Prepared Low Stress Cubic Boron Nitride Film by Physical Vapor Deposition

We present low stress cubic boron nitride (cBN) films with a transition layer deposited on the metal alloy substrates by tuned substrate radio-frequency magnetron sputtering. The films were characterized by Fourier transform infrared spectroscopy and transmission electron microscopy (TEM). The IR peak position of cubic boron nitride at 1006.3 cm⁻¹, which is close to the stressless state, indicates that the film has very low internal stress. The TEM image shows that pure CBN phase exists on the surface of the film. Several phases of boron nitride were found at the medium implantation dose. It is believed that the transition from the low ordered phases to cBN phase occurred during implantation.     

The effect of the exchangeable metallic cation on the colloid properties of laponite treated with acridine orangea spectrophotometric study

The adsorption of the cationic dye acridine orange (AO) by different monoionic laponites leads to changes in the colloid properties of this synthetic mineral in aqueous solutions. The organic cation is adsorbed by the mechanism of cation exchange. Small amounts of adsorbed dye keep the clay in a peptized state with all metallic cations. Greater amounts of AO result in the neutralization of the electric charge of the clay, and its flocculation. In excess AO the charge of the clay platelets becomes positive and the clay is peptized. The colloid properties are studied by absorbance curves in which the absorbance is described as a function of the degree of saturation with constant clay concentrations or with constant dye concentrations. In the absorbance curves three regions can be identified. The transition between the first and second or the second and third regions depend on the exchangeable metallic cation initially present in the clay. The spectrophotometric method is useful in identifying the presence of tactoids and flocculation mechanism, whether it results in card-house or in book-house flocs.     

Structure of the 18-Crown-6 Complex with Ammonium Hexafluorosilicate and Water

The crystalline host–guest type complex [(18-crown-6NH₄)₂][SiF₆]4H₂Ohas been obtained as the result of the interaction of SiF₄2NH₃ with 18-crown-6 (18C6) in an aqueous medium. Crystal data: monoclinic, space groupC 2 c, a=26.541(2), b=8.363(2), c=20.469(2) Å, = 122.43(1)°and Z=4. The final R-value is 0.070 for 3253 reflections with I 2(I).The crystals consist of the complex [NH₄18C6]⁺ cations, [SiF₆]^2-anions and water molecules. The ammonium cation is hydrogen bonded by three of its H-atoms to the crown ether oxygen atoms with N(1) O separations2.923(5)–2.940(5) Å and by the fourth H-atom to the fluorine atom of thehexafluorosilicate anion, the N(1)F(4) distance being 2.797(6) Å.The conformation of the macrocycle and the hydrogen-bond geometry in thecomplex cation closely resemble those in related adducts between 18-crown-6and ammonium salts. All crystal components are connected via a system of hydrogen bonds into a ribbon along the b axis in the unit cell.     

Extraction-spectrophotometric study on the vanadium(V)-2,3-dihydroxynaphthalene — iodonitrotetrazolium chloride — water — chloroform system and its analytical application

The formation of a new ternary ion-associate complex of vanadium(V) with 2,3-dihydroxynaphthalene and iodonitrotetrazolium chloride with a composition ratio of 1:2:1 is reported. The complex is quantitatively extracted from water into chloroform. The molar absorptivity (ɛ) of the extract at λ _max=340 nm is 2.5 × 10⁴ dm³/mol cm, and Beer’s law is obeyed for concentrations ranging from 0.1 to 0.9 μg/cm³ V(V). The following constants are determined: the extraction constant, the association constant, the distribution constant, and the recovery factor. The effects of foreign ions and reagents are studied. A selective and sensitive method is developed for determination of vanadium in steels.     

