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    10 May 2006, Volume 27 Issue 5
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    高等学校化学学报2006年第27卷第5期目次
    2006, 27(5):  0.  doi:
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    In-situ Synthesis of CdS-ZnS Core-shell Structure Quantum Dots Inside PAMAM Dendrimer Templates
    CONG Ri-Min, LUO Yun-Jun*, LI Guo-Ping, TAN Hui-Min
    2006, 27(5):  793-796.  doi:
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    CdS-ZnS core-shell structure quantum dots(QDs) were in-situ synthesized inside PAMAM dendrimer templates of generation 4、5(containing 64 ester end groups). The size distribution of the well-dispersed QDs was narrow and the average diameter was about 23 nm as shown in HRTEM images. The red shift of the absorption spectra suggested the formation of the coreshell structure. Also the EDS confirmed that the QDs were comprised of CdS and ZnS. ZnS shell of appropriate thickness effectively eliminated the noradiactive centers and the PL efficiency was improved to 31%. An organic shell covering the CdS-ZnS core-shell QDs formed via the PAMAM dendrimers, which prevented the conglomeration of QDs, passivated the hanging bonds and improved the PL efficiency. Furthermore, the excellent solubility of PAMAM dendrimers in solvents with different polarities endowed the QDs good solubility and made the QDs more stable.

    Influence of NH4Cl on Formation, Structure and Properties of Titania Nanocrystals
    LI Dao-Rong, SUN Ling-Na, HU Chang-Wen
    2006, 27(5):  797-800. 
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    TiO2 nanocrystals were synthesized by the method of volatilization and decomposition of TiCl4 in the existence of NH4Cl. The influence of NH4Cl on the structure of crystalline phase and the properties of the sample was discussed. The samples were characterized by XRD, TEM, IR, specific surface areas and thermal analysis. The samples completely changed to anatase phase and are nanocrystals with a diameter less than 7 nm by calcination at 150 ℃ for 5 h; the samples calcined at 300-600 ℃ with the particle diameter about 9-23 nm are composed of pure anatase TiO2; the samples calcined at 700 ℃ with the particle diameter of about 33 nm are composed of a large quantity of anatase phase and a little amount of rutile phase. By dynamics analysis of crystal growth, calcination below 700 ℃, there are two kinds of driving power to crystal growth, and 400 ℃ is the turning point: calcination below 400 ℃ the required energy of crystal growth is 8.23 kJ/mol; calcination at above 400 ℃ the required energy of crystal growth is 45.71 kJ/mol. The catalytic activity of the samples calcined at 200 ℃, which had the largest specific surface area and the particle diameter is about 7 nm, are the highest in the reaction of methyl orange decomposition.

    Preparation and Antibacterial Activity of Amino Acid Polyoxometalate Self-assembled Multilayer Films
    KONG Yo-Mei, BANG Jun, XUE Bo, BO Li-Na, XIN Zhi-Feng, LI Li, LIU Jun
    2006, 27(5):  801-804. 
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    (CTA)0.2(HGly)2.8［PMo12O40］·nH2O(1)  nanoparticles(nano-1) with an average diameter of 30 nm were prepared by using reverse micelles under mild hydrothermal conditions and characterized by TEM(HRTEM), IR, XRD, XPS and CV. To enhance the application of the nanoparticles, multilayer films of nano\|1 and polycation polyethyleneimine(PEI) were prepared by the layerbylayer(LBL) self-assembled technique. UV-Vis spectroscopy was used to monitor the layer-by-layer assembling process of the films which were also verified by CV. The antibacterial activities of the nanoparticles and the as\|prepared multilayer films against Escherichia coli(E. coli) were investigated. Antibacterial tests indicate that both the nanoparticles and the multilayer films exhibited an efficient antibacterial activity, and the films have more merit.

    Studies on Crystal Structure of ZnO Films by the Mis-orientation
    HOU Chang-Min1, HUANG Ke-Ke1, GAO Zhong-Min1, MA Yan2, DU Guo-Tong2, LI Xiang-Shan1, FENG Shou-Hua 1*
    2006, 27(5):  805-807.  doi:
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    ZnO(0002) films were grown on sapphire(0006) substrate by metal-organic chemical vapor deposition(MOCVD) and were characterized by X ray diffraction(XRD) and scanning electronic microscope(SEM). SEM and XRD results show that the columnar crystals grew along caxis and were vertical to the(0006) plane of the substrate. There exist grain boundaries and grain interstitials among the crystals. The Ф scanning curves of the(10-13) plane for ZnO films show that the misorientation among columnar crystals ranged from 3° to 30°. The full wide at half maximum(FWHM) of rocking curves of(0002) plane for the ZnO films is above 2.6°. Grain sizes at different thicknesses illustrate that the column is composed of the grains with different sizes. The big mismatch heteroepilayer ZnO films are columnar polycrystals orienting along c axis.

