Polyfluorinated hydrazones in organic syntheses

The reaction of poly- and perfluoroaldehyde hydrazones with hydrazine hydrate was studied. A new preparative method for obtaining the hitherto inaccessibleN,N-unsubstituted bis-hydrazones of polyfluorinated -oxoaldehydes was developed based on this reaction.For Part 2, seeIzv. Akad. Nauk, Ser. Khim., 1995, 2465 [Russ. Chem. Bull, 1995,44, 2360 (Engl. Transl.)].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2526–2527, December, 1995.This study was financially supported by the Russian Foundation for Basic Research (Grant No. 94-03-08548) and the International Science Foundation (Grant Nos. NDL 000 and NDL 300).     

Condensed rare-earth metal-rich tellurides. Extension of layered Sc6PdTe2-type compounds to yttrium and lutetium analogues and to Y7Te2, the limiting binary member

Six isotypic R₆ZTe₂ phases have been synthesized in Ta at elevated temperatures and characterized by single crystal X-ray refinements for R=Y, Z=Rh, Pd, Ag, Y and for R=Lu, Z=Cu, Ag. All crystallize in the Sc₆PdTe₂-type structure, Pnma, Z=4, a∼21.5 Å, b∼4.1 Å, c∼11.4 Å. The results can be viewed as the replacement of Te3 atoms in the parent isotypic Sc₂Te (or in the hypothetical Y₂Te or Lu₂Te analogues) by the above the Z, the Y example giving the new binary phase Y₇Te₂. The shorter (and stronger) metal-metal bonds concentrate in the region of metal (Z, Y) substitution, as revealed by larger integrated crystal orbital Hamilton population (ICOHP) values derived from linear muffin-tin-orbital (LMTO) calculations. Partial densities-of-states data for Y₇Te₂ reflect a similar behavior. Individual R-R bond distances are seen to deviate appreciably from the more fundamental overlap population measures for each.     

Enhanced visible-light-driven photodegradation of Acid Orange 7 azo dye in aqueous solution using Fe-N co-doped TiO2

FeN -co-doped TiO₂ photocatalysts are prepared by sol–gel method using titanium tetraisopropoxide, urea and iron(II) acetylacetonate as precursors of titania, nitrogen and iron, respectively. The prepared samples are analysed from chemical-physical point of view by X-ray diffraction (XRD), Raman spectroscopy, UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), specific surface area measurements and scanning electron microscopy (FESEM). UV–Vis DRS spectra evidence that the co-doping of TiO₂ with N and Fe leads to the narrowing of the band gap value (2.7 eV) with respect to Fe-doped TiO₂ (2.8 eV) and N-doped TiO₂ (2.9–3 eV). XRD patterns show that photocatalysts are mainly in anatase phase and Fe and N ions are successfully incorporated into the TiO₂ lattice. The average crystallite size of Fe-N co-doped TiO₂ is slightly lower than the other samples and equal to about 7 nm and the specific surface area of the co-doped sample results to be 117 m² g⁻¹. Photocatalytic performances of all prepared samples are evaluated by analysing the degradation of Acid Orange 7 azo dye under visible light irradiation. Photocatalytic efficiency obtained using FeN co-doped TiO₂ strongly increases compared to undoped TiO₂, N-doped TiO₂ and Fe-doped TiO₂ photocatalysts. In detail, using the co-doped photocatalyst, dye discoloration and mineralization result equal to about 90 and 83% after 60 min of LEDs visible light irradiation, underlining the best performances of the FeN co-doped TiO₂ photocatalyst both in terms of treatment time and electric energy consumption.     

常见饮料中痕量铝的分光光度法研究

新试剂5-溴水杨基荧光酮可在pH5.5～6.8的六次甲基四胺缓冲溶液中,与铝,溴化十六烷基吡啶形成稳定的红色三元配合物。最大吸收波长约为568nm,摩尔吸光系数高达1.7×10~5L mol~(-1)·cm~1,常见金属离子很少干扰。据此,建立了测定微量铝的方法。其线性范围为0～6μg/25ml回收率在96％～103％之间。本文测定了常见饮茶,饮料及饮水中的微量铝。     

Fluorine-doped nanocrystalline SnO2 powders prepared via a single molecular precursor method as anode materials for Li-ion batteries

Fluorine-doped nanocrystalline tin dioxide materials (F:SnO₂) have been successfully prepared by the sol-gel process from a single molecular precursor followed by a thermal treatment at 450-650 °C. The resulting materials were characterized by FTIR spectroscopy, powder X-ray diffraction, nitrogen adsorption porosimetry (BET) and transmission electron microscopy (TEM). The mean particle size increased from 5 to 20 nm and the specific surface area decreased from 123 to 37 m²/g as the temperature of heat treatment was risen from 450 to 650 °C. Fluorine-doped nanocrystalline SnO₂ exhibited capacity of 560, 502, and 702 mA h/g with 48%, 50%, and 40% capacity retention after 25 cycles between 1.2 V and 50 mV at the rate of 25 mA/g, respectively. In comparison, commercial SnO₂ showed an initial capacity of 388 mA h/g, with only 23% capacity retention after 25 cycles.     

