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    10 May 2012, Volume 33 Issue 05
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    Content
    Cover and Content of Chemical Journal of Chinese Universities Vol.33 No.5(2012)
    2012, 33(05):  0-0. 
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    Review
    Recent Progress in Single-Molecule Force Spectroscopy Study of Polymers
    ZHANG Wei, KOU Xiao-Long, ZHANG Wen-Ke
    2012, 33(05):  861-875.  doi:10.3969/j.issn.0251-0790.2012.05.001
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    The investigations on inter- or intra-molecular interactions in polymer systems at the single-molecule level are of pivotal importance in revealing the relationship between structure and function and eventually getting good controls on the corresponding function. Atomic force microscopy(AFM)-based single-molecule force spectroscopy(SMFS) has been used widely in the field of single-molecule study due to its friendly user interface(i.e., easy to use and can work in both aqueous solution and organic solvents) and world-wide commercialization. In this article, we introduced recent advancements in AFM-based single-molecule force spectroscopy study of polymer(including biopolymer and synthetic polymer) interactions. For biopolymer system, we first introduced typical force fingerprints of nucleic acid, protein and polysaccharides, and then discussed the force-fingerprint-based investigation of molecular interactions. For synthetic polymer system, the relationship between primary structure and single chain elasticity was discussed first, and then the effects of both single chain aggregates and the bulk aggregates on the elasticity of polymer chains were discussed.
    Article: Inorganic Chemistry
    Synthesis, Structure and Surface Photovoltage Characterization of [Co(en)3]2(Zr2F12)(ZrF6H2O)稨2O
    HAN Yi-De, DU Yu, LI Yi, SONG Xiao-Wei, YU Ji-Hong, XU Ru-Ren
    2012, 33(05):  876-879.  doi:10.3969/j.issn.0251-0790.2012.05.002
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    [Co(en)3]2(Zr2F12)(ZrF6H2O)·H2O(1) was prepared successfully at room temperature and structurally characterized by single-crystal X-ray diffraction analysis. Crystal data for compound 1 are as follows: monoclinic, C2/c, a=3.06110(17) nm, b=0.877680(5) nm, c=1.50811(9) nm, β=118.897°, V=3.547(4) nm3, Z=8. Compound 1 consists of one binuclear [Zr2F12]4-unit, one mono-nuclear [ZrF6H2O]2- unit, one cobalt ammine complex [Co(en)3]3+ unit and one water molecule, among which exist extensive hydrogen bonds. The surface photovoltage spectrum of compound 1 exhibit a signal at 339 nm, which is attributed to the cooperative behaviors between cobalt ammine complex and metal fluoride ions through interactions of them.
    Controlled-preparation of Twined Plate-like ZnO
    LV Chun-Yan, ZHANG Wei-Wei, ZHANG Qian, CHI Wen-Yang, HE Chan, LI Ji-Xue
    2012, 33(05):  880-884.  doi:10.3969/j.issn.0251-0790.2012.05.003
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    Twined plate-like ZnO crystals were prepared by hydrothermal method with the help of zinc acetate and potassium citrate. XRD, TEM, SEM, SAED, EDX and photoluminescence spectra were employed to characterize the crystal phase, morphologies, the chemical compositions and photoluminescence properties of the ZnO samples. The growth mechanism of ZnO was tentatively investigated. The obtained twined plate-like product is about 4 μm in diameter and 600 nm in thickness, which is wurtzite hexagonal structure ZnO. The experimental results show that the molar ratio of zinc acetate to potassium citrate and reaction temperature have greater influences on the morphology of ZnO, and potassium citrate plays a key role in modulating the morpho-logy of ZnO. The controlled-preparation of ZnO can be successfully achieved by regulating the molar ratio of zinc acetate to potassium citrate. Furthermore, the twined plate-like ZnO exhibit excellent optical property.
    Preparation and Characterization of Bifunctional Fluorescent Magnetic Dendrimer Microspheres
    GU Yin-Jun, WANG Xiu-Ling, ZHAO Qin, CHEN Gong, LIU Yong-Jian, ZHANG Li-Jie
    2012, 33(05):  885-891.  doi:10.3969/j.issn.0251-0790.2012.05.004
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    Three generations of magnetic and luminescent dendrimer microspheres were prepared. Superparamagnetic Fe3O4 nanoparticles were first prepared by hydrothermal coprecipitation of ferric and ferrous ions, followed by the modification of their surfaces with dendrimers. The surface-modified Fe3O4 nanoparticles were then linked to CdSe/CdS quantum dots(QDs), which were modified with thioglycolic acid to form the Fe3O4/CdSe/CdS fluorescent magnetic nanocomposites through the adsorption and bonding of the amino groups on the surfaces of Fe3O4 and the carboxyl groups on CdSe/CdS QDs. The structure and properties of the nanocompo-sites were characterized by Fourier transform infrared spectrometer(FTIR), elemental analysis(EA), transmission electron microscope(TEM), energy dispersive spectrometer(EDS), vibrating sample magnetometer(VSM), photoluminescence(PL) and UV-Vis spectrameters. The results show that the average size of three generations of nanocomposites are 15, 34 and 49 nm, respectively, the fluorescence property of G1F is the best with a fluorescent quantum yield up to 24.1%, while the magnetic property of G0F is the optimal with a saturation magnetization of 15.96 A穖2/kg. The synthesized bifunctional nanocomposites are expected to be widely used in immune detection, luminescence detection, targeted therapy, magnetic separation and so on.
    Synthesis, Crystal Structure and Magnetic Properties of an Oxalato- and Oxamido-bridged One-dimensional Mn(Ⅱ)-Cu(Ⅱ) Complex
    HU Kong-Qiu, KOU Hui-Zhong
    2012, 33(05):  892-896.  doi:10.3969/j.issn.0251-0790.2012.05.005
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    A new complex, [Cu(L)(H2O)Mn(C2O4)]·4H2O(H2L=1,4,8,11-tetraazacyclotetradecane-2,3-dione), was synthesized and structurally characterized by X-ray diffraction. The complex crystallizes in monoclinic space group P21/n with a=0.97471(5) nm, b=0.89316(5) nm, c=2.35635(11) nm, β=92.441(2)°, V=2.04951(18) nm3, Dc=1.691 Mg/m3, Z=4, R1=0.0607, wR2=0.1915(based on F2). The complex consists of [CuL(H2O)], Mn(Ⅱ), oxalate and lattice H2O molecules. Through the alternate oxalate bridges, the Mn(Ⅱ) ions form a zig-zag one-dimensional chain, while the other two coordination sites of the Mn(Ⅱ) ion are occupied by two oxygen atoms from L2- of [CuL(H2O)], giving rise to a mixed oxalate- and oxamido-bridged one-dimensional bimetallic complex. Magnetic studies show the presence of antiferromagnetic interaction between the Cu(Ⅱ) and Mn(Ⅱ) ions and between the adjacent Mn(Ⅱ) ions. Best fit to the experimental data by means of MAGPACK software gives the magnetic coupling constant of JCu-Mn=-13.1 cm-1 and JMn-Mn=-0.87 cm-1.
