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.     

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.     

Crystal structure of the synthetic analog of radtkeite Hg<Subscript>3</Subscript>S<Subscript>2</Subscript>Cl<Subscript>1.00</Subscript>I<Subscript>1.00</Subscript>

The results of structural studies of the synthetic analog of the radtkeite mineral Hg₃S₂Cl_1.00I_1.00 are analyzed. The crystal structure of the compound has been refined; the unit cell parameters are a _m = 16.827(4) , b _m = 9.117(1) , c _m = 13.165(5) , = 130.17(2)°, V = 1543.3(8) ³, space group C2/m, Z = 8, R = 0.0527. A possible transition a ₀ = a _m; b ₀ = a _m + 2c _m; c ₀ = –b _m to the pseudo-orthorhombic F cell previously determined for radtkeite, where one of the angles ( ₀ ) is slightly different from 90° (89.55°), has been found. Each sulfur atom in the structure is bonded to three mercury atoms, forming SHg₃ umbrellas with distances 2.240(6) –2.474(8) and angles HgSHg 94.7(2)°–102.9(2)°. The SHg₃ fragments are linked through Hg vertices to form corrugated [Hg₁₂S₈] layers. The halogen atoms lie inside and between the [Hg₁₂S₈] layers; the distances are Hg-Cl and Hg-I 2.783(7) , 2.961(7) , and 3.083(4) –3.311(3) , respectively.Original Russian Text Copyright © 2004 by N. V. Pervukhina, S. V. Borisov, S. A. Magarill, D. Yu. Naumov, V. I. Vasiliev, and B. G. NenashevTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 755–758, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Phase equilibria in the CdI<Subscript>2</Subscript>-Bi<Subscript>2</Subscript>O<Subscript>3</Subscript> system

The phase diagram of the system CdI₂-Bi₂O₃ is studied by means of X-ray diffraction, differential thermal analysis and measurements of the density of the material. As a result of the synthetic and peritectic interactions, two incongruently melting intermediate phases i.e. phase A — CdI₂·2Bi₂O₃ and phase B — CdI₂·4Bi₂O₃ (stable in the temperature interval 370–850°C) are formed.The phase A exists in two polymorphic forms with a temperature of the phase transition T =320–370°C. The unit cell parameters at low temperature modification of -CdI₂°2Bi₂O₃ were determined. (a=1.032 nm, b=1.046 nm, c=1.046 nm, =115.02°, =109.11° and =82.04°). The phases A and B have fields of homogeneity.The authors acknowledge thankfully the financial support for this work from the Ministry of Education and Science (Fond Scientific investigations — contract TN-1102).     

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.     

Quantum-chemical study of C<Subscript>n</Subscript>F2<Subscript><Emphasis Type="Italic">n</Emphasis>+2</Subscript> conformers. Structure and IR spectra

Quantum-chemical calculations of the geometrical structure and vibrational spectra of C_nF_2n+2 oligomers (n = 5–8) in the chain and branched conformations are reported. The lengthening of the chain of C_nF_2n+2 does not substantially affect the geometrical parameters of the oligomers. In all cases under study, the most optimal structure of the molecule is a zigzag chain with bond lengths R(C-C) = 1.53 –1.54 and R(C-F) = 1.36 –1.34 ; the chain is rolled into a helix, which makes an angle of 17° with the plane. The IR spectra are sensitive to the structural deficiency of oligomers C_nF_2n+2 associated with the lateral trifluoromethyl groups formed in the chain; the spectra can be used for revealing defects of this type in the structure of polytetrafluoroethylene (PTFE). The possibility of defects associated with the lateral CF₃ groups in the structure of PTFE and its low-temperature modifications is explained based on the calculated total energies of C_nF2 _n+2.Original Russian Text Copyright © 2004 by L. N. Ignatieva, A. Yu. Beloliptsev, S. G. Kozlova, and V. M. BuznikTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 632–643, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

An <Emphasis Type="Italic">ab initio </Emphasis> Quantum-Chemical Study of C<Subscript>6</Subscript>H<Subscript>5</Subscript>S(O)CH<Subscript>3</Subscript> and C<Subscript>6</Subscript>H<Subscript>5</Subscript>S(O)CF<Subscript>3</Subscript>