    Preparation and Photoluminescence of a Novel Bipolar Small Organic Molecular Compound and Its Al3+ Complex
    XIANG Neng-Jun 1,2, LEE Tik-Ho2, LEUNG Louis M2, SO Shu Kong 3,
    SHI Jian-Xin1 , GONG Meng-Lian1*
    2006, 27(5):  808-811.  doi:
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    A novel organic compound containing an holetransporting arylamine group and an electron-transporting 1,3,4-oxadiazole unit, 2-(5-(4-(diphenylamino)phenyl)-1,3,4-oxadiazol-2-yl)phenol(HPOT), was designed and synthesized by using facile multi-steps reactions with a high yield. With this synthesized-compound as the ligand, a new aluminum(Ⅲ) complex, tri(2-(5-(4(diphenylamino)phenyl)-1,3,4-oxadiazol-2-yl)phenonate) aluminum, (AlPOT), was synthesized. Photoluminescence measurements showed that these two compounds emit intensely blue light under near-ultraviolet excitation with high fluorescence quantum yields of 0.76 and 0.68, respectively, while TG analysis confirmed their high heatstability, indicating that they are high efficient bluelight-emitting materials. All the results provide a basic knowledge for fabrication of corresponding organic lightemitting diodes.

    Synthesis and Crystal Structure of a Tetramer Chiral Complex ｛［Cu(C20H26N4O2)Cl］Cl·4H2O｝4
    HE Yun-Fei1, CHEN Min-Qin2, DAI Li-Yi1, ZHANG Gui-Rong1, LI Qiang1, WANG Lin-Sheng 1*
    2006, 27(5):  812-816.  doi:
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    N,N′-bis(L-phenylalanyl)ethane-1,2-diamine was prepared by using L-phenylalanine and ethanediamine. The synthetic process was improved. The ligand reacted with copper dichloride to form the chiral coordination compound. The single crystal was obtained in methanol solution. It is shown by X-ray structural studies that the crystal belongs to the tetragonal system and the space group is I4. The lattice parameters are as follows: a=2.504 4(4) nm, b=2.504 4(4) nm, c=0.870 7(3) nm, V=5.461(2) nm 3, Dc=1.365 g/cm3, Z=8. In the structure of the complex, the Cu(Ⅱ) cation is coordinated by two nitrogen atoms, two oxygen atoms and one chlorine atom.

    Preparation, Structure and Properties of Molybdate Modified Zinc Phosphate Coating on Magnesium Alloy AZ91D
    LI Guang-Yu, LIAN Jian-She*, NIU Li-Yuan, JIANG Zhong-Hao, JIANG Qing
    2006, 27(5):  817-820.  doi:
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    Uniform and dense molybdate modified zinc phosphate coatings were formed on the magnesium alloy AZ91D surfaces by using a phosphating bath containing molybdtate and corrosion inhibitor. Phase components of coatings were analyzed by XRD. Morphology and compositions of coatings were analyzed by SEM and EDS. The results indicate that the phosphate coatings consist mainly of Zn3(PO4)2·4H2Oand Zn. When molybdate was added in the bath, phosphate coatings became denser and crackfree. The phosphate coatings obtained from the bath containing 1.5 g/L sodium molybdate exhibit denser microstructure and higher concentration of metallic zinc. A corrosion test estimating the corrosion resistance of conversion coating on magnesium alloy was proposed. Phosphating reaction mechanism on the magnesium alloy AZ91D surfaces was also investigated.

    Synthesis, Crystal Structure and Bioactivity of two Novel Complexes N,N′-Bis(o-oxy-acetate)benzylethylenediamine with Co(Ⅱ) and N-(o-oxy-acetate)benzylethylene Diamine with Cu(Ⅱ)
    LI Hui1, WANG Jing2, QIN Feng-Mei1, ZHOU Dao-Wei 1* , ZHU Dong-Sheng 2*
    2006, 27(5):  821-825.  doi:
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    The complex Co(Ⅱ)L1·H2O(2)［L1=N,N′-bis(o-oxy-acetate)benzylethylenediamine(1)］ was synthesized by the reactions of compound 1 and Co(Ⅱ) dichloride in the solvents of water, and Cu(Ⅱ)ClL2·2H2O(3)［L2=N-(o-oxyacetate)benzylethylene diamine］ was prepared by o-oxy-acetatebenzaldehyde, ethylene diamine and Cu(Ⅱ) dichloride through onestep procedure in water. Complexes 2 and 3 were characterized by elemental analysis, 1H NMR, FTIR spectroscopy and single crystal X-ray diffraction analysis. There are two independent molecules(host molecule) and two water molecules(guest molecule) in one asymmetric unit of complex 2, the Co(Ⅱ) atom exhibits a distorted trigonal prismatic column geometry. There are one molecule(host molecule) and two water molecules in each unit of complex 3, the Cu(Ⅱ) atom exhibits a distorted square cone geometry. Simultaneously, the effects of different concentration levels of complexes 2 and 3 on germination and seedling growth of soybean seeds were investigated through experiment. It can be concluded that soybean seeds could germinate at all of the four concentrations of complexes 2 and 3. But germination percentage, rate of germination and index of vigor were lower than control, which illustrated that as concentration of complexes 2 and 3 increased, germination and seedling growth of soybean seeds were blocked.

