钨酸钠/过氧化氢体系对葡甲苷伯羟基的选择催化氧化

采用钨酸钠/过氧化氢体系对甲基葡萄糖苷的伯羟基进行选择催化氧化制备葡萄糖醛酸及其内酯,考察了不同催化氧化工艺条件对反应收率的影响,产物用HPLC检测,同时对反应机理进行了初步探讨。 结果表明, 该体系对葡甲苷伯羟基的氧化具有较好的催化活性和反应选择性,葡萄糖醛酸及其内酯总收率可达到74.07%。 与传统的淀粉硝酸氧化法工艺相比,该方法具有资源节约、环境友好的特点。     

Synthesis and Structure of a New Mixed-polyoxometalate （W/Mo） Compound： H5K{[Co（H2O）5]2（H2Mo3.24W8.76O42）}·19H2O

One new polyoxometalate compound connected via cobalt/potassium cations,namely H5K{[Co（H2O）5]2（H2Mo3.24W8.76O42）}·19H2O 1,was prepared and characterized by ele- mental analysis and IR spectroscopy. Single-crystal X-ray diffraction analysis result reveals that anions of {[Co（H2O）5]2（H2Mo3.24W8.76O42）}6- in compound 1 are linked by potassium cations to form one- dimensional chain,based on which a three-dimensional network is further constructed with the help of hydrogen bonds. Crystal data： H67Co2KMo3.24O72W8.76,Mr = 3297.87,monoclinic,C2/c,a = 19.0126（10）,b = 16.6025（5）,c = 19.1908（10）A,β = 106.713（1）°,V = 5801.8（5） A^3,Z = 4,Dc = 3.755 g/cm^3,F（000） = 5961,μ = 18.730 mm^-1,R = 0.0569 and wR = 0.1437 （I 〉 2σ（I））.     

W-SBA-15介孔分子筛的直接合成及其对环己烯环氧化反应的催化性能

 分别以Na2WO4和H2WO4为钨源,以正硅酸四乙酯为硅源直接合成了W-SBA-15介孔分子筛样品,并用小角XRD,N2吸附,FT-IR,UV-Vis,SEM和XRF等手段对合成的分子筛进行了表征. 结果表明,只用P123(EO20PO70EO20)为模板剂时,分子筛中钨的含量只是投料量的一半; 而以P123和十六烷基三甲基溴化铵为混合模板剂时,钨能有效地掺杂到SBA-15分子筛中. 当原料中的Si/W摩尔比为40时,W-SBA-15分子筛中的钨物种以高度分散状态存在,且以H2WO4为钨源比以Na2WO4为钨源更易将钨掺杂到SBA-15介孔分子筛中. W-SBA-15分子筛催化剂对环己烯环氧化反应具有较高的催化活性.     

A quantitative study of sodium tungstate protective effect on pancreatic beta cells in streptozotocin-induced diabetic rats

Diabetes is a major public health problem. Development of new therapies that are able to improve glycemia management, cure diabetes, and can even protect from it, are of great interest. This study investigated the protective effect of sodium tungstate against STZ-induced beta-cell damages by means of stereological methods. Sixty rats were divided into six groups: control (C), tungstate-treated control (TC), STZ-induced diabetic (D), STZ-induced diabetic rats were treated by sodium tungstate from 1 week before STZ injection (TDB), food-restricted diabetic (FRD), and diabetic rats treated with sodium tungstate 1 week after STZ administration (TDA). Stereological estimation of pancreas volume, islets volume density, volume-weighted mean islets volume and mass of beta cells, islets, and pancreas and total number of islets were done. Islets volume density, volume-weighted mean islets volume, and mass of beta cells, islets, and pancreas of TDB group was significantly higher than D, FRD and TDA groups (P < 0.001) and was comparable to controls (C and TC groups). Total number of islets, pancreas wet weight and volume did not show any significant changes between these groups (P > 0.05).Results suggested that sodium tungstate preserves pancreatic beta cells from STZ-induced damages and diabetes induction in rats.     

白钨矿结构的钨,钼酸盐晶体的光吸收边及其起因

比较了一些白钨矿结构的钨，钼酸盐晶体（如未掺杂的ＣａＷＯ４，ＰｂＷＯ４，ＣａＭｏＯ，ＰｂＭｏＯ４晶体）的透射光谱，发现这些晶体的光吸收边的相对位置用普遍认为的观点，即白钨矿结构的钨，钼酸盐晶体的光吸收边起源于具有Ｔｄ对称性的Ｗ（Ｍｏ）Ｏ＾２－４基团的电子从ｔ１轨道的２ｅ轨道的转移激发，不能给出了圆满阐释，而应代之以新的观点，作者认为这类晶体的光吸收可能起因于Ｄ２ｄ对称的Ｗ（Ｍｏ）Ｏ＾２－４基团内的     

