O)2]·nH2O, was synthesized and characterized using X-ray crystallography, IR and optical spectroscopy. Americium atoms are coordinated by citrate anions acting as tetradentate ligands. All carboxylic and hydroxylic groups of citric acid are deprotonated. By this means, complex anions [Am3(Citr)4...

The program of 10th International Symposium on Technetium and Rhenium - Science and Utilization

The submission of your abstract has been successfully processed. Abstract submitted: <https://events.synchrotron.org.au/event/54/call-for-abstracts/my-abstracts>. Status of your abstract: <https://events.synchrotron.org.au/event/54 /call-for-abstracts/8/>. Title: Unusual redox neighborhood in technetium compounds Content Techetium has a great numbe...

A series of new pertechnetate, perrhenate, and perchlorate compounds of hexavalent U, Np, and Pu containing isonicotinic acid were synthesized. Their crystal structures were determined by X-ray diffractometry. In all compounds, actinide atoms are found in pentagonal bipyramidal surroundings. They are coordinated by 2 to 4 isonicotinic acid molecule...

The analysis of reported data on the interaction of ozone with alkaline solutions of PuVI leads to the conclusion that the process of ozonation involves reactions O3 + OH– → HO2⁻ + O2, O3 + + HO2⁻ + OH– → O3⁻ + O2⁻ + H2O and O3 + O2⁻ → O3⁻ + O2. The O3⁻ radical ion oxidizes PuVI, the HO2⁻ and O2⁻ anions reduce PuVII and PuVI and react with O3⁻. Usi...

Technetium acid as a solid compound having an intense deep red color. It is known for more than 60 years, but neither its exact composition nor the mechanism of transformation from its colorless pertechnetate 'parent' were supported with informative data, despite numerous attempts by various investigators [1, 2]. In the thermodynamic survey [3] the...

Nitrogen-bearing ligands have received a lot of attention focused primarily on liquid-liquid extraction and separation of lanthanides and actinides. To modelise the complexation mechanism and to understand more deeply the electronic and thermodynamic properties of complexes formed in solution, compound structural data are needed. The present work d...

Single crystals of [Th(TMP)6(NO3)2][Th(TMP)2(NO3)5]2 (1), [Th(TMP)4(NO3)3][Th(TMP)2(NO3)5] (2), [U(DMP)3(NO3)] (3), [Np(DMP)3(NO3)] (4), and [Pu(DMP)2(NO3)2(H2O)]·H2O (5) have been synthesized and their structures have been determined by X-ray analysis. IR and optical spectra of polycrystalline compounds 3 and 4 were measured at room temperature. T...

The M-O bond lengths in the lanthanide series show a well-known behaviour due to lanthanide contraction, including so-called “gadolinium break”. All three bond lengths show a good linear correlation with Shannon ionic radii for Y3+ and Ln3+ ions with coordination number 9. Nevertheless, the slopes of these dependences are different (0.957(16) for O...

The data published on values of redox potentials E of heptavalent Np, Pu, Am, Ru and Mn and octavalent Ru and Pu were analyzed. The half-life ( τ 1/2 ) for reduction reactions of heptavalent metal by water in aqueous alkaline solutions was also analyzed. The decrease in the half life stability of actinide in water with the redox potential for 3− ch...

In the title compound, (CH6N3)[U(C6H4NO2)3O2], the uranyl group is coordinated by two O and two N atoms from two chelating picolinate ligands, and one O atom from a third picolinate ligand. The coordination environment of the UVI atom (N2O5) is distorted penta­gonal–bipyramidal. In the crystal, all amino groups are involved in the formation of N—H⋯...

Single crystals of [Th(TMP)(4)(DMP)(2)](2)[ClO4](4) and [UO2(TMP)(DMP)(NO3)](2) have been synthesized and their structures have been determined by X-ray diffraction analysis. The complexes of Th(IV) and U(VI) contain simultaneously both the molecular ligand trimethyl phosphate (TMP) and the anion dimethyl phosphate. The main structural motif in Th(...

A formation of Am(VI) carbonate complexes has been observed under ozonation of Am(III) in guanidinium carbonate solutions. New [C(NH2) 3]4[AmO2(CO3)3] ·2H2O tricarbonate complex has been isolated and studied by the X-ray analysis. The Am atom has oxygen environment as distorted hexagonal bipyramid with three CO32- ions in equatorial plane and oxyge...

The title compounds, Na[{AmO2}(C2H3O2)3], (I), and (CH6N3)[{AmO2}(C4H5O2)3], (II), contain complex anions in which AmO2²⁺ cations are surrounded by three bidentate-chelating carboxyl­ate groups. The atoms of the AmO2 group and the Na atoms in (I) are situated on threefold axes. All the atoms in (II) occupy general positions. Both compounds are isom...