    High Sensitive Tobramycin Detection Using a Novel Signaling Aptamer
    ZHOU Cui-Song 1, 2, JIANG Ya-Xin2, WANG Jun2, MA Bao-Cheng2, LI Meng-Long1*, FANG Xiao-Hong 2*
    2006, 27(5):  826-829.  doi:
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    Aptamers are a new class of oligonucleotides generated from in vitro selection with a high affinity and specificity. In this paper, a novel luminescence detection method was developed by using RNA aptamers and a DNA light switching complex, [Ru(phen)2(dppz)]2+, as a signaling aptamer for the detection of drug tobramycin. The results showed that the method was highly sensitive and selective with the detection limit down to 10 nmol/L. The method was also very simple and could realize direct detection without separation in solution, and offers a new approach for the exploitation and application of aptamers in drug analysis.

    Application of Carboxylic Carbon Nanotubes to the Spectrophotometric Determination of Lead with DBH-PF
    MAO Lei-Lei, WANG Zong-Hua*, XING Lin-Lin, YAN Yong-Chen, CHEN Yue
    2006, 27(5):  830-833.  doi:
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    Carboxylic carbon nanotubes were used in the chromogenic reaction for the determination of lead with 2,3,7-trihydroxy-9-(3,5-dibromo-4-hydroxyphenyl)flunrone(DBH-PF). A red complex was formed in the borate buffer solution in a pH range of 9.4-10.0 The maximum absorption of the complex appeared at 558.0 nm, and the apparent molar absorptivity was 5.62×104 L·mol-1·cm-1. The linearity of the Pb2+ in mass concentration ranges from 1 μg to 50 μg per 25 mL of solution with a correlation coefficient of 0.999 6. This method has been applied to the determination of trace lead in cosmetics successfully.

    Studies on Mechanism of Acetonitrile-salts Stacking Method in Capillary Electrophoresis
    KONG Yu*, ZHAO Yong-Xi, WANG Bo
    2006, 27(5):  834-838.  doi:
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    Acetonitrile-salt stacking method(ASS), as a new developed on-line stacking method in capillary electrophoresis, is suitable for stacking and analyzing low concentration analytes, which contain high concentrations of salts, and it has the huge practical potential in bio-analysis area. However, the applications are limited as the mechanism of ASS is not clear. In this work, the effects of sample matrix, experimental factors ect. on stacking were systematically studied. A new reasonable hypothesis about the mechanism of ASS was proved to be an “acetonitrile caused quick large volume stacking combined with NaCl induced pseudo isotachophoresis” procedure, and several experiments were carried out to improve the conclusion.

    Ordered Multilayer Film Electrode Containing Glucose Oxidase Based on Layer-by-layer Self-reaction
    SUN Ying-Ying, ZHAO Shuang, YANG Wei-Wei, SUN Chang-Qing*
    2006, 27(5):  839-844.  doi:
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    Highly stable glucose oxidase(GOx) multilayer films were fabricated on cystamine modified gold electrode surfaces by layer-by-layer self-reaction of periodate-oxidized glucose oxidase. The fabricated process was followed by electrochemical impedance spectroscopy. The experimental results showed that the film was homogeneous and formed in an ordered manner. The gold electrode modified with the GOx multilayers showed excellent electrocatalytical response to the oxidation of glucose when ferrocenemethanol was used as an artificial redox mediator. From the analysis of voltammetric signal, the coverage of active enzyme on the electrode surface was estimated, which had a linear relationship with the number of GOx besides the first layer. This suggested that the analytical performance such as sensitivity, detection limit, and so on, was tunable by controlling the number of the fabricated GOx layer. In addition, the biosensor exhibited a good reproducibility and stability.

    A New Method for Preparation of Gene Carriers Based on Silica Micro-particles
    LIN Xia, HE Xiao-Xiao, WANG Ke-Min*, TAN Wei-Hong
    2006, 27(5):  845-848.  doi:
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    A new method for the preparation of gene carriers based on silica micro-particles(SiMPs) was reported. Silica micro-particles were synthesized by the hydrolysis of tetraethoxy\|silane in ethanol and ammonia, and then modified with poly-L-lysine(PLL) molecules via the electrostatic interaction to form PLL-SiMPs complexes as the gene carriers. These gene carriers can deliver pEGFP into COS-7 cells to accomplish GFP expression. This new method is simple and rapid and will be of great potential to be widely applied in gene transfection and gene therapy.

    Resonance Rayleigh Scattering Spectral Method for Determination of Methylene Blue with Gold Nanoparticle as Probe
    LU Qun-Min, HE You-Qiu, LIU Shao-Pu*, LIU Zhong-Fang
    2006, 27(5):  849-852.  doi:
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    In a neutral or weak alkaline medium(pH=6.5-9.5), the gold nanoparticle can combine with methylene blue by the virtue of electrostatic and hydrophobic interaction, forming aggregate with bigger diameters(average diameter increase from 12 to 20 nm ). The aggregate arouse Resonance Rayleigh Scattering(RRS) intensity enhancing greatly. The maximum scattering peaks are at 371 nm. Under optimum conditions, there is a linear relationship between scattering intensity(ΔI)　and the concentration of methylene blue. This method has a high sensitivity. So gold nanoparticle can be used as the RRS probe of high sensitivity for methylene blue. The detection limit of methylene blue is 21.17 ng/mL. The method which is simple and rapid has good selectivity. It was successfully applied to the detection of methylene blue in clinic serum samples.

