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10 May 2014, Volume 35 Issue 5

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Cover and Content of Chemical Journal of Chinese Universities Vol.35 No.5(2014)

2014, 35(5):  0-0. 

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Review

Current Status and Future Prospects of Polymeric Nanocarrier for Tumor Targeting^†

YU Haiyang, TANG Zhaohui, SONG Wantong, DENG Mingxiao, CHEN Xuesi

2014, 35(5):  903-916.  doi:10.7503/cjcu20130849

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This paper reviewed the progress of polymer nanocarriers for tumor targeting delivery and controlled release of anticancer drugs, and elaborated the researching status of polymer nano-carriers with passive tumor targeting, active targeting, biodegradability, pH-sensitivity, reductive sensitivity, enzyme sensitivity and temperature-sensitivity. Future direction of relative research was discussed.



Articles: Inorganic Chemistry

Preparation and Magnetic Performance of Fe₃O₄/TiO₂ Hybrid Nanostructure^†

XU Man, DUAN Weijie, JIAO Shihui, PANG Guangsheng

2014, 35(5):  917-920.  doi:10.7503/cjcu20140114

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Using TiO₂ nanowires and Fe(NO₃)₃·9H₂O as raw materials, Fe₃O₄ nanoparticles/TiO₂ nanowires hybrid nanostructure was fabricated in a system with diethylene glycol as the solvent. High-resolution transmission electron microscopy(HRTEM) observation demonstrates that the Fe₃O₄ nanoparticles are addressed on the TiO₂ nanowires. Effective connection forms between the Fe₃O₄ nanoparticles and TiO₂ nanowires. Magnetic study shows that the hybrid nanostructure’s blocking temperature is significantly lower than that of pure Fe₃O₄ nanoparticles with the same diameters.



Preparation, Phase Structure Control and Luminescent Properties of Bi_1-xEu_xPO₄ Nanophosphors^†

ZHENG Yunlong, ZHAO Minglei, LI Liping, LI Guangshe, ZHANG Xitian

2014, 35(5):  921-927.  doi:10.7503/cjcu20131300

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We synthesized a series of hexagonal phase Bi_1-xEu_xPO₄ by a room-temperature co-precipitation method. The phase structure transformation from hexagonal phase to high temperature monoclinic phase, then to low temperature monoclinic phase was achieved by calcinations and grinding, respectively. Concerning the luminescent properties, the internal quantum yield of the grinded samples for Bi_0.95Eu_0.05PO₄ is 5% higher than that of the calcined samples. These luminescent changes were further discussed in terms of the phase structure and particle size.



Synthesis, Crystal Structure and Catalytic Performance of Zinc Complex Containing 2-(Aminomethyl)pyridine Ligand^†

LIU Chao, ZHUO Xin, ZHANG Hu, LIU Xinhua

2014, 35(5):  928-933.  doi:10.7503/cjcu20131290

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A novel zinc metal complex [Zn( AMPy)₂(OAc)]₂[Zn(OAc)₄] [AMPy=2-(aminomethyl)pyridine] was synthesized by the reaction of zinc acetate to 2-(aminomethyl)pyridine ligand. The structure of the complex was characterized by ¹H NMR, IR, elemental analysis and X-ray single crystal diffraction. The crystal structural analyses show that the complex belongs to triclinic system, space group is P\begin{array}{c}\overline{1}\end{array} with a=1.07360(19) nm, b=1.2491(2) nm, c=1.8976(3) nm, α=83.809(2)°, β=89.595(2)°, γ=65.708(2)°, V=2.3039(7) nm³, Z=2. The complex molecular consists of three different coordinated zinc ions which are connected by intramolecular hydrogen bonds into a total molecular, and 2D network structure is further formed by intermolecular hydrogen bonds. The catalytic performance of the metal complex in Henry reaction was studied, and the optimum catalytic conditions were obtained. The results show that the complex exhibits a high catalytic performance with 9%(molar fraction) of catalyst loading, methanol as solvent and reaction at room temperature for 20 h.



Ionic Liquid-assisted Synthesis of Anatase TiO₂ Nanotubes and Their UV Light Photocatalytic Activities^†

WU Liyan, LIU Zhifang, QIN Qing, CAO Yaan, ZHENG Wenjun

2014, 35(5):  934-940.  doi:10.7503/cjcu20131201

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Hydrogen titanate nanotubes with high crystallinity were prepared under the ionic liquid [Bmim]OH-assisted hydrothermal conditions and then converted into anatase TiO₂ nanotubes by calcination at 470 ℃ for 2 h. The phases, morphologies and specific surface areas of the resulting samples were investigated by means of powder X-ray diffraction(XRD), transmission electron microscopy(TEM), Raman spectroscopy and Brunauer-Emmett-Teller(BET) surface area analysis. The results indicated that the specific surface area and the pore size of anatase TiO₂ nanotubes were ca. 355 m²/g and 25 nm, respectively. Both anatase TiO₂ nanotubes and hydrogen titanate nanotubes exhibited high UV-light-driven photocatalytic degradation activity of parachlorophenol. The photodegradation efficiency of parachlorophenol reached 44% by anatase TiO₂ nanotubes, in 1 h of reaction. The introduction of ionic liquid could not only enlarge the temperature range of hydrothermal synthesis, but also benefit for improving the crystallinity of hydrogen titanate nanotubes.



