- Comparisons of plutonium, thorium, and cerium tellurite sulfates
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The hydrothermal reaction of PuCl3 or CeCl3 with TeO2 in the presence of sulfuric acid under the comparable conditions results in the crystallization of Pu(TeO3)(SO4) or Ce2(Te2O5)(SO4)2, respectively. Pu(TeO3)(SO4) and its isotypic compound Th(TeO3)(SO4) are characterized by a neutral layer structure with no interlamellar charge-balancing ions. However, Ce 2(Te2O5)(SO4)2 possesses a completely different dense three-dimensional framework. Bond valence calculation and UV-vis-NIR spectra indicate that the Ce compound is trivalent whereas the Pu and Th compounds are tetravalent leading to the formation of significantly different compounds. Pu(TeO3)(SO4), Th(TeO3)(SO4), and Ce2(Te2O 5)(SO4)2 represent the first plutonium/thorium/cerium tellurite sulfate compounds. Our study strongly suggests that the chemistries of Pu and Ce are not the same, and this is another example of the failure of Ce as a surrogate.
- Lin, Jian,Cross, Justin N.,Diwu, Juan,Meredith, Nathan A.,Albrecht-Schmitt, Thomas E.
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- Probing the Influence of Acidity and Temperature to Th(IV) on Hydrolysis, Nucleation, and Structural Topology
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Systematic control of the molar ratio between thorium hydroxides and selenic acid and their reaction temperature under hydrothermal conditions results in four novel thorium-based selenate complexes, namely, [Th8O4(OH)8(SeO4)6(H2O)16]·(SeO4)2·13H2O (Th-1), [Th8O4(OH)8(SeO4)8(H2O)13]·7H2O (Th-2), Th(OH)2(SeO4)H2O (Th-3), and Th3(SeO4)6(H2O)6·2.5H2O (Th-4), as well as the thorium mixed selenite selenate compound Th(SeO3)(SeO4) (Th-5). Smaller [H2SeO4]/[Th(IV)] ratio or lower temperature give rise to the formation of octameric [Th8(μ3-O)4(μ2-OH)8]16+ cores in Th-1/Th-2 and infinite [Th(μ2-OH)2H2O]2+ chains in Th-3, respectively. Increasing the [H2SeO4]/[Th(IV)] ratio or elevating the temperature generates a microporous (11.3 ? voids) open-framework Th-4, a monomeric thorium species without oxo/hydroxyl ligands, and a three-dimensional thorium structure Th-5. Formation of these compounds suggests that variables including acidity and temperature play a critical role in the hydrolysis and oligomerization of ThIV ions. Increasing acidity limits the deprotonation of water molecules and formation of nucleophilic hydroxo/oxo-aquo Th species, and high temperature appears to suppress the olation/oxolation hydrolysis reactions, which in both ways limit the formation of the thorium oligomers.
- Lin, Jian,Qie, Meiying,Zhang, Linjuan,Wang, Xiaomei,Lin, Yuejian,Liu, Wei,Bao, Hongliang,Wang, Jianqiang
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- Structures of dimeric hydrolysis products of thorium
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Three unique thorium dimeric compounds have been crystallized from either direct hydrolysis of Th4+(aq)/HCl or titration of Th(OH) 4(am) with Th(NO3)4(aq) and their structures determined using single-crystal X-ray diffraction. The compound [Th 2(μ2-OH)2(NO3)6(H 2O)6]H2O (1) is identical to that identified previously by Johansson. Two additional unreported compounds have been identified, [Th2(μ2-OH)2(NO 3)4(H2O)8](NO3) 2 (2) and [Th2(μ2-OH)2Cl 2(H2O)12]Cl4· 2H2O (3). 1 crystallizes in the monoclinic space group P21/c, with a = 6.792(2) A, b = 11.710(4) A, c = 13.778(5) A, and β = 102.714(5)° and 2 crystallizes in the monoclinic space group P2 1/n, with a = 6.926(5) A, b = 7.207(1), A, c = 21.502(1) A, and β = 96.380(1)°. The chloride-containing dimer, 3, crystallizes in triclinic P1, with a = 8.080(2) A, b = 8.880(2) A, c = 9.013(2) A, α = 97.41(3)°, β = 91.00(3), and γ = 116.54(3)°. We also present high-energy X-ray scattering data demonstrating the presence of the hydroxo-bridged moiety in solution and discuss our findings in the context of known solid-state structures. The three structures demonstrate 11-, 10-, and 9-coordinate thorium, respectively, and coupled with the scattering experiments provide additional structural and chemical insight into tetravalent actinide hydrolysis.
