Extraction of f-elements from nitric acid solutions with phosphoryl ketones

The extraction ability and selectivity of a series of phosphoryl ketones Ph₂P(O)CH₂C(O)Me, and Ph₂P(O)CRR’CH₂C(O)Me (R = H, Me; R’ = H, Me, n-C₅H₁₁, Ph, 2-thienyl, 2-furyl) towards trivalent lanthanides (La^III, Nd^III, Ho^III, Yb^III) and actinides (U^VI, Th^IV) were studied. The efficiency and selectivity of the new ligands in the extraction of f-elements from nitric acid solutions into chloroform were compared to those of model phosphine oxide Ph₂P(O)Bu and known extractants: tributyl phosphate (BuO)₃P(O), trioctylphosphine oxide (C₈H₁₇)₃P(O), and carbamoylmethyl phosphine oxide Ph₂P(O)CH₂C(O)NBu₂.     

α- and β-diphenylphosphorylated secondary alkanols: I. general method of synthesis and extraction properties towards <Emphasis Type="Italic">f</Emphasis>-elements

A simple and effective general method of synthesis of α- and β-diphenylphosphorylated secondary alkanols by the reduction of the corresponding phosphorylalkanones with NaBH4 was developed. The extraction properties of the resulting phosphorylalkanols Ph₂P(O)(CR₂)_nCH₂CH(OH)Me (n = 0, 1; R = H, Me) were studied in the recovery of f-elements (La^III, Nd^III, Ho^III, Yb^III, U^VI, Th^IV) from nitric acid solutions into chloroform and compared with those of both related phosphorylketones and known extractants (n-BuO)₃PO, (n-C₈H₁₇)₃PO, and Ph₂P(O)CH₂C(O)N(n-Bu)₂.     

Acetyl-containing phosphine oxides as extractants for actinides and lanthanides

Extraction capability and selectivity of acetyl-containing phosphine oxides R₂P(O)CMe₂CH₂C(O)Me (R = Pr, Bu, n-C₅H₁₁, n-C₆H₁₃, n-C₈H₁₇, Ph) toward actinides (U^VI, Th^IV) and trivalent lanthanides (La^III, Nd^III, Ho^III, Yb^III) were studied. The new ligands were shown to be more efficient and selective in the extraction of uranium, thorium, and heavy lanthanides from nitric acid solutions into chloroform as compared to the known extractants such as carbamoylphosphine oxide Ph₂P(O)CH₂C(O)NBu₂, trioctylphosphine oxide (n-C₈H₁₇)₃P(O), and tributyl phosphate (n-BuO)₃P(O).     

Binuclear Copper(II) Complexes with Terpene Bicyclic Optically Active Iminoalcohol: Synthesis,Structure, and Magnetic Properties

Methods were developed for synthesizing the 3-Carene derivative (1R)-1-|(1R,2R,5R)-2-benzyl-3-imino-6,6-dimethylbicyclo[3.1.0]hex-2-yl}-ethanol (HL) and stable copper(II) complexes [Cu₂(H₂O)L₂(CH₃COO)₂] · H₂O (IV), [Cu₂L₂Cl₂] (V), and [Cu₂L₂Br₂] (VI). According to X-ray diffraction data, IVand Vhave molecular binuclear structures with a planar Cu₂O₂cycle. The CuOCu angles are equal to 102.2°, 102.8° (IV) and 103.2°, 103.8° (V). The L^–terpene ligand acts as a tridentate cyclic bridge. A strong antiferromagnetic exchange interaction between the unpaired electrons of the copper(II) ions was detected in compounds IV–VIusing the static magnetic susceptibility method. The –2Jparameter for IV, V, and VIis equal to 660, 1000, and 1060 cm^–1, respectively.     