基于钨酸镍与氧化锌复合材料的电化学传感平台检测吲哚美辛EI北大核心CSCD

采用一锅法制备了钨酸镍与氧化锌复合材料(NiWO_(4)-ZnO),并对其进行了形貌表征、元素分析及比表面积测试,构筑了一种吲哚美辛电化学传感器。研究发现,NiWO_(4)-ZnO复合材料修饰玻碳电极对吲哚美辛表现出较高的检测灵敏度,在最优的实验条件下,吲哚美辛浓度与氧化峰电流成正比,在250~1082 pmol/L范围内呈现良好的线性关系,线性相关系数为0.9970,检出限为66.6 pmol/L。吲哚美辛电化学传感器应用于实际样品中吲哚美辛的测定,回收率为95.1%~98.3%,相对标准偏差为2.3%~3.8%,该传感器可用于药物分析领域。     

Some contribution to W(VI)-peroxo-chemistry: Synthesis,spectroscopic characterization,reactivity and DFT studies

Synthesis of white microcrystalline oxodiperoxotungstate(VI) complexes, K[WO(O₂)₂(L)(H₂O)]·H₂O, (L ?= ?salicylate, 5-chlorosalicylate, 4-hydroxybenzoate) have been achieved from reaction of Na₂WO₄·2H₂O with 30% H₂O₂ and the respective hetero-ligands at pH Ca. 7–7.5 in aqueous medium. The newly synthesized compounds were comprehensively characterized by elemental analyses, spectral studies, room temperature magnetic moment measurements and mass spectrometric studies. Infrared spectra suggest that, peroxo groups are bonded to the WO⁺⁴ center in a triangular bidentate (C_2v) fashion and the hetero-ligands benzene-core hydroxycarboxylic acids viz. salicylic acid, 5-chlorosalicylic acid, 4-hydroxybenzoic acid in anoinic form are coordinated in monodentate manner. Compounds are fairly stable in aqueous solution for sufficient period of time. The results of mass spectrometric analysis lend support to the molecular composition of the complexes ascertained on the basis of elemental analyses and spectroscopic studies. Compound potassium(aquo)(5-chlorosalicylato)oxodiperoxotungstate(VI)monohydrate, K[WO(O₂)₂(5-chlorosalicylate)(H₂O)]·H₂O, act as an oxidant of bromide ion in aqueous phase bromination of chosen organic substrates to their corresponding bromo organics. Density Functional Theory (TD-DFT) calculations were performed on the synthesized complexes substantiated the experimentally obtained results. The TD-DFT optimized structures are in excellent agreement with the results of elemental analyses, spectral as well as mass spectrometric data.     

Corrosion inhibition of AISI 1020 steel based on tungstate anion and amoxicillin as corrosion inhibitors in 0.05 mol l−1 NaCl solution or inserted into cellulose acetate films

Sodium tungstate and amoxicillin were used separately or combined in a solution containing 0.05 mol l^?1 NaCl or inserted into cellulose acetate films as a corrosion inhibition method for American Iron and Steel Institute (AISI) 1020 steel. The electrochemical behavior of AISI 1020 steel was characterized using open‐circuit potential, anodic polarization and electrochemistry impedance spectroscopy. The inhibitor effect of tungstate anions was proved, and its combination with amoxicillin was considered inferior when tungstate was used alone. This behavior was attributed to weaker adsorption of amoxicillin when compared with the adsorption of tungstate anion both deposited on the alloy and into the cellulose acetate film on the steel. Copyright © 2014 John Wiley & Sons, Ltd.     

水热法合成CaWO4荧光体的研究

钨酸钙是X射线和紫外线常用的发光材料,通常都用高温固相反应法合成,我们曾研究过用微波热法合成[1].水热法是合成无机微孔材料、快离子导体等物质的重要方法,但用来合成荧光体仍少有报道.     

Synthese und Struktur von Cs11[(WN2,5O1,5)2](N3)2, ein Caesiumoxonitridomonowolframat(VI)-azid

Synthesis and Structure of Cs₁₁[(WN_2,5O_1,5)₂](N₃)₂, a Cesium Oxo Nitrido Monotungstate(VI) Azide Cs₁₁[(WN_2,5O_1,5)₂](N₃)₂ results from the reaction of a mixture of CsNH₂, W and WO₃ at 620 °C in autoclaves. It crystallizes monoclinic in the space group C2/m with the lattice parameters a = 12.421(4) Å, b = 11.568(6) Å, c = 10.516(4) Å, β = 118.71(3)° and Z = 4. The crystal structure is built up by isolated tetrahedra [WX₄] with X = N, O, which are connected by cesium cations. Between the cesium ions lie azide ions separated from the anions [WX₄]. The tungsten atoms and azide ions together build up the motif of a distorted arrangement of the CsCl structure type.