Synthesis of 1,3,1′,5′,6′,7′-hexahydro-3,3′-biindolyl-2,4′-dione derivatives by cyclization of 3-alkylideneoxindoles with enaminone

The reaction between 3-alkylideneoxindoles 1 and 3-aminocyclohex-2-enone 2 was studied, and an efficient synthesis of 1,3,1′,5′,6′,7′-hexahydro-3,3′-biindolyl-2,4′-dione derivatives was developed by a sequential Michael addition followed by intramolecular condensation catalyzed by nickel dichloride hexahydrate. The reaction mechanism is discussed.     

CO2 sorption in wet ordered mesoporous silica kit-6: effects of water content and mechanism on enhanced sorption capacity

The sorption isotherms of CO₂ in wet ordered mesoporous silica KIT-6 with different amounts of pre-adsorbed water were firstly collected experimentally using a volumetric method in the temperature range of 275–281 K. The isotherms show an inflection point indicating CO₂ hydrates form in the pore spaces which is proofed by the enthalpy change calculated at the inflection pressure, and the quantity of water content shows considerable effect on the sorption capacity of CO₂. The highest enhancement of sorption capacity in the presence of water is observed in wet KIT-6 sample with water loadings of 2.48, which is about 12.80 mmol/g and 1.86 times than that on dry sample. However, the saturation capacity is still far less than that what can be stored merely in the form of hydrates due to the low ratio of water utilization because of the large pore and the polar surface of KIT-6.     

Three dimension Liesegang rings of calcium hydrophosphate in gelatin

Three dimensional Liesegang spherical layers of CaHPO₄ in gelatin ball were performed by employing CaCl₂ and Na₂HPO₄ as the inner and outer electrolyte, respectively. Effects of concentrations of inner and outer electrolyte as well as pH on the morphologies of Liesegang rings (LRs) were investigated. As a result, it was observed that the time law, spacing law and width law found in 1D/2D gel systems were obeyed in this 3D gelatin system. The interaction of Ca²⁺ and HPO₄ ^2? with gelatin matrix played a key role to the formation of LRs due to the existence of carboxylic groups on the gelatin chains. Using Ca²⁺ as the inner electrolyte, LRs were prepared. However, employing HPO₄ ^2? as inner electrolyte, LRs were not obtained. Moreover, pH of gelatin solution greatly impacted on the formation of LRs. The number of LRs increased with the decrease of pH, whereas the width inversely decreased. pH 4.40 was a turn point, from which the spacing coefficient abruptly increased as pH increased. All these results indicated that the network was created by the interaction of Ca²⁺ and –COO^? of gelatin chains, which dominated the formation of CaHPO₄ LRs in gelatin.     

Microwave sintering of nickel ferrite nanoparticles processed via sol–gel method

Magnetic nickel ferrite (NiFe₂O₄) was prepared by sol–gel process and calcined in the 2.45 GHz singlemode microwave furnace to synthesize nickel nanopowder. The sol–gel method was used for the processing of the NiFe₂O₄ powder because of its potential for making fine, pure and homogeneous powders. Sol–gel is a chemical method that has the possibility of synthesizing a reproducible material. Microwave energy is used for the calcining of this powder and the sintering of the NiFe₂O₄ samples. Its use for calcination has the advantage of reducing the total processing time and the soak temperature. In addition to the above combination of sol–gel and microwave processing yields to nanoscale particles and a more uniform distribution of their sizes. X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy and vibrating sample magnetometer were carried out to investigate structural, elemental, morphological and magnetic aspects of NiFe₂O₄. The results showed that the mean size and the saturation magnetization of the NiFe₂O₄ nanoparticles are about 30 nm and 55.27 emu/g, respectively. This method could be used as an alternative to other chemical methods in order to obtain NiFe₂O₄ nanoparticles.     

毛细管电泳电化学发光法分离测定奶粉中的二聚氰胺和三聚氰胺

基于二聚氰胺和三聚氰胺在Pt盘电极上对Ru(bpy)2+3的发光有增敏效果,建立了毛细管电泳电化学发光法同时分离检测乳制品中二聚氰胺和三聚氰胺的含量的新方法。进行实验条件优化,采用5 mmol/L Ru(bpy)32++60 mmol/L pH 8.5磷酸缓冲液,10 kV×10 s电动进样,光电倍增管高压为900 V,检测电位为1.18V,分离电压为12 kV,使得二聚氰胺和三聚氰胺得到了很好的分离检测,对奶粉样品进行添加回收率实验,二聚氰胺和三聚氰胺的回收率分别为94.6%~97.8%和95.9%~97.4%,相对标准偏差分别为3.2%~4.6%和2.7%~4.1%。     