2-(8-羟基喹啉-5-磺酸-7-偶氮)-1,8-二羟基-3,6-萘二磺酸与牛血清白蛋白的相互作用

用平衡透析法和分光光度法研究了 2 (8 羟基喹啉 5 磺酸 7 偶氮 ) 1,8 二羟基 3,6 萘二磺酸与牛血清白蛋白 (BSA)在酸性溶液中的结合反应 ,认为 8Q5SAC与BSA之间的结合力是以静电引力为主的非共键作用力 ,并探讨了其结合模型。在 2 98K下 ,测得这一反应的最大结合数为 35～ 40 ,结合常数为 6 .1× 10 5L mol。还研究了溶液基本条件如酸度和离子强度等对 8Q5SAC与牛血清白蛋白分子复合物形成的影响 ,在pH =3.34条件下 ,标准工作曲线的线性范围为 0 .2 0～ 46 .90mg L。     

Peritektische Zersetzung von YBa2Cu3O7−x

During the heating of YBCO a peritectic reaction takes place at 1020C, which can be described by: 2YBa₂Cu₃O_7–xY₂BaCuO₅+L+(1-2x)/2O₂ (1) whereL = 3BaCuO₂ +2CuO is a fluid with limited amount of yttrium.It has been reported, that many parameters can influence the reaction. From one side not only the starting size of grains but also the heating rate have an influence on the resulting Y₂BaCuO₅-phase. From the other side, there is a change of the peritectical temperature caused by changing of the partial pressure of O₂ and the presence of parasitic phase.From general kinetic consideration one can draw the conclusion, that different mechanisms (nucleation, phase-boundary reaction and diffusion) can control the reaction.Using DTA/TG measurements, the peritectic reaction has been examined. Classical kinetic methods (Kissinger and Friedman) has been used. The Friedman method has given the dependence of the activation energy from reaction degree. This suggests many steps reactions. The dependence of the DTA-peaks from the heat rate suggest a parallel steps of reaction. This assumption can be motivated by evaluation of free O₂, one solid and liquid phase formation. Amount of this phases depends on the heating rate. Additionally X-ray and microscopic methods has been used. In this way was shown, that the perovskit structure is stable up to peritectical temperature and than is dramatically destroyed. From microscopic observations has been got information about shape and size of solid phase and it's creation as a function of temperature, time and starting grain size.

Die Arbeit wurde BMBF gefördert und durch Land NRW unterschtützt.     

铟(Ⅲ)-7-(1-苯偶氮)-8-羟基喹啉-5-磺酸钠的配位吸附波及其应用

在ｐＨ４．５的 ０．０１５ ｍｏｌ／Ｌ ＨＡｃ－ＮａＡｃ介质中，Ｉｎ铟（Ⅲ）－７－（１－苯偶氮）－８－羟基喹啉－５－磺酸钠（ＢＱ）在滴汞电极上于－０．６６５－０．７０ Ｖ（ｖｓ．ＳＣＥ）电位处得到络合物的吸附还原波，其一阶导数峰电流Ｉ＇ｐ与Ｉｎ（Ⅲ）浓度在４．０× １０~（－８）～３．５ × １０~（－６）ｍｏｌ／Ｌ范围内呈良好的线性关系，检测限为１．６ × １０~（－８）ｍｏｌ／Ｌ Ｉｎ（Ⅲ）．应用该法测定了铅粉和氢氧化铝样品中的微量铟，结果令人满意。对电极反应机理进行了探讨。     

Crystal Structure of (6S,9S,13R,14S)-7,8-Didehydro-3,7-dimethoxy-17-methylmorphinan-4,6-diol

1 INTRODUCTION (9S,13R,14S)-7,8-Didehydro-3,7-dimethoxy-4-hydroxy-17-methylmorphinan-6-one I is an impor- tant natural product that was used to ease pain, decrease blood pressure and diminish inflammation. In order to study the stereochemistry of the reduction of I with potassium boronhydride, the crystal structure of the title compound II was determined by X-ray diffraction method. 2 EXPERIMENTAL 2. 1 Instrument The melting point was measured on a Yanagimoto MP-500 apparatus…