    A Facile Synthetic Route for an Important Sensing Material Fluorescent Conjugated Polymer PPESO3
    ZHANG Tao, FAN Hong-Liang, ZHOU Jian-Guang, LIU Guo-Liang, JIN Qin-Han*
    2006, 27(5):  853-855.  doi:
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    A facile synthetic route for conjugated polymer PPESO3 was proposed, through which not only the procedure was simplified, but also the dealkylation by BBr3 was avoided, and therefore, the preparing difficulty and danger were greatly reduced, which was obviously beneficial to the preparation and application of PPESO3. At the same time, the interactions between PPESO3 and nonionic surfactant(PVP) were investigated. The results indicate that the aggregation of polymer backbone was effectively broken up and the steady complexes consisted of PPESO3 and PVP were formed which would contribute to the preparation of highly sensitive bio-sensors due to the affinity of PVP to biological macromolecules.

    A Novel Method for Capillary Electrophoresis Directly Analyzing Trace Amounts Analytes in the Water-immiscible Solution Samples
    FANG Huai-Fang, ZENG Zhao-Rui*, LIU Lan, PANG Dai-Wen
    2006, 27(5):  856-858.  doi:
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    This paper describes a novel method in which solvent microextraction(SME) is followed by on\|line back-extraction-field amplified sample injection(OLBE-FASI) in capillary zone electrophoresis(CZE). The water-immiscible solution sample, sealed with water plug in the sample vial, was used for direct electroinjection. The water plug with moderate content of organic solvent, low-conductivity, and the presence of a small amount of H+ provided the highest sensitivity for analyzing positively chargeable compounds, such as cocaine and thebaine. The linear range was 0.040—4, 0.040—2 μg/mL, with the square of the correlation coefficient(r2)>0.997, respectively. Detection limits were in the range of 5—10 ng/mL.

    Sesquiterpene Lactones from Cyathocline purpurea
    LI Jie-Jiang, MA Guo-Xi, LUO Lei, ZHANG Xi-Tai
    2006, 27(5):  859-862. 
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    Cyathocline purpurea(Buch-Ham ex D Don) O Ktze is a folk drug used to treat inflammations and pulmonary tuberculosis in Yunnan Province. Cytotoxicity screening of extracts and its fractions from C. purpurea was carried out by L1210 cell. Isolation of chemical constituents by column chromatography was undertaken in step with cytotoxicity test. The structures of constituents were identified by spectroscopic and chemical methods. The chloroform and ethyl acetate extracts possess cytotoxic activity with IC50′s being 3.5 and 2.8 μg/mL, respectively. Three sesquiterpene lactones were established as Santamarin(compound 1), 9β-acetoxycostunolide(compound 2) and 9β-acetoxypathenolide(compound 3). Their IC50 were 0.41, 0.89, 0.59 μg/mL by L1210 cell respectively. The three constituents were obtained for the first time from this plant. They are all anticancer active constituents. The last one is a new compound.

    Synthesis and Application of Bis(2-benzothiazolydiazoamino)3,3′,5,5′-Tetramethylbiphenyl
    LIAO Xue-Meng, FENG Feng, CHEN Ze-Zhong
    2006, 27(5):  863-866. 
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    With the aid of combining 3,3′,5,5′-tetramethylbiphenyl with benzothiazole through triazene group, a new fluorescent reagent bis(2-benzothiazolydiazoamino)3,3′,5,5′-tetramethylbiphenyl(BBTDTMB) was synthesized. The product was confirmed by means of elemental analysis, 1H NMR and infrared spectra. Its excitation and emission wavelengths were 342 nm and 420 nm in a basic medium, respectively. This new reagent reacts with Ag(Ⅰ) in a slightly basic medium to form a 1∶2 complex, by which silver ion causes the fluorescence quenching of the new fluoresent reagent. The reaction showed a high selectivity and a high sensitivity for Ag(Ⅰ). A new spectrofluorimetric method for the determination of trace Ag(Ⅰ) with this reagent was developed. The linear range of determination for Ag(Ⅰ) was 1.0—240 μg/L with a detection limit of 0.5 μg/L. The method is a selective, sensitive, and simple analytical procedure, and was used for the determination of trace Ag(Ⅰ) in hair and tea with satisfactory results.

    Syntheses of Novel Tricyclic Fused Heterocycles:［1,2,4］Triazolo［1,5a］［1］ benzazepine and ［1,2,4］
    Triazolo［1,5a］quinoline Derivatives
    BAI He-Xiang, MENG Jing-Jing, WANG Quan-Rui, DAO Feng-Gang
    2006, 27(5):  867-870. 
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    Oxidation of αtetralone ethoxycarbonylhydrazone(1) with lead tetraacetate afforded the bicyclic geminal ethyl azoester 2. On addition of equimolecular aluminum trichloride, the azocarbenium salt 3 was generated in situ as a reactive intermediate, which could be trapped by the cycloadditions to the triple bonds of nitriles giving 3H1,2,4-triazolium salts. These initially cycloadducts couldn′t be isolated but underwent smooth 1,2-aryl-shift with concurrent ring enlargement and insertion of a nitrogen atom to the carbon skeleton to provide the tricyclic salts 4a—4c, from which the literature unprecedentate ［1,2,4］triazolo［1,5-a］［1］benzazepinium picrates 6a—6c were obtained in 23%~56% yields upon hydrolytic removal of the Nethoxycarbonyl group and subsequent treatment of the resulted heterocycles 5 with picric acid. Analogously, the novel 4,5dihydro-［1,2,4］triazolo［1,5-a］quinolinium picrates(12a—12c) were prepared from 2,3dihydro-1-indanone in moderate yields.