The comparison of the physicochemical behavior of the actinides with that of the lanthanides can be justified by the analogy of their electronic structure, as each of the series is made up of elements corresponding to the filling of a given (n)f atomic shell. However relatively few points of comparison are available, given the lack of available str...

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This study concerns the formation of complexes with actinides at oxidation state +IV, from Th to Am, through a lacunary heteropolyanion ligand P(2)W(17)O(61)(10-). The preparation of original single crystals of complexes with 1:2 stoichiometry provided structural data through single-crystal X-ray diffraction for the entire An(IV) series. An(IV) ato...

The coordination complexes of trivalent f-element pertechnetates and perrhenates with some N-donor ligands were determined by using X-ray structural analysis: Nd3+ perrhenate with 2,6-bis(tetramethylfurano)-1,2,4-triazin-3-yl)-pyridine ([Nd(FBTP)3ReO4](ReO4)2·2H2O (I)), tris(2-pyridylmethyl)amine ([Nd(TPA)(ReO4)3] (II)) and N,N′-tetraethylmalonamid...

U(IV) oxidation by oxygen in weakly acidic and neutral solutions at pH 1.5–7.4 has been found to proceed by a pseudo-first order reaction with an induction period dependent on the accumulation of U(VI). The presence or the addition of U(VI) accelerates U(IV) oxidation. The rate constants of U(IV) oxidation by air have been determined. The oxidation...

The unsaturated phosphotungstate K 10 P 2 W 17 O 61 and silicotungstate K 8 SiW 11 O 39 are strong and selective complexants of An(IV) in aqueous solution. In presence of these complexants, the redox properties of actinides are changed drastically due to stabilization of the tetravalent actinides. Redox potentials of Fe(III)/Fe(II) and U(VI)/U(IV)...

Actinide elements and their chemistry have a significant number of applications. Bringing together contributions from the leading experts in the field, Recent Advances in Actinide Science covers six main topics: * Analysis, the environment and biotransformations * Coordination and organometallic chemistry * Heavy elements * Nuclear fuels, materials...

Actinide elements and their chemistry have a significant number of applications. Bringing together contributions from the leading experts in the field, Recent Advances in Actinide Science covers six main topics: * Analysis, the environment and biotransformations * Coordination and organometallic chemistry * Heavy elements * Nuclear fuels, materials...

Following the previous work, luminescent properties of Eu3+ ions in powder sample Eu[Cr0.1, Al0.9 (OH)6 Mo6 O18 ].11H2O was studied in detail. Experimental results revealed that there were three Eu3+ centers in the system. The dominant one can transfer its excitation energy to Cr3+ ions, as studied before. By conducting site-selective excitation at...

Synthesis and properties of Np(V) compounds formed with nitrogen planar ligand Tptz. Under special conditions, Np(V) compounds are formed with N-donor aromatic ligands. In this work, synthesis as well as optical properties and thermal stability of solids [NpO2Cl(Tptz)H2O]·H2O (I) and NpO2Br(Tptz)·n H2O (II) are investigated. To cite this article: N...

The hydrolysis and interaction of Np(IV) and Pu(IV) with orthosilicic acid, Si(OH) 4 , were studied in 0.1–1.0 M ionic strength aqueous solutions. Spectrophotometry was used to study these reactions at about 10 –4 M Np(IV) and Pu(IV) concentrations. The first hydrolysis constants, K hydr , agree with the majority of earlier spectrophotometric and p...

The luminescent properties of (NH4)3[Cr(OH)6Mo6O18]·nH2O were investigated for the first time. It was determined that two centers, single Cr3+ ion and Cr3+ ion pair, are responsible for the luminescence properties of this compound. By conducting time-resolved and temperature-dependent emission spectra, energy transfer between the two centers was ob...

The luminescent properties of (NH4)3[Cr(OH)6Mo6O18]·nH2O were investigated for the first time. It was determined that two centers, single Cr3+ ion and Cr3+ ion pair, are responsible for the luminescence properties of this compound. By conducting time-resolved and temperature-dependent emission spectra, energy transfer between the two centers was ob...

(NpO2)(2)SiO4.2H(2)O (I) and (PuO2)(2)SiO4.2H(2)O (II) have been prepared by hydrothermal synthesis technique. Chemical composition of (I) was attributed to the compound from its isostructurality with (UO2)(2)SiO4.2H(2)O; crystal unit cell parameters of (NpO2)(2)SiO4.2H(2)O have been refined as orthorhombic, a = 8.365(5) Angstrom, b = 11.089(5) Ang...