Electrospinning Preparation and Visible-light Photocatalytic Activity of MoO₃/V₂O₅ Heterostructures^†

CHUAI Hongyuan, ZHOU Defeng, ZHU Xiaofei, YANG Guocheng, LI Zhaohui

2014, 35(5):  941-948.  doi:10.7503/cjcu20131114

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MoO₃/V₂O₅ heterostructures with high photocatalytic activity in visible light region were synthesized via electrospinning technique and sol-gel process. The morphologies and structures of MoO₃/V₂O₅ heterostructures were characterized by X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and UV-visible diffuse reflectance spectroscopy. The photocatalytic performances of MoO₃/V₂O₅ heterostructures were evaluated by the photodegradation of methylene blue(MB) under visible light irradiation. The results indicated that heterojunctions between MoO₃ and V₂O₅ were formed when the n(Mo)/n(V) ratio was above 1∶8, and the separation of photogenerated electron-hole pairs on MoO₃/V₂O₅ heterostructures was promoted, which made the decolorization rate of MB by MoO₃/V₂O₅ heterostructures much higher than usage of pure V₂O₅ nanofibers. The optimum n(V)/n(Mo) ratio of MoO₃/V₂O₅ heterostructures was found to be about 1∶6 and the decolorization rate of MB could be reached 97.24%. In addition, the photocatalytic mechanism of the MoO₃/V₂O₅ heterostructures was further analyzed and discussed.



Synthesis of Water-soluble C₆₀ Nanoparticles Under Ultrasonication and Investigation of Their Photoluminescence Property^†

LI Bing, YAO Mingguang, LI Chunjie, DU Mingrun, LIU Bingbing

2014, 35(5):  949-953.  doi:10.7503/cjcu20131020

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C₆₀ nanoparticles(C₆₀NPs) were prepared through a modified ultrasonic process. The effects of ultrasonic bath temperature on the particle size and distribution of C₆₀NPs, as well as the photoluminescence spectroscopy(PL) property of C₆₀NPs were studied. The results show that as the ultrasonic bath temperature increase, the average particle size of C₆₀NPs decrease and the dispersibility of C₆₀NPs improve obviously. Thermogravimetric analysis(TGA) and infrared(IR) spectroscopy measurements indicate that water and solvent accounte for 57% of the total mass of C₆₀NPs. After heating at 200 ℃, the particle size of C₆₀NPs is significantly reduced, and subsequently the water soluble C₆₀ quantum dots without solvent are obtained. The PL intensity from such water soluble C₆₀ quantum dots is about one order of magnitude higher than that from the as-prepared C₆₀NPs.



Analytical Chemistry

Comparative Chromatographic Method for Rapid Screening of Target Ionic Liquids^†

LIU Chaoqing, WANG Xiaoyi, ZHAO Jingqiang, CHEN Chunyue

2014, 35(5):  954-958.  doi:10.7503/cjcu20131288

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Analytical chemists learn the polarity of chromatographic stationary phase by testing the Rohrschneider-McReynolds constants in chromatographic columns, while chemical engineers acquire the selectivity and solubility of solvents by determining solubility parameters. However, in evaluating the properties of ionic liquids, they are not as useful as in general solvents. Sometimes the probe molecules have no peaks, and sometimes the solubility parameters calculated are not as what we predict. In order to overcome the shortages of the existing methods, a comparative chromatographic method was established, in which a well-known ionic liquid was used as a reference stationary liquid into the reference column, and new design ionic liquids as a sample stationary liquid filling into the sample column. With 7 solvents(n-hexane, ethyl acetate, benzene, 2-ketone, pyridine, n-butanol and nitro propane) as probe molecules, the adjusted retention time and asymmetry factor as the index, the target ionic liquids can be selected.



Organic Chemistry

Stereospecific Synthesis of ω-Amino-β-D-furanoribosyl cetic Acid Based on Microwave Assisted ittig-Michael Tandem Reaction^†

MA Donglai, LI Xiaoliu, HAO Le, ZHANG Pingzhu, CHEN Hua, ZHAO Ying

2014, 35(5):  959-964.  doi:10.7503/cjcu20131054

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An efficient and stereoselective method for synthesizing ω-amino-β-D-furanoribosylactic ester was established based on the microwave assisted Wittig-Michael tandem reaction of acetone protection of D-ribose(2) and Ylide 3(Ph₃P═CHCOOEt), and followed by ω-azidation and reduction. The microwave assisted Wittig-Michael addition reaction was carried out effectively and β-stereoselectively in CH₃CN at 115 ℃ with a yield up to 91% within 10 min, and the α-stereomer could easily converted to the thermodynamically more stable β-stereomer during workup in basic condition. The calculation results of quantum chemistry show that β-isomer 4b is higher than α-isomer 4a in thermodynamic stability. The structures of the compounds were identified by spectral analyses of ¹H NMR, ¹³C NMR and HRMS.