    Studies on Anions Recognition of N-Nitrophenyl-1H-pyrrole-2-carboxamide
    YIN Zhen-Meng, HE Jia-Qi, CHENG Jin-Pei
    2006, 27(5):  871-874. 
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    Molecular recognition of anion is currently an expanding area of research especially in the context of designing anion sensors. Herein, two nitrophenyl pyrrolic amide receptors, p-nitrophenyl-1H-pyrrole-2-carboxamide(1) and m-nitrophenyl-1H-pyrrole-2-carboxamide(2), were synthesized by coupling pyrrole-2-carboxylic acid with nitroaniline in the presence of dicyclohexylcarbodiimide(DCC). The structure of compound 2 was characterized by X-ray crystallography. It is revealed that hydrogen bonding interaction and π-π stacking played an important role in the selfassembly of compound 2. The anions recognition of the two compounds were studied by the UV-Vis method in highly polar solvent of DMSO. Both compounds show a significant color change when F- and H2PO-4 were added indicating they would be new colorimetric sensors for the two anions.

    Purification and Characterization of a New Type of Harpins from Xanthomonas oryzae Pathovars
    LIU Xu-Zhong, WANG Jin-Sheng
    2006, 27(5):  875-879. 
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    The Harpins produced by two pathovars(pv. oryzae and pv. oryzicola) of Xanthomonas oryzae are different from the reported harpins. The recombinant E.coli strains HRF1 and HRF2 harbored hrf1 gene of pv. oryzae and hrf2 gene of pv. oryzicola, respectively. After induced by IPTG, the Cell Free Crude Solution(CFCS) of hrf1 and hrf2 can elicit hypersensitive reaction(HR) on tobacco leaves. Precipitated CFCS with(NH4)2SO4(30%—60%), purified with HiPrep Q XL ion exchange and Mini prepared NativePAGE(10%), two single bands with molecular weights of 15 600 and 15 300, and about pI=4.5 were respectively obtained. The results show the same characteristics to other Harpins: elicit HR, induce TMV resistance on tobacco leaves, sensitive to protease K and stable to heat. Their biological activity can be inhibited by eucaryota metabolic inhibitors(cycloheximide, actinomycin D and LaCl3). Meanwhile, serological experiments of the proteins with ODD indicate that cross reactions have occurred in two Harpins from pv.oryzae and pv.oryzicola.

    Studies on the Properties of Chitosan/Chondroitin Sulfate Blend Film as Corneal Endothelial Cell Carrier and Transplantation Trail
    CHEN Li-Huan, LIU Mo-Shun, HAN Bao-Qin, LI Xiao-Juan, YANG Chao-Zhong
    2006, 27(5):  880-884. 
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    Chitosan/chondroitin sulfate blend film was prepared by solution casting/ particulate leaching technique and characterized by transparence, SEM, FTIR and X-ray diffraction. Its biocompatibilities and biodegradability in vitro and in vivo were also evaluated. The results indicate that the blend film had an excellent transparence, uniform structure and appropriate pore size. Chitosan and chondroitin sulfate can disperse to molecules level and strong interaction existed between molecules. The blend film had favorable biocompatibility and biodegradability. The attachment and growth of rabbit corneal endothelial cells on the blend film was studied by cell culture. The attached cells were able to proliferate and grow near confluent. The blend film showed to be a good carrier for attachment and growth of corneal endothelial cell. Corneal endothelial cellloaded blend film was transplanted into rabbit eyes with endothelium scraped. The eyes remained transparent after surgery for 56 d, then the cornea became edema and many new blood vessels appeared. But the cornea regains transparence and new vascular disappear after surgery for 230 d.

    Syntheses and Characterization of Poly(γ-benzyl-L-glutamate) Containing Liver Targeting Group in Main Chain
    CHA RuiTao, DU Tian, YUAN Zhi*
    2006, 27(5):  885-887.  doi:
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    tarted from the liver targeting compounds(glycyrrhizin, glycyrrhetinicacid, bile acid), six amine-terminated compounds were prepared via two-step reactions. The NMR experiments provided the direct evidence of the existence of amide. The polymers were synthesized by polymerizing of BLG-NCA initiated by each of six amineterminated compounds. The liver targeting group was introduced to the main chain of the polymer. The molecular weight of the resultant polymers was adjusted by changing the molar ratio of monomer BLG-NCA to initiator. The product structure was characterized by GPC, FTIR and 1 H NMR. The results demonstrate that amine-terminated compounds containing liver targeting group could initiate the polymerization of BLG-NCA.

