Synthesis of complex cesium hydrosulfatophosphates

Solubility of the CsH₂PO₄-CsHSO₄-H₂O system has been studied using the isothermal method (25.0°C); the compounds Cs₄(HSO₄)₃(H₂PO₄), Cs₃(HSO₄)₂(H₂PO₄), and Cs₅(HSO₄)₂(H₂PO₄)₃ have been found to form; Cs₅(HSO₄)₂(H₂PO₄)₃ has been obtained for the first time. Single crystals of the isolated phases have been grown. Their composition has been determined, and agreement between the results of studying solid phases in the CsH₂PO₄-CsHSO₄-H₂O and these single-crystal samples has been demonstrated. X-ray diffraction analysis of these phases has been carried out.     

The electrochemical reduction of an unsaturated mixed-metal cluster anion: Synthesis and x-ray crystal structure of [(Ph3P)2N][{Os3H(CO)10}2Ag]

The unsaturated mixed-metal cluster anion [{Os₃H(CO)₁₀}₂Ag]^? has been prepared by the reaction of [(Ph₃P)₂N][Os₃H(CO)₁₁] with Ag[PF₆], and the anion has been shown by an X-ray analysis to consist of an Ag^I atom linking together two “Os₃H(CO)₁₀” fragments. The electrochemistry of this complex has been investigated and it has been shown to undergo two one-electron reductions.     

Thiosemicarbazone complexes of the platinum metals. A story of variable coordination modes

Salicylaldehyde thiosemicarbazone (H₂saltsc) reacts with [M(PPh₃)₃X₂] (M = Ru, Os; X = Cl, Br) to afford complexes of type [M(PPh₃)₂(Hsaltsc)₂], in which the salicylaldehyde thiosemicarbazone ligand is coordinated to the metal as a bidentate N,S-donor forming a four-membered chelate ring. Reaction of benzaldehyde thiosemicarbazones (Hbztsc-R) with [M(PPh₃)₃X₂] also affords complexes of similar type, viz. [M(PPh₃)₂(bztsc-R)₂], in which the benzaldehyde thiosemicarbazones have also been found to coordinate the metal as a bidentate N,S-donor forming a four-membered chelate ring as before. Reaction of the Hbztsc-R ligands has also been carried out with [M(bpy)₂X₂] (M = Ru, Os; X = Cl, Br), which has afforded complexes of type [M(bpy)₂(bztsc-R)]⁺, which have been isolated as perchlorate salts. Coordination mode of bztsc-R has been found to be the same as before. Structure of the Hbztsc-OMe ligand has been determined and some molecular modelling studies have been carried out determine the reason for the observed mode of coordination. Reaction of acetone thiosemicarbazone (Hactsc) has then been carried out with [M(bpy)₂X₂] to afford the [M(bpy)₂(actsc)]ClO₄ complexes, in which the actsc ligand coordinates the metal as a bidentate N,S-donorformingafive-membered chelate ring. Reaction of H₂saltsc has been carried out with [Ru(bpy)₂Cl₂] to prepare the [Ru(bpy)₂(Hsaltsc)]ClO₄ complex, which has then been reacted with one equivalent of nickel perchlorate to afford an octanuclear complex of type [Ru(bpy)₂(saltsc-H)₄Ni₄](ClO₄)₄.     

Structural and electrical conductivity studies of Li x AlZr[PO4]3 (x = 1.8, 2.0, 2.2), solid electrolyte for lithium-rechargeable batteries

In the present study, Li _x AlZr[PO₄]₃ (x = 1.8, 2.0, 2.2) has been prepared by the Pechini-type polymerizable precursor method, and structural and electrical analyses have been performed. Formation of the compound has been confirmed from X-ray diffraction pattern. Vibrational analysis has been performed using Fourier transform infrared spectroscopy. Ion transport mechanism has been analyzed using the AC impedance technique. Electrical characterization reveals that the maximum conductivity (4.4 × 10^?5S cm^?1) has been observed for the sample Li_2.2AlZr[PO₄]₃ at 673K.     