Modification of Acaudina Molpadioides Hydrolysates by Plastein Reaction and Preparation of ACE Inhibitory Peptides^†

SHEN Qingqing, ZENG Mingyong, ZHAO Yuanhui

2014, 35(5):  965-970.  doi:10.7503/cjcu20130951

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The effect of modification by plastein reaction on the angiotensin converting enzyme(ACE) inhibitory activity of Acaudina molpadioides hydrolysates and its peptides was researched to show that the ACE inhibitory activity of modified peptide decreased definitely, compared with the activity of original hydrolysates. The stability of the modified peptides to simulated gastrointestinal digestion was tested in vitro. The result showed that the ACE inhibitory activities of the peptides could be enhanced by digestive enzyme. Toxicity test showed no toxic to the MDCK cells while concentration was less than 10 mg/mL, and low concentration could promote the cells’ growth. A novel ACE inhibitory peptide was isolated from modified product using different methods including ultrafiltration, Sephadex G-15 gel filtration and RP-HPLC. The purified ACE inhibitory peptide was sequenced as NQNFVQYTTNT with an IC₅₀ value of 3.67 μmol/L. The accurate sites of ACE that the peptide bind to were determined through the computer assisted software SYBYL, and UV spectra analysis proved that some changes could be observed in the binding of ACE and peptides.



Controlled Release of Corrosion Inhibitor from Intelligent Nanocontainers Based on Acid and Base Dual-responsive^†

YANG Nianwang, CHEN Tao, FU Jiajun

2014, 35(5):  971-975.  doi:10.7503/cjcu20130880

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Hollow mesoporous silica nanoparticles(HMSs) were prepared using polystyrene microspheres(PS) as hard templates. The supramolecular nanovalves in the form of bistable pseudorotaxane molecules were installed on the surface of the HMSs and achieved the acidic and basic dual stimuli-responsive release effects of corrosion inhibitor molecules, benzotriazole(BTA). The morphology and structure of HMSs were characte-rized by transmission electron microscope(TEM), X-ray diffraction assay(XRD), Brunauer-Emmett-Teller(BET) and Barrett-Joyner-Halenda(BJH) analyses. The surface functionalization of HMSs was demonstrated by Fourier transform infrared spectrometer(FTIR) and thermogravimetric analysis(TGA). The release performances of BTA at different pH values were monitored by UV-Vis spectrophotometer. The results showed that the HMSs were monodispersed nanospheres and the specific surface area was 1141.16 m²/g. The intelligent nanocontainers constructed by the supramolecular self-assembly technology realized “zero premature release” at neutral condition and remarkable release at acidic or alkaline conditions.



Amyloid Fibril Formation by β-Casein and Its Influence Factor^†

LIU Jihua, John A.Carver, David C. Thorn

2014, 35(5):  976-980.  doi:10.7503/cjcu20130873

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β-Casein is the second abundant among the casein proteins in bovine milk and reported to exhibite biological activities. In this study, the focus was placed on the influence of lipids and heparin sulphate to β-casein fibril formation. In order to study the time course of fibril formation by β-casein, the samples were incubated and picked up at specific times and tested by ThT assay and transmission electron microscopy. The results showed that amyloid fibrils were not formed by β-casein incubated in pH=5.4—9.0 at 65 ℃ for 252 h, which suggested that β-casein is a good molecular chaperone. The β-casein fibril formation was promoted in the presence of longer-chain phosphatidylcholine lipids(D6PC and D9PC), which indicated that the interaction of β-casein with biomembrane of mammary gland abundant with lipids maybe caused β-casein structure changed from native to more β-sheet. Heparin sulphate, a major component of the extracellular matrix and a species which is commonly associated with extracellular amyloid deposits, interacted with β-casein to promote its aggregation. It is supposed that Corpora Amylacea is associated with mastitis because of high expression of heparin sulphate in inflamed mammary. This study explored that it is possible for chaperon proteins to form amyloid fibrils influenced by components in vivo and lose its chaperon effects.



Synthesis and In vitro Anticancer Activity of Novel Quinazoline Derivatives Containing Thiosemicarbazone Structure^†

LIU Haibin, LÜ Ping, PAN Ningning, AI Limei, LIU Yongxiang

2014, 35(5):  981-988.  doi:10.7503/cjcu20130837

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To find new EGFR inhibitors, 15 novel quinazoline derivatives containing thiosemicarbazone structure were designed and synthesized from 2-amino-4,5-dimethoxybenzoic acid and formamidine acetate by the cyclization, chlorination, amination and condensation reactions. All structures of target compounds were confirmed by ¹H NMR, ¹³C NMR, HRMS and elemental analysis. The in vitro anticancer activities of compounds 6a—6o against EGFR over-expressing of MCF-7(Human breast cancer), A549(Human pulmonary adenocarcinoma) and PC3(Human prostate cancer) cell lines were tested using colorimetric MTT assay. The results indicated that several compounds showed potent activity. Compounds 6a and 6o were more potent than Lapatinib, but slightly weaker than ADM against the three cell lines. The IC₅₀ values of compounds 6a and 6o against MCF-7 cell line were 6.97 and 6.99 μmol/L, against A549 were 5.15 and 3.11 μmol/L and against PC3 were 2.30 and 1.42 μmol/L, respectively. Preliminary structure-activity relationship was also discussed.