    Synthesis of a Novel Host-calix[4]arene Derivative and Its Application to Recognition Analysis of Lanthanide Ions
    LIU Zhi-Lian1,2, LIANG Zhi1,2, JIANG Lin1,2, GAO Yun-Hua1*
    2006, 27(5):  888-890.  doi:
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    The synthesis of the novel host compound carrying two spirobenzopyran groups was described. Its structure was confirmed by 1H NMR, IR and elemental analysis. It was shown that the novel host can recognize lanthanide ions selectively with significant spectral shifts in visible region and enhanced absorbance. Thus, the compound can be used to recognize lanthanide ions by naked eyes. The selectivity was relative to size-fit effect. The order of spectral changes was Yb3+>Er3+>Gd3+>Dy3+>Eu3+>Pr3+>La3+, which is opposite to the order of the radii of lanthanide ions. We discussed the possible binding mechanism with analyzing the different UV-Vis spectral changes resulted by addition of the investigated ions.

    Cloning, Fusion Expression and Purification of SPAP2 Domain Gene
    HU Xin1, ZHANG Xiao-Ping2, WANG Shao-Feng1, JIAO Ming1, YAN Xin-Ying1, FU Xue-Qi1*
    2006, 27(5):  891-893.  doi:
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    SPAP2, a transmembrane protein, is an Ig family receptor containing both ITIMs (immunoreceptor tyrosine-based inhibition motifs) and ITAMs (immunoreceptor tyrosine-based activation motifs). The extracellular portion of SPAP2 contains six immunoglobulin-like domains and its intracellular segment has two ITAMs and two ITIMs. Sequence alignment with the genomic database reveals that the SPAP2 gene contains 16 exons and is localized at chromosome 1q21. SPAP2 is consisted of 734 amino acids, and the intercellular portion of SPAP2 contains 137 amino acids. Tyrosine-phosphorylated SPAP2 is specifically associated with SH2 domain-containing tyrosine kinases and SH2 domain-containing tyrosine phosphatases, which lead to the initiation of signal transduction. SPAP2CT gene was amplified by PCR with SPAP2 full-length DNA as the template and cloned to the pBluescript Ⅱ KS vector. pGex-2T-SPAP2CT, the expression vector of dissoluble fusion protein, was constructed and transferred into E.coli of DE3-plysS. The fusion protein GST-SPAP2CT was expressed efficiently and purified by FFQ ion exchange chromatography and GSH affinity chromatography. The result indicates that we have constructed steady expression vector pGex-2T-SPAP2CT, which was expressed in E.coli. The molecular weight of the dissoluble fusion protein is 46 000, the productivity of GST-SPAP2CT protein is 10% and the purity is over 90% after the purification.

    Esterifications of Cyclohexanone with Methyl Acrylate and (S)-3-(2′-Oxocyclohexyl)-propionic Acid with Alcohols
    WANG Hui-Ping1,3, SHANG Yan-Mei1, WANG Lei1, LI Ye-Zhi1,2*, HUANG Hua-Min1
    2006, 27(5):  894-896.  doi:
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    The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters. The catalysts generally preferred are sulfuric acid or p\|toluenesulfonic acid. But the products esters were racemic when (S)-3-(2′-oxocyclohexyl) propionic acid reacts with alcohols in the presence of sulfuric acid or with p\|toluenesulfonic acid as catalyst. We replace sulfuric acid with Fe2(SO4)3·xH2O as the catalyst. The optical compound (S)-methy-3-(2′-oxocyclohexyl)propionate, (S)-ethyl-3-(2′-oxocyclohexyl)propionate and (S)-n-butyl-3-(2′-oxocyclohexyl)propionate were obtained. In this paper we also reported that cyclohexanone reacted with methyl acrylate in the presence of potassium thiazolidine-2-thione-4-carboxylate (R)TTCA·K as the chiral catalyst to afford optically active (S)-3-(2′-oxocy-clohexyl) propionate. The mechanism of reaction of cyclohexanone with methyl acrylate in the presence of (R)TTCA·K as the catalyst would be a complex process.

    Experimental and Theoretical Studies on the Structures, IR Spectrum and Inter-molecular Interaction of p-Methoxybenzaldoxime
    LIN Xian-Jie1, XU Wei-Ren 1,2, WANG Jian-Wu1, LIU Cheng-Bu 1*
    2006, 27(5):  897-900.  doi:
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    The melting point, crystal structure, IR spectrum and inter-molecular interaction of Z and E p-methoxybenzaldoxime were studied by experiment and ab initio method. There exists obvious difference in physical properties including melting point, crystal structure and IR spectrum between Z and E p-methoxybenzaldoxime. The double zigzag chain and the repeated unit, dimmer, were found in Z and E p-methoxybenzaldoxime crystal respectively. It is shown that the type of crystal, the intensity of H-bond and the distribution of charge are the essential factors resulting in the abnormality of the melting point and IR spectrum of p-methoxybenzaldoxime.

    Luminescence Properties and Substituent Effect of Bis(4-R-1,2-diphenyl|
    cyclopentadienyl) Zirconium Dichloride Compounds
    MEI Ze-Min1,3, DING Hong2, MU Ying1*, SU Qing1
    2006, 27(5):  901-904.  doi:
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    The electronic absorption and luminescence behavior of a number of bis(4-R-1,2-diphenylcyclopentadienyl)zirconium dichloride complexes (4-R-1,2-Ph2Cp)2ZrCl2[R=H(2), Me(3), Ph(4)] in anhydrous n-hexane were studied under an atmosphere of nitrogen. The research results showed that the electronic absorption and luminescence behavior of these compounds can be tuned by the variation of the substituents on the cyclopentadienyl groups. The absorption and emission wavelength of these complexes decreases in an order of R = Ph>CH3>H. As a result, complex 2 is a blue color emitter, while complex 4 is a green color emitter.

