Complexation processes in KF-SbF<Subscript>3</Subscript>-H<Subscript>2</Subscript>O system studied by calorimetric titration

Complexation in a KF-SbF₃-H₂O system is studied in a range of molar ratios of fluorides KF : SbF₃= (0.1–2) : 1 by calorimetric titration. The equilibrium formation constants of complexes KSb₂F₇, KSbF₄, and K₂SbF₅ (5.8×10⁵±800, 3.3×10⁴±500, and 1.9×10⁶± 950, respectively) and the changes in enthalpy (–31.75± 0.74, –28.15±0.44, and –25.5±0.64 J mol^–1, respectively) and entropy (4±7, –8±5, and –35±9 J mol^–1 K^–1, respectively) are determined. The thermodynamic stability of the antimony(III) fluoride complexes is found to increase on going from KSb₂F₇ to K₂SbF₅.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 168–171.Original Russian Text Copyright © 2005 by Kovaleva, Zemnukhova, Lebedeva, Fedorishcheva.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Mechanism of Cp<Subscript>2</Subscript>ZrCl<Subscript>2</Subscript>-catalyzed olefin hydroalumination by alkylalanes

The composition of intermediates of the Cp₂ZrCl₂-catalyzed hydroalumination of α-olefins by isobutylalanes (HAlBuⁱ ₂, AlBuⁱ ₃, ClAlBuⁱ ₂) was studied by dynamic ¹H and ¹³C NMR pectroscopy. The reaction of Cp₂ZrCl₂ with isobutylalanes affords the complex (Cp₂ZrHCl·HAlBuⁱ ₂)₂ responsible for α-olefin hydroalumination.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 311–322, February, 2005.     

A Strong Luminescent Quaternary Dimeric Complex [Tb(BAA)<Subscript>2</Subscript>(Phen)(NO<Subscript>3</Subscript>)]<Subscript>2</Subscript>: Hydrothermal Synthesis,Structure, and Photophysics

In terms of the molecular fragment principle, a quaternary complex is assembled under hydrothermal conditions and characterized as [Tb(BAA)₂(Phen)(NO₃)]₂ (BAA is benzoyl acetic acid, Phen is 1,10- phenanthroline) by elementary analysis and IR, UV, fluorescence excitation, and emission spectra. The X-ray single-crystal diffraction data indicate that the title complex crystallizes in triclinic system, space group , with unit cell parameters a = 8.953(6), b = 13.332(9), c = 13.431(9) Å, α = 60.669(7)°, β = 89.649(8)°, γ = 72.068(9)°, V = 1309.3(15) ų, ρ(calcd) = ∼ 1.703 g/cm³, Z = 1 (per dimeric unit), F(000) = 664, GOOF = 1.071, R ₁ = 0.0627. The terbium complex forms a dimer with a coordination number of nine in which each pair of adjacent terbium ions is bridged by four BAA groups via two types of coordination modes. The dimer exhibits strong green luminescence of Tb³⁺.__________From Koordinatsionnaya Khimiya, Vol. 31, No. 6, 2005, pp. 472–478.Original English Text Copyright © 2005 by Bai, Yan, Chen.     

Synthesis of nonequilibrium Ir<Subscript>x</Subscript>Re<Subscript>1-x</Subscript> solid solutions. Crystal structure of [Ir(NH<Subscript>3</Subscript>)<Subscript>5</Subscript>Cl]<Subscript>2</Subscript>[ReCl<Subscript>6</Subscript>]Cl<Subscript>2</Subscript>

Synthesis of five binary complex salts with an [Ir(NH₃)₅Cl]²⁺ complex cation is described. The counterions are [ReCl₆]^2–, [IrCl₆]^2–, [ReBr₆]^2–, and Cl^–. A polycrystal X-ray diffraction study has been performed for [Ir(NH₃)₅Cl]₂[ReCl₆]Cl₂, and its crystal structure has been determined. A series of Ir _x Re_1–x phases (0.5 x > 1) were obtained by reductive thermolysis. For the Ir-Re system, the history of the V/Z(x) dependence has been refined.Original Russian Text Copyright © 2004 by S. A. Gromilov, S. V. Korenev, I. V. Korolkov, K. V. Yusenko, and I. A. BaidinaTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 508–515, May–June 2004.     