The potential functions of internal rotation around the C -S bond in the C₆H₅S(O)CH₃ and C₆H₅S(O)CF₃ molecules were obtained by ab initio MP2(full)/6-31+G* calculations. The stationary points were identified by solving the vibrational problems. The structures in which the plane of the C -S-C bonds is approximately perpendicular to the benzene ring plane correspond to the energy minimum. The barriers to rotation around the C -S bond, corrected for the zero-point vibration energy, are 21.29 [C₆H₅S(O)CH₃] and 28.98 [C₆H₅S(O)CF₃] kJ mol⁻¹. The bond angles (deg) are as follows: 95.7 (CSC), 107.1 (C SO), 106.3 (C SO) in C₆H₅S(O)CH₃; 93.5 (CSC), 108.2 (C SO), 105.2 (C SO) in C₆H₅S(O)CF₃. The bond lengths are as follows (Å): 1.520 (S=O), 1.804 (C -S), 1.810 (C -S) in C₆H₅S(O)CH₃; 1.507 (S=O), 1.799 (C -S), 1.870 (C -S) in C₆H₅S(O)CF₃. According to the results of NBO calculations, the formally double S=O bond consists of a strongly polarized covalent σ bond (S→O) and an almost ionic bond. An increase in the S=O bond multiplicity relative to a single bond is mainly due to hyperconjugation by the mechanism n(O)→σ*(C -S) and n(O)→σ*(C -S) and, to a lesser extent, by interaction of the oxygen lone electron pairs with the Rydberg orbitals of the S atoms, characterized by a large contribution of the d component.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 1, 2005, pp. 96–104.Original Russian Text Copyright © 2005 by Bzhezovskii, Il’chenko, Chura, Gorb, Yagupol’skii.     

Interatomic interactions and electronic structure of NbSe<Subscript>2</Subscript> and Nb<Subscript>1.25</Subscript>Se<Subscript>2</Subscript> nanotubes

Atomic models of achiral NbSe₂ nanotubes are suggested. Band structure calculations have been performed to investigate the electronic structure and determine the parameters of interatomic interactions. The distribution of the density of states and pair bond occupancies of NbSe₂ nanotubes are analyzed in relation to the type of the atomic configuration and the tube diameter; the results are compared with the band structure of the 2H-NbSe₂ crystal. Calculations have been carried out on hypothetical superstoichiometric nanotubes with a formal composition Nb_1.25Se₂ as possible quasi-one-dimensional nanoforms of autointercalated niobium diselenide.Original Russian Text Copyright © 2004 by A. N. Enyashin, V. V. Ivanovskaya, I. R. Shein, Yu. N. Makurin, N. I. Medvedeva, A. A. Sofronov, and A. L. IvanovskiiTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 579–588, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Thermodynamic characteristics of the system NaNO<Subscript>2</Subscript>-NaNO<Subscript>3</Subscript>

The activities and activity coefficients of the components of the system NaNO₂-NaNO₃, obtained from experimental saturated vapor pressures measured at 798, 823, and 848 K, were used to calculate the total and excess partial molar Gibbs energies , , entropies , , and total relative and excess thermodynamic properties G, G ^ex, S, S ^ex of the system.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004, pp. 1747–1749.Original Russian Text Copyright © 2004 by Glazov, Dukhanin, Dkhaibe, Losev.     

Low-dimensional compounds containing cyano groups. IX. Preparation,structure and properties of the [Cu(bpy)<Subscript>2</Subscript>(dca)]CF<Subscript>3</Subscript>SO<Subscript>3</Subscript> complex

The ionic [Cu(C₂N₃)(C₁₀H₈N₂)₂](CF₃SO₃) compound, which contains two crystallographic independent formula units, is formed by [Cu(bpy)₂(dca)]⁺ complex cations (bpy=2,2-bipyridine, dca=dicyanamide) and uncoordinated CF₃SO ₃ ^– anions, which are in a staggered conformation. The shapes of coordination polyhedra around both copper atoms, which are fivefold coordinated by two bpy molecules and one dca ligand monodentately coordinated through a cyano N atom in the equatorial plane at a distance of 2.001(3)Å for the first and 1.988(4)Å for the second polyhedron, are distorted trigonal bipyramids. Besides the ionic forces the structure is stabilized by weak C–H...O hydrogen bonds and possible – interactions between pyridine rings of bpy molecules. Along with the structural-spectral correlation we discuss the thermal decomposition of the title complex.     