    Design and Preparation of SiO2/SiO2-TiO2 Antireflective Coating with Excellent Environmental Resistance
    YE Long-Qiang, ZHANG Xin-Xiang, XIAO Bo, YE Hai-Ping, JIANG Bo
    2012, 33(05):  897-901.  doi:10.3969/j.issn.0251-0790.2012.05.006
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    Double-layer antireflective(AR) coatings on K9 glass with excellent environmental resistance and abrasion-resistance were designed and prepared. Using tetraethylorthosilicate(TEOS) and titanium tetraisopropoxide(TTIP) as precursor, respectively, SiO2 and TiO2 sols were prepared via sol-gel process with hydrochloric acid as catalyst. SiO2-TiO2 composite films were prepared by mixing the SiO2 and TiO2 sols and then dip-coating on the substrates. The refractive indices of the composite films were controlled by adjusting the SiO2/TiO2 ratio and the thickness was controlled by adjusting the dip-coating speed. It was found that the maximum transmittance of the double-layer AR coatings reached 99.9% and could be adjusted to match a specific wavelength. The transmittance did not decrease after abrasion test, indicating an excellent abrasion-resistance of the AR coating. Hydroxyl terminated hexamethyldisiloxane(HMDS) treatment was further performed to improve the hydrophobicity, the environmental resistance and durability of the AR coatings.
    Analytical Chemistry
    Enantioseparation of Chiral Alcohols on Acellulose Derivative Immobilized onto Spherical Mesoporous SBA-15 by High Performance Liquid Chromatography
    DU Ming-Xia, QIAN Xian-Hua, WANG Li-Ping, SHAO Xin, LI Wen-Zhi
    2012, 33(05):  902-907.  doi:10.3969/j.issn.0251-0790.2012.05.007
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    Ordered mesoporous SBA-15 silica spheres were synthesized using the triblock copolymer, Pluronic P123, as the template with the assistance of KCl and 1,3,5-trimethylbenzene in the acidic condition. The obtained SBA-15 silica spheres with the particle size of 4.5 μm, pore size of 22.8 nm, surface area of 546.99 m2/g, and pore volume of 1.747 m3/g were used as the support in high-performance liquid chromatography(HPLC). The 3,5-dimethylphenylcarbamates of cellulose bearing about 3% of 3-(triethoxysilyl)propyl residues was immobilized onto SBA-15 particles by intermolecular polycondensation of the triethoxysilyl groups as the chiral stationary phase(CSP). The CSP was evaluated by HPLC for ten chiral alcohols with the eluents containing chloroform and tetrahydrofuran, which cannot be used with the conventional coated-type CSPs. Using the eluents, this CSP showed higher chiral recognition abilities to compare with that CSP based the same cellulose derivative bonded onto silica gel. The results indicated that the mesoporous SBA-15 spheres could be used as a good candidate for HPLC packings.
    Novel Air Flow Assisted Ionization Ion Source and Its Performance on Various Types of Mass Analyzer
    HE Jiu-Ming, LUO Zhi-Gang, TANG Fei, CHEN Yi, GONG Tao, HE Jing-Jing, ZHANG Rui-Ping, WANG Xiao-Hao, ZEPER Abliz
    2012, 33(05):  908-913.  doi:10.3969/j.issn.0251-0790.2012.05.008
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    The growth of the field of ambient mass spectrometry(MS) is rapid because of its advantage on direct MS analysis with minimum or without sample pretreatment. Ion source is one of the key techniques for mass spectrometer. This paper described the advanced development of air flow assisted ionization ion source(AFAI) and its performance on various types of mass analyzer. The maximum extracting gas flow rate was improved up to 75 L/min, and the sensitivity of the AFAI was investigated with higher extracting gas flow rate. AFAI ion source was installed on various types of mass analyzer including time of flight(TOF), Q-TRAP and Q-TOF via a corresponding modularized interface. Therefore, the full mass scan, product ion scan, precursor ion scan, neutral loss scan and accurate mass measurement would be carried out for ambient MS analysis with AFAI. The advanced development of the AFAI would promote its applications.
    Preparation of a pH-Responsive Carrier Based on Mesoporous Silica Nanoparticles and Its Application for Controlled Release
    CAO Jie, HE Ding-Geng, HE Xiao-Xiao, WANG Ke-Min, ZHAO Ying-Xiang
    2012, 33(05):  914-918.  doi:10.3969/j.issn.0251-0790.2012.05.009
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    A pH-responsive carrier was prepared by electrostatic interaction between positively charged mesoporous silica nanoparticles and negatively charged poly(acrylic acid). The physical and chemical properties of the as-synthesized mesoporous silica nanoparticles were characterized by transmission electron microscopy(TEM), X-ray diffraction assay(XRD), Fourier transform infrared spectroscopy(FTIR), Brunauer-Emmett-Teller(BET) and Barrett-Joyner-Halenda(BJH) analyses. Loading efficiency and controlled release properties of the carrier were investigated with Cl2 dyes as guest molecules. It was demonstrated that the mesoporous silica nanoparticles carrier was very sensitive to pH and exhibited good property of pH-responsive release. At neutral pH, positively charged nanoparticles interacted with negatively charged poly(acrylic acid) by electrostatic adsorption, resulting in the closing of the mesopores. The dyes could hardly be released from the nanoparticles. When the pH value was decreased, the percentage release of dye molecules increased. The dye was released sharply when the pH value was lower than 5. Cumulative release of the dye reached to 98％ at pH=1.0, 280 min. These results demonstrated that the release of the guest molecules could be controlled by pH adjustment. This new type of pH-responsive controlled release system based on mesoporous silica nanoparticles has the advantages of simply synthesis, low cost, and large load capacity, which made it have potential application in drug controlled release.
    Synthesis of 2'-Borono-benzaldehyde-7-(8-hydroxy-5-sulfoacid) Quinoline Hydrazone and Recognition of Pb2+
    XIAO Min, ZHANG Li-Na, WU Fang-Ying
    2012, 33(05):  919-924.  doi:10.3969/j.issn.0251-0790.2012.05.010
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    2', 3' and 4'-borono-benzaldehyde-7-(8-hydroxy-5-sulfoacid) quinoline hydrazone derivatives(1-3) were synthesized. The influences of host molecules with boric acid at different replace positions on the recognition of metal ions was investigated. The combining ability of host compounds with lead ion was compared. Research results showed that 2'-borono benzaldehyde-7-(8-hydroxy-5-sulfoacid) quinoline hydrazone(1) possessed highly selective binding and recognition to Pb2+in the KH2PO4-NaOH buffer solution with a pH value of 7.0. The 1∶1 complexes between host 1 and lead ion formed and they emitted strong fluorescence. The binding ability of host 1 with Pb2+ was the strongest among hosts 1-3. The emission wavelength of complex 1-Pb2+ was 477 nm and the binding constant was 1.1×103 L/mol. The presence of the other metal ions led fluorescent spectra of hosts 1-3 little change, for example Mn2+, Cu2+, Mg2+, Fe2+, Ca2+, Co2+, Hg2+, Ni2+, Cd2+, Ag+ and so on. Fluorescence intensity and the concentration of Pb2+ presented good linear relationship from 0.36 μmol/L to 10 μmol/L with a correlation coefficient of 0.9976(n=16), the detection limit of method was 0.23 μmol/L. The method was used to detect Pb2+in water sample from environment with the recovery of 92%-108%.