Specific features of the thermodynamics of activation in the LaNi<Subscript>5</Subscript>-H<Subscript>2</Subscript> and CeNi<Subscript>5</Subscript>-H<Subscript>2</Subscript> systems

Using heat conducting Tian—Calvet calorimetry and volumetric measurements, the first hydrogen absorption—desorption cycles in the LaNi₅-H₂ and CeNi₅-H₂ systems were studied. The pressure—composition isotherms were plotted, the equilibrium pressures of hydrogen along the absorption and desorption branches and in the region of hysteresis for different activation steps were determined, and the enthalpies of phase transitions α → β and β → α were calculated. The profiles of the heat evolution curves were analyzed. It was concluded that the mechanism of the reactions studied changes upon activation.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 134–139, January, 2005.     

ESR Study of the Formation of O<Stack><Subscript>2</Subscript><Superscript>−</Superscript></Stack> Radical Anions on Oxidized CeO<Subscript>2</Subscript> and CeO<Subscript>2</Subscript>/ZrO<Subscript>2</Subscript> Adsorbing a CO + O<Subscript>2</Subscript> Mixture

It is demonstrated by ESR measurements that O ₂ ⁻ (CO + O₂) radical anions result from CO + O₂ adsorption on the oxidized surface of CeO₂. These radical anions are stabilized in the coordination sphere of Ce⁴⁺ cations located in isolated and associated anionic vacancies. This reaction shows an activation behavior determined by CO adsorption. The variation of O ₂ ⁻ (CO + O₂) concentration with CO adsorption temperature suggests that surface carbonates and carboxylates participate in this reaction. In the (0.5– 10.0)%CeO₂/ZrO₂ system, O ₂ ⁻ forms on supported CeO₂ and is stabilized on Ce⁴⁺ and Zr⁴⁺ cations. The stability of O ₂ ⁻ -Ce⁴⁺ complexes is lower on supported CeO₂ than on unsupported CeO₂, indicating a strong interaction between the cerium cations and the support.__________Translated from Kinetika i Kataliz, Vol. 46, No. 3, 2005, pp. 423–429.Original Russian Text Copyright © 2005 by Il’ichev, Kuli-zade, Korchak.     

Interaction of Cl<Subscript>2</Subscript> and SO<Subscript>2</Subscript> with Finely Divided In<Subscript>2</Subscript>O<Subscript>3</Subscript>

The effect of O₂, Cl₂, and SO₂ on electrophysical and sorption properties of powdered In₂O₃ with a large specific area is studied at 23–200°C. The specimen is most sensitive to Cl₂ and SO₂ at near-room temperatures.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 529–536.Original Russian Text Copyright © 2005 by Vinokurova, Derlyukova.     

Electrochemical Synthesis of Co-intercalation Compounds in the Graphite-H<Subscript>2</Subscript>SO<Subscript>4</Subscript>-H<Subscript>3</Subscript>PO<Subscript>4</Subscript>System

Anodic oxidation of highly oriented pyrolytic graphite in an electrolyte containing concentrated sulfuric and anhydrous phosphoric acids is studied for the first time. The synthesis was carried out under galvanostatic conditions at a current I = 0.5 mA and an elevated temperature (t = 80°C). Intercalation compounds of graphite (ICG) are shown to form at all concentration ratios of H₂SO₄ and H³PO⁴ acids. The intercalation compound of step I forms in solutions containing more than 80 wt % H₂SO₄, a mixture of compounds of intercalation steps I and II forms in 60% H²SO⁴, intercalation step II is realized in the sulfuric acid concentration range from 10 to 40%, and a mixture of compounds of intercalation steps III and II is formed in 5% H₂SO₄ solutions. The threshold concentration of H₂SO₄ intercalation is ∼2%. With the decrease in active intercalate (H₂SO₄) concentration, the charging curves are gradually smoothed, the intercalation step number increases, and the potentials of ICG formation also increase. As the sulfuric acid concentration in the electrolyte changes from 96 to 40 wt %, the filled-layer thickness d _i in ICG monotonously increases from 0.803 to 0.820 nm, which apparently is associated with the greater size of phosphoric acid molecules. With further increase in H₃PO₄ concentration in solution, d _i remains unchanged. According to the results of chemical analysis, both acids are simultaneously incorporated into the graphite interplanar spacing and their ratio in ICG is determined by the electrolyte composition.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 651–655.Original Russian Text Copyright © 2005 by Leshin, Sorokina, Avdeev.     

