An in situ STM study on the long-range surface restructuring of Au(1 1 1) in a non-chloroaluminumated ionic liquid

We report an in situ STM study of a potential-dependent long-range surface restructuring of Au(1 1 1) electrode in neat 1-butyl-3-methylimidazolium tetrafluoroborates (BMIBF₄) ionic liquid. Au(1 1 1) undergoes a significant long-range surface restructuring upon cathodic excursion to −1.0 V vs. Pt quasi-reference. The restructuring involves the formation of tiny pits, which then develops into a stable worm-like network with an average width of the network grids 2 nm. Electrochemical annealing occurs at the cathodic limit with the presence of a reduction product of cation BMI⁺. A smooth surface is recovered with the appearance of the typical (√3 × 22) reconstruction of Au(1 1 1). The surface restructuring is reestablished upon anodic excursion to −1.3 V after the adsorbed reduction product is oxidized. The long-range surface restructuring phenomenon is tentatively explained as a result of partial charge transfer to the weakly adsorbed BMI⁺, which reduces the metal–metal cohesive energy. In addition, the synergetic effect of the counter anion BF₄⁻ may also be involved. The results provide a knowledge of Au(1 1 1) electrode behavior in the neat ionic liquid and are beneficial to understanding in situ STM results involving surface morphological changes in such a media.     

手性5-l-(艹孟)氧基丁内酯并[3,4-d]-3-取代基-异(口恶)唑啉类化合物的合成

研究了手性元5-(R)-(l-(艹孟)氧基)-2(5H)-呋喃酮与取代苯甲醛肟以次氯酸钙作为氧化剂进行的区域选择性原位1,3-偶极环加成反应,同步生成两个新的手性中心,得到了一系列光学纯丁内酯并[3,4-d]-3-取代基-异(口恶)唑啉类化合物;应用波谱学手段及X射线单晶衍射法确证了产物的绝对构型,并对产物的核磁共振氢谱规律性加以总结.     

包覆型纳米铜-银双金属粉研究

目前,导电胶或者电磁波屏蔽涂料用的导电性填料主要有三类,一是铜粉,二是银粉,三是铜-银双金属粉。铜粉具有来源广、价格低廉、导电性好等优点,但其抗氧化性能弱;银粉导电性与抗氧化性好,但其资源日益匮乏。大量的研究试图通过对铜粉进行表面改性来提高其性能。表面改性有两种方法,一是包膜处理,用SiO2溶胶处理铜粉,铜粉抗氧化性能提高,但其表面导电性能大大降低犤1犦;另一类方法是在铜粉表面覆盖一层导电性能与抗氧化性能均佳的银或金而制成双金属粉末犤2～5犦。制取高性能的铜-银双金属粉是该领域的研究重点。目前获得铜-银双金属粉的方…     

MCM-41-HY复合分子筛的合成及其在深度加氢脱硫中的应用

在水热条件下合成了包覆型MCM-41-HY复合分子筛.采用XRD、N2气吸附和SEM等方法对其进行了表征.结果表明,MCM-41-HY复合分子筛和MCM-41与H型Y沸石(HY)的机械混合物明显不同,在复合分子筛MCM-41-HY中,中孔相MCM-41附晶生长在HY沸石上,将HY包覆起来.以二苯并噻吩为模型化合物,考察了该材料担载NiMo催化剂的加氢脱硫活性.结果表明,MCM-41-HY复合分子筛与MCM-41和HY的机械混合物担载NiMo催化剂的加氢脱硫(HDS)活性相当,但MCM-41-HY复合分子筛担载NiMo催化剂的裂化活性较低.其裂化活性不同的原因在于其载体孔道结构和酸性位的分布不同.     

Preparation ,Structural Characterization and Luminescent Property of Binucleasr Silver（Ⅰ）Complex Formed by Benzotriazole and 1—Hydroxymethyl Benzotriazole

Dinuclear silver (I) six‐membered ring complex [Ag₂ (bta)₂ ‐(hmbta)₂] (ClO₄)₂ (3) has been synthesized by the reaction of benzotriazole (bta) (1) and 1‐hydroxymethyl benzotriazole (hmbta) (2) with Ag (CH₃CN)₄ClO₄. The structures of compound 2 and Complex 3 have been studied by single crystal X‐ray diffraction analysis. The change of luminescent intensity of 1, 2 and 3 was reported. Compound 2 crystallizes in the monoclinic system with space group P2 (1)/c, a = 0.7655 (10) nm, b = 1.0126 (14) nm, c =0.9502 (13) nm, β = 95.07 (2)°, V = 0.7337 (17) nm³ and Z = 4. Complex 3 crystallizes in the triclinic system with space group P1, a = 0.73611 (18) nm, b = 0.9152 (2) nm, c = 1.2277 (3) nm, β = 87.170 (5)°, V = 0.8221 (3) nm³ and Z = 1. The main structural feature of complex 3 is a symmetric dinuclear six‐membered ring formed by two silver (I) atoms and four N‐atoms from two benzotriazoles. The second structural feature of complex 3 is the τ‐τ stacking interaction between two adjacent molecular planes, which forms the two‐dimentional layer structure. Besides, compared with 2, the luminescent intensity of complex 3 shows a remarkable enhancement.     

