A copper- and amine-free sonogashira reaction employing aminophosphines as ligands

An efficient Pd-catalyzed Sonogashira coupling reaction was achieved in the absence of a copper salt or amine with an inorganic base and easily prepared, air-stable aminophosphine ligands in commonly used organic solvents; good to excellent yields were obtained. Under optimized reaction conditions, the Sonogashira coupling reaction occurred selectively when an enyne substrate was employed and no Heck reaction product was detected; acetone-masked acetylene and trimethylsilylacetylene can also be efficiently coupled, providing a method to make terminal alkynes.     

Formation of nanostructured polymer filaments in nanochannels

We describe the use of hard etching methods to create nanodimensional channels and their use as templates for the formation of polymer filament arrays with precise dimensional and orientational control in a single integrated step. The procedure is general as illustrated by the radical, coordination, and photochemical polymerizations that were performed in these nanochannels. The nanochannel templates (20 nm high, 20-200 nm wide, and 100 mum long) were fabricated by the combined use of electron-beam lithography and a sacrificial metal line etching technique. Radical polymerization of acrylates, metal-catalyzed polymerization of norbornene, and photochemical polymerization of 1,4-diiodothiophene were carried out in these nanochannels. The polymers grown follow the dimensions and orientation of the channels, and the polymer filaments can be released without breaking. The approach opens up the possibility of just-in-place manufacturing and processing of patterns and devices from nanostructured polymers using well-established polymer chemistry.     

Electropherograms in capillary zone electrophoresis plotted as a function of the quantity of electric charge

We have plotted electropherograms in capillary zone electrophoresis (CZE) as a function of the quantity of electric charge (Q) in order to eliminate the dependency of the analyte peak areas, as well as that of the migration times, upon both the capillary temperature and the applied voltage. The procedure is based on an idea of a migration index (MI) and an adjusted migration index (AMI) which were originally proposed by Lee and Yeung. The value of Q is measured accurately and calculated easily because it is given by a product of the electrophoretic current and the migration times, where the index MI is derived by dividing the value of Q by the effective volume of the capillary. By calculating the CZE peak area from the newly plotted electropherogram, improvement in precision in quantitative analysis is expected. Concerning AMI, careful treatment is required in its application to analyte peaks whose migration time is close to that of the neutral marker. Experimental data and discussions concerning the migration indices are presented.     

Dawson结构钨钒磷杂多化合物催化苯酚过氧化氢的羟化作用及其羟化机理

合成了系列Ｄａｗｓｏｎ结构钨钒磷杂多化合物（Ｃｐｙｒ）７＋ｎＰ２Ｗ１８－ｎＶｎＯ６２（ｎ＝１～３），并用ＩＲ，ＮＭＲ等手段对其结构进行了表征．考察了这类杂多化合物对苯酚过氧化氢的羟化活性，探讨了反应机理．     

丙氨酰-谷氨酰胺的简便有效合成

谷氨酰胺 (Ｇｌｎ)是肠道必需氨基酸 ,是肠粘膜细胞氧化的重要燃料。肠粘膜缺乏Ｇｌｎ将严重损伤肠屏障功能 ,创伤性休克及化疗应激可加重损害 ,导致肠粘膜萎缩 ,肠道细菌移位 ,甚至促发脓毒症和多器官功能不全 (ＭＯＤＳ) [1] 。但Ｇｌｎ性质不稳定 ,不能耐高温消毒 ,因此 ,一般氨基酸制剂不含Ｇｌｎ。Ａｌａ Ｇｌｎ为Ｇｌｎ代谢前体 ,溶解度高 ,性质较Ｇｌｎ稳定 ,能耐受热灭菌 ,在体内数分钟即分解出Ｇｌｎ ,能部分补偿肠道所需Ｇｌｎ ,减少严重创伤及腹腔注射化疗药物 5 氟尿嘧啶 (5 ＦＵ)引发的小肠粘膜形态功能改变 ,细菌移位 ,降低…     

