巧用智能手机测定抗贫血药物中铁的含量

铁离子和硫氰化钾反应生成稳定的血红色络合物硫氰化铁,用智能手机拍摄所得图像的颜色反映在图像的RGB值上。随着该溶液浓度的增大,溶液颜色逐渐加深,反映在拍摄的图像中颜色的RGB值也在变化,并且得出该溶液颜色的R值与溶液的浓度成线性关系。结果显示,用该实验方法测得的抗贫血药物中铁的含量与用紫外分光光度法测得同一药品中铁的含量相比误差为5%;并且该实验方法在中学的化学实验课中很容易实现,避免了学生用目视比色法测量抗贫血药物中铁的含量时因标准溶液的色阶选择不合适而导致实验的失败。     

基于有机磷酸类MOFs前驱体制备Ni2P/C复合材料

以镍为金属中心、 对二甲苯二磷酸为有机配体, 构筑了一种有机磷酸类Ni-MOF前驱体, 再经过一步碳化, 原位制备出多孔碳包覆Ni₂P纳米颗粒的复合材料. 该复合材料保留了前驱体的片状形貌, 比表面积可达202 m²/g, 复合材料中的Ni₂P纳米颗粒具有良好的结晶度, 颗粒均匀且无团聚现象. 在锂离子电池性能测试中, 该Ni₂P/C复合结构在缓解材料体积膨胀的同时提高了材料的电子和离子电导率, 进而提高了材料的电化学性能. 在0.2 C的电流密度下, 材料首次充、 放电比容量分别为247和226 mA·h·g^-1, 库仑效率可达91.7%, 循环200圈后, 库仑效率接近100%.     

Toward the total synthesis of elisapterosin B: A Hg(OTf)(2)-promoted diastereoselective intramolecular Friedel-Crafts alkylation reaction

As part of an approach to the synthesis of the antitubercular agent elisapterosin B, we prepared two different chiral, non-racemic olefinic substrates and examined their diastereoselective ring closure using mercury salts. The effort yielded potential precursors to elisapterosin B in good yield with good to excellent diastereocontrol.     

Phase transfer and its applications in nanotechnology

As nanoparticle syntheses in aqueous and organic systems have their own merits and drawbacks, specific applications may call for the transfer of newly formed nanoparticles from a polar to a non-polar environment (or vice versa) after synthesis. This critical review focuses on the application of phase transfer in nanoparticle synthesis, and features core-shell structures in bimetallic nanoparticles, replacement reactions in organic media, and catalytic properties of various nanostructures. It also describes the reversible organic and aqueous phase transfer of semiconductor and metallic nanoparticles for biological applications, and the use of phase transfer in depositing noble metals on semiconductor nanoparticles (258 references).     

Composition dependence of the photocatalytic activities of BiOCl(1-x)Br(x) solid solutions under visible light

We prepared BiOCl(1-x)Br(x) (x=0-1) solid solutions and characterized their structures, morphologies, and photocatalytic properties by X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy, Raman spectroscopy, photocurrent and photocatalytic activity measurements and also by density functional theory calculations for BiOCl, BiOBr, BiOCl(0.5)Br(0.5). Under visible-light irradiation BiOCl(1-x)Br(x) exhibits a stronger photocatalytic activity than do BiOCl and BiOBr, with the activity reaching the maximum at x=0.5 and decreasing gradually as x is increased toward 1 or decreased toward 0. This trend is closely mimicked by the photogenerated current of BiOCl(1-x)Br(x) , indicating that the enhanced photocatalytic activity of BiOCl(1-x)Br(x) with respect to those of BiOCl and BiOBr originates from the trapping of photogenerated carriers. Our electronic structure calculations for BiOCl(0.5)Br(0.5) with the anion (O(2-), Cl(-), Br(-)) and cation (Bi(3+)) vacancies suggest that the trapping of photogenerated carriers is caused most likely by Bi(3+) cation vacancies, which generate hole states above the conduction band maximum.     

Dynamic pH junction-sweeping for on-line focusing of dipeptides in capillary electrophoresis with laser-induced fluorescence detection

In this paper, we developed a simple and effective on-line focusing technique combining dynamic pH junction and sweeping by capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection. Dynamic pH junction-sweeping is defined when the sample has a different buffer pH (dynamic pH junction condition) and is devoid of micelles (sweeping condition) relative to the background electrolyte (BGE). This hyphenated focusing mode was applied to the sensitive and selective focusing of four dipeptides: Tyr-Phe, Tyr-Leu, Trp-Gly, and Ala-Gln. Picomolar detectability of these dipeptides by CE-LIF detection was demonstrated through effective focusing of large sample volumes (up to 39% capillary length) using the dual pH junction-sweeping focusing mode. 25 mmol L(-1) sodium dihydrogen phosphate, pH 2.5 was used as the sample matrix, and 100 mmol L(-1) borate, 21 mmol L(-1) sodium dodecylsulfate (SDS), 16 mmol L(-1) Brij35, pH 9.0 as the background solution (BGS). The concentration detection limits (S/N = 3) of the four dipeptides were in the range of 1.0-5.0 pmol L(-1). The developed method has been successfully used for the determination of dipeptides in human serum samples.     

New Dammarane‐Type Saponins from the Rhizomes of Panax japonicus

Phytochemical investigation of the rhizomes of Panax japonicus C. A. Meyer (Araliaceae) resulted in the isolation of two new dammarane‐type triterpenoid saponins, yesanchinoside R₁ ( 1 ) and yesanchinoside R₂ ( 2 ), together with one new natural product, 6′′′‐O‐acetylginsenoside Re ( 3 ). In addition, 25 known compounds, including 23 triterpenoid saponins, 4 – 26 , β‐sitosterol 3‐O‐β‐D ‐glucopyranoside ( 27 ), and ecdysterone ( 28 ), were also identified. The known saponins 12, 15 , and 18 – 22 were reported for the first time from the title plant. Their structures were elucidated on the basis of detailed spectroscopic analyses, including 1D‐ and 2D‐NMR techniques, as well as acidic hydrolysis.     

Theoretical studies on thermochemistry for conversion of 5-chloromethylfurfural into valuable chemicals

Recently, 5-chloromethylfurfural (CMF) was proposed as a central intermediate in the conversion of carbohydrate-based material into useful organic commodities. In the present work, we have calculated the thermochemistry using the highly accurate G4 theory and several state-of-art density functional theory (DFT) methods (e.g., X1, M06-2X, B2PLYP-D, and XYG3) for the conversion from CMF to 5-hydroxymethylfurfural (HMF) and levulinic acid (LA) in water, and that to biofuels 5-ethoxymethylfurfural (EMF) and ethyllevulinate (EL) in alcohol. New reaction mechanisms have been proposed, which complement the well-recognized Horvat mechanisms. The assessment of DFT methods suggested that XYG3 be a viable method for biomass related thermochemistry calculations.