    Denatured Ribonuclease Refolding by Glutathione Bonding Column
    KE Cong-Yu, MENG Zu-Chao
    2012, 33(05):  925-930.  doi:10.3969/j.issn.0251-0790.2012.05.011
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    The renaturation of denatured ribonuclease was studied by covalent bonding the glutathione/glutathione disulfide(GSH/GSSG) to the surface of stationary phase. The results showed that the glutathione bonding column had a typical characters of weak-cation exchange, under the mode of ion-exchange chromatography(IEC), the column had a better column efficiency and four kinds of standard proteins could be baseline separated. With the protein concentration of 5 mg/mL, flow rate of 0.2 mL/min and no GSH/GSSG in mobile phase, the bioactivity recovery of denatured ribonuclease could reach (39.5?3.8)% refolded by glutathione bonding column, which was almost zero by common IEC column. The glutathione bonding column had an evident promoter action to the right refolding of denatured proteins disulfide bonds. Moreover, the bioactivity recovery could reach (81.5?4.3)% by adding GSH/GSSG to sample collections directly. These results may be useful for the development of protein folding liquid chromatography(PFLC) and in reducing the cost of proteins folding.
    Fabrication of Micro/Nanofluidic Chip on Glass Substrate and Its Application for Electrokinetic Concentration of Proteins
    DONG Yuan-Yuan, HU Xian-Qiao, CHEN Shuang, LU Hua, HE Qiao-Hong, CHEN Heng-Wu
    2012, 33(05):  931-936.  doi:10.3969/j.issn.0251-0790.2012.05.012
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    A simple and cost-effective double-lithography and double wet-etching method(abbriciated as double-etching technique) was developed for fabricating the full glass chips with hybrid micro- and nanochannels. The microchannels were firstly constructed on a glass substrate by standard UV photolithography and wet etching technique. After washing away the rest photoresist and spin coating of a new layer of photoresist on the microchannel-structured glass substrate, nanochannels with a depth less than 100 nm were prepared on the same substrate by second lithography and wet etching. Finally, the channel-structured glass substrate was sealed to a cover glass plate using room temperature bonding technique. Without clean room facilities and expensive facilities, fluidic chips with hybrid micro-and nanochannel network were fabricated with high yields. The analytical features of those fluidic chips were demonstrated by the successful concentration of fluorescein isothiocyanate(FITC)-labeled human serum albumin(HSA) via electrokinetic ion trapping. Enrichment factor of more than 200 was achieved for 0.5 mg/mL of FITC-HSA solutions within 30 s.
    Microwave Medium Tube-based Microwave-assisted Extraction of Organophosphorus Pesticides in Fruit Samples
    WANG Zi-Ming, ZHAO Xin, XU Xu, SU Rui, ZHANG Han-Qi
    2012, 33(05):  937-941.  doi:10.3969/j.issn.0251-0790.2012.05.013
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    Microwave absorption medium tube(MAMT) was firstly used to heat sample system, a new microwave-assisted extraction method was proposed and used for extracting four organophosphorus pesticides in fruit samples. In addition, a new portable microwave extraction apparatus(PMEA) was assembled in the laboratory and applied in this study. Because no polar solvent was used, the extract obtained by non-polar solvent(hexane) could be analysed directly by GC-MS without any clean-up step. The MAMT was made by sealing graphite powders in glass tube, which can be reused. The PMEA could be used in field environmental samples pretreatment. Some experimental parameters, such as type of extraction solvent, solid-to-liquid ratio, extraction temperature, and extraction time, were investigated. Four organophosphorus pesticides could be extracted from fruit samples within 8 min, and the recoveries obtained were 79.4%-107.6% with RSD <12.20%(n=3). The limits of detection for the analytes were found to be 0.15-0.42 μg/kg. The results indicated that the proposed method was simple, efficient and feasible.
    Solidification of Superamolecule Ordering Assembly Liquid Phase Microextraction and Its Application for the Determination and Evaluation for Lignans Quality in Schisandra Chinensis(Turcz.) Baill
    XUE Xue, ZHANG Hong-Fen, BAI Xiao-Hong, YUE Yuan
    2012, 33(05):  942-947.  doi:10.3969/j.issn.0251-0790.2012.05.014
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    The extraction mechanism of solidification of superamolecule ordering assembly liquid phase microextraction(SSMOALPME) was proposed based on the change in the UV spectra of lignan compounds before and after the solidification of floating organic drop liquid phase microextraction(SFODLPME). SSMOALPME coupled with high performance liquid chromatography(HPLC) was introduced for the determination and eva-luation of five low abundance lignan compounds in Schisandra chinensis(Turcz.) Baill from different origins. Under the optimized parameters, the linear ranges of schisandrol A, schisantherin A, schizandrin A, schizandrin B and schizandrin C were 2.48×10-3-6.21, 2.27×10-3-28.5, 2.31×10-3-28.8, 2.27×10-3-5.69 and 1.05×10-3-5.25 μg/mL, the limits of detection(LODs) were 0.4, 0.4, 0.4, 0.08 and 0.08 ng/mL, respectively, the intra and inter RSDs were less than 9.7%, the mean recoveries of analytes in traditional Chinese medicines(TCMs) were between 91.9% and 104.7%, and the enrichment factors(EFs) were in the range of 39-529 for SFODLPME. There was no significant difference in results determined lignan compounds in Schisandra chinensis(Turcz.) Baill by this method and Pharmacopoeia method (P=95%). SSMOALPME-HPLC provide the theoretic foundation and experimental evidence for reflecting bioactive component characteristics of multicomponent, multi-targets, synergistic effect, and establishing scientific quality control methods in TCMs.
    Degradation and Removal of Sulfadiazine from Waters by a Novel Polymer-supported Hydrous Manganese Dioxide(HMO)
    GAO Jun, SHENG G. Daniel, QIU Yu-Ping
    2012, 33(05):  948-953.  doi:10.3969/j.issn.0251-0790.2012.05.015
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    A new polymer-supported hydrous manganese dioxide(HMO-201) was prepared by impregnating HMO onto a porous polystyrene anion exchange resin(D201) through ion exchange, oxidation and reduction. The removal of sulfadiazine(SD) by HMO-201 was evaluated as a function of solution pH, background electrolyte NaCl and dissolved organic matter(DOM). HPLC-MS results showed that the removal of SD by HMO-201 was due to degradation rather than adsorption. The results indicated that the removal of 0.01 mmol/L SD reached 99.9% at pH=1.0 within 120 min. The SD degradation followed the pseudo-first-order kinetics. SD removal efficiency was little affected by ionic strength and DOM. With simulated SD wastewater containing NaCl and DOM, SD removal efficiency remained above 99% within 240 min for up to ten batches of continuous operation. Fixed-bed column experiment results of HMO-201 showed that SD remained undetected after 2000 bed volume simulated SD wastewater was passed through the column. HMO-201 was effective for the removal of sulfonamide antibiotics commonly found in the environment. It could be reused without a significant loss of capacity and thus has a great potential of real-world applications.

    Organic Chemistry
    Solvent-free Synthesis of 1,4-Dihydropyridine Derivatives under Ultrasonic Irradiation with Ytterbium Nitrate as Catalyst
    ZHAO Xing-Hua, MU Shu-Yong, ZHAO Li
    2012, 33(05):  954-957.  doi:10.3969/j.issn.0251-0790.2012.05.016
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    1,4-Dihydropyridine(DHP) derivatives are important class of pharmacological active compounds. In order to develop enriched methods for synthesis of 1,4-dihydropyridine derivatives, an one-pot four component Hantzsch condensation reaction of aryl aldehydes, 5,5-dimethyl-1,3-cyclohex-aedione, ethyl acetoacetate and ammonium acetate was investigated by employing Yb(NO3)3 as catalyst, without solvent under ultrasonic irradiation at room temperature. It was found that the reaction was carried out in the presence of Yb(NO3)3, the yield ranged from 86% to 97%, the reaction time was 15-35 min. Compared to the classical Hantzsch condensation reaction, the main advantages of the present procedure were milder conditions, shorter reaction time and higher yields, which afforded an effective method to synthesize 1,4-dihydropyridine derivatives. Further study showed that Yb(NO3)3 was environmentally friendly and reused for three times without any noticeable decrease in the catalytic activity.