微波作用下2,5-二取代-1,3,4-噁二唑的合成

2 ,5 二取代 1 ,3 ,4 二唑可用作药品 ,光敏物质 ,闪烁体 ,激光材料 ,高分子液晶单体等[1- 5] 。一种是以芳香酸与水合肼作为原料用多聚磷酸作为脱水环合剂来合成此类化合物[6 ] ,另一种是由芳香酸转变为芳香酰氯或酯 ,再与水合肼反应得到单酰肼或二酰肼 ,最后用三氯氧磷[7] ,五氧化二磷和五氯化磷[8] ,一氯三甲硅[9] 脱水环合 ;此外 ,用水合肼和尿素合成得到的氨基脲代替水合肼 ,与芳香酸缩合合成二唑[10 ] ,这些方法共同的缺陷是 :环合时间较长 ,少者 4～ 5ｈ ,多则 8ｈ。近年来 ,微波技术在有机合成及其杂环化合物的合成中得到了广…     

Diaqua­bis[2′‐(4,5‐diaza­fluoren‐9‐yl­idene)picolinohydrazidato‐κ2N,O]zinc(II) tetra­hydrate: a metal–water chain complex containing cyclic water hexa­mers

In the title compound, [Zn(C₁₇H₁₀N₅O)₂(H₂O)₂]·4H₂O, cyclic water hexa­mers forming one‐dimensional metal–water chains are observed. The water clusters are trapped by the co‐operative association of coordination inter­actions and hydrogen bonds. The Zn^II ion resides on a centre of symmetry and is in an octa­hedral coordination environment comprising two O atoms and two N atoms from two 2′‐(4,5‐diaza­fluoren‐9‐yl­idene)picolinohydrazidate ligands and two water mol­ecules.     

Cu（I）/Diamine-catalyzed Aryl-alkyne Coupling Reactions

Arylalkynes are important building blocks for the synthesis of natural products,pharmaceuticals,and artificial molecular devices1.They are often synthesized via the Pd-catalyzed Sonogashira coupling reactions between aryl halides and terminal alkynes2,3.Unfortunately,it remains difficult to apply the Sonogashira reaction to industrial scale and/or pharmaceutical synthesis,due to the high cost of Pd and the difficulty in removing the toxic Pd residues from the reaction products.Thus it is wor…     

Two salts of 5‐sulfosalicylic acid and 3‐aminopyridine

5‐Sulfosalicylic acid (5‐SSA) and 3‐aminopyridine (3‐APy) crystallize in the same solvent system, resulting in two kinds of 1:1 proton‐transfer organic adduct, namely 3‐aminopyridinium 3‐carboxy‐4‐hydroxybenzenesulfonate monohydrate, C₅H₇N₂⁺·C₇H₅O₆S⁻·H₂O or 3‐APy·5‐SSA·H₂O, (I), and the anhydrous adduct, C₅H₇N₂⁺·C₇H₅O₆S⁻ or 3‐APy·5‐SSA, (II). Both compounds have extensively hydrogen‐bonded three‐dimensional layered polymer structures, with interlayer homo‐ and heterogeneous π–π interactions in (I) and (II), respectively.     

Linear alkyl benzene sulphonate (LAS) degradation by immobilized Pseudomonas aeruginosa under low intensity ultrasound

We studied the LAS degradation of immobilized Pseudomonas aeruginosa with low-intensity ultrasonic and the influence of original LAS concentration, pH, rotary velocity and different conditions of low-intensity ultrasonic irradiation on the degradation of LAS. In our experiment, the degradation rate of LAS was the main index. We found that low-intensity ultrasonic irradiation could improve the metabolism of microorganism cells and promote the LAS biodegradation of immobilized cells. In the experiment, 50 mg/l LAS were used to simulate wastewater, and low-intensity ultrasonic was considered. We found the influence was obvious, and the optimal degradation rate was acquired when the conditions of ultrasonic were frequency 24 kHz, power 8 W, stimulation time 5 s, intermissive time 30 s, and total time 10 min. The LAS degradation rate of immobilized cells with ultrasonic were respectively 40% and 9.5% higher than that of the suspending cells and immobilized cells without irradiation.