Synthesis and Crystal Structure of a Novel Ethyl 5-(4-(2-Phenylacetamido)phenyl)-1H-pyrazole-3-carboxylate as an Acrosin Inhibitor

The title compound (ethyl5-(4-(2-phenylacetamido)phenyl)-1H-pyrazole-3-carboxy- late, C20H19N3O3) was synthesized by the reaction of Claisen condensation, cyclization, reduction and acylation. The structure was characterized by X-ray diffraction, MS, NMR and IR. It belongs to the monoclinic system, space group C2/c with a = 22.723(9), b = 9.324(4), c = 18.890(8) , β = 114.259(6)°, V = 3649(3) 3, Dc = 1.272 Mg·m-3, Z = 8, Mr = 349.38, μ = 0.087 mm-1, F(000) = 1472, the final R = 0.0615 and wR = 0.1643. The biological test shows that the title compound has a moderate acrosin inhibition activity.     

Interactions of polyelectrolyte brushes with oppositely charged surfactants

Using Brownian dynamics simulations, we study the effect of the charge ratio, the surfactant length, and the grafting density on the conformational behavior of the complex formed by the polyelectrolyte brush with oppositely charged surfactants. In our simulations, the polyelectrolyte chains and surfactants are represented by a coarse-grained bead-spring model, and the solvent is treated implicitly. It is found that varying the charge ratio induces different morphologies of surfactant aggregates adsorbed onto the brush. At high charge ratios, the density profiles of surfactant monomers indicate that surfactant aggregates exhibit a layer-by-layer arrangement. The surfactant length has a strong effect on the adsorption behavior of surfactants. The lengthening of surfactant leads to a collapsed brush configuration, but a reswelling of the brush with further increasing the surfactant length is observed. The collapse of the brush is attributed to the enhancement of surfactants binding to polyelectrolyte chains. The reswelling is due to an increase in the volume of adsorbed surfactant aggregates. At the largest grafting density investigated, enhanced excluded volume interactions limit the adsorption of surfactant within the polyelectrolyte brush. We also find that end monomers in polyelectrolyte chains exhibit a bimodal distribution in cases of large surfactant lengths and high charge ratios.     

荧光光谱法研究双醋瑞因与人血清白蛋白的相互作用

在模拟人体生理条件下（pH=7.40）,采用荧光光谱法研究双醋瑞因与人血清白蛋白的相互作用。 采用2种方法计算不同温度下其结合常数KA、结合位点数n,同时对2种计算方法进行了比较;并根据热力学参数确定了双醋瑞因与人血清白蛋白之间的作用力类型。 根据Forster非辐射能量转移原理,确定了双醋瑞因与人血清白蛋白相互结合时供能体 受能体间的作用距离和能量转移效率,并用同步荧光光谱研究了双醋瑞因对人血清白蛋白构象的影响。 结果表明,双醋瑞因与人血清白蛋白之间主要是以静态猝灭为主;结合距离r=2.88 nm,能量转移效率E=0.273 8,二者主要凭借氢键和范德华力进行结合。     

电感耦合等离子体原子发射光谱法(ICP-AES)测定金鸡胶囊中的7种无机元素

建立了测定金鸡胶囊中Ca、Mg、Mn、Fe、Cu、Zn和Sr 7种无机元素含量的分析方法.采用浓硝酸和高氯酸(8+2)的混合酸溶解样品,利用电感耦合等离子体原子发射光谱法(ICP-AES)对各种元素进行测定.金鸡胶囊含有丰富的对人体有益的无机元素,对待测样品的测定结果表明,Ca、Mg、Fe、Mn、Zn、Sr和Cu的含量...     

乙炔与H2O分子之间的氢键结构与性质

采用B3LYP方法,在6-311++G水平上优化得到了H2O…C2H2氢键复合物的σ-n和H-π型两种稳定构型,并进行频率分析,讨论了相关自然键红外振动光谱的红移现象.采用NBO理论对σ-n和H-π氢键复合物形成过程中的电荷转移的类型进行了分析讨论.分子间的氢键相互作用能结果表明,σ-n型比H-π型氢键复合物更稳定.     

Mechanistic Study of Unprecedented Highly Regioselective Hydrocyanation of Terminal Alkynes: Insight into the Origins of the Regioselectivity and Ligand Effects

Density functional theory (DFT) calculations were performed to gain insight into the mechanism of the nickel-catalyzed hydrocyanation of terminal alkynes with Zn(CN)₂ and water to exclusively generate the branched nitrile with excellent Markovnikov selectivity. After precatalyst activation to give the LNi(0) active species, the transformation proceeds via the following steps: (1) oxidative addition of H₂O to the LNi(0) provides the intermediate LNi(II)H(OH); (2) ligand exchange of LNi(II)H(OH) with Zn(CN)₂ gives the intermediate LNi(II)H(CN); (3) alkyne insertion to the LNi(II)H(CN) forms the alkenyl nickel complex, followed by the reductive elimination step reaching the final product. This mechanism is kinetically and thermodynamically more favorable than that of the experimental proposed ones. On the basis of the experimental observations, more water molecules cannot further improve the reaction as it has also been rationalized. Furthermore, the origin of the high regioselectivity of the product, the variable effectiveness of the metal mediator as function of ligands, as well as the high yield of the alkyl-substituted alkynes substrates, is analyzed in detail. © 2019 Wiley Periodicals, Inc.     

Synthesis and Electronic Structure of Triazasubporphyrin with Peripherally Low Symmetric Push-pull Substitutions

Peripherally low symmetric substitution with electron-donating(EDG)and electron-withdrawing(EWG)substituents caused the rational modulation of geometric structure and even the electronic structure of triazasubporphyrin,the smallest 14πconjugated aza-porphyrinoids.Both structural characterization and spectroscopic investigation were discussed to provide an in-depth understanding of the relationship between peripheral push-pull substituents and SubPz core.     

Synthesis,crystal structure and optical property of manganese (II) halides based on pyridine ionic liquids with high quantum yield

Transition Metal Chemistry - Two novel tetrahedral Mn (II) halide single-crystals [(C7H10N)2][MnCl4] (1) and [(C7H10N)2][MnBr4] (2), based on pyridine ionic liquids, have been successfully...     

高效液相色谱-四极杆/飞行时间质谱鉴定阿莫西林克拉维酸钾干混悬剂中的未知组分

采用高效液相色谱-四极杆/飞行时间质谱(HPLC-QTOF/MS)建立了阿莫西林克拉维酸钾混悬剂(ACPS)中未知组分的鉴定方法,以BDS Hypersil C18(4.6 mm×250 mm,5μm)为色谱柱,以乙腈-水(0.1%甲酸)为流动相,流速为1 mL/min。比较了中国药典方法和HPLC-QTOF/MS方法的相关性;利用半制备液相色谱收集未知组分,并在HPLC-QTOF/MS体系中进行定位和确认,确定未知组分在液质体系中的出峰位置和准确分子量;筛查混合空白辅料成分,并通过与标准品比对,利用HPLC-QTOF/MS鉴定ACPS的未知组分为糖精钠。方法可为抗生素药品中未知组分的鉴定提供参考。     

聚氨酯泡沫富集-ICP-AES法测定土壤及水系沉积物中铊含量

本文建立了一种以聚氨酯泡沫富集-ICP-AES法测定土壤及水系沉积物中铊含量的分析方法,利用正交实验,确定最佳实验条件,方法的检出限为0.01mg/L,经对土壤及水系沉积物成分分析标准物质的检测,结果与推荐值相符,相对误差小于10%,相对标准偏差(RSD,n=10)在1.9%-4.9%之间。