    Stereoselective Synthesis of Glycosyl Acrylate Derivatives by Microwave Assisted Wittig Reaction
    WANG Wei, LI Xiao-Liu, LI Rui, ZHANG Ping-Zhu, CHEN Hua
    2012, 33(05):  958-963.  doi:10.3969/j.issn.0251-0790.2012.05.017
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    In order to develop an efficient, practical and stereoselective method for synthesizing glycosyl acrylate derivatives, the microwave assisted Wittig reaction of sugar ketone(1) and lactones(4) with ylide 2(Ph3PCHCOOEt) was investigated in a sealed microwave reactor in various temperatures and solvents. The reaction was carried out effectively and stereoselectively in xylene at 180 ℃ with a yield up to 80% within 10 min.
    Partial Acid Hydrolytic Characteristics and Methylation Analysis of Pentosans from Black-grained Wheat Bran
    SUN Yuan-Lin, GU Xiao-Hong, SHAN Fang, ZHANG Jun-Ming, CUI Wu-Wei
    2012, 33(05):  964-968.  doi:10.3969/j.issn.0251-0790.2012.05.018
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    The hydrolytic characteristics and the structural features of substitute degree as well as substitute patterns of pentosans(AEPH) from black-grained wheat bran were analyzed. AEPH was hydrolyzed with 0.02, 0.1, and 0.2 mol/L trifluoroacetic acid(TFA), respectively. The structural features and Mw of AEPH were studied with methylation methods, combined with GC-MS and HPLC instruments. The results indicated that the residues of sugar constituents were mainly Araf and Xylp, with an Ara/Xyl(A/X) ratio of 0.60 and a high average molecular weight(Mw) of 3.81×105. AEPH contained a xylan backbone of 1→4 linked Xylp residues which was mono- or disubstituted with Araf groups at position O3, O2 or at both O2 and O3 positions. The relative composition ratio of un-, mono-, and di-substituted Xylp in the arabinoxylan fraction was 57.7∶22.0∶6.2, with a high proportion of unsubstituted to substituted Xylp(2.1), and a very low proportion of di- to monosubstituted Xylp residues(d/m, 0.3). Araf side groups were linked to Xylp residues of the backbone as terminal Araf single units. Moreover, small quantities of 1→2, and 1→5 linked Araf indicated the presence of short arabinan side chains terminated with T-Xylp residues.
    Synthesis and Biological Evaluation of Oleanane Triterpenoid with γ-Lactone Functionality in Ring C
    QIAN Shan, WU Yong, HE Yu-Xin, WANG Zhou-Yu, YANG Wen-Yu, CHEN Xin
    2012, 33(05):  969-975.  doi:10.3969/j.issn.0251-0790.2012.05.019
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    Some oleanolic acid(OA) derivatives with γ-lactone functionality in ring C had better H2O solubi-lity and bioavailability than OA. Preliminary biological screening in vitro of these derivatives for 12 responding protein targets and cells of frequent diseases was processed. This investigation revealed that lactone 13 showed significant activity(IC50=3.58 μg/mL) against Cathepsin K, and was found to be a potent leader compound for the treatment of osteoporosis. Preliminary structure-activity relationship analysis indicated that the γ-lactone and glyco-groups were active groups.
    Synthesis, Antioxidant and Anticancer Activities of 1,2,5-Selenadiazole Pyrimidine Heterocyclic Derivative ASPO
    HUANG Xiao-Chun, ZHENG Jun-Sheng, CHEN Tian-Feng, ZHANG Yi-Bo, LUO Yi, ZHENG Wen-Jie
    2012, 33(05):  976-982.  doi:10.3969/j.issn.0251-0790.2012.05.020
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    The trace element selenium(Se) is an essential nutrient of fundamental importance to human and animal. Epidemiological, preclinical and clinical studies have supported the role of Se as potent cancer chemopreventive agents. Se-containing heterocyclic compounds have attracted more and more attention due to their anticancer potential and interesting chemical properties. In the present study, a selenadiazole pyrimidine heterocyclic derivative 5-amino-[1,2,5]selenadiazolo-[3,4-d]pyrimidin-7-ol(ASPO) was synthesized and characterized by ESI-MS, 1H NMR, elemental analysis, IR, UV-Vis absorption spectroscopy and fluorescence spectroscopy. Its antioxidant and anticancer activities were evaluated. The results show that ASPO can effectively scavenge the 2,2'-azinobis-3-ethylbenzothiazolin-6-sulfonic acid(ABTS) and 1,1-diphenyl-2-picryhydrazyl(DPPH) free radicals in a dose-dependent manner, demonstrating its strong antioxidant activity. The in vitro anticancer activities of ASPO were screened by MTT assay against various cancer cell lines and it was found that ASPO could effectively inhibit cancer cell growth, especially A-375 human melanoma cells. Further investigation on the action mode show that ASPO induces Sub-G1 peak accumulation, chromatin condensation and the formation of apoptotic bodies in a dose-dependent manner in A-375 cells, indicating that apoptosis is the main mechanism accounting for the anticancer action of ASPO. Moreover, it was showed that ASPO could bind to CT-DNA by minor groove. The results support that ASPO induces cancer cell apoptosis through its interaction with DNA.
    Biological Chemistry
    A Tetrapeptide Containing Selenium(SecRGD) with Glutathione Peroxidase Activity
    ZOU Xian-Feng, LV Shao-Wu
    2012, 33(05):  983-987.  doi:10.3969/j.issn.0251-0790.2012.05.021
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    Glutathione peroxidase(GPx) is the most crucial antioxidant enzyme in a variety of organisms. Here, base on the Arg-Gly-Asp(RGD), a tetrapeptide containing selenium(SeCRGD) was chemically synthesized. The existential state of the peptide was investigated by ESI-MS and hydride generation atom fluorescence spectral analysis. The GPx activities and the kinetics of the peptide were determined by the enzyme coupling method. The antioxidant effect of the peptide was evaluated based on MTT assay. The results showed that a kind of oxide form, SecRGD-dimer, was confirmed by ESI-MS and selenium content analysis. The peptide had GPx activity of 5.54 U/μmol and more than that of Ebselen. As native enzyme, a ping-pong mechanism was observed in steady-state kinetics studies. Moreover, the novel selenopeptide occupied merits of small molecular weight, good solubility in water and low toxicity. Especially, the peptide was found that could protect Vero cells from the injury induced by H2O2. Thus, the novel selenopeptide possesses a good potential in medicinal application.