Structure of Zn<Subscript>3</Subscript>P<Subscript>2</Subscript>

The structure of Z_n3P₂ (P 4₂/nmc, a = b = 8. 0785 Å, c = 11. 3966 Å) was solved and refined to R = 3. 2% in a precision X-ray diffraction experiment (λ-MoK _a, graphite monochromator on a primary beam, 27,496 reflections) . Interatomic distances and bond angles have been determined. The fcc lattice of the structure is built from phosphorus atoms, and the zinc atoms occupy 3/4 of all tetrahedral voids; the structure is described by two equivalent models where 1/4 occupied (by zinc atoms) and 1/4 vacant voids change places. The zinc atoms that occupy the voids following the diamond principle do not change places.Original Russian Text Copyright © 2004 by I. E. Zanin, K. B. Aleinikova, M. M. Afanasiev, and M. Yu. Antipin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 889–892, September–October, 2004.     

<Emphasis Type="Italic">Ab initio</Emphasis> structural study of M(mda)<Subscript>2</Subscript> complexes (M = Be,Mg, Ca; mda = C<Subscript>3</Subscript>O<Subscript>2</Subscript>H<Subscript>3</Subscript>)

The structure of M(mda)₂ (M = Be, Mg, Ca; mda = C₃O₂H₃) bis-complexes was investigated by the ab initio Hartree-Fock method and by including electron correlation in terms of second order Möller-Plesset perturbation theory; for calculations we used triple-zeta valence basis sets complemented with polarization functions. Two most probable geometrical nuclear configurations (D _2h and D _2d ) are considered for each molecule. The structure with two mutually orthogonal chelate ligands (D _2d symmetry) corresponds to the potential energy surface (PES) minimum. The planar D _2h configuration corresponds to the first order saddle point on PES; consequently, its relative energy determines the height of the barrier to the D _2d D _2h D _2d intramolecular rearrangement. Correlation equations that relate the calculated values of equilibrium internuclear distances, force constants, and rearrangement barrier heights to the value of the ionic radius of the metal atom have been obtained. These correlations were employed to evaluate the molecular constants for Sr(mda)₂ and Ba(mda)₂. The theoretical data are compared with the available experimental literature data.Original Russian Text Copyright © 2004 by V. V. Sliznev, S. B. Lapshina, and G. V. GirichevTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 611–623, July–August, 2004This revised version was published online in April 2005 with a corrected cover date.     

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 and Structure of the Copper(II) Complex with <Emphasis Type="Italic">ortho</Emphasis>-Phthalic Acid and 1-Methylimidazole [Cu(HPht)<Subscript>2</Subscript>(1-CH<Subscript>3</Subscript>Im)<Subscript>2</Subscript>]

A new Cu(II) complex [Cu(HPht)₂(1-CH₃Im)₂] (I), where HPht is the monoanion of o-phthalic acid and 1-CH₃Im is 1-methylimidazole, is synthesized and characterized by IR spectroscopy, thermogravimetry, and X-ray diffraction analysis. Compound I contains molecular complexes in which the o-phthalic acid residue is monodeprotonated and linked to a metal through the carboxyl group in a 1,3-chelate mode. The cis-octahedral coordination of copper is formed by two HPht residues and two 1-CH₃Im molecules. The distances are Cu-N1.945(6) Å, Cu-O2.018(5) Å and 2.374(6) Å. Polymeric chains are formed in complex I due to intermolecular hydrogen bonds. The chains are unified into layers by the interactions between the 1-CH₃Im molecules of the adjacent complexes.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 8, 2005, pp. 630–635.Original Russian Text Copyright © 2005 by Gherco.     

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.     

