聚合物{[CuII(Hpb) (mal)]H2O}n :单体的量子化学计算和磁性研究

{[Cu^Ⅱ（Hpb）（mal）]H=O}n （Hpb=2-2＇-pyridylbenzimidazole, mal=maleic acid） is a helical chain-like polymer complex. In order to investigate the electronic structure of the complex, the monomer Cu^Ⅱ（Hpb）（mal） was obturated with different functional groups respectively. For these selective segments, the geometry optimizations were conducted by using hybrid DFT （B3LYP）methods to find that the structure obturated with H2O was better consistent with the experiment, and then this model would be used to latter calculations, such as the frontier molecular orbital and the NBO charge population analysis. In addition the magnetic behaviors of this complex were analyzed by experiments and the weak antiferromagnetic couple between copper（Ⅱ） ions was observed. The exchange coupling constant was calculated by DFT based on the spin broken symmetry formalism. The calculated coupling constants were in good agreement with the experimental data.     

Synthesis, Crystal Structure, Properties and Thermoanalysis of Complexes of Cu（Ⅱ） and Ni（Ⅱ） with Taurine-5-chlorosalicylaldelyde Schiff Base

The reactions of transition metal salts with taurine 5‐chlorosalicylaldelyde Schiff base gave two complexes [Ni(TCSSB)(H₂O)₃].H₂O (1) and [Cu(TCSSB)(H₂O)₂]₂[Cu(TCSSB)₂].6H₂O (2) (TCSSB=taurine‐5‐chlorosalicylaldelyde Schiff base), which were characterized by elemental analysis and X‐ray diffraction analysis. The complex 1 crystallized in monoclinic system with space group P2 ₁/c, and a=1.4816(2) nm, b=1.3953(2) nm, c= 0.7466(1) nm, β= 100.499(3)°, V=1.5176(4) nm³, Z=4, and an infinite 3‐D network structure was formed by hydrogen bonds among sulfo group, crystal water and coordinated water. Complex 2 crystallized in triclinic system with space group P1 , with the cell parameters: a = 0.6413(2) nm, b= 1.4596(3) nm, c= 1.6188(4) nm, a= 102.473(5)°, β= 98.979(4)°, γ=101.739°, V=1.4165(6) nm³, Z=1. The coordination environment between Cu(1) and Cu(2) is different. Cu(1) is slightly distorted square pyramidal while Cu(2) is distorted square‐plane. The complex 1 is mononuclear while the complex 2 is made up of two coordinated subunits, namely [Cu(TCSSB)₂] and [CU(TCSSB)(H₂O)₂]₂. Besides that the TG‐DTG of the complex 1 was analyzed, the thermal decomposition reaction of the complex was studied under a non‐isothermal condition by TG‐DTG. The TG and DTG curves indicate that the complex was decomposed in three stages: .     

A Novel Uranyl Complex with Dimeric Lacunary Polyoxoanion: [(A-α-SiW<Subscript>9</Subscript>O<Subscript>33</Subscript>)<Subscript>2</Subscript>K{UO<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)}<Subscript>2</Subscript>]<Superscript>11−</Superscript>

A novel uranyl complex with dimeric lacunary polyoxoanion like open-mouthed clam, Na₅[(A-α-SiW₉O₃₃H₃)₂K{UO₂(H₂O)}₂], was prepared and characterized by elemental analysis, infrared and ultraviolet–visible spectroscopy and single crystal X-ray diffraction. In the anion, two A-α-SiW₉O₃₄¹⁰⁻ groups share two terminal oxygen atoms O_d′ derived from removal of three corner-shared W atoms from saturated α-Keggin anion, forming a dimeric anion with an open mouth in which potassium ion and uranyl ions are coordinated. Uranium atom adopts a pentagonal bipyramidal geometry. The coordinating anions are linked by sodium ions via coordination of terminal or bridging oxygen atoms, forming two-dimensional layer arrangement. Between the layers are the hydrogen bonds from which a supramolecular architecture is created. UV–VIS spectrum gives W–O and U–O charge transfer transitions at 230–265 and 432 nm, showing the change of geometry of the polyanion and weakening of the U–O bonds of the uranyl cation. Electronic supplementary material The online version of this article () contains supplementary material, which is available to authorized users.     