The first ruthenium(II) complex with benzotriazole and pyridylcarboxylato ligands

The reaction of [RuCl₂(PPh₃)₃] with 1-(2-pyridylcarbonyl)benzotriazole has been examined. A new ruthenium(II) complex–[RuCl(PPh₃)₂(C₆H₅N₃)(C₅H₄NCO₂)] has been obtained and characterized by IR and UV–Vis measurements. The crystal structure of the complex has been determined. The electronic spectrum of the complex has been calculated by TDDFT method.     

Synthesis,molecular, crystal and electronic structure of [RuCl<Subscript>2</Subscript>(PPh<Subscript>3</Subscript>)<Subscript>2</Subscript>(3,5-Me<Subscript>2</Subscript>HPz)<Subscript>2</Subscript>]

The reaction of [RuCl₂(PPh₃)₃] complex with dimethylpyrazole has been examined. A new ruthenium complex—[RuCl₂(PPh₃)₂(3,5-Me₂HPz)₂] has been obtained and characterized by IR, ¹H NMR and UV-VIS measurements. Crystal and molecular structure of the complex has been determined. The electronic structure of the complex has been calculated by TDDFT method.     

The vibrational spectrum and normal coordinate analysis of chlorodifluoromethane,CHClF2

The vibrational spectrum of chlorodifluoromethane has been reexamined. The i.r. and Raman spectra of the three isotopic species, ¹²CHClF₂, ¹³CHClF₂ and ¹²CDClF₂, have been obtained with better accuracy and higher resolution than in previous work. An SCF ab initio geometry optimization and quadratic force field calculation have been performed, and this force field has been further optimized to best fit the observed frequencies. The absorption spectrum of the ν₄, 2ν₆ region has been recorded at high resolution (0.002 cm⁻¹) and an analysis of the Fermi resonance perturbation has been carried out.     

Crystallization of silico-phosphate glasses

Silico-phosphate glasses of Ca_3/2PO₄-SiO₂ and NaCaPO₄-SiO₂ systems have been the topic of our studies. Microscopic and EDX investigations which have been carried out have shown that liquation occurs only in the case of glasses belonging to the NaCaPO₄-SiO₂ system. Additionally, it has been found that there are significant differences in the chemical compositions of the matrix and the inclusions. Based on the spectroscopic investigations it has been shown that the glasses of both series are characterized by complex domain composition and the structure of domains is close to that of the corresponding crystalline phase. Interpretation of the DTA results has been based on the knowledge of the texture and the structure of the materials studied. It has been found that liquation of the glasses is a multi-step process in which the matrix and the inclusions crystallize separately. Multi-step crystallization of the glasses belonging to the NaCaPO₄-SiO₂ system has been confirmed by the high temperature XRD investigations.     

Preparation of nanostructured thin films of yttrium aluminum garnet (Y<Subscript>3</Subscript>Al<Subscript>5</Subscript>O<Subscript>12</Subscript>) by Sol—Gel technology

The synthesis of hydrolytically active heteroligand coordination compounds [M(C₅H₇O₂)_3–x(C₅H₁₁Oⁱ)_x] (where M = Al³⁺ and Y³⁺) using aluminum and yttrium acetylacetonates has been studied. The gel formation kinetics in their solutions upon hydrolysis and polycondensation has also been studied. Thin films of a solution of these precursors have been applied to polished sapphire substrates by dip coating. The crystallization of nanostructured yttrium aluminum garnet (Y₃Al₅O₁₂) films during heat treatment of xerogel coatings under various conditions has been studied. How the phase composition, microstructure, and particle size depend on the synthesis parameters has been recognized.     