Synthesis and Self-assembly of Triblock Oligomers Containing Anthracene Unit^†

LIU Yang, ZHU Jikai, WANG Zhuoshi, ZHONG Keli, JIN Guangri, CHEN Tie, JIN Longyi

2014, 35(5):  989-994.  doi:10.7503/cjcu20130817

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Rod-coil molecules, consisting of a flexible and a rigid block, have a strong tendency to self-organize into a various supramolecular nanostructures in the bulk state. Coil-rod-coil triblock cruciform compounds 1 and 2 incorporating anthracene unit were synthesized through Sonogashira coupling reaction. Molecular structures of these compounds were characterized by ¹H NMR and MALDI-TOF mass spectroscopy. The self-assembling behaviors of these molecules were investigated by means of differential scanning calorimetry(DSC), thermal polarized optical microscopy(POM), small-angle and wide-angle X-ray scattering(SAXS and WAXS) at the bulk state. In liquid crystalline mesophase, compounds 1 connecting with poly(ethylene oxide)(PEO) as flexible chains self-assembles into oblique columnar phase(Col_o) and nematic phase, while compound 2 containing alkyl flexible chain self-assembles into lamellar structure(L) in the solid state, and has not shown liquid crystalline phase.



Physical Chemistry

Controllable Preparation of CdTiO₃ Nanorods and Their Photocatalytic Properties for Hydrogen Production^†

QU Yang, ZHOU Wei, REN Zhiyu, PAN Kai, JIANG Le, FU Honggang

2014, 35(5):  995-999.  doi:10.7503/cjcu20140103

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CdTiO₃ nanorods with different length were prepared from titanium glycolate nanorod template, combined with wet impregnation method and further calcination. The samples were characteried by scanning electron microscope(SEM), transmission electron microscope(TEM), wide-angle X-ray diffractometer(XRD), Fourier transform infrared spectrometer(FTIR), thermogravimetric analyser(TG) and ultraviolet-visible spectrometer(UV-Vis). The prepared CdTiO₃ nanorods are uniform with high crystallinity and high purity, and are about 50, 20, 10 μm in length, respectively. After loaded 1%(mass fraction) platinum as co-catalyst, their photocatalytic properties for H₂ production were studied. Compared with CdTiO₃ nanoparticles, the CdTiO₃ nanorods show higher photocatalytic activity. The H₂ producton performance for the longest nanorods is up to 52.9 μmol/h.



Theoretical Studies on the Structures and Spectroscopic Properties of N-Heterocyclic Carbene-pyridine-based Ruthenium Sensitizers^†

XIA Xiquan, ZHANG Hui, ZHANG Guiling

2014, 35(5):  1000-1006.  doi:10.7503/cjcu20140060

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Using bidentate N-heterocyclic carbene-pyridine ligands in substitution for two thiocyanates of the N749, a series of novel thiocyanate-free cyclometalated ruthenium polypyridine complexes(1—4) was designed. These complexes were studied theoretically using density functional theory(DFT) and time-dependent density functional theory(TD-DFT) techniques to explore their geometry structures, electronic structures and the spectral properties. The calculations indicate that the lowest-energy absorption of complexes 1—4 in CH₃CN solution is calculated at around 800 nm, arise from the MLCT/LLCT transition.



Surface Thermodynamic Properties of Micro/nano Peanut-shaped CaMo\begin{array}{c}{O_4}^{†}\end{array}

FAN Gaochao, MA Zhao, HUANG Zaiyin, TAN Xuecai, YAO Xianchao

2014, 35(5):  1007-1010.  doi:10.7503/cjcu20140062

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Mirco/nano peanut-shaped CaMoO₄ with three different sizes were prepared via reverse-microemulsion method at room temperature. Based on the essential difference between thermodynamic properties of nano CaMoO₄ and bulk CaMoO₄, the equations for acquiring molar surface thermodynamic functions of nano CaMoO₄ were derived via combining the basic theory of chemical thermodynamics with thermokinetic principle. According to the derived equations, molar surface thermodynamic functions such as molar surface enthalpy, molar surface Gibbs free energy and molar surface entropy of the synthesized peanut-like mirco/nano CaMoO₄ were successfully gained by in situ microcalorimetry. The results demonstrated that the size has significant influence on surface thermodynamic properties. Along with the size reducing, the molar surface enthalpy, molar surface Gibbs free energy and molar surface entropy increased.



Superhydrophobic to Icephobic Properties of Micro/nano-structure Composite Surfaces^†

WEN Mengxi, ZHENG Yongmei

2014, 35(5):  1011-1015.  doi:10.7503/cjcu20140050

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A micro/nano-structure surface which composed of organic materials and ZnO nanohairs was obtained by replica method and hydrothermal method. The cycle of the micro-structure is about 300 μm and the height of micro-structure is about 70 μm. The length and diameter of nano-structure are 2—3 μm and 300—500 nm, respectively. The results show that the micro/nano-structure surfaces have low adhesion, low temperature superhydrophobic properties and long icing delay time. This study has a good reference value on the design of hydrophobic/icing delay materials.