Coordinated lanthanide metal complexes ofN-benzoylglycine hydrazide

Summary N-benzoylglycine hydrazide (BzGH) reacts with trivalent lanthanide metal ions forming complexes of the type [Ln(BzGH)₂Cl(H₂O)₂]Cl₂·nH₂O, where Ln=La^III, Pr^III, Nd^III, Sm^III, Eu^III, Gd^III, Tb^III, Dy^III, or Y^III;n=1 or 2. The structures of the complexes have been studied by conductance, magnetic, electronic, i.r.,¹H n.m.r. and¹³C n.m.r. spectral techniques. The nephelauxetic ratio, the bonding parameter, Sinha's parameter and the covalency angular overlap parameter have been calculated from the electronic spectra of Pr^III, Nd^III and Sm^III complexes. Seven-coordination is proposed in the Nd^III complex. The i.r. and¹H n.m.r. spectral data suggest bidentate BzGH in all the complexes.     

Studies on coordination chemistry of a nitrogen–sulfur donor ligand with lighter and heavier metal ions and biological activities of its complexes

Complexes of S-benzyldithiocarbazate (SBDTC) with lighter and heavier metals, viz., Cr^III, Fe^III, Sb^III, Zr^IV, Th^IV and U^VI have been prepared and characterized by elemental analyses, conductivity measurements, and spectral studies. The complexes: [Cr(SBDTCA)₃],^** [Fe(SBDTCA)₃], [Sb(SBDTCA)₃], [Sb(SBDTCA)₂Cl · H₂O], [Zr(O)(SBDTCA)₂ · H₂O], [Th(SBDTCA)(NO₃)₃ · H₂O)], and [U(O)₂(SBDTCA)₂] were all prepared in alkaline media. They were all hexa-coordinated with bidentate, uninegative chelation of the ligand. [Fe(SBDTCA)₃], [Sb(SBDTCA)₃] and [Sb(SBDTCA)₂Cl · H₂O] were strongly effective against bacteria giving clear inhibition zones with Pseudomonas aeruginosa and Bacillus cereus. The compounds showed poor antifungal activity. The antimony complexes were strongly cytotoxic against leukemic cells with CD₅₀ values of 3.2–6.7 g cm^–3 as compared to the CD₅₀ value of 14.5 g cm^–3 of the free SbCl₃ molecule.     

Preparation of AmIV and AmVI in bicarbonate and carbonate solutions using xenon compounds

Xe compounds, XeF₂, Na₄XeO₆, and XeO₃, were used to oxidize Am^III in carbonate and bicarbonate aqueous solutions. XeF₂ and XeO₃ may be used to obtain Am^IV in solutions, whereas Na₄XeO₆ oxidizes Am^III into Am^IV+An^V+Am^VI or into Am^VI if present in excess. XeO³ reacts with Am^III to give Am^IV only under UV irradiation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 953–954, May, 1994.     

Complexes of a tridentate ONS Schiff base. Synthesis and biological properties

Several new complexes of a tridentate ONS Schiff base derived from the condensation of S-benzyldithiocarbazate with salicylaldehyde have been characterised by elemental analyses, molar conductivity measurements and by i.r. and electronic spectra. The Schiff base (HONSH) behaves as a dinegatively charged ligand coordinating through the thiolo sulphur, the azomethine nitrogen and the hydroxyl oxygen. It forms mono-ligand complexes: [M(ONS)X], [M=Ni^II, Cu^II, Cr^III, Sb^III, Zn^II, Zr^IV or U^VI with X = H₂O, Cl]. The ligand produced a bis-chelated complex of composition [Th(ONS)₂] with Th^IV. Square-planar structures are proposed for the Ni^II and Cu^II complexes. Antimicrobial tests indicate that the Schiff base and five of the metal complexes of Cu^II, Ni^II, U^VI, Zn^II and Sb^III are strongly active against bacteria. Ni^II and Sb^III complexes were the most effective against Pseudomonas aeruginosa (gram negative), while the Cu^II complex proved to be best against Bacillus cereus (gram positive bacteria). Antifungal activities were also noted with the Schiff base and the U^VI complex. These compounds showed positive results against Candida albicans fungi, however, none of them were effective against Aspergillus ochraceous fungi. The Schiff base and its zinc and antimony complexes are strongly active against leukemic cells (CD₅₀ = 2.3–4.3 μg cm⁻³) while the copper, uranium and thorium complexes are moderately active (CD₅₀ = 6.9–9.5 μg cm⁻³). The nickel, zirconium and chromium complexes were found to be inactive. This revised version was published online in June 2006 with corrections to the Cover Date.     