    Effects of Dimethyl Sulfoxide and Tetrahydrofuran on the Catalytic Kinetics and Molecular Spectra of Pepsin
    LI Chun-Yi, HUANG Zhuo-Lie, LI Li-Jia, WU Guang-Hong, HE Ping, ZHU Guo-Hui
    2012, 33(05):  988-995.  doi:10.3969/j.issn.0251-0790.2012.05.022
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    In order to approach the effects and action mechanism of dimethyl sulfoxide(DMSO) and tetrahydrofuran(THF) on pepsin, the catalytic activity, kinetics parameters, ultraviolet absorption spectra, ultraviolet differential spectra, and fluorescence emission spectra of pepsin were investigated. It was indicated that pepsin activity was enhanced by 83.4% as the enzyme was treated with 9%DMSO. But when pepsin was treated with 1%THF the enzyme activity was enhanced only by 3.59%. In hydrochloric acid solution the kinetics parameter of the enzyme, Km=2.22 mg/mL, vmax=1.1?106 U/mg Pro. In 9%DMSO, Km=1.50 mg/mL, vmax=0.5?106 U/mg Pro. In 1%THF, Km=1.91 mg/mL and vmax=0.51?106 U/mg Pro. In 9%DMSO the ultraviolet absorption of pepsin peptide bonds was strongly inhibited. But the ultraviolet absorption of aromatic amino acids of pepsin was not inhibited. The ultraviolet absorption of pepsin molecules was not influenced obviously in 1%THF. Both in 9%DMSO and in 1%THF the ultraviolet differential spectra of pepsin showed obvious positive and negative peaks. The fluorescence emission peak of pepsin enzyme moved to short wavelength direction by 1 nm in 9%DMSO. But in 1% THF the fluorescence emission spectrum did not change obviously. It was concluded from these results that the conformation of pepsin molecules changed obviously in both 9%DMSO and 1%THF. This led the Km value of the enzyme descended and the affinity of the enzyme to substrates enhanced. So the catalysis activities of the enzyme were increased in some extent in these solutions.
    Modeling of 3D Structure of Pseudorabies Virus(PRV) Thymidine Kinase and Its Ligand Designing
    WANG Yin, YANG Ze-Xiao, YAO Xue-Ping
    2012, 33(05):  996-1000.  doi:10.3969/j.issn.0251-0790.2012.05.023
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    To research the methods for the prevention and control of pseudorabies virus(PRV), the thymidine kinase(TK) gene of PRV was amplified with PRV DNA as the template by PCR, and cloned into pMD18-T Vector, sequenced and translated into the amino acid sequence of TK using DNAStar software. Then the three-dimensional(3D) structure mode of TK was constructed by the homology modeling method, and the model reliability was determined by both Ramachandran plot and Profile-3D image. InsightⅡ/Binding site, Delphi and Affinity modules were used to explore the possible functional sites and interaction model of the TK and its inhibitor. The results show that Site 1 are the possible active sites and a new low molecular inhibitor, N-phenyl-N'-methylurea, is designed, and the special hydrogen-band interaction may play an important role in inhibiting the enzyme activity. These results may provide new theoretical references and pathway through PRV-TK inhibitors designing to the study of methods of PRV control.
    Physical Chemistry
    Effects of Surface Properties and Microstructures of Carbon Nanofibers on Their Electrocatalytic Activity for Oxygen Reduction Reaction
    JIANG Yue, QIN Yuan-Hang, NIU Dong-Fang, ZHANG Xin-Sheng, ZHOU Xing-Gui, SUN Shi-Gang, YUAN Wei-Kang
    2012, 33(05):  1001-1006.  doi:10.3969/j.issn.0251-0790.2012.05.024
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    Two types of carbon nanofibers(CNFs), tubular CNFs(t-CNFs) and fish-bone CNFs(f-CNFs) were synthesized and the effects of surface properties of CNFs on their electrocatalytic activity for oxygen reduction reaction(ORR) in alkaline media were investigated. Oxygen- and nitrogen-containing functional groups were introduced onto the CNF surface by sonochemical oxidation in mixed acids(concentrated sulfuric acid and nitric acid) and ammonia, respectively. The ORR activities of the CNF catalyst were measured in an oxygen-saturated 0.1 mol/L KOH electrolyte solution by rotating disk electrode(RDE) technique. The RDE results show that the electrocatalytic activities of the two types of CNFs increase in the same sequence untreated CNFs < oxygen-containing CNFs < nitrogen-containing CNFs, while the f-CNFs-based catalysts have higher electrocatalytic activities for ORR than t-CNFs-based counterparts. The results indicate that both the surface properties and the microstructures of CNFs have effects on the electrocatalytic activity of CNFs for ORR, although the former may have a dominant effect.

    Electrocatalytic Performance of Cathodic Ir-Fe/C Catalyst in Direct Methanol Fuel Cell
    GUO Qi, LI Lin-Ru, LU Liang, JI Yun, LU Tian-Hong
    2012, 33(05):  1007-1010.  doi:10.3969/j.issn.0251-0790.2012.05.025
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    Ir-Fe/C catalyst was prepared. The electrocatalytic activity of the Ir-Fe/C catalyst for the oxygen reduction and its methanol tolerance ability were investigated, based on the characterization with X-ray diffractometer(XRD) and energy dispersive spectrometer(EDS). The results show that the onset potentials of the oxygen reduction at the Ir/C and Ir-Fe/C catalyst electrodes are 0.57 and 0.65 V, respectively, and the current densities at 0.2 V are 4.6 and 5.8 mA/cm2, respectively. It indicates that the electrocatalytic activity of the Ir-Fe/C catalyst for the oxygen reduction is better than that of the Ir/C catalyst. In addition, the Ir-Fe/C catalyst possesses the high methanol tolerance ability. These results lay a strong basis for the use of the Ir-Fe/C cathodic catalyst in direct methanol fuel cell(DMFC).
    Nucleation Mechanism and Electrocatalysis of Pd NPs onto ITO Electrode in the Electrochemical Deposition Process
    TANG Jing, TIAN Xiao-Chun, LIU Yue-Qiang, LIN Jian-Hang
    2012, 33(05):  1011-1016.  doi:10.3969/j.issn.0251-0790.2012.05.026
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    Pd nanoparticles(NPs) electrodeposited onto indium tin oxide(ITO) surface were applied to the study of the electrocatalytic activity of ethanol. Firstly, cyclic voltammetry and chronoamperometry were employed to study the deposition mechanism at the initial stage of Pd electrodeposition on ITO. The deposition process was irreversible which was controlled by the diffusion of [PdCl4]2-, and the diffusion coefficient of[PdCl4]2- was calculated to be 2.19?10-5 cm2/s. Comparing the current transient data at different potentials with those predicted by the instantaneous and progressive nucleation models under diffusion control, progressive three-dimensional nucleation mechanism was proposed for the nucleation of Pd on ITO at -0.1 V. The mechanism changed to the instantaneous nucleation mode at -0.3 V. FESEM images of the electrodeposits show that the size of Pd NPs is affected by the deposition potential and the deposition period. Secondly, the structure of Pd NPs was analyzed with XRD and the electrochemical behavior on ITO was studied in the solution of 0.5 mol/L H2SO4, respectively. Finally, the obtained Pd NPs/ITO were applied in the electrocatalysis of 1.0 mol/L ethanol in alkaline solution, which displayed superior electrocatalytic activity.
    Poisoning of Acetone to Electrooxidation of 2-Propanol at Pd Electrode
    LIU Yao, ZENG Ya-Chao, LIU Ran, WANG Gui-Ling, CAO Dian-Xue
    2012, 33(05):  1017-1020.  doi:10.3969/j.issn.0251-0790.2012.05.027
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    The effects of acetone concentration and reaction temperature on the electrooxidation of 2-propanol at Pd electrode were investigated by cyclic voltammetry and chronoamperometry. The results show that acetone significantly poisons the electrocatalytic activity of Pd for 2-propanol oxidation. A competitive adsorption mechanism was proposed to interpret the poisoning effect.