Synthesis of Carbon-doped Mesoporous TiO₂ Visible-light Photocatalytic Materials via One Pot Solvothermal Method^†

DING Shuang, ZHU Guowei, WANG Runwei, ZHANG Zongtao, QIU Shilun

2014, 35(5):  1016-1022.  doi:10.7503/cjcu20131301

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C doped TiO₂ mesoporous materials with spherical morphology were synthesized via solvothermal method in ethanol, using tetrabutyl titanate(TBOT) as the titanium source under template-free condition. The synthesized samples were characterized by XRD, SEM, TEM, N₂ adsorption-desorption, XPS, UV-Vis, and photocatalytic degradation of RhB. The results indicated that, the synthesized samples were pure phase anatase TiO₂, and they had morphology of uniform size spheres with the accumulation of the nanoparticles. The crystallinity and morphology of the synthesized samples could be regulated by the volume of adding acetic acid during the synthesis process. The results showed trace of C atoms getting into TiO₂ crystal lattice, replacing the position of O atoms, narrowing the band gap of TiO₂, and leading to the enhancement of visible light absorption. Photocatalytic test confirmed its excellent adsorption property and photocatalytic activity under visible light, which have very important meaning for solving environmental problems in current society.



Theoretical Studies on the Reaction Pathways of l-C_nH(n=5,6)+\begin{array}{c}{O_2}^{†}\end{array}

ZHU Weiwei, DING Yihong

2014, 35(5):  1023-1028.  doi:10.7503/cjcu20131295

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The C_nH free radicals were reported to play an important role in interstellar chemistry. The oxidation processes of C_nH radicals with n=1—4 had been explored by means of the theoretical and experimental methods. To further understand the reaction properties of the long carbon chain radicals, we report the first theoretical survey of the l-C₅H+O₂ and l-C₆H+O₂ reactions at the CCSD(T)/CC-PVTZ+ZPVE//B3LYP/6-311++G(d,p) level. The carbon transfer was found to be the main pathway in the l-C₅H+O₂ reaction, giving the main product P₂(CO₂+C₄H). Yet, the case is a little different for l-C₆H+O₂. The energy barrier between the C,O-exchange[resulting in P1(CO+HC₅O)] and the oxygen transfer[resulting in P3(³O+HC₆O)] is only 0.4 kJ/mol, indicative of their co-predominance. The present results were compared with the shorter l-C_nH radicals with O₂.



N/S Co-doped Non-precious Metal as Non-platinum Cathode Catalyst for Alkaline Membrane Fuel Cells^†

XU Li, PAN Guoshun, LIANG Xiaolu, LUO Guihai, Zou Chunli, CHEN Gaopan

2014, 35(5):  1029-1036.  doi:10.7503/cjcu20131208

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N/S co-doped non-precious metal material for the oxygen reduction reaction(ORR) was prepared with ferrous sulfate heptahydrate(FeSO₄·7H₂O), pyrrole and p-toluenesulfonic acid(TsOH) as Fe, N and S precursors supported on vulcan XC 72R, and followed by heat treatment in an inert atmosphere at 600 ℃. The electrochemical techniques such as cyclic voltammetry(CV) and rotating disk electrode(RDE) were employed with the Koutechy-Levich theory to make clear the ORR kinetical constants and the reaction mechanism. It is found that the catalysts dual-doped with TsOH show significantly improved ORR activity relative to the TsOH-free one. The overall electron transfer numbers for the catalyzed ORR are determined to be 3.899 and 3.098, respectively, for the catalysts with and without TsOH-doping. And these catalysts exhibit superior methanol tolerance to commercial 40%Pt/C catalyst. The XRD results demonstrate the decomposition of the precursors because of pyrolysis and formation of Fe-N_x-C active surface groups and some less active species. XPS analysis indicate that the pyrrolic-N groups are the most active sites and sulfur species are also structurally bonded to carbon in the forms of C—S_n—C and oxidized —SO_n— bonds, which are beneficial for ORR.



Brownian Dynamics Simulation Study on the Hierarchical Self-assembly of ACB Triblock Patchy Particles^†

LI Yang, LI Yanchun

2014, 35(5):  1037-1043.  doi:10.7503/cjcu20131158

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The hierarchical self-assembly of ACB triblock patchy particles were investigated via Brownian Dynamics(BD) method. The self-assembly product of first stage was set as the initial structure for the second stage self-assembly. By regulation the interaction between patch B as well as the concentration of patchy particles, the factors of influence the ordered structures were studied. Via properly designing the assembly models, routes and rules, we can obtain the formation of honeycomb network structure and diamond structures, respectively. The results revealed that the strong attraction between patch B was good for honeycomb network structure formation in solution with suitable patchy particle concentrations. But it was necessary to choose the appropriate attraction between patch B and the concentration to get the diamond mounted structures.