On the initiation of combustion of O<Subscript>2</Subscript>-O<Subscript>3</Subscript> mixtures in the course of laser-induced asymmetrical ozone vibrations

The kinetics of ignition of O₂-O₃ mixtures upon the excitation of O₃ molecules by laser radiation with a wavelength #x03BB;_I of 9.695 µm is considered. The stimulation of asymmetrical vibrations of O₃ molecules was shown to produce more efficient dissociation of O₃ molecules, faster heating of the mixture, and, as a consequence, a decrease in the induction time and ignition temperature. Even when the energy of radiation applied to the gas is low (E _in 0.15 J/cm²), the ignition temperature of pure ozone can be reduced from 520 to 300 K at a pressure of 10³ Pa.Translated from Kinetika i Kataliz, Vol. 45, No. 6, 2004, pp. 897–903.Original Russian Text Copyright © 2004 by Lukhovitskii, Starik, Titova.     

Reactions in AB<Subscript>5</Subscript>-NH<Subscript>3</Subscript> systems

Treatment of intermetallic compounds LaNi₅ and SmCo₅ with ammonia (initial ammonia pressure 0.6– 0.7 MPa) in the presence of 10 wt% NH₄Cl as an activator results in hydrogenation of these compounds or, in the case of SmCo₅, in disproportionation to form Sm₂Co₇H_x. In some cases, the intermetallic matrix decomposes under this treatment.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1765–1769.Original Russian Text Copyright © 2004 by Fokin, Shulga, Tarasov, Fokina, Korobov, Burlakova, Shilkin.This revised version was published online in April 2005 with a corrected cover date.     

Nitration of phenylpropiolic acid derivatives in HSO<Subscript>3</Subscript>F and reactions of vinyl type cations formed therefrom

Nitration of phenylpropiolic acid derivatives ArCCX (X=CN, CO₂Me) in HSO₃F at –75...–50°C afforded mononitro compounds, for instance, m-O₂NC₆H₄CCX. Vinyl type cations generated in HSO₃F from methyl 3-arylpropiolates ArC⁺=CHCO₂Me react along two pathways. The first among them results in formation of fluorosulfonates ArC(OSO₂F)=CHCO₂Me, and the second one after the attack of vinyl cation on the aryl moiety of the substrate affords a dimer that on nitration is converted into a nitro product with conserved triple bond.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 11, 2004, pp. 1665–1677.Original Russian Text Copyright © 2004 by Savechenkov, Rudenko, Vasilev.     

Magneto-optic and luminescent properties of tellurite glass TeO<Subscript>2</Subscript>-ZnCl<Subscript>2</Subscript> doped with rare-earth elements

Tellurite glasses were synthesized on the basis of the binary system composed of 70 mol % TeO₂ and 30 mol % ZnCl₂ and doped with Nd³⁺, Pr³⁺, Tb³⁺, Er³⁺, Yb³⁺, Ho³⁺. The physicochemical, luminescent, and magneto-optic properties of these glasses were studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 8, 2004, pp. 1262–1265.Original Russian Text Copyright © 2004 by Grishin, Gurev, Intyushin, Elliev, Pavlova, Savikin.     

Surface acid sites of H<Subscript>3</Subscript>PW<Subscript>12</Subscript>O<Subscript>40</Subscript> as studied by the adsorption of stable nitroxyl radicals

The surface acidity of H₃PW₁₂O₄₀ and Na_xH_3-xPW₁₂O₄₀(x = 1-3) was studied using the adsorption of 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (TEMPON) and 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (TEMPOL) radicals. It was found that the amount of surface proton sites determined from the adsorption of TEMPON decreased with the degree of substitution of Na⁺ cations for protons. A correlation between amount of strong surface proton sites and catalytic activity of Na_xH_3-xPW₁₂O₄₀(x = 0-3) in the dealkylation reaction of 2,6-di-tert-butyl-4-methylphenol was found.Translated from Kinetika i Kataliz, Vol. 46, No. 1, 2005, pp. 131–136.Original Russian Text Copyright © 2005 by Timofeeva, Ayupov, Volodin, Pak, Volkova, Echevskii.