Remarkably efficient oxidative coupling of N,N-dialkylarylamines in water mediated by cerium(IV) ammonium nitrate

A highly effective, economical, and environmentally friendly method using of CAN as oxidant and water as solvent for oxidative coupling of N,N-dialkylarylamines was reported.     

Molecular structure and pseudopolymorphism of squamtin A from Annona squamosa

The cyclopeptide, squamtin A (1, formula: C₃₉H₆₀O₁₁N₈S), was found to crystallized in two pseudopolymorphisms, i.e. 1·(H₂O)_3.5 and 1·(H₂O)_3.9. The composition of the amino acids and their linkage sequences are the same. The main differences between the two kinds of crystals lie in the positions and occupancies of the water molecules, the positions of the sulfur atoms and the conformation of the side chains. The absolute configuration of 1 is established by X-ray analysis in combination with the Marfey's analysis of its hydrolysates.     

电场对含高氯酸锂盐的互穿网络高分子快离子导体的电导的影响

研究了直流电场对含ＬｉＣｌＯ４的聚氧化乙烯（ＰＥＯ）４００与环氧树脂形成的液晶态互穿网络高分子忆禽子导体的电导率的影响。在室温至９０℃范围内，电导率随外加电压增加面降低。外加电压越高，对电导率变化的影响越大。     

Simultaneous Determination of Oxytetra- cycline, Doxycycline, Tetracycline and Chlortetracycline in Tetracycline Antibiotics by High-Performance Liquid Chromatog- raphy with Fluorescence Detection

A simple, rapid and sensitive high-performance liquid chromatographic method with fluorescence detection for the simultaneous determination of oxytetracycline, doxycycline, tetracycline and chlortetracycline was developed, and successfully applied to the analysis of commercial tetracycline antibiotics. The separation was performed on a reverse-phase C₁₈ column with a gradient elution composed of methanol and sodium acetate buffer (containing disodium ethylenediaminetetraacetate and calcium chloride, pH 8.10) as the mobile phase, and fluorescence detection at 532 nm (excitation at 380 nm). The detection limits for oxytetracycline, doxycycline, tetracycline and chlortetracycline were 0.1, 0.5, 0.3 and 0.4 g L^–1, respectively. Data with respect to precision and accuracy were reported and discussed.     

New insights into the effects of self-association of the cation [Au[C(NHMe)(2)](2)](+) on its solid state structure and luminescence

Colorless [Au[C(NHMe)(2)](2)]X.H(2)O (X = Cl or Br) crystallize as dimers with Au.Au separations of 3.1231(3) A (Cl salt) and 3.1297(4) A (Br salt) between the linear, two-coordinate cations, and there is no direct interaction of Au(I) with the halide ions which are hydrogen bonded to ligand N-H groups and the water molecules. The luminescence of these dimers occurs at higher energy than that observed in extended chains of the same cation in the corresponding (PF(6))(-) and (BF(4))(-) salts and shows the important effects of aggregation on the observed luminescence.     

Cu（Ⅱ）—胱氨酸络合物吸附波的研究及蛋白质中胱氨酸的测定

研究了Cu(Ⅱ)-胱氨酸络合物极谱波的性质;提出了一种用示波极谱法测定蛋白质中胱氨酸的新方法,可在8.0×10~(-4)mol/L Cu~(2+)+8.0×10~(-3)mol/L三乙醇胺的溶液中测定0.05～20mg/L的胱氨酸。     

Interaction between sodium tanshinone IIA sulfonate and the adriamycin semiquinone free radical: A possible mechanism for antagonizing adriamycin-induced cardiotoxity