Polarographic study of the reaction between cerium(IV) and thiocyanate

Summary Polarographic studies have been made of the reaction between Cerium(IV) and potassium thiocyanate in acidic medium. Ce^IVin the concentration range 2 · 10^–4 M to 5 · 10^–3 M was found to be reduced to Ce^III by thiocyanate ion. One equivalent of thiocyanate reduced 4–6 equivalents of Ce^IV in the concentration range studied.

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Zusammenfassung Die Reaktion zwischen Cer^IV und Kaliumthiocyanat wurde in saurem Medium polarographisch untersucht. Cer^III wurde im Bereich von 2 · 10^–4 m bis 5 · 10^–3 m von Thiocyanat zu Cer^III reduziert. In diesem Konzentrationsbereich entsprachen einem Äquivalent Thiocyanat 4–6 Äquivalente Cer^IV.

     

Methoxokomplexe drei-, vier- und fünfwertiger Zentralatome

The complex formation with CH₃O^? of As^III, Sb^III, Ge^IV, Nb^IV, Se^IV, Te^IV, Ti^IV, Sn^IV and Mo^V has been investigated in absolute methanolic solutions containing (CH₃)₄NCl, LiCl, or Lithiumtosylate (μ = 1; 20.0°) by means of pH-titrations. The relations between the stoichiometry of the reactions and the shape of the buffer regions, as well as the concentration-dependance of these buffer regions are discussed.     

Osmium(IV) Binuclear Nonelectrolytic Oxo-Bridged Carboxylates. Molecular Structure of [Os2 IV(μ-O)(μ-O2CCCl3)2Cl4(PPh3)2] · CH2Cl2

The reactions between trans-[Os^VIO₂Cl₂L₂] (L = PPh₃, AsPh₃, SbPh₃) and carboxylic acids RCO₂H (R = CH₃, C(CH₃)₃, CH₂Cl, CCl₃, CF₃) are studied. The resulting binuclear compounds were found to have the general formula [Os₂ ^IV(-O)(-O₂CR)₂Cl₄(L)₂] (L = PPh₃; R = CH₃, C(CH₃)₃, CH₂Cl, CCl₃, CF₃, and L = AsPh₃; R = CH₃, CH₂Cl, CCl₃, CF₃). X-ray diffraction analysis revealed that the [Os₂ ^IV(-O)(-O₂CCCl₃)₂Cl₄(PPh₃)₂] · CH₂Cl₂ complex crystallizes in a triclinic system with space group P ; a = 10.747(2) Å, b = 19.291(4) Å, c = 24.614(5) Å, = 100.08(3)°, = 90.63(3)°, = 97.05(3)°, V = 4983.5(17) ų, Z = 4. The Os(-O)Os angle is 142.2(7)°. The interaction of trans-[Os^VIO₂Cl₂(SbPh₃)₂] with all the acids under study is attended by intramolecular redox reaction resulting in SbCl₂Ph₃.     

Synthetic studies of organodi-π-cyclopentadienyl- titanium (III) derivatives

Two synthetic routes to compounds of the type π-Cp₂Ti^IIIR (R=CH₃, CH₂Si(CH₃)₃, C₆F₅) have been investigated: (a) chemical reduction of π-Cp₂Ti^IV(R)Cl by zinc or aluminum metal in tetrahydrofuran, and (b) conventional organometallic syntheses using organo-lithium or -magnesium reagents and [π-Cp₂Ti^IIICl]₂. The preferred route is via an organolithium reagent, since chemical reduction gives a mixture of products. Green, monomeric complexes (R = CH₂Si(CH₃)₃, C₆F₅) were isolated and characterised. From the reaction of π-Cp₂Ti^IVCl₂ and trimethylsilylmethyllithium in a 1/1 ratio, π-CpTi^IV [CH₂Si(CH₃)₃]₃ was obtained. Unlike π-Cp₂Ti^IIIC₆F₅, π-Cp₂Ti^IIICH₂Si(CH₃)₃ does not form a blue complex with molecular nitrogen.     