    Electrocatalytic Properties of Pt-TiO2 Nanotubes Electrode Prepared by Pulse Electrodeposition Method
    MENG Xiang-Long, LI Hong-Yi, WANG Jin-Shu
    2012, 33(05):  1021-1024.  doi:10.3969/j.issn.0251-0790.2012.05.028
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    Platinum(Pt) nanoflower structure was electrodeposited on the surface of the aligned TiO2 nanotube, which was fabricated by anodic oxidation on titanium samples. The obtained electrode was characterized by XRD and SEM. The experiment results show that Pt is dispersed on the TiO2 nanotubes in the shape of nanoflowers, particle size is 25.6 nm based on the calculations of XRD. Compared with pure Pt and clean TiO2 nanotube arrays, the hybrid electrodes' electrocatalytic activity for methanol oxidation has been greatly improved. The oxidation current densities on Pt-TiO2 nanotubes electrode are 40 times higher than that of pure platinum electrode. The hybrid electrode shows promising applications in many fields, such as direct methanol fuel cell, treatment of polluted water and so on.
    Flow Behavior of Aqueous Solution of Exopolysaccharide Secreted by a Deep-sea Mesophilic Bacterium
    LI Hai-Ping, LIU Sheng-Bo, HOU Wan-Guo
    2012, 33(05):  1025-1030.  doi:10.3969/j.issn.0251-0790.2012.05.029
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    Shear-induced flow behavior of aqueous solution of exopolysaccharide(EPS) secreted by a deep-sea mesophilic bacterium(SM-A87) was investigated in a coaxial cylindrical measurement system(Z41 DIN) used in the Haake RS 75 Rheometer(Germany), and emphasis was placed on the influence of solution concentration, temperature, pH value and NaCl concentration on Reynolds number(Re) and critical Reynolds number(Rec) of the solution. The results showed that Re decreased but Rec increased gradually with solution concentration inereasing or temperature and NaCl concentration decreasing. As pH value increased from 3 to 12, Re and Rec were initially almost constant, but at pH value higher than 7, Re increased accompanied with Rec decreasing. The relationship between Rec and temperature were fitted well by an Arrhenium-like equation while that between Rec and solution concentration by a power law model.
    Fabrication and Photocatalytic Property of Three-dimensional ZnO Hierarchical Structure
    PAN Chao, DONG Li, QIU Jie-Shan
    2012, 33(05):  1031-1035.  doi:10.3969/j.issn.0251-0790.2012.05.030
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    Three-dimensional ZnO hierarchical structures with high densities of secondary ZnO nanowires grown on primary ZnO fibers were fabricated through a co-precipitation reaction growth on the electrospinning PVA/zinc acetate nanofibers template followed by an annealing process in air. The structural analyses showed that as-prepared amorphous ZnC2O4 nanowires converted into wurtzite ZnO after annealing. The morphology of the ZnO hierarchical structures could be further controlled by adjusting the molar ratio of H2C2O4 to EtOH. The hierarchical structured ZnO sample shows an enhanced photocatalytic performance compared with the other nanostructured ZnO powders of nanoparticles, and nanofibers, which can be attributed to the special structural feature with an open and secondary ZnO nanowire that significantly facilitates the diffusion and mass transportation of acetaldehyde molecules and oxygen species in photochemical reaction of acetaldehyde degradation.
    Controlled Synthesis of Nd2(CO3)3?8H2O Particles in the Media of Reverse Microemulsions
    ZHU Wen-Qing, XING Xi-Ping, ZHANG Chao, YUAN Yu-Kun, CHEN Ya-Shao
    2012, 33(05):  1036-1040.  doi:10.3969/j.issn.0251-0790.2012.05.031
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    Nd2(CO3)3?8H2O particles were prepared in water/oil(W/O) reverse microemulsion composed of cetyltrimethylammonium bromide(CTAB), n-butanol, n-octane, Nd(NO3)3?6H2O aqueous solution, Na2CO3 aqueous solution by the microemulsion-assisted solvothermal method. The influences of the molar ratio of water to CTAB and the concentration of Nd(NO3)3 on the morphologies and sizes of Nd2(CO3)3?8H2O particles were studied. The structures, morphologies and sizes of the nanoparticles were characterized by X-ray powder diffraction(XRD), differential scanning calorimetry and thermal gravimetric analysis(DSC-TGA), scanning electron microscope(SEM) and transmission electron microscope(TEM). The possible formation mechanism of the morphologies structure of Nd2(CO3)3?8H2O was proposed. The Nd2(CO3)3 particles with polyhedral, fishtail-like and needle-like shapes were controlledly synthesized via the microemulsion-assisted solvothermal method by regulating the molar ratio of water to CTAB. The size of the needle-like Nd2(CO3)3?8H2O particles decreased with increase of the concentration of Nd(NO3)3.
    Scattering Imaging of Cervical Cancer Cell by Laser Scanning Confocal Microscopy with Gold Nano-probes
    CHEN Na, QIN Song-Bing, ZHANG Bing-Bo, ZHANG Xu-Guang, ZHOU Ju-Ying, TU Yu
    2012, 33(05):  1041-1045.  doi:10.3969/j.issn.0251-0790.2012.05.032
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    The quantities and activities of folate receptor are higher in tumor cells than those in normal cells, so it has become the ideal ligand for targeted therapy of tumor. Due to the unique optical property of gold nanoparticles(AuNPs), the scattering light from AuNPs can be detected when they are excited by a single laser. Based on these principles, in this study AuNPs with uniform size were prepared, then modified with folic acid(FA), the resulting AuNPs-FA were used as targeting probes for imaging of cervical cancer cells(Hela). The specific scattering imaging could be researched by laser scanning confocal microscopy(LSCM). The results show that the effect of intaking of AuNPs-FA is stronger than that of AuNPs by the cervical cancer cells. However, with the extension of time, the difference will gradually decrease. So the AuNPs-FA has a good targeting property to label the cervical cancer cells in the right time.
    Preparation and Characterization of LaVO4/TiO2 Nanotubes and Their Application in Photocatalytic Degradation of Gaseous Toluene under Visible Light
    ZOU Xue-Jun, LI Xin-Yong, ZHAO Qi-Dong, CHEN Guo-Hua
    2012, 33(05):  1046-1049.  doi:10.3969/j.issn.0251-0790.2012.05.033
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    LaVO4/TiO2 nanotubes, which can response for visible light, were prepared by a facile hydrothermal method, and characterized by TEM, XRD and N2 adsorption-desorption measurements as well as surface photovoltage spectroscopy. The photocatalytic activity of the LaVO4/TiO2 nanotubes was evaluated by degradation of gaseous toluene under visible light(λ＞420 nm) irradiation. The doped LaVO4 reduced the average crystal size, enhanced specific surface area and shifted the optical absorption edge to the visible region of TiO2. The photocatalytic activity of LaVO4/TiO2 nanotubes was increased by 47% than pure TiO2 nanotubes.
    First-principles Study of Ti-doped SnO2 Semiconductor Solid Solutions
    JIA Jin-Qian, XIE Xue-Jia, LIANG Zhen-Hai, ZHANG Xiao-Chao, FAN Cai-Mei, HAN Pei-De
    2012, 33(05):  1050-1056.  doi:10.3969/j.issn.0251-0790.2012.05.034
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    Ti doping SnO2 solid solution is an important part of titanium based oxide proof-acid anode. Electronic structures of Sn1-xTixO2 solid solutions(x=0, 1/12, 1/8, 1/6, 1/4, 1/2, 3/4, 5/6) were investigated by first-principles calculations based on the density functional theory. The energy band structures, density of states and Mulliken charge population were analyzed. The results show that the corresponding lattice parameters reduce linearly with composition, Ti-O bond covalent nature is stronger than that of Sn-O bond, band gap is still direct band gap after doping, and the band gap gradually decreases with the increase of doping ratio. The Sn0.5Ti0.5O2 solid solution has the highest stability because of its minimum formation energy value of -6.11 eV. These results provide a theoretical basis for the study and development of titanium based oxide electrode materials.