Optical Properties and Solubility of Ozone in CCl<Subscript>4</Subscript> at Low Temperature

Ozone was concentrated in ССl₄ matrix at successive cooling. It has been shown that absorption spectra of ozone in ССl₄ (λ_max 258 nm) are practically identical to these in an aqueous solution. Vibrational structure typical of gaseous ozone over the Chappuis range has been retained. Position and shape of the bands for the О₃–ССl₄ system are independent of temperature. Molar absorptivity of the Chappuis band has been measured (ε₆₀₀ 8.0±0.3 M^–1 cm^–1), on the basis of which limiting solubility of ozone in the CCl₄ at 760 mmHg has been determined.     

Synthesis and characterisation of [RuCl2(PPh3)2(C16H11NO)] complex

The reaction of [RuCl₂(PPh₃)₃] complex with 1-isoquinolyl phenyl ketone has been examined. A new ruthenium(II) complexes–[RuCl₂(PPh₃)₂(C₁₆H₁₁NO)] has been obtained and characterised by IR and UV-VIS measurements. Crystal structure of the complex has been determined. The electronic spectrum of the complex has been calculated by TDDFT method.     

Cadmium vanadates of potassium,rubidium, and cesium

The solid-phase reactions between the components have been used to study the equilibrium phase composition of the systems M₂O(M₂CO₃)-CdO-V₂O₅ (M = K, Rb, or Cs) in the range of the subsolidus temperatures. New potassium cadmium vanadates KCd₃V₃O₁₁, K₂Cd₅(VO₄)₄, and K₂Cd₄V₄O₁₅ have been synthesized. A monoclinic solid solution has been identified on the basis of the KCd₄(VO₄)₃ structure. Double orthovanadate RbCdVO₄ has been prepared for the first time. Equilibrium phase diagrams have been constructed using both previously known compounds, and those synthesized by us. The effect of the size factor (the M⁺ ion radius) on the phase formation and phase equilibria in the systems in question has been traced.     

Complexation of inorganic anions by β-cyclodextrin studied by polarography and 1H NMR

Abstract

Complexation of o-chloronitrobenzene with β-cyclodextrin has been studied in 0.1 M aqueous solutions containing PF₆ ^?, ClO₄ ^?, C₂O₄ ^2-, SCN^?, SO₄ ^2- and F^? anions by a polarographic method. Using an equation which takes account of the change in the cyclodextrin concentration due to the simultaneous complexation of the anion, both stability constants have been calculated. Interaction of the ClO₄ ^? anion with β-cyclodextrin has been confirmed by ¹H NMR techniques. It has been found that the ClO₄ ^? anion is trapped in the β-cyclodextrin cavity. The stability constant has been calculated. Results of polarographic and ¹H NMR studies have been compared.     

Phase equilibria and thermodynamics of coexisting phases in rare-earth element-iron-oxygen systems. III. The europium-iron-oxygen system

X-ray and microstructural analysis methods were used to study the possibility of cationic nonstoichiometry in intermediate phases of the ferroperovskite-ferrogarnet type of the Eu₂O₃Fe₂O₃ system. It is shown that at 1350°C europium ferroperovskite has a narrow range of nonstoichiometry in the direction of excess iron oxide. The character of phase changes in the EuFeO system during changes in P_O2 has been studied; the equilibrium pressure of oxygen on ferrogarnet and magnetite has been calculated, and an equilibrium phase diagram of the type log P_O2 = f(composition) at 1473°K has been constructed. The relative stability of europium ferroperovskite and ferrogarnet has been evaluated.     

Effective IR Laser Conversion of Carbon-13 Enriched Chlorodifluoromethane to Dibromodifluoromethane

Infrared laser conversion of chlorodifluoromethane (CF₂HCl) enriched in ¹³C to 31%, to dibromodifluoromethane (CF₂Br₂) with the same enrichment has been studied. Optimum conditions have been found, and effective laser synthesis of macroscopic amounts (1 g) of CF₂Br₂ has been carried out. IR absorption spectra of synthesized CF₂Br₂ with a ¹³C concentration of 31% have been recorded. The ¹³C isotope shifts of the ν₁, ν₆, and ν₈ modes have been measured.     