Mn12-Acetate Complexes Studied as Single Molecules

The phenomenon of single molecule magnet (SMM) behavior of mixed valent Mn₁₂ coordination clusters of general formula [Mn^III₈Mn^IV₄O₁₂(RCOO)₁₆(H₂O)₄] had been exemplified by bulk samples of the archetypal [Mn^III₈Mn^IV₄O₁₂(CH₃COO)₁₆(H₂O)₄] (4) molecule, and the molecular origin of the observed magnetic behavior has found support from extensive studies on the Mn₁₂ system within crystalline material or on molecules attached to a variety of surfaces. Here we report the magnetic signature of the isolated cationic species [Mn₁₂O₁₂(CH₃COO)₁₅(CH₃CN)]⁺ (1) by gas phase X-ray Magnetic Circular Dichroism (XMCD) spectroscopy, and we find it closely resembling that of the corresponding bulk samples. Furthermore, we report broken symmetry DFT calculations of spin densities and single ion tensors of the isolated, optimized complexes [Mn₁₂O₁₂(CH₃COO)₁₅(CH₃CN)]⁺ (1) , [Mn₁₂O₁₂(CH₃COO)₁₆] (2) , [Mn₁₂O₁₂(CH₃COO)₁₆(H₂O)₄] (3) , and the complex in bulk geometry [Mn^III₈Mn^IV₄O₁₂(CH₃COO)₁₆(H₂O)₄] (5) . The found magnetic fingerprints – experiment and theory alike – are of a remarkable robustness: The Mn^IV₄ core bears almost no magnetic anisotropy while the surrounding Mn^III₈ ring is highly anisotropic. These signatures are truly intrinsic properties of the Mn₁₂ core scaffold within all of these complexes and largely void of the environment. This likely holds irrespective of bulk packing effects.     

Rh(I) carbonyl carboxylato complexes: Spectral and structural characteristics. Some reactions of coordinated formate group

Complexes [Rh(µ-RCOO)(CO₂)]₂ , where R = H, CH₃,CF₃ (I, II, III, respectively) are synthesized by reacting anhydrous carboxylic acids with Rh(Acac)(CO₂) crystals. In compounds I, II, III, and trans-Rh(RCOO)(PPh₃)₂(CO), where R = H, CH₃, CF₃ (IV, V, VI, respectively), (CO) and ¹J(CRh) increase and ¹³C decreases with the increasing electronegativity of R (CH₃ < H < CF₃). In the case complexes IV, V, and VI, the values of ³¹P and ¹ J(PRh) decrease in the same order. Complexes I and V are studied by X-ray diffraction analysis. Intramolecular (2.946 Å) and intermolecular (3.127 Å) Rh-Rh distances in a columnar structure I are close, i.e., the structure contains infinite chains of metal atoms. Interaction of IV with chlorinated solvents results in trans-RhCl(PPh₃)₂(CO). When heated with an excess of PPh₃ in propanol-2, compound IV transforms to HRh(PPh₃)₃(CO). The latter reaction was suggested as a basis of a new method that can be used to obtain HRh(PPh₃)₃(CO).Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 2, 2005, pp. 132–142.Original Russian Text Copyright © 2005 by Varshavskii, Cherkasova, Podkorytov, Korlyukov, Khrustalev, Nikolskii.     