New uranyl complex with imidazolidine-2-one [UO<Subscript>2</Subscript>(Imon)<Subscript>4</Subscript>(H<Subscript>2</Subscript>O)](ClO<Subscript>4</Subscript>)<Subscript>2</Subscript>: Structure and some properties

A complex of uranyl perchlorate with imidazolidine-2-one as the molecular ligand, [UO₂(Imon)₄(H₂O)](ClO₄)₂ (I), was synthesized and structurally characterized by X-ray diffraction analysis. The coordination number of the uranium atom is 7. The nearest environment of the uranyl ion includes four O atoms of the imidazolidine-2-one molecules and one O atom of the water molecule. The perchlorate anions are outer-sphere ligands. The crystals are monoclinic: space group P2₁/c; a = 16.294(3) Å, b = 16.135(3) Å, c = 9.987(2) Å, = 97.69 (3)°, V = 2603.0 (9) ų, (calcd) = 2.117 g/cm³, Z = 4. The IR and luminescence spectra of the complex were recorded.Translated from Koordinatsionnaya Khimiya, Vol. 30, No. 12, 2004, pp. 919–924.Original Russian Text Copyright © 2004 by Andreev, Antipin, Budantseva, Tuchina, Serezhkina, Fedoseev, Yusov.     

Magnetic properties of a dinuclear complex (2,3-Me<Subscript>2</Subscript>C<Subscript>5</Subscript>H<Subscript>3</Subscript>N)<Subscript>2</Subscript>Fe<Subscript>2</Subscript>(μ-OOCCMe<Subscript>3</Subscript>)<Subscript>4</Subscript> with “China lantern” structure

Magnetic characteristics of the dinuclear complex (2,3-Me₂C₅H₃N)₂Fe₂(μ-OOCCMe₃)₄ (1) were studied in the temperature interval 2–300 K. The magnetic behavior of complex 1 was interpreted in terms of the orbital-dependent exchange theory with allowance for the temperature dependence of the populations of the split ⁵T_2g ground-state components of the Fe^II ions. The calculated values of the orbital-dependent exchange parameters are in good agreement with the results reported for dinuclear carboxylates of other 3d-transition metals and suggest the existence of strong ferromagnetism in some types of heterodinuclear carboxylates.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2035–2039, October, 2004.     

The Emission Characteristics of Laser Plume from the PbGa<Subscript>2</Subscript>S<Subscript>4</Subscript> Crystal Surface

Averaged spectra and oscilloscope traces of emission of laser plasma in vacuum produced by the impact of neodymium laser radiation (τ = 20 ns, λ = 1.06 µm, f = 12 Hz, W =10⁸–10⁹ W/cm²) on Pb, Ga, and polycrystalline PbGa₂S₄ targets were studied. From spectroscopic diagnostic data, the electron temperature, the recombination time of singly charged ions, and the number density of electrons in the laser plume of lead gallium sulfide were determined. An analysis of the results is given.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 5, 2005, pp. 396–400.Original Russian Text Copyright © 2005 by Shuaibov, Chuchman.     

Crystal structure of Ba(VUO<Subscript>6</Subscript>)<Subscript>2</Subscript>

The crystal structure of Ba(VUO₆)₂ was determined by X-ray diffraction at 243 K: monoclinic crystal system, space group P2₁/c, unit cell parameters a=6.4992(6) Å, b=8.3803(8) Å, c=10.4235(9) Å, =104.749(2) °, Z=2. The structure contains close-packed [VUO₆] ₂ ^- layers formed by the dimers of the flattened U₂O₁₂ pentagonal bipyramids and by the dimers of V₂O₈ square pyramids. The neighboring layers are bound by the statistically distributed barium atoms.Original Russian Text Copyright © 2004 by E. V. Alekseev, E. V. Suleimanov, E. V. Chuprunov, and G. K. FukinTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 544–548, May–June 2004.     