- Wilson, Richard E.,Skanthakumar,Sigmon, Ginger,Burns, Peter C.,Soderholm
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- Complexes of Th(iv) with neutral O-N-N-O hybrid ligands: A thermodynamic and crystallographic study
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The thermodynamics of Th(iv) complexes with N,N,N′,N′-tetramethyl-2,2′-bipyridine-6,6′-dicarboxamide (TMBiPDA) and N,N,N′,N′-tetramethyl-1,10-phenanthroline-2,9-dicarboxamide (TMPhenDA) in CH3OH/10%(v)H2O (CH3OH?:?H2O = 9?:?1 by volume) were determined by spectrophotometry and calorimetry. The ligand TMBiPDA/TMPhenDA coordinates with the central Th atom by the tetradentate (O-N-N-O) mode, which is validated by 1H NMR in solution and crystallography in the solid. The single crystal X-ray diffraction data show that ten-coordinated thorium coordinates with two ligand molecules and two solvent molecules (water or methanol). Both ThL and ThL2 complexes (L = TMPhenDA or TMBiPDA) were detected in solution. In thermodynamics, the formation of all complexes is driven by both enthalpy and entropy. In a comparison, enthalpy is more favorable to the formation of TMBiPDA complexes, while entropy is more favorable to the formation of TMPhenDA complexes; the entropy advantages of the TMPhenDA complexes override the enthalpy advantages of the corresponding TMBiPDA complexes, giving the TMPhenDA complexes higher stability constants than the TMBiPDA complexes. In crystallography, ligand distortions occur in ThL2 complexes, and TMBiDA distorts more than TMPhenDA does; the Th-O and Th-N bonds involving TMBiPDA are slightly shorter than those involving TMPhenDA.
- Yang, Yanqiu,Lv, Lina,Liu, Yunnu,Chen, Baihua,Liu, Jun,Li, Xingliang,Luo, Shunzhong
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- Characterization of Thorium-Pyrazinoic acid complexation and its decorporation efficacy in human cells and blood
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Thorium (Th) exposure to the human beings is a radiochemical hazard and the chelation therapy by suitable drugs is the major prevention approach to deal with. The present studies aimed at usage of pyrazinoic acid (PCA), which is a prodrug to treat tuberculosis, for its usage as decorporating agent for thorium from human body. The present studies provide a comprehensive knowledge on the chemical interaction and biological efficacy of pyrazinoic acid (PCA) for decorporation of Thorium from the human body. The thermodynamic parameters for Th-PCA speciation are determined by both experiment and theory. The potentiometric data analysis and Electro-Spray Ionization Mass Spectrometry (ESI-MS) studies revealed the formation of MLi (i = 1–4) species with the decrease in stepwise stability constants. All the species formations are endothermic reactions and are predominantly entropy-driven. Biological experiments using human erythrocytes, whole blood and normal human lung cells showed cytocompatibility and decorporation ability of PCA for Thorium. Density functional calculations have been carried out to get insights on interaction process at molecular level. The experimental results and theoretical predictions found to be in line with each other. Present findings on complexation of Th by PCA and its evaluation in human cells and blood would further motivate determination of its safety levels and decorporation efficacy in animal models.
- Dumpala, Rama Mohana Rao,Das, Sourav Kumar,Ali, Manjoor,Boda, Anil,Kumar, Pranaw,Rawat, Neetika,Kumar, Amit,Ali, Sk Musharaf
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