    Stability Analysis of Berberine Fragment Ions by Mass Spectrometry and Quantum Chemistry Studies on Fragmentation Mechanism
    CHEN Lan-Hui 1,2 , HU Dong-Hua 1,2 , WANG Dao-Wu2, YANG Shuang-Yang1, SU Zhong-Min 1* , Liu Shu-Ying 2*
    2006, 27(5):  905-908.  doi:
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    Mass spectrometry and quantum chemistry DFT-B3LYP method were used to study the stabilities of berberine fragment ions. Binding energy was employed to study the activity of main radicals fragmented from the molecule. Theoretical methods including geometry parameter analysis as well as frontier molecular orbital analysis were combined to explore the possible CIDMS mechanism. It was shown that the methyl of C9 was more active than the methyl of C10, with a much smaller binding energy. Geometry parameter analysis confirmed that with the departure of hydrogen, it was easier for the carbonyl radical to leave from the molecule, which was in agreement with CID experiment.

    Preparation and Characterization of Nanocrystalline Ni-Mo as Cathode Catalyst via RF Magnetron Sputtering
    HUANG Jin-Zhao1, XU Zheng 1,3* , LI Hai-Ling2, KANG Guo-Hu2, WANG Wen-Jing2
    2006, 27(5):  909-913.  doi:
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    Ni-Mo alloy thin film was prepared by RF magnetron sputtering method, and the film was used as cathode catalyst in photoelectrochemical hydrogen production from solar energy firstly. The crystallinity, composition, surface morphology and crystalline size were characterized by XRD, EDS, SEM and AFM experiments. The electrochemical behavior of the film were studied by steady-state polarization plots and electrochemical impedance spectroscopy. The results mentioned above show that under the conditions of the higher working pressure, lower substrate temperature and the longer target distance the Ni-Mo alloy thin film obtained possesses a good electrocatalytic activity. Additionally, the electrocatalytic activity of the film was also enhanced with the decreasing of crystalline size and increasing of molybdenum content. The hydrogen overpotential of hydrogen evolution reaction is 177.7 mV at current density 100 mA/cm2. The ratelimiting step was electrochemical desorption.

    Composition of Cu/SiO2 Nanometer Aerogel and Its Catalytic Properties for CO Oxidation
    ZHAO Hui-Zhong1,2*, GE Shan1, WANG Hou-Zhi 1,2, ZHANG Wen-Jie2
    2006, 27(5):  914-919.  doi:
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    A series of Cu/SiO2 nanometer aerogel catalysts with different molar ratios of Cu to Si were prepared by sol-gel-SCFD methods and characterized by TEM, XRD, physisorption analysis instrument, micro-reactor and gas chromatogram. It was found that SiO2 was amorphous and Cu was highly dispersed on the SiO2 particles, and the structure consists of mesopores. The BET analysis indicates that the samples have a high specific surface area more than 140 m2·g-1. The catalytic activities investigation show that the content of copper and the different phases of reactive species all affected the activities of the samples. When n(Cu)/n(Si)=2, the temperature of entire oxidation of CO upon the sample was reduced to 210 ℃. After calcination at a low temperature, the nanometer particles of Cu and Cu2O transformed into nanometer CuO, the temperature of CO full conversion to CO2 was further decreased. Adding small amounts of cerium dopant into the composition can change the reactive species from CuO, Cu2O to Cu, which can further reduce the temperature of tstart, t50 and t90 of the samples. The kinetics research demonstrates that essential of the decrease of the CO oxidation temperature was the decrease of activation energy of CO oxidation reaction.

    Chiral Discrimination of N-[4(1-pyrene)butyroyl]-D/L-phenylalanine in Binding with Tellurium/Selenium Bridged-bis-β-cyclodextrins
    HAO Ya-Qiong1, WANG Li-Xu1, MA Li-Jun1, WU Yu-Qing1*, LIU Jun-Qiu1, LUO Gui-Min2, YANG Guang-Di1
    2006, 27(5):  920-924.  doi:
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    The binding ability and chiral discrimination of β-cyclodextrin(β-CD), 2,2′-diseleno-bridged β-cyclodextrins(2-SeCD)and 2,2′-ditelluro-bridged β-cyclodextrins(2-TeCD)with PPs were investigated in aqueous solution by using UV-Vis and fluorescence spectroscopy as well as MM2 calculation. The stability constants of complexes were obtained by using least-square curve fitting. From the results of UV-Vis and fluorescence spectroscopy, it was shown that β-CD could not form inclusion complexation with PPs while 2-SeCD and 2-TeCD could. The binding ability between 2-TeCD and PDP was higher(Ks=2.33×104 L/mol) than that of 2-SeCD/PDP(Ks=3.03×103 L/mol). Meanwhile, the high chiral discrimination of PPs was also performed in binding with 2-TeCD(KD/KL=3.84)and 2-SeCD(KD/KL=2.61). Furthermore, the MM2 calculation illustrates that PPs were located between the two cavities of 2-SeCD or 2-TeCD, however, the dihedral angle between phenyl ring and pyrene ring was different from each other when they were included in two bis-cyclodextrins. Meanwhile, MM2 also demonstrates that the intermolecular hydrogen bonding interaction in 2-TeCD/PPs complex was relative stronger than that in 2-SeCD/PPs.