Synthesis,structural and catalytic activity of binaphthyl macrocyclic complexes

The binaphthyl macrocyclic ligand, N,N′-diethyl-[3,3′-(2,2′-dihydroxy-1,1′-binaphthyl)carboxamide]-2,2′-dihydroxy-1,1′-binaphthyl-3,3′-dicarboxylic acid (DDCDB), has been synthesized and investigated. The ligand (DDCDB) and its metal complexes involving Cu^II, Zn^II, UO ₂ ^II , Th^IV, Ce^III, Mo^VI and W^VI ions have been prepared and characterized by spectral (i.r., u.v.–vis.), elemental analyses, magnetic moments and thermal analyses measurements. DDCDB behaves as a tridentate ligand towards Cu^II, Zn^II and UO ₂ ^II ions coordinating via CO, NH and the deprotonated naphthyl OH groups in a ratio of 2:1 (M:L). On the other hand, DDCDB behaves in a bidentate manner coordinatingvia the NH and the deprotonated naphthyl OH groups only in case of the Th^IV, Ce^III, Mo^VI, and W^IV ions and in ratio 1:1 (M:L). Results of thermal measurements confirm the existence of solvent molecules inside and outside the coordination sphere. Th^VI complex has been applied for the hydrolysis of phosphodiester and the results show a significant rate enhancement of ~5.8 million fold with respect to the auto-hydrolysis of bis-(p-nitrophenyl) phosphate (BNPP) under the same conditions Also, Cu^II complex accelerates the photodegradation of the hazardous pollutant (acid green dye) in the presence of hydrogen peroxide by degrading 90% of the dye within 23 min.     

Study of substituent effects on rotational isomers and monomer–dimer equilibria of the 3-carboxy group in 4-substituted (R)-2-(3,4-methylenedioxyphenyl)-6-isopropyloxy-2H-chromen-3-carboxylic acids in dilute CCl4 and CHCl3 solutions by FTIR spectroscopy

FTIR spectra of the title carboxylic acids (I–III) with 4-substituents (H, CH₃ or C₆H₅) and their related compounds IV–VI with 4-(substituted phenyl) groups were measured in dilute CCl₄ and CHCl₃ solutions. The concentration dependence of FTIR spectra of I–IV was also measured in these solutions. These spectra were subjected to curve analysis in order to quantitatively identify the rotational isomers of 3-carboxy group attributable to steric hindrance of the 4-substituents. For I, II and III–VI, two, four and five ν(CO) bands were observed for their carboxy groups, respectively, indicative of monomer–dimer equilibrium and two and three kinds of rotational isomers for II and III–VI, respectively. Compounds III–VI were found to form intra-molecular hydrogen bonds between the trans-type of the 3-carboxy group and the π-electrons in the 4-benzene ring. We have worked out a method to estimate the association constant (K) of complicated monomer–dimer equilibria such as II–VI. The K values of I–IV decrease remarkably in the order of H (I), C₆H₅ (III), CH₃ (II) and C₆H₄-p-OCH₃ (IV) in CCl₄ and I, II, III and IV in CHCl₃; these orders are discussed.     

N-Alkyl-N′-[(alkyl/aryl)(alkoxy/aroxy)phosphoryl]ureas: synthesis and extraction properties toward f-elements

A reaction of chlorophosphonates R¹R²P(O)Cl with NaOCN and subsequent treatment with octylamine lead to phosphorylureas R¹R²P(O)NHC(O)NHC₈H₁₇-n (R¹ = EtO, PhO; R² = Me, Ph). Their extraction capability toward U^VI and a number of tervalent lanthanides (La^III, Nd^III, Ho^III, Yb^III) was studied. Efficiency and selectivity of these ligands in the extraction of f-elements from nitric acid solutions to chloroform were compared with extraction properties of a model phosphine oxide-type phosphorylurea MePhP(O)NHC(O)NHC₈H₁₇-n and carbamoylphosphine oxide Ph₂P(O)CH₂C(O)NBu₂.     

A study on synthesis and thermal,spectral and biological properties of carboxylato-Mg(II) and carboxylato-Cu(II) complexes with bioactive ligands