Potentiometric determination of iron using a fluoride ion-selective electrode-the application of the Apple II-ISE intelligent ion analyzer

A new method for determining iron is based on both nonlinear regression calibration plots and parabolic interpolation using a fluoride ion-selective electrode (ISE) and the Apple II-ISE intelligent ion Analyzer developed by ourselves. The experimental conditions for determining iron are discussed. The appropriate acidity of the experimental solution is pH 3, controlled by total ionic strength adjustment buffer (TISAB) that is composed of glycine (aminoacetic acid), nitric acid and sodium nitrate. The suitable total concentration of fluoride is equal to the highest concentration of iron in the standard series. Because the mathematical model of the method coincides with the experimental data the Apple II-ISE intelligent ion Analyzer can perform data acquisition and data processing, and the performance of fluoride electrode is excellent, the new method for determination of iron is fast and accurate. This method has been used successfully in the determination of iron in mineral samples.     

4'-磺酰腙苯并-15-冠-5的合成及阴离子识别研究

由苯并-15-冠-5经磺酰化、肼解两步合成了4’-磺酰肼苯并-15-冠-5(2).后者与芳香醛在室温下发生缩合制得了一系列未见文献报道的冠醚化磺酰腙类化合物3a～3h,产物经元素分析,IR,1H NMR,13C NMR,MS确证了其结构.利用紫外-可见吸收光谱考查了其对不同阴离子的识别作用,结果表明,化合物3d,3e,3h对碱性较强的阴离子有较强的选择性识别作用.     

Synthesis and characterization of monodisperse magnetic composite particles for magnetorheological fluid materials

Monodisperse magnetic composite particles (MCP) were prepared and characterized for a study of magnetic field-responsive fluids. Magnetic composite particles used are iron oxide-coated polymer composite particles, which were synthesized through in situ coating of iron oxide onto pre-existing polymer particles by the reduction of ferrous fluids. For a uniform and bulk coating of iron oxide, the porous structure was introduced into the substrate polymer particles through a two-step seeded polymerization method. Moreover, surface cyano-functionality was born from acrylonitrile unit of substrate polymer and it played an important role in obtaining successful uniform coating. The structure of the composite particle was analyzed by using a thermo gravimetric analysis (TGA) and a X-ray diffraction (XRD) analysis. The magnetization property of the particle was also observed. Then, the rheological properties of monodisperse magnetorheological (MR) suspensions of magnetic composite particles were examined under a magnetic field using a parallel-plate type commercial rheometer. From the rheological measurements, it was found that MR properties of the magnetic composite suspensions are dependent on the iron oxide content and the fluid composition.     

Structural Characteristics of Xyloglucan – Congo Red Aggregates as Observed by Small Angle X-ray Scattering

Xyloglucan is a type of hemicellulose with a cellulose backbone containing (1→6)-α-xylose or (1→2)-β-galactoxylose as a side chain. It is soluble in water. Its aqueous solution forms a gel or gel-like precipitate by addition of Congo red. Xyloglucan gel structures with various concentrations of Congo red were observed by small angle X-ray scattering (SAXS) at the nano-level. SAXS results indicated that the xyloglucan chains interacted with Congo red, and that an increase of concentration of Congo red induced a characteristic cross-linking domain, which consisted of a flat structure containing stacked xyloglucan chain assemblies. The Congo red molecules are inserted between the xyloglucan chains.     

Metal-ion adsorption on carboxyl-bearing self-assembled monolayers covalently bound to magnetic nanoparticles

Hematite nanoparticles have been functionalized with a self-assembled monolayer of undecanoic acid (UA) by covalent attachment via siloxane groups. The number density of carboxylic/carboxylate groups on the surface was determined by titration, yielding values on the order of 10(14) UA molecules/cm(2) and thus consistent with a closed-packed monolayer. The ability of these functionalized particles to adsorb Cd(2+) in the ppm range was demonstrated using in situ anodic stripping voltammetry.