Study of a fluorescence quenching mechanism of enoxacin and its determination in human serum and urine samples

The maximum emission wavelength of dopamine is 317 nm with excitation at 290 nm. The relative fluorescence intensity of dopamine decreased in the presence of enoxacin, which showed that fluorescence quenching occurred. The Stern-Volmer (S-V) plot showed a nonlinear relationship between the relative fluorescence intensity of dopamine and the concentration of enoxain. The quenching mechanism was studied and the results suggested that both dynamic and static quenching processes were responsible for the observed positive deviation in the S-V plot. When the S-V plot was modified by logarithm, the linear relationship was obtained between logF ₀/F and C in the range of 0.10 to 13.0 μg/mL (where F ₀ is the relative fluorescence intensity of dopamine, F is the relative fluorescence intensity of dopamine in the presence of enoxacin, and C is the concentration of enoxacin). The fluorescence quenching method for the determination of enoxacin was developed. The linear regression equation of the calibration graph of enoxacin was C = 13.70 (logF ₀/F) − 0.5836, with the correlation coefficient 0.9984. The detection limit was 2.0 ng/mL and the relative standard deviation was 2.52%. The effects of pH, the stability of dopamine in the presence of enoxacin, and foreign ions on the determination of enoxacin have been examined. The recovery of enoxacin was from 94.9 to 103.0% in a human serum sample and from 94.9 to 108.0% in a urine sample. The method is simple, rapid, and can be used for the determination of enoxacin in human serum and urine samples with satisfactory results. The text was submitted by the authors in English.     

Dually responsive multiblock copolymers via RAFT polymerization: Synthesis of temperature- and redox-responsive copolymers of PNIPAM and PDMAEMA

We report synthesis of temperature- and redox-responsive multiblock copolymers by reversible addition-fragmentation chain transfer (RAFT) polymerization. Well-defined α,ω-bis(dithioester)-functionalized poly(N-isopropylacrylamide) (PNIPAM) and poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) were prepared using 1,4-bis(thiobenzoylthiomethyl)benzene and 1,4-bis(2-(thiobenzoylthio)prop-2-yl)benzene as RAFT agents, respectively. Dually responsive multiblock copolymers were synthesized in a single aminolysis/oxidation step from the α,ω-bis(dithioester)-terminated PNIPAM and PDMAEMA. The copolymers and their stimulus-responsive behavior were characterized by size exclusion chromatography, NMR, light scattering and atomic force microscopy. Due to the presence of redox-sensitive disulfide bonds between the blocks, the copolymers were readily reduced to the starting polymer blocks. The presence of temperature-responsive PNIPAM blocks provided the copolymers with the ability to assemble into core-shell nanostructures with hydrophobic PNIPAM as a core and cationic PDMAEMA as stabilizing shell when above the phase transition temperatures of PNIPAM. The temperature-induced assembly of the copolymers also showed substantial pH sensitivity. The phase transition temperature increased with decreasing pH, while molecular weight of the assemblies decreased.     

Capillary electrophoresis with wavelength-resolved laser-induced fluorescence detection

Capillary electrophoresis (CE) enables rapid separations with high separation efficiency and compatibility with small sample volumes. Laser-induced fluorescence detection can result in extremely low limits of detection in CE. Single-channel fluorescence detection, however, furnishes little qualitative information about a species being detected, except for its CE migration time. Use of multidimensional information often enables unambiguous identification of analytes. Combination of CE with information-rich wavelength-resolved fluorescence detection is analogous with ultraviolet-visible diode-array detection and furnishes both qualitative and quantitative chemical information about target species. This review discusses recent advances in wavelength-resolved laser-induced fluorescence detection coupled with CE, with an emphasis on instrument design.     

Laser-assisted electron capture by a fast proton from a hydrogen atom

The first Born approximation is used to study the laser-assisted electron capture by a fast proton from a hydrogen atom. The laser modification on differential cross section peaks sharply in the forward direction. With the impact energy increasing, the change in integral cross section becomes notable. The more intense the laser, the greater the cross section is; the lower the frequency, the greater the cross section.     

微型集成化色谱仪

用微制造技术和色谱原理结合，以全新的概念和设计思维研制色谱仪一微型集成化色谱仪。这种仪器的整个色谱部分在基片上制成。集微型进样器，细内径毛细管柱和微型固体检测器于一体，功耗不过几瓦，重不过几百克，而分析速度比现有仪器提高近一个数量级，检测灵敏度可达１０＾－６Ｖ／Ｖ。这种仪器的制作过程类似半导体器件，能大批量，性能高度重复可靠、而成本极为低廉地制造出来，彻底改变传统色谱仪器的生产方式。本文给出这种仪     

Preparation and characterization of nitrogen-doped titanium dioxides

A type of high visible-light active titanium oxinitride(TiO2-xNx) powder was prepared by a simple proc-ess:the calcination of the hydrated titanium dioxide at the atmosphere of ammonia-argon using a tu-bular electric furnace at high temperatures. The hydrated titanium dioxide was synthesized as the precursor of TiO2-xNx using titanic acid as raw material,which came from sulfate technique of produc-ing titanium white. The effects of temperature and reaction time on the nitrogen content,grain size and crystal structure were studied. The visible-light activity and photocatalysis capability of the powder were also investigated.     

表面电沉积Ni—La2O3复合镀层的Fe26Cr1Mo不锈钢的氧化行为研究

Ｆｅ２６Ｃｒ１Ｍｏ不锈钢在９００℃氧化时，生成的氧化层在冷却过程中大量剥落，经表面共电沉积ＮｉＬａ２Ｏ３复合镀层后，抗热循环能力明显提高。