含有羧基配体的蝎型钒氧配合物的合成、结构及其热分解动力学

设计合成了两种新型的以聚吡唑硼酸盐、氨基酸为配体的钒氧配合物VO[phCH2CH(NH2)COO][HB(pz)3](1)和VO(3,5-Me2pz)[HB(3,5-Me2pz)3](CH3COO)(2). 通过元素分析、红外光谱对配合物进行了表征, 并利用单晶X射线衍射技术解析了它们的结构. 非等温热分解动力学研究表明, 配合物1和2的热分解反应都是分两步进行的. 通过计算, 配合物1热分解的第一步反应的可能机理为成核与生长(n=1/4); 第二步反应的可能机理为化学反应. 其非等温动力学方程分别为, dα/dT=(A/β)e-E/RT(1/4)(1-α)[-ln(1-α)]-3 和dα/dT=(A/β)e-E/RT(1-α)2. 分解反应的表观活化能分别是223.52 和331.94 kJ·mol-1; 指前因子ln(A/s-1)分别是49.67 和57.50. 配合物2 热分解的第一步反应的可能机理为化学反应; 第二步反应的可能机理为成核与生长(n=1/2). 其非等温动力学方程分别为, dα/dT=(A/β)e-E/RT(1-α)2, 和dα/dT=(A/β)e-E/RT(1/2)(1-α)[-ln(1-α)]-1. 分解反应的表观活化能分别是300.56 和444.72 kJ·mol-1; 指前因子ln(A/s-1)分别是75.53 和92.50.     

New organic metals: Radical cation salts of bis(ethylenedioxo)tetrathiafulvalene with halide mercurate anions

Radical cation salts with halide mercurate anions were obtained by the electrochemical oxidation of bis(ethylenedioxo)tetrathiafulvalene (BEDO-TTF), and their conductivity was studied. The compounds (BEDO-TTF)₄Hg₃X₈ (X = Cl or Br), (BEDO-TTF)₄Hg_3.5I₉, and (BEDO-TTF)₂HgBr₃ possess the conductivity of the metallic type down to helium temperatures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1167–1170, May, 1996.     

Cation recognition by new diester- and diamide-calix[4]arenediquinones and a diamide-benzo-15-crown-5-calix[4]arene

The synthesis, metal, ammonium and alkyl ammonium cation coordination chemistry and electrochemical recognition studies of new diester-and diamide-calix[4]arenediquinone receptors are described. In addition the synthesis and coordination properties of a novel diamide benzo-15-crown-5-calix[4]arene molecule is reported.This paper is dedicated to the commemorative issue on the 50th anniversary of calixarenes.     

Theoretical study of the thermal interconversion mechanism between the norbornadiene and quadricyclane radical cations

Geometry optimizations at the UHF/6-31G^* and UMP2/6-31G^* levels of theory were performed to find the transition state in the interconversion between norbornadiene (N) and quadricyclane (Q) radical cations. Two transition structures, TS^+·₁ and TS^+·₂, were obtained which have C₁ and C₂ symmetry, respectively. Vibrational analysis at the UHF and UMP2 levels of theory and IRC calculation showed that TS^+·₁ is the true transition state connecting N^+· and Q^+·, while TS^+·₂ is a second order saddle point.     

Non-empirical INDO-MO calculations on some vanadium(IV) halides

ODIN, a non-empirical INDO-MO scheme, has been used to determine the ground state electronic configurations for the tetrahedral molecules, VCl₄ and VBr₄. A ² E ground state was obtained for both molecules. The Photoelectron spectrum and the electronic spectrum have been calculated for VCl₄, and a satisfactory correlation with the corresponding experimental data was made. Also, ODIN was employed to evaluate electronic transition energies and the photoelectron spectrum of VBr₄.     

Two parameter donor-acceptor approach to solvent effects on the electrode kinetics of cations

A two parameter approach to solvent variations in the electroreduction rate constants of cobalt complexes and europium cations is presented and discussed in terms of solvent—solute and solvent—solvent interactions.

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Ein Zwei-Parameter Donor-Acceptor-Ansatz für Lösungsmitteleffekte bei der Elektrodenkinetik von Kationen (Kurze Mitteilung)

Zusammenfassung Es wird eine Zwei-Parameter-Annäherung der Lösungsmitteleinflüsse auf die Geschwindigkeitskonstanten der Elektroreduktion von Kobalt-Komplexen und Europium-Kationen präsentiert und auf der Basis von Lösungsmittel—gelöster Stoff- und Lösungsmittel—Lösungsmittel-Wechselwirkung diskutiert.