Effects of Temperature on the Antibacterial Activity and Structural Change of the C-terminal Polypeptide of the Sea Cucumber Lysozyme^†

WU Yao, LIANG Wenjing, LI Cheng, SHANG Xu, CONG Lina

2014, 35(5):  1044-1050.  doi:10.7503/cjcu20131144

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The recombinant polypeptide derived from C-terminal domain of the lysozyme from the sea cucumber Stichopus japonicus(SjLys-C) was used to detect the effect of temperature variation on the antibacterial activity and its structural change. The E. coli Rosetta-gamiB(DE3) pLysS was chosen as the new expression host to gain the recombinant C-terminal polypeptide of sea cucumber lysozyme successfully. Based on the antibacterial test, the fusion protein SjLys-C produced by the new host displayed potent inhibitive effect on the growth of M. lysodeikticus, S. aureus, P. aeruginosa and V. parahaemolyticus. In addition, the inhibitive activities about three tested bacteria were enhanced about 5%—22% after the fusion protein heated in 100 ℃ for 40 min. The molecule dynamic(MD) simulation was made to discover the conformational changes of SjLys-C after the heated treatment. The molecule dynamic simulation demonstrated that SjLys-C remained a stable conformation under the higher temperature condition. But several parts of amino acid residues on the SjLys-C were rearranged and the space distance between two active sites of Ser18 and His48 was closer at 100 ℃. The results might discover a new interpretation of the antibacterial function under the heated treatment of the sea cucumber lysozyme polypeptide.



Improvement of Electrochemical Performance of SnO₂ Anode by Polypyrrole with Different Morphologies^†

PENG Peng, WEN Zhaoyin, LIU Yu, YANG Jianhua

2014, 35(5):  1051-1056.  doi:10.7503/cjcu20131034

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SnO₂/polypyrrole composites as anode material of lithium ion batteries were in-situ prepared by an one-step precipitation in the suspension of the polypyrrole synthesized in advance. It is found that the morpho-logy of polypyrrole has an obvious effect on the electrochemical performance of SnO₂/polypyrrole composite anode. The granular polypyrrole(G-PPy) displayed advantages over the tubular polypyrrole. The composite containing G-PPy reached the first coulombic efficiency of 77.6% and remained a reversible specific capacity higher than 600 mA·h/g after 60 cycles. The good flexibility and adhesion of polypyrrole could make a contribution to the enhancement of the electrochemical performance of SnO₂ based anode.



Effects of Ionic Liquids with Different Anion Composition on Cell Growth, Metabolism and Catalysis Characteristics of Penicillium purpurogenum Li-3^†

LI Yang, CAO Hong, OUYANG Qiaofeng, LI Chun, ZHENG Lanlan, ZHANG Xin

2014, 35(5):  1057-1062.  doi:10.7503/cjcu20130859

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The wild-type Penicillium purpurogenum Li-3 strain is capable of expressing highly β-glucuronidase, a intracellular enzyme with excellent ability to biotransform glycyrrhizin(GL) into glycyrrhetinic acid monoglucuronide(GAMG) possessing best biological function. To improve the production of GAMG, the effects of ionic liquids with different anion composition on Penicillium purpurogenum Li-3 cells properties of growth, metabolism, permeability of cell membrane and catalysis were studied in this paper. The results showed that [Bmim]Ac and [Bmim]Tf₂N had obvious inhibitory effects on cell growth and metabolism. Six kinds of ionic liquids all improved the permeability of cell membrane, and [Bmim]Ac was the most remarkable. In the two catalytic medium respectively containing 25% hydrophobic [Bmim]PF₆ and [Bmim]Tf₂N, conversion rates of substrate GL were 82.73% and 89.84%, and the yields of GAMG were 68.65% and 76.23%, respectively. Thus, the substrate GL conversion increased slightly, but the yield of GAMG were about two times higher than that in the pure buffer solution without ionic liquids(conversion rate of GL 81.82%, yield of GAMG 33.31%). It was obvious that hydrophobic [Bmim]PF₆ and [Bmim]Tf₂N were capable of promoting the selectivity of the whole cell catalysis. While hydrophilic [Bmim]Ac, [Bmim]Cl and [Bmim]NO₃ obviously had inhibition in different degrees on the cell’s catalytic activity. These results indicated that the anions in ionic liquids played a crucial role as biological catalytic medium.



Homology Modeling and S₁' Binding Pocket Characteristics of MMP-26^†

TU Guogang, LIU Chao, LIAO Yijing, XIONG Shengtao, LI Shaohua

2014, 35(5):  1063-1067.  doi:10.7503/cjcu20130811

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Human matrix metalloproteinase-26(MMP-26/endometase/matrilysin-2) is a newly identified MMP and its structure has not been reported. With the crystal structure of MMP-12 as structural template, the 3D structure of MMP-26 was built by homology modeling, and S₁' binding pocket characteristics was studied. Residue His233 inserted S₁' binding pocket and limited the depth of the pocket, consistent with the interme-diate size prediction. So MMP-26 belongs to intermediate-pocket MMPs. On the basis of the modeling, the interactions of inhibition GM6001 with MMP-26 were investigated. Carbonyl oxygen and hydroxyl oxygen of hydroxamic acid structure were in bidentate coordinated mode with catalytic zinc ion, which was consistent with the characteristics of hydroxamic acids MMPs inhibitors. This work suggests that molecular modeling is a useful tool to understand structure-activity relationships and provides new insight for rational inhibitor design that may distinguish MMPs with deep versus intermediate S₁' pockets.