Energetic aspects in description of metal—hydrogen—boron bonds in (B<Subscript>10</Subscript>H<Subscript>14</Subscript>)<Subscript>2</Subscript>Pt and (B<Subscript>8</Subscript>C<Subscript>12</Subscript>H<Subscript>14</Subscript>)<Subscript>2</Subscript>Pt complexes

The energies of formation of platinum complexes with borohydrides B₁₀H₁₄ and B₁₀H ₁₄ ^2- or carboranes B₈C₂H₁₄ and B₈C₂H ₁₄ ^2- were considered in terms of the structure—thermodynamics model. The thermodynamic stability of these complexes was substantiated.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 2, 2005, pp. 149–152. Original Russian Text Copyright © 2005 by Ionov, Kuznetsov.     

Ionic conduction of a high-temperature modification of Lu<Subscript>2</Subscript>Ti<Subscript>2</Subscript>O<Subscript>7</Subscript>

A nanoceramic product of the composition Lu₂Ti₂O₇ is synthesized by a coprecipitation method with a subsequent sublimation drying and an annealing at 650–1650°C. The conduction of Lu₂Ti₂O₇ synthesized at 1650°C is ionic (10^–3 S cm^–1 at 800°C). Thus, a new material with a high ionic conduction has been discovered. The ordering in Lu₂Ti₂O₇ is studied by methods of RFA, RSA, IK spectroscopy, electron microscopy, and impedance spectroscopy. The existence of a low-temperature phase transition fluorite-pyrochlore at 800°C and a high-temperature conversion order-disorder at 1650°C are established.Translated from Elektrokhimiya, Vol. 41, No. 3, 2005, pp. 298–303.Original Russian Text Copyright © 2005 by Shlyakhtina, Ukshe, Shcherbakova.     

Synthesis of Schiff bases and benzylamino derivatives containing [1-B<Subscript>10</Subscript>H<Subscript>9</Subscript>NH<Subscript>3</Subscript>]<Superscript>−</Superscript> anion

Reactions of an amino derivative of the closo-decaborate anion [1-B₁₀H₉NH₃]^– with aromatic aldehydes afforded Schiff bases [1-B₁₀H₉NH=CHAr]^– (Ar=Ph, C₆H₄-2-OMe, or C₆H₄-4-NHCOMe). The reduction of the latter with sodium borohydride gave the corresponding benzylamino derivatives [1-B₁₀H₉NH₂CH₂Ar]^–.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2004–2007, September, 2004.     

Microstructure and Conduction of Composites Bi<Subscript>2</Subscript>CuO<Subscript>4</Subscript>-Bi<Subscript>2</Subscript>O<Subscript>3</Subscript> Near the Eutectic Melting Point

Microstructure and conduction of ceramic composites Bi₂CuO₄ + xBi₂O₃ (x = 5, 10, 15, 20 wt %) near the eutectic melting point (770°C) are studied. Bismuth oxide, initially randomly distributed over the ceramics bulk, after quenching from temperatures exceeding the eutectic melting point, becomes localized at triple junctions and grain boundaries in Bi₂CuO₄, which is caused by wetting grain boundaries and forming a liquid-channel structure. The jumpwise change in the composites’ conductivity near 730 and 770°C caused by polymorphic transformation of Bi₂O₃ and the eutectic melting with simultaneous formation of a liquid-channel structure. Transport numbers of the oxygen ion are measured at 770°C by coulomb-volumetric method. The conduction by oxygen ions increases in the composites with decreasing average size of Bi₂CuO₄ crystallites.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 596–601.Original Russian Text Copyright © 2005 by Lyskov, Metlin, Belousov, Tret’yakov.     

Mononuclear manganese(II) and manganese(III) complexes of N<Subscript>2</Subscript>O donors involving amine and phenolate ligands: absorption spectra,electrochemistry and crystal structure of [Mn(L<Subscript>3</Subscript>)<Subscript>2</Subscript>](ClO<Subscript>4</Subscript>)