丙烯腈、己二腈和丙腈与水的二元体系液-液相平衡数据的测定和关联(英文)

采用平衡法测定了丙烯腈+水、己二腈+水、丙腈+水三个二元体系在不同温度(303.15、313.15、323.15、333.15K)下的液-液相平衡数据;并采用NRTL(α=0.2,α=0.3)模型和UNIQUAC模型对液-液平衡数据进行了关联.结果显示,NRTL和UNIQUAC模型对三个二元体系在不同温度下的互溶度关联的目标函数值均小于1×10-17,实验值与计算值吻合较好,绝对偏差小于0.009,关联精度较高.该研究结果可为丙烯腈、丙腈和水三元平衡溶解度数据的模拟和预测提供可靠的基础数据,并对电解二聚法生产己二腈中电解液的分离提纯工艺具有一定的指导意义.     

四种黄酮类化合物与牛血清白蛋白相互作用的光谱分析

在人体生理pH条件下,利用紫外吸收光谱和荧光光谱研究了槲皮素(QUE)、大豆甙元(DAI)、4′,7-二甲氧基-3′-异黄酮磺酸钠(DISS)和3′-大豆甙元磺酸钠(DSS)四种黄酮类化合物与牛血清白蛋白(BSA)的相互作用,结合反应机理对其进行了初步探讨;并计算了结合位点数和结合常数.紫外吸收光谱分析结果表明,在pH=7.4条件下,黄酮类化合物中疏水性的苯环与BSA疏水腔中的氨基酸残基发生作用,从而导致药物分子的吸收峰红移,用Scatchard拟合法可求得DAI及DSS与BSA的结合常数.荧光光谱分析结果表明,BSA对DAI、DISS和DSS均有明显的敏化增强效应,计算得到的增强速率常数分别为1.39×1011,7.72×1011和1.93×1012L·s-1·mol-1,并可求得结合位点数和结合常数.     

基于丙二酰胺的不对称双子表面活性剂的合成及其乳化性能

将二(3-二甲氨基丙基)丙二酰胺分别与溴代十六烷和溴代十四烷反应,生成的季铵盐化产物经丙酮-乙腈重结晶,得到含丙二酰胺基的不对称阳离子双子(Gemini)表面活性剂(命名为16-9-14),总收率为45.9%(以溴代十六烷计);利用红外光谱和核磁共振谱表征了合成产物的结构,采用电导法测定了其临界胶束浓度(CMC),采用滴体积法测定了其临界张力(γCMC),进而初步探讨了其发泡沫性能和乳化性能.结果表明,合成的Gemini表面活性剂的CMC为1.57×10-4 mol/L,γCMC为38.45mN/m;其发泡性能和乳化性能优于相应的单子表面活性剂.     

萘酰亚胺类荧光分子探针的研究进展

荧光分子探针作为一种有效的金属离子检测手段,不仅使用方便,而且具有高灵敏度,高选择性等突出的优点.作者综述了萘酰亚胺类荧光分子探针的最新研究进展;指出萘酰亚胺化合物具有独特的荧光化学性质(如荧光量子产率高、荧光发射波长适中、斯托克斯位移大、光稳定性好、结构易于修饰等),因此被广泛应用于荧光探针研究领域,并且在合成、离子识别、检测及细胞成像等方面不断取得新的应用.     

Redox Dyshomeostasis Strategy for Hypoxic Tumor Therapy Based on DNAzyme-Loaded Electrophilic ZIFs

Redox homeostasis is one of the main reasons for reactive oxygen species (ROS) tolerance in hypoxic tumors, limiting ROS-mediated tumor therapy. Proposed herein is a redox dyshomeostasis (RDH) strategy based on a nanoplatform, FeCysPW@ZIF-82@CAT Dz, to disrupt redox homeostasis, and its application to improve ROS-mediated hypoxic tumor therapy. Once endocytosed by tumor cells, the catalase DNAzyme (CAT Dz) loaded zeolitic imidazole framework-82 (ZIF-82@CAT Dz) shell can be degraded into Zn²⁺ as cofactors for CAT Dz mediated CAT silencing and electrophilic ligands for glutathione (GSH) depletion under hypoxia, both of which lead to intracellular RDH and H₂O₂ accumulation. These “disordered” cells show reduced resistance to ROS and are effectively killed by ferrous cysteine-phosphotungstate (FeCysPW) induced chemodynamic therapy (CDT). In vitro and in vivo data demonstrate that the pH/hypoxia/H₂O₂ triple stimuli responsive nanocomposite can efficiently kill hypoxic tumors. Overall, the RDH strategy provides a new way of thinking about ROS-mediated treatment of hypoxic tumors.