Polymer Chemistry

Monte Carlo Simulation of the Shear Effects on the Sol-gel Transition of Block Copolymers in Solution^†

LI Liangyi, LI Zhanwei, FU Cuiliu, SUN Zhaoyan, AN Lijia, SUN Yanbo

2014, 35(5):  1068-1074.  doi:10.7503/cjcu20140027

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By using nonequilibrium Monte Carlo simulation approach, the shearing effects on the sol-gel transition of ABA telechelic triblock copolymers in a B block selective solvent were investigated. The simulation results show that the shear makes the sol-gel transition concentration area shifting to lower concentrations. Microscopic structure properties of the solution under shearing were simulated, such as the fractions of chains with different conformations, micelle aggregation number and micelle number, cluster aggregation number and cluster number, average size of a single chain and the stretching degree of chains. The shear makes polymer chains stretched, so telechelic chains have more opportunity to form bridge conformation, which might be the reason why a certain extent shear promotes the sol-gel transition process.



Mechanical and Tribological Properties of PEEK Coatings with Different Melt Indexes Prepared by Electrostatic Powder Spray Technique^†

ZHU Shiyang, ZHANG Yunhe, LI Qingwei, JI Fangang, GUAN Shaowei

2014, 35(5):  1075-1079.  doi:10.7503/cjcu20140006

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Poly-ether-ether-ketone(PEEK) coatings with different melt indexes(MI) were prepared on the stainless steel substrate via electrostatic powder spraying method. Amorphous coatings were obtained by quenching the as-melted coatings into the ice-water medium. Semi-crystalline coatings were obtained by annealing the amorphous coatings in an oven for 30 min at 260 ℃. The XRD results indicates that the structure of PEEK coatings transforms from amorphous to semi-crystalline via the treatment of annealing. The hardness and the behavior friction of the PEEK coatings were tested. The result demonstrates that by the same treatment, the PEEK coatings with larger MI have higher crystallinity. The semi-crystalline PEEK coatings have higher hardness, lower friction coefficient and better wear rate than the amorphous ones. The poor fluidity of PEEK-A with lower MI leads to the rough coatings. Both of the PEEK-B and PEEK-C with larger MI can form smooth coatings and the friction coefficients and wear rates of them are stable. The friction coefficients of semi-crystalline coatings B and C are less than 0.15, and the wear rates are less than 20×10^-6 mm³/(N·m). Therefore PEEK with larger MI is more suitable for the preparation of PEEK coating by electrostatic spraying.



Preparation and Characterization of PS-b-P2VP/Fe₃O₄ Nanocomposites^†

ZHANG Zhijie, GONG Jiang, TAN Haiying, YAO Kun, TANG Tao

2014, 35(5):  1080-1085.  doi:10.7503/cjcu20131296

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Oleic acid modified Fe₃O₄ nanoparticles(OA-Fe₃O₄) with uniform particle size were blended with polystyrene-b-poly(2-vinyl pyridine)(PS-b-P2VP) that had micro-phase separation structure using solution-mixing method. The resultant PS-b-P2VP/Fe₃O₄ nanocomposites were superparamagnetic. The results showed that OA-Fe₃O₄ nanoparticles were dispersed in the PS phase of PS-b-P2VP, when the mass fraction of OA-Fe₃O₄ was 1%, 3%, 5% and 10%. However, when the content of OA-Fe₃O₄ was 8%, the dispersion of OA-Fe₃O₄ particles in the PS-b-P2VP matrix changed dramatically. In this case, the nanoparticles formed large aggregates, which were dispersed across PS-b-P2VP matrix. Meanwhile the rheological properties of PS-b-P2VP/Fe₃O₄ nanocomposites also changed.



Synthesis and Properties of a Novel Boron-containing Poly(arylether ketone) and Its Application in the Preparation of Azo Poly(aryl ether ketone)^†

WANG Yongpeng, LIU Mengzhu, ZHANG Yuxuan, LIN Yingjian, SHANG Yingshuang, ZHU Xuanbo, ZHANG Haibo, JIANG Zhenhua

2014, 35(5):  1086-1092.  doi:10.7503/cjcu20131109

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Novel poly(aryl ether ketone)s with pendant pinacolboronate groups(PAEK-Bpin) and boric acid groups(PAEK-BOH) were synthesized. PAEK-Bpin was prepared by the borylation of poly(aryl ether ketone) in the presence of [IrCl(COD)]₂ and dtbpy. The quantitative introduction of borate can be controlled by the amount of Bis(pinacolato)diboron(B₂pin₂). PAEK-BOH was obtained under the action of NaIO₄. Azo-PAEK was obtained via Suzuki-Miyaura reaction. The structure and property characterizations of all related products were carried out using ¹H-nuclear magnetic resonance(¹H NMR), ultraviolet and visible spectrophotometer(UV-Vis), gel permeation chromatography(GPC), differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA). The results of structure characterization suggest that products are synthesized. The results of GPC show that Ir catalyst and Suzuki-Miyaura reaction do not affect the molecular weight of the polymers. DSC results indicate that the glass transition temperature of PAEK-Bpin increases with the increase of the amount of boronate. However, PAEK-Bpin has good solubility in most of polar aprotic solvents. The preparation of boron-containing poly(aryl ether ketone) provides more broad prospects for further functionalization of the poly(aryl ether ketone).