Preparation, crystal structure and properties re-vealed through IR and visible absorption spectroscopy study of Np(V,VI), Pu(VI) compounds formed with pertechnetate anions are reported. Spectrophotometric study of Np(V) and Pu(VI) in NH 4 TcO 4 aqueous solutions (TcO 4 − concentration ranging between 0.2–0.5 M) shows only a slight interaction of Np...

A new method of synthesis of oxide tungsten bronzes containing lanthanide (Ln) Nd and Eu, based on thermal degradation of polyoxotungstate compounds, is proposed. The simplicity of the method allows to consider this class of compounds with chemical formula, Ln x WO 3 , as potential inert target for incineration or transmutation of minor actinides,...

Crystalline compounds of trivalent Eu, Tb formed with Al(OH)6Mo6O183− and Cr(OH)6Mo6O183− anions were prepared from solutions containing lanthanide(III) and (NH4)3M(OH)6Mo6O18 (M=Al,Cr). Stoichiometric compounds containing both Eu and Gd were also prepared. The calculated mean value of hydration numbers of lanthanide ions, n=7.6±1.4, is consistent...

The new compounds Ln[M(OH)6Mo6O18]11H2O (Ln = Tb, Eu and M = Al, Cr) were synthesized and their luminescence properties analysed and discussed. Results show that there is a very efficient energy transfer from Eu3+ (Tb3+) to Cr3+ ions in Eu[Cr(OH)6Mo6O18]11H2O and Tb[Cr(OH)6Mo6O18]11H2O. The transfer strongly quenches Eu3+ (Tb3+) luminescence and gr...

The new neptunium(V) complex [NpO2(bipy)(H2O)3](NO3) was synthesised, and its structure was determined by X-ray diffraction analysis and IR spectroscopy.

The compounds of actinides (Np and Pu) in an oxidation state of +7 with AlIII and rare-earth metals were prepared in aqueous solutions and characterised by IR and UV–VIS spectra.

Formation and leaching properties of the precipitates and sludges in Savannah River Tanks are analiesed

A Mössbauer effect method was used to study the formation of mixed hydroxides in the alkaline coprecipitation of Pu(IV) or Np(IV) with Fe(III). The Mössbauer spectra of mixed 239Pu(IV)-Fe(III) and 237Np(IV)-Fe(III) hydroxide samples differ from that of pure α-FeO(OH) formed in aqueous basic solutions. Alkaline coprecipitation of Np(V) or Np(VI) wit...

The structure and luminescence characteristics of new lanthanide complexes with the heteropoly anion Al(OH)6Mo6O183– were examined.

The structure and luminescence characteristics of new lanthanide complexes with the heteropoly anion Al(OH)$_6$Mo$_6$O$_{18}^{3-}$ were examined.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

Synthesis of large crystals of the europium-doped iodo- and telluromolybdate compounds is described and structural determination is performed. K(NH4)[RE(IMo6O24)(H2O)(5)]. 4H(2)O, REIMo, RE = La-Eu, is triclinic and (NH4)(3)[RE(TeMo6O24)(H2O)(5)]. 4H(2)O, RETeMo, RE = La-Eu, monoclinic. The rare-earth ion occupies in both compounds C-s symmetry sit...

Optical and far-IR spectroscopy techniques have shown that the spectroscopic properties of Np(VI) and Pu(VI) compounds formed with different tetrahedral anions XO42- (X = S, Se, Cr) are depending on the nature of the central atom X in the oxoanions. Changes in electronic transition energies within the ground state configuration are mainly due to cr...

Several techniques, X-ray diffraction, thermogravimetry, IR and optical spectroscopy were applied to study the formation of solid Np(VI) and Pu(VI) compounds with SO42- oxoanions. In case of solutions containing equimolar amounts of NpO22+ and cesium sulfate only one compound Cs2(NpO2)2(SO4)3 was obtained in crystalline form. But in solutions conta...

This work was designed for further investigations of coordination compounds of penta- and hexavalent actinides with tetrahedral XO42−-anions. Although a high similarity in the structure and properties of AnO22+ compounds with XO42−-anions (where An=Np, Pu) was expected, our data on the behaviour of AnO22+ compounds in aqueous solutions pointed to m...

In systematic studies of actinide chemistry in alkaline solution, it was found that Pu(IV) hydrous oxide can remove significant amounts of plutonium present in higher oxidation states from solution. By spectrophotometry it was found that the capture of Pu(VI) by Pu(IV) hydrous oxide is negligible whereas Pu(V) and Np(V) are highly adsorbed. Quantit...