A number of mononuclear manganese(II) and manganese(III) complexes have been synthesized from tridentate N₂O aminophenol ligands (HL₁–HL₅) formed by reduction of corresponding Schiff bases with NaBH₄. Three types of tridentate N₂O aminophenols have been prepared by reducing with NaBH₄which are (a) Schiff bases obtained by bromo salicylaldehyde reaction with N,N-dimethyl/N,N-diethyl ethylene diamine (HL₁, HL₂), (b) Schiff bases obtained by condensing salicylaldehyde/bromo salicylaldehyde and picolyl amine (HL₃, HL₄), (c) pyridine-2-aldehyde and 2-aminophenol (HL₅). All the manganese complexes have been prepared by direct addition of manganese perchlorate to the corresponding ligands and were characterized by the combination of i.r., u.v.–vis spectroscopy, magnetic moments and electrochemical studies. The u.v.–vis spectra of all of the manganese(III) complexes show two weak d–d transitions in the 630–520 nm region, which support a distorted octahedral geometry. The electron transfer properties of all of the manganese(III) complexes (1–4 and 6) exhibit mostly similar characteristics consisting two redox couples corresponding to the Mn^III → Mn^II reductions and Mn^III → Mn^IV oxidations. The electronic effect on the potential has also been studied by changing different substituents in the ligands. In all cases, an electron-donating group stabilizes the higher oxidation state and electron withdrawing group prefers the lower oxidation state. The cyclic voltammogram of [Mn^II(L₅)₂] shows an irreversible oxidation Mn^II → Mn^III at −0.88 V, followed by another quasi-reversible oxidation Mn^III → Mn^IV at +0.48 V. The manganese(III) complex (3) [Mn(L₃)₂]ClO₄has been characterized by X-ray crystallography.     

Synthesis of hydroxyapatite by hydrolysis of α-Ca<Subscript>3</Subscript>(PO<Subscript>4</Subscript>)<Subscript>2</Subscript>

Conditions for hydroxyapatite (HAP) synthesis in aqueous solutions by hydrolysis of α-Ca₃(PO₄)₂ were studied. Temperature exerts a substantial effect on the rate of α-Ca₃(PO₄)₂ hydrolysis and also changes the morphology of the reaction products. At 40 °C, the plate-like intersecting (perpendicular to the surface of the initial particles) crystals of HAP grow. Their maximum size after the 24-h hydrolysis is 1–2 µm. Needle like HAP crystals are formed upon boiling of the suspension. The morphology observed for the HAP particles agrees well with the conclusions obtained by analysis of the kinetics of tricalcium phosphate hydrolysis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 78–85, January, 2005.     

Crystal Structure of Sodium Perchloratotriacetatoneptunate(V) Monohydrate Na<Subscript>3</Subscript>NpO<Subscript>2</Subscript>(OOCCH<Subscript>3</Subscript>)<Subscript>3</Subscript>ClO<Subscript>4</Subscript> · H<Subscript>2</Subscript>O

The crystal structure of Na₃NpO₂(OOCCH₃)₃ClO₄ · H₂O was studied by single-crystal X-ray diffraction method. The structure is composed of the complex anions NpO₂(OOCCH₃)₃]²⁻, perchlorate anions, Na cations, and water molecules. The oxygen environment of Np(V) is a hexagonal bipyramid whose equatorial plane is formed by the oxygen atoms of three acetate ions. In addition to the acetate anions, the structure contains the perchlorate ion whose oxygen atoms, except for one, are included in the coordination environment of Na⁺ cations.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 8, 2005, pp. 636–640.Original Russian Text Copyright © 2005 by Charushnikova, Fedoseev, Starikova.     

Solid Electrolytes Based on KAlO<Subscript>2</Subscript>-TiO<Subscript>2</Subscript>: The Crystalline Structure and Conduction

The structure of solid high-conductance potassium electrolytes K_{1 − x} Al_{1 − x} Ti_xO₂ (x = 0.1; 0.2) at 25 and 575°C is studied by a powder neutron diffraction analysis with the application of full-profile Rietveld analysis. Inserting titanium ions removes in potassium aluminate the phase transition at 540°C and the conductance anisotropy typical for its low-temperature form. Both structures are identical (fcc lattice, space group Fd3m). Experiment and calculation coincide best under the assumption that the potassium sublattice is disordered. The conductance increase upon inserting ions Ti⁴⁺ is due, apart from stabilization of the fcc structure, to formation of additional potassium vacancies and larger channels for the migration of potassium cations (ions Ti⁴⁺ are larger than ions Al³⁺).__________Translated from Elektrokhimiya, Vol. 41, No. 7, 2005, pp. 878–883.Original Russian Text Copyright © 2005 by Burmakin, Voronin, Akhtyamova, Berger, Shekhtman.