Summary Synthesis, elemental (CHN), spectral (FTIR), thermogravimetry (TG), differential thermal analysis (DTA) and complexometric titration have been applied to the investigation of the thermal behavior and structure of the complexes: Mg(ac)₂(mpc)₃·3H₂O(I), Mg(Clac)₂(mpc)₂·3H₂O(II), Mg(Cl₂ac)₂(mpc)₂·3H₂O(III), Mg(Cl₃ac)₂(mpc)₂·3H₂O(IV) and [Cu(ac)₂(mpc)]₂·3H₂O(V) (ac=CH₃COO^-, Clac=ClCH₂COO^-, Cl₂ac=Cl₂CHCOO^-, Cl₃ac=Cl₃CCOO^- and mpc=methyl-3-pyridyl carbamate). Thermal decomposition of these complexes is a multi-stage processes. The composition of the complexes and the solid state intermediate and resultant products of thermolysis had been identified by means of elemental analysis and complexometric titration. The possible scheme of decomposition of the complexes is suggested. Heating the complexes first resulted in a release of water molecules. The TG results show that the loss of the volatile ligand (mpc) occurs in one step for complexes II, IV and V, and in two steps for complexes I and III. The final solid product of thermal decomposition was MgO or CuO. The thermal stability of the complexes can be ordered in the sequence: I=II<IV<III<V. Mpc was coordinated to Mg(II) or Cu(II) through the nitrogen atom of its heterocyclic ring. IR data suggest to a unidentate coordination of carboxylates to magnesium or copper n complexes I-V. The preliminary studies have shown that the complexes do have antimicrobial activities against bacteria, yeasts and/or fungi. The highest antimicrobial activities were manifested by the complex V.     

Solvent extraction and spectrophotometric determination of uranium (VI)

Summary Solvent extraction of uranium-sodium diethyldithiocarbamate with ethylmethyl ketone and separation from titanium, zirconium, thorium, lanthanum and cerium has been described. It has been found that 11.75 to 47.00 mg of uranium can be extracted from a binary mixture containing 4.78 to 19.04 mg of titanium, 9.12 to 36.48 mg of zirconium, 116.0 to 460.0 mg of thorium, 6.95 to 27.8 mg of lanthanum or 7.06 to 28.24 mg of cerium at pH 3.0. The pH range between which the separations may be carried out successfully is 2.0 to 3.5. The following cations interfere in the separations: Cu^II, Fe^III, Co^II, Bi^III, Ni^II, Cr^VI, Te^IV, Se^IV, Ag^I, Hg^II, As^III, Sn^IV, Pb^IV, Cd^II, Mo^VI, Mn^II, V^V, Zn^II, In^III, Tl^I, W^VI, Os^VIII and Nb^V.

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Zusammenfassung Uran kann durch Extraktion als Diäthyldithiocarbamidat mit Methyläthylketon von Ti, Zr, Th, La oder Ce getrennt werden. Der günstigste pH-Bereich liegt zwischen 2,0 und 3,5. Die Trennungen wurden mit folgenden Mengen durchgeführt: U (11,75–47,00 mg); Ti (4,78 bis 19,04 mg), Zr (9,12–36,48 mg) Th (116,0–460,0 mg), La (6,95–27,8 mg), Ce (7,06–28,24 mg). Folgende Ionen verursachen Störungen: Cu^II, Fe^III, Co^II, Bi^III, Ni^II, Cr^VI, Te^IV, Se^IV, Ag^I, Hg^II, As^III, Sn^IV, Pb^IV, Cd^II, Mo^VI, Mn^II, V^VI, Zn^II, In^III, Tl^I, W^VI, Os^VIII sowie Nb^V.

     

Study on the equilibrium in the M(CH3COO)2 ? CH3OH ? H2O system (M  Mg2+, Ca2+, Ba2+) at 25°C

The complex formation and dehydration processes in the system M(CH₃COO)₂? CH₃OH? H₂O have been studied by the methods of the physico-chemical analysis at 25°C; (M = Mg²⁺, Ca²⁺ and Ba²⁺). In the Mg(CH₃COO)₂? CH₃OH? H₂O system. methanol was found to behave as a solvent in which complex formation reactions take place, including also methanolation of Mg²⁺. The fields of equilibrium existence of two new compounds have been found: Mg(CH₃COO)₂ · 3H₂O · CH₃OH and Mg(CH₃COO)₂ · 1,5 CH₃OH. In the systems M(CH₃COO)₂? CH₃OH? H₂O (M = Ca²⁺, Ba²⁺), methanol was found to react as a dehydrating reagent.