    Theoretical Study of Second-order Nonlinear Optical Properties of Hexamolybdates-substituted Carbon Nanotubes
    MA Teng-Ying, GUAN Wei, WEN Shi-Zheng, LANG Zhong-Ling, YAN Li-Kai, SU Zhong-Min
    2012, 33(05):  1057-1062.  doi:10.3969/j.issn.0251-0790.2012.05.035
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    The nonlinear optical(NLO) properties of [Mo6O19]2-decorated single wall carbon nanotubes(SWCNT) were investigated by density functional theory(DFT). These special organic-inorganic hybrids possess a large second-order NLO response. It is noteworthy that the second-order NLO behavior can be switched by the variable angle between [Mo6O19]2- and CNT and the stability of systems shows the regular trends. The characteristic of the charge-transfer transition corresponding to the dominant contributions to the static second-order polarizibility(βvec) values indicates that the variable anchoring angles of [Mo6O19]2- can influence the intramolecular donor or acceptor character. When the anchoring angle of [Mo6O19]2- becomes 30°, the complex exhibits the largest βvec value; besides, the polyoxometalate(POM) cluster acts as the acceptor and the CNT as the donor. Furthermore, the incorporation of an electron donor(the amido group) leads to a larger βvec value at the end of the CNT segment.
    Theoretic Prediction of Heat Decomposition Stability for General Organic Molecular or Drug
    DING Xiao-Qin, DING Jun-Jie, LI Da-Yu, SUN Yang, CHEN Ji-Sheng
    2012, 33(05):  1063-1068.  doi:10.3969/j.issn.0251-0790.2012.05.036
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    Density functional theory(DFT) calculations at the B3LYP/6-31G+(d,p) level were carried out for 32 random selected compounds in training set and 43 ones in testing set after determining the experimental half decomposition temperature Td(1/2) or partial ones from literature. The calculated quantum chemical descriptors were used to construct quantitative structure-property relationship(QSPR) models of quadrupole moments(Qii) parameters with the molar thermal decomposition function Yd(1/2). The equation of QSPR is Yd(1/2)=-8.65747-3.8954Qii for training set possessing a correlation coefficient of r2=-0.99297, cross validation XV-r2=0.99188 and F-test=4237.343321. Further, the proposed model is validated by examining 43 compounds in testing set with a correlation coefficient of 0.92304 between prediction and experiment Td(1/2) values and a correlation coefficient of 0.99345 between prediction and experiment Yd values. The selected compounds rank well with a certain space distribution of structure descriptors. The developed equation can be used to predict the heat decomposition stability for new designed or synthesized compounds or drugs in virtual screening.
    Interaction Between ArginaseⅠand Butylphthalide
    LI Shuai, HUANG Xu-Ri, ZHAO Gang, SUN Ruo-Xi, GAO Xue-Feng
    2012, 33(05):  1069-1073.  doi:10.3969/j.issn.0251-0790.2012.05.037
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    Arginase Ⅰ is one of the two subtypes of arginase, mainly exists in the cytoplasm of the liver, brain and other place. Arginine can be metabolized to ornithine, and then ornithine metabolized to polyamines. In this paper it was suggested that arginase Ⅰ might play an role of target for n-butylphthalide(NBP) by metabonomics, and then the interaction between arginase Ⅰ and chiral butylphthalide(L- and D-) was studied via molecular docking and molecular dynamics simulations, and it was found that complex L-NBP-arginase Ⅰ was more stable. The experimental results confirmed that L-NBP has the obvious activation function to arginase Ⅰ, but the D-NBP does not have obvious influence on arginase Ⅰ.
    Polymer Chemistry
    Preparation and Characterization of Fluorescent Nanofiber Based on Fluorescein
    WANG Heng-Guo, LIU Da-Hai, ZHANG Chao-Qun, LI Yao-Xian, YANG Qing-Biao, DU Jian-Shi
    2012, 33(05):  1074-1077.  doi:10.3969/j.issn.0251-0790.2012.05.038
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    The novel fluorescent nanofiber films were synthesized by aminating available electrospun polyacrylonitrile nanofibers with ethylenediamine and then immobilizing fluorescein covalently through a Mannich reaction. The resulting fluorescent nanofibers have been confirmed by fluorescence spectra, field-emission scanning electron microscopy(FE-SEM) and Fourier transform infrared(FTIR) spectrum. Results show that the synthesized nanofibers exhibit strong fluorescence, which show fluorescein was immobilized covalently into the electrospun nanofiber films. Further modification of electrospun films with fluorescent molecules presents the possibility of practical sensing applications of the electrospun films.
    Preparation of a Silicone Resin-type Packaging Material with High Refractive Index for Light Emitting Diodes
    YANG Xiong-Fa, YANG Lin-Lin, CAO Cheng, ZHU Xiao-Biao, HUA Xi-Lin, ZHENG Qun-Liang, SONG Guang-Xin, WU Lian-Bin, LAI Guo-Qiao
    2012, 33(05):  1078-1083.  doi:10.3969/j.issn.0251-0790.2012.05.039
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    A novel high refractive index and high transparent silicone resin-type material for the packaging of light emitting diode(LED) was introduced. The methylphenyl vinyl silicone resin was synthesized by cohydrolysis of MePhSiCl2 with Me2SiCl2, MeViSiCl2 and PhSiCl3, then by co-condensation polymerization catalyzed by KOH and end-capped with Me3SiCl. Then the silicone material for LED packaging was prepared with the produced methylphenyl vinyl silicone resin, methylphenyl hydrosilicone oil and Karstedt's catalyst. The methylphenyl vinyl silicone resins were characterized by FTIR and 1H NMR. The silicone resins prepared with very high transmittance at range of 400-800 nm after cured. The LED packaged with the silicone resin-type materials exhibited higher luminous flux, higher light efficiency, narrower color-rendering index and higher color-temperature consistency.
    Preparation of EuF3 Nanocrystals/PNIPAm Complex Hydrogel and Its Thermosensitive Fluorescent Performance
    SONG Qiu-Sheng, YANG Yang, ZHU Xiao-Fei
    2012, 33(05):  1084-1089.  doi:10.3969/j.issn.0251-0790.2012.05.040
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    EuF3 nanocrystals were synthesized with undecylenic acid as surfactant, via liquid-solid-solution synthesis(LSS) strategy, then they were treated with CCl4 to obtain reactive EuF3 nanocrystals decorated with C-Cl groups on their surface. A series of complex hydrogels of EuF3 nanocrystals/PNIPAm with different contents of EuF3 nanocrystal were prepared via atom transfer radical polymerization(ATRP) method. The microstructure and performance of the EuF3 nanocrystal and the complexes hydrogels were characterized by HRTEM, XRD, FTIR, DSC and PL. The results suggest that the nanocrystal is hexagonal EuF3 and size polydisperse, the main size of which is about 10, 20 and 50 nm. With the increased content of nanocrystal, the lower critical solution temperature(LCST) of complex hydrogel decreased. The fluorescence performance of complex hydrogels was influenced greatly by both the ambient temperature and the content of nanocrystal.