Synthesis,crystal and spectroscopic characterization of [RuHCl(CO)(PPh3)2(pyrazine)]

The reaction of [RuHCl(CO)(PPh₃)₃] with pyrazine has been examined and a ruthenium(II) complex – [RuHCl(CO)(PPh₃)₂(C₄H₄N₂)] -- has been obtained. The compound has been studied by IR, UV–Vis spectroscopy, and X-ray crystallography. The molecular orbital diagram of the complex has been calculated with density functional theory (DFT). The spin-allowed singlet--singlet electronic transitions of the complex have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of the compound has been discussed on this basis.     

On the effect of low-energy ion bombardment on polystyrene and polymethylmethacrylate etch rates in rf plasmas

The effect of low-energy ion bombardment on CD₄/O₂ and CF₃X (X=F, Cl, Br) plasma etching has been assessed by applying controlled rf bias voltages on polystyrene (PS) and polymethylmethacrylate (PMMA) samples. In both cases ion bombardment has been found to have a chemical effect. In the case of CF₄/O₂ discharges, ion bombardment has been found to change the relative etching efficiency of different mixtures. In the case of CF₃X plasmas, ion bombardment has been found to alter PMMA and PS etch rates in a different way. In particular, the ratios between CF₄ and CF₃X (X=Cl, Br) etch rates of PS have been found to decrease with increasing bias voltage. This effect has been tentatively attributed to an ion bombardment-induced enhancement of the reaction between the aromatic ring and halogen molecules formed in CF₃Cl and CF₃Br discharges.     

The application of solid sorbents for the purification of aluminum contaminated chemicals used as modifiers in electrothermal atomic absorption spectrometry

Various microcolumns with solid sorbents (ion exchange resins, functionalised cellulose sorbents, chelating resins) have been tested with respect to their ability for the purification of aluminum contaminated chemicals used as modifiers in electrothermal atomic absorption spectrometry. The purification of NaNO₃, Mg(NO₃)₂, K₂SO₄ and (NH₄)₂HPO₄ has been the most effective with an almost 100% efficiency, when Spheron-Oxine was used as chelating resin. The sorption of aluminum from KOH solution has been found to be very high (around 90%) for all investigated sorbents. However, the best results have been obtained with anion-exchange resins. It has been difficult to purify concentrated mineral acids (HCl, H₂SO₄). A retention of aluminum above 80% has been achieved only when Cellex P, Chelex 100 or Amberlite XAD-2 have been used.     

An unusual oxo-bridged rhenium complex with the Re centers in different coordination environments

The reaction of the complex [ReOBr₃(PPh₃)₂] with 3,5-dimethylpyrazole (3,5-Me₂pzH) in acidified acetone at room temperature has been examined and a novel dinuclear oxocompound, [{ReOBr₄}(μ-O){ReO(3,5-Me₂pzH)₄}], has been obtained. It has been studied by IR, UV–Vis spectroscopy, magnetization measurements and X-ray crystallography. The electronic structure of [{ReOBr₄}(μ-O){ReO(3,5-Me₂pzH)₄}] has been calculated with the density functional theory (DFT) method. The spin-allowed singlet–singlet electronic transitions of [{ReOBr₄}(μ-O){ReO(3,5-Me₂pzH)₄}] have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of the title compound has been discussed on this basis.     

Low Temperature n-alkanes Bromination without Catalysts

It has been observed that Ba (BrF₄)₂ demonstrated a high reactivity towards normal alkanes from C₆H₁₄ to C₁₆H₃₄. It has been found that the reactions ran with intensive self-heating and release of elemental bromine. The GC-MS analysis showed that the main product of Ba (BrF₄)₂ interaction with each alkane was its 3-bromoderivative. The optimal interaction parameters have been found. The heat effects of the reaction have been determined by the isothermal calorimetric method, it has been found that the heat effect of the bromination increased with the increase of the length of carbon chain of alkane.