Adriamycin (ADR) is a powerful and widely used antitumor drug, but its dose dependent cardiotoxicity limits its application. This side effect is believed to be caused by the adriamycin semiquinone free radical (ASFR). The primary focus of this work is to test effects of sodium tanshinone IIA sulfonate (STS) on ASFR and adriamycin–induced lipid peroxidation. It was found that ADR, whether in the system of heart homogenate, heart mitochondria or heart submitochondria, with NADH as the substrate or in xanthine/xanthine oxidase under anaerobic conditions, all produced ASFR rapidly. STS was shown to effectively scavenge ASFR in all these systems and postpone the appearance of ASFR. The delayed time was proportional to the amount of STS. Under aerobic conditions, ASFR could be oxidized to generate oxygen free radicals. STS could not scavenge these oxygen free radicals, but it could effectively scavenge lipid free radicals generated from membrane lipid peroxidation of heart mitochondria. STS could significantly reduce mitochondrial swelling and lipid peroxidation induced by ADR. Animal experiments show that treatment of STS could inhibit endogenous lipid peroxidation caused by ADR. Here, a protective mechanism of STS is suggested that STS can rapidly and univalently oxidize ASFR, causing the cycle of adriamycin between its quinone form and semiquinone form and inhibiting the accumulation of ASFR. Under aerobic condition, STS can protect heart mitochondria by scavenging lipid free radicals generated from adriamycin-induced mitochondrial lipid peroxidation. This investigation shows that STS may be a physiological drug to antagonize the cardiotoxicity of ADR.     

甲基膦酸二甲庚脂-HBr体系萃取色层法分离微量镉及其应用

本文提出了以 P350为固定相,硅胶为载体,1.0mol/L HBr 为流动相,采用水作洗脱液的萃取柱色层分离微量镉的新方法。研究了分离条件,萃取保留机理和干扰等。用制定的方法对铅锌矿和冶炼电转尘中微量镉进行了分离测定,均获得良好结果。回收率在95～102％之间。     

Vapor pressure measurement for water,methanol, ethanol,and their binary mixtures in the presence of an ionic liquid 1-ethyl-3-methylimidazolium dimethylphosphate

Vapor pressure data were measured for water, methanol and ethanol as well as their binary mixtures with an ionic liquid (IL) 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM][DMP]) at varying temperature and IL-content ranging from mass fraction of 0.10–0.70 by a quasi-static method. The vapor pressure data for the IL-containing binary systems were correlated using NRTL equation with average absolute relative deviation (ARD) within 0.0076, and the binary NRTL parameters was used for predicting the vapor pressure of the IL-containing ternary systems with reasonable accuracy. In addition, the infinite activity coefficients of solvents in [EMIM][DMP] and isobaric vapor–liquid equilibrium for IL-containing ternary systems at 101.325 kPa and mass fraction of IL being 0.5 were predicted with the regressed NRTL parameters. The results indicate that ionic liquid [EMIM][DMP] can depress the volatility of the solvents of water, methanol and ethanol but to a varying degree, leading to the variation of relative volatility of a solvent and even removal of azeotrope for water–ethanol mixture.     

Microwave-assisted synthesis of sulfide M2S3 (m = Bi, Sb) nanorods using an ionic liquid

Single-crystalline Bi(2)S(3) and Sb(2)S(3) nanorods have been successfully synthesized by the microwave-assisted ionic liquid method. The starting reagents were Bi(2)O(3) or Sb(2)O(3), HCl, Na(2)S(2)O(3), and ethylene glycol (EG) or ethanolamine, and the ionic liquid used was 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF(4)]). Our experiments showed that the ionic liquid played an important role in the morphology of M(2)S(3) (M = Bi, Sb). Single-crystalline Bi(2)S(3) nanorods could be prepared in the presence of [BMIM][BF(4)]. However, urchinlike Bi(2)S(3) structures consisting of nanorods were formed without using [BMIM][BF(4)]. Single-crystalline Sb(2)S(3) nanorods were obtained in the presence of [BMIM][BF(4)]. However, single-crystalline Sb(2)S(3) nanosheets could be prepared in the absence of [BMIM][BF(4)]. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and electron diffraction (ED).