    Preparation of Polyimide Nanofiber Membrane with Gradient Wettability by Electrospinning
    WANG Shu-Ying, LI Min, GONG Guang-Ming, WANG Jing-Ming, WU Jun-Tao, JIANG Lei
    2012, 33(05):  1090-1094.  doi:10.3969/j.issn.0251-0790.2012.05.041
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    Radial polyimide(PI) nanofiber membrane was prepared on an asymmetric electrode by electrospinning. The morphology and arragement of the nanofiber on the PI membrane were observed by environmental scanning electron microscope(ESEM). The wettability was characterized by the apparent contact angle and the surface adhesive effect was characterized by the high-sensitivity microelectromechanical balance system. The effect of the microstructures on the contact angle and adhesive force was analyzed. The experimental results show that the PI nanofibers exhibit novel gradient microstructures. Particularly, the PI nanofibers were in a radial pattern from dense to sparse along the direction of triangular electrode to curved electrode. The diameter of the PI nanofibers was uniform and their surfaces were smooth. The distance between the adjacent fibers was from a few microns to tens of microns. The unique gradient microstructure of PI nanofiber membrane results in the gradient density of the surface chemical substance and they are crucial to the gradient changes of the contact angle and adhesive force.
    Copolymerization of Norbornene with Isoprene Catalyzed by TiCl4/Al(#em/em#-Bu)3 System
    LI Xin, NI Xu-Feng, SHEN Zhi-Quan
    2012, 33(05):  1095-1099.  doi:10.3969/j.issn.0251-0790.2012.05.042
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    Copolymerization of norbornene(NBE) with isoprene(IP) catalyzed by traditional Ziegler-Natta system composed of TiCl4 and Al(#em/em#-Bu)3 was studied. The PNBE-co-IP copolymers obtained have number-average molecular weights of 2.0×104-6.5×104 as well as relatively narrow molecular weight distribution from the range of 1.5 to 2.9, and soluble in common organic solvents. The influences of catalyst composition, polymerization conditions, and the monomer feeding ratio on the copolymerization were investigated. The copolymer with 96% yield, 45%(molar fraction) of NBE, and number-average molecular weight of 6.5×104 can be prepared under the following optimum conditions: n(NBE)∶n(IP)=4∶6, n(Al)∶n(Ti)=5∶1, n(Monomer)∶n(Ti)=200∶1, 40 ℃, polymerized in toluene for 6 h. The NBE content in copolymer can be controlled in the range of 26%-60% by varying the feeding ratio of comonomer, and the Tg of the copolymer increased with the increasing of NBE content in copolymer. The microstructures of the obtained copolymers were confirmed by 1H NMR and 13C DEPT135 NMR, and indicate that the NBE monomer undergo an addition-type polymerization during the copolymerization with isoprene. The reactivity ratios of two monomers were determined to be rNBE=0.07 and rIP=0.44 by the Kelen-Tüdös method.
    Synthesis and Properties of Poly(aryl ether sulfones) Functionalized with Pendant Perfluoroalkyl Sulfonic Acid for Proton Exchange Membrane
    WANG Yong-Peng, YUE Xi-Gui, PANG Jin-Hui, LI Xue-Feng, LI Na, ZHANG Hai-Bo, JIANG Zhen-Hua
    2012, 33(05):  1100-1105.  doi:10.3969/j.issn.0251-0790.2012.05.043
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    A novel poly(arylene ether sulfone) with a perfluoroalkyl sulfonic acid pendant(PES-PSA) was synthesized by Ullman coupling of poly{oxy-4,4'-oxy-4,4'-diphenylsulfone}(PES-Br) and potassium 1,1,2,2-tetrafluoro-2-(1,1,2,2-tetrafluoro-2-iodo-ethoxy)ethanesulfonate(PSA-K). The introduction of the perfluoroalkyl sulfonic acids was successfully carried out with high conversion(c.a. 50%) to yield the desired polymer. Even with a low ion exchange capacity(IEC) of 0.907 meq./g, PES-PSA exhibited a high proton conductivity of 0.039 S/cm at 80 ℃ under 100% relative humidity. The low IEC makes the membrane own good dimensional stability and thermal stability. Other membrane properties, such as thermal properties and water uptake were also investigated in detail.
    Synthesis and Characterization of Sulfonated Polyamides
    ZHAO Jing, XU Hong-Jie, FANG Jian-Hua, YIN Jie
    2012, 33(05):  1106-1109.  doi:10.3969/j.issn.0251-0790.2012.05.044
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    Two kinds of sulfonated monomers were synthesized, i.e., 1,4-bis(4-carboxyphenoxy)benzene-2-sulfonate(BCPOBS-Na) and 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid(ODADS). Then non-sulfonated monomer was reacted with sulfonated monemoer, respectively, via the Yamazaki-Higashi phosphorylation method in the presence of triphenylphosphite(TPP), pyridine(Py) and halide salts to give high molecular sulfonated aromatic polyamides(SPA-1 and SPA-2). The polymers were obtained in quantitative yields with inherent viscosities between 0.6 and 0.8 dL/g. The structures and properties of obtained solfonated polyamides were confirmed by FTIR, 1H NMR and TGA. The results show good solubility in polar solvents, high thermal stability, good film forming ability and excellent mechanical properties.
    Synthesis and Properties of Cholesterol Graft Chitosan
    DING Shan, TANG Min-Jian, ZHOU Chang-Ren, MIN Xiang, TIAN Jin-Huan, LI Li-Hua
    2012, 33(05):  1110-1115.  doi:10.3969/j.issn.0251-0790.2012.05.045
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    Cholesterol-modified chitosan conjugate with succinyl linkages(CHCS) was synthesized and cha-racterized by Fourier transform infrared(FTIR) and proton nuclear magnetic resonance(1H NMR) spectra. The extent of grafting cholesterol was characterized by elemental analyzer. The properties of CHCS and chitosar(CS) were studied by water contact angle test, biomineralization and cell culture. The results show that the contact angle of CHCS is larger than that of CS. In the process of biomineraliation, CHCS can stable the deposited calcium phosphorus salt. The relationships between CHCS/CS and 3T3 cells were studied by MTT method and cytoske-leton fluorescence staining. The results show that CHCS can promote the cell's adhesion, stretched and proliferation. The introduction of cholesterol can promote the ability of chitosan as biomaterials.
    Polydispersity Effect on Phase Behavior of Diblock Copolymer
    YAO Wei-Guo, ZHOU Hong-Mei, DOU Yan-Li, ZHAO Xue, HOU Lin
    2012, 33(05):  1116-1120.  doi:10.3969/j.issn.0251-0790.2012.05.046
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    Effect of polydispersity on phase behavior of diblock copolymer was studied by Monte Carlo simulation. In order to evaluate the polydispersity effect, block copolymer blends including three different components were utilized as models in the simulation. By controlling the weight fractions of the component in copolymer blend, the influence of two different types of polydispersity effects (i.e. overall polydispersity effect and single block polydispersity effect, respectively) on order-disorder transition(ODT), conformations, and chain size of polymers were investigated. The results show that the increasing of index of polydispersity(PDI) can cause the ODT temperature slightly shifts to a lower temperature region. And it can also induce the increasing of the spacing thickness of the newly formed lamellar structure. Based on microscopic conformation analysis, polymer chains tend to stretch more at larger PDIs, which reveals the decreasing of accumulation degree of polymer chains. Therefore, the inhibition effect on fluctuation diminishes and the disordered phase shifts to the lower temperature region.
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