Fabrication and Surface Properties of Hydrolyticly Function-switchable Polymer Brush^†

SHI Suqing, ZHAO Yang, ZHANG Qin, GAO Na, YANG Yang, GONG Yongkuan

2014, 35(5):  1093-1099.  doi:10.7503/cjcu20131092

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A hydrolysable cationic polycarboxybetaine ester polymer brush(PCBMA-1C2) was fabricated by photografting method with surface-coupled tertiary amine as hetergenous hydrogen donor and benzophenone(BP) as photosensitizer. The hydrolysis of PCBMA-1C2 modified surface was evaluated by studying the hydrolysis behavior of CBMA-1C2 monomer under different ammonium hydroxide concentrations. X-ray photoelectron spectroscopy(XPS) and water contact angle were used to monitor the chemical changes and hydrophilicity, respectively. The protein adsorption and platelet adhesion experiments were used to evaluate the interaction between the material surface and the biomolecules. The results show that when the concentrations of ammonium hydroxide are 0.1, 0.2, 0.3 and 0.4 mol/L, the degrees of hydrolysis(DH) of terminal ester of CBMA-1C2 monomer are 6%, 43%, 56% and almost 100%, respectively. Compared with Glass-PCBMA-1C2 surface, with the increase of DH, the protein adsorption of BSA are reduced by 3%, 76%, 93% and 96%, and that of Fg are reduced by 11%, 45%, 90% and 96%, respectively. When DH>50%, the hydrolyzed Glass-PCBMA-1C2 surface exhibits good resistance of protein adsorption and platelet adhesion.



Preparation and Characterization of Modified Graphene Oxide/Polyethersulfone Positively Charged Hybrid Nanofiltration Membrane^†

YU Liang, ZHANG Yatao, LIU Jindun

2014, 35(5):  1100-1105.  doi:10.7503/cjcu20130962

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Graphene oxide(GO) has received tremendous attention thanks to its unique two-dimensional feature, fantastic mechanical and chemical properties. In this paper, GO was fabricated and then was modified by chitosan. After the quaternization of modified GO, the positively charged material was used as inorganic additive to prepare polyethersulfone(PES) hybrid nanofiltration membrane with phase inversion method using N,N-dimethylacetamide(DMAc) as solvent, polyvinylpyrrolidone(PVP) as pore-forming agent. The effect of modified GO content on the separating property of hybrid membranes was investigated. The results suggested that the positively charged nanofiltration membranes were prepared successfully without the changes of morphology. With the increase of modified GO content, the water flux and separation selectivity of hybrid membranes were improved significantly and it was proposed that the best additive quantity of modified GO was round 0.5%(mass fraction).



Fabrication of the Columnar Structure with Gold Nanobowl Arrays Based on Colloidal Lithography^†

XUE Peihong, WANG Tieqiang, AI Bin, YE Shunsheng, LI Dongfeng, ZHANG Junhu

2014, 35(5):  1106-1110.  doi:10.7503/cjcu20130946

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A novel method was developed to fabricate the structure of a bowl on the top of column on nano/micro scale by selectively etching the photoresist oligomer film using the silica microspheres as masks. The gold nanobowl was formed on the top of the columnar structure as depositing a layor of Au on the surface of sample. By adjusting etching time, the dimension of columnar structure can be controlled. The characteristic transmission band of the material shows a obvious red shift from 500 nm to 760 nm when the height of the columnar structure increases. To investigate the optical property caused by the unique structure and the distribution of electric field around the noble metal, the method of the finite difference time domain was used. The high intensity of electric field was found at the edges and bottom of the gold nanobowl, which is the main influencing factor of the red shift.



Preparation of pH-Sensitive Fluorescent Poly(acryl-2-aminoethy-lammonium hydrochloride) with Porphyrin or Fluorene by One-pot Method^†

LIU Nan, WU Yonggang, BAI Libin, WANG Yuan, HUANG Haichao, ZHAO Hongchi, BA Xinwu

2014, 35(5):  1111-1118.  doi:10.7503/cjcu20130840

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Poly(N-tert-butoxycarbonyl-N'-acryloyl-1,2-diaminoethane)(PBAEN) with dithioester as end groups was prepared via reversible addition-fragmentation chain transfer polymerization(RAFT). The one-pot method, which the reduction of dithioester and Click reaction between thiol and epoxy group were conducted simultaneously, was used to prepared fluorescently label poly(N-acryloyl-1,2-diaminoethane hydrochloride)-porphyrin(PAEN-EPT) and poly(N-acryloyl-1,2-diaminoethane hydrochloride)-fluorene(PAEN-DEPF). The fluorescence intensity of PAEN-EPT and PAEN-DEPF in aqueous solution decreased dramatically as pH≥7 due to the polymer chain shrinking. The PAEN-EPT and PAEN-DEPF showed the pH-response. In addition, the quantum yield for PAEN-EPT aqueous solution could reach 0.096.