    Studies on Properties of Ionic Liquid EMIFeCl4 Based on Transition Metal
    ZHANG Qing-Guo1,2, GUANG Wei2, TONG Jing2, JIN Zhen-Xing 1*
    2006, 27(5):  925-928.  doi:
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    An ionic liquid(IL) EMIFeCl4 was prepared by directly mixing FeCl3 and 1-methyl-3-ethylimidazolium chloride with a molar ratio 1/1 under dry argon atmosphere. The densities, and surface tension of the pure IL were determined in the temperature range from 293.15 K to (343.15±0.1) K. The properties for the ionic liquids were discussed by using Glasser′s theory. The crystal energy of ionic liquid is much lower than ionic solid and this is the underlying reason for forming ionic liquid at room temperature. In addition, a new theoretical model of ionic liquid, that is interstice model, was applied to calculating the thermal expansion coefficient of EMIFeCl4. And the magnitude order of the thermal expansion coefficient, α, calculated by the theoretical model is in good agreement with experimental value. The result shows that there is much reasonableness for the interstice model of ionic liquid.

    Conversion of n-Octane over Modified Nano-crystallite ZSM-5 Catalyst
    ZHANG Pei-Qing 1* , GUO Hong-Chen2, WANG Xiang-Sheng2, GUO Xin-Wen2
    2006, 27(5):  929-934.  doi:
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    By combining alkaline medium hydrothermal treatment with loading mixed rare earth oxide, zinc oxide(or gallium oxide) on nanoscale ZSM-5(20—50 nm) as the active component, respectively, the modified nanoscale ZSM5 catalysts were prepared, and characterized by TEM, XRF, IR, XRD and so on. The aromatization and isomerization of n-octane were used as the model reactions. The effects of the total acid amount, the acid strength distribution and the molar ratio of L to B acid sites on performance of aromatization and isomerization of the modified nanoscale HZSM-5 catalysts were investigated, and the relationship between acid strength and molar ratio of L to B acid sites and coking was also studied. The results indicate that the decrease of the total acid amount and the reduction of acid strength of the nanoscale HZSM-5 catalysts modified by combining alkaline medium hydrothermal treatment with loading mixed rare earth oxide resulted in weakening aromatization activity, strengthening isomerization activity and improving stability obviously. On the basis of the alkaline medium hydrothermal treatment and loading mixed rare earth oxide, the acid properties of the nanoscale HZSM-5 catalyst were regulated again after loading proper amount of zinc oxide(or gallium oxide), as a result, the total acid amount of catalysts increased, stronger acid sites of the catalysts decreased, the Brnsted acid sites of the catalyst decreased lightly, the Lewis acid sites of the catalyst increased obviously and the molar ratio of L to B acid sites of the catalyst increased. The proper molar ratio of L to B(1.4—1.7) and the synergistic action between Lewis acid sites and Bronsted acid sites made the catalysts have a stronger and more stable aromatization and isomerization activity, the rate of coking of the catalyst declined. The yields of aromatics and isoparaffins in the products over the combining modification nanoscale HZSM-5 catalysts reached about 50% and 30%, respectively, the selectivity of the alkyl-aromatics(mainly C7—C9) and iso-paraffins(mainly C4—C6) with a high Octane Number attained 84% and 80%, respectively.

    Preparation and Characterization of Langmuir-Blodgett Film of Charge-transfer Complex of 2-Octadecyl-7,7,8,8-tetracyanoquino-dimethane and 3,3′,5,5′-Tetramethylbenzidine
    WANG Yi-Bing1,2, LU Fei1,2, WEI Ping-Hui1, XI Shi-Quan1, WANG Hai-Shui1*
    2006, 27(5):  935-938.  doi:
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    Langmuir-Blodgett(LB) films of the mixed-stack charge-transfer(CT) complex of 2-octadecyl-7,7,8,8-tetracyanoquinodimethane(C18TCNQ) and 3,3′,5,5′-tetramethylbenzidine(TMB) were prepared. The structures, molecular orientation and morphology of TMB·C18TCNQ in LB films were characterized by infrared(IR), ultraviolet-visible-near infrared(UV-Vis-NIR) spectroscopies and atomic force microscopy(AFM). From the UV-Vis-NIR and IR spectra, it could be concluded that the TMB·C18TCNQ complex is in a mixed\|stacked arrangement style, and the chromophore planes of both C18TCNQ and TMB are nearly perpendicular to the substrate surface. AFM image shows that the morphology of five-layer LB film of the complex consists of many two-dimensional hexagonal flake microcrystals. The width of these flake microcrystals is about 180 nm.

    NMR Study on Inclusion-complex of Cyclodextrin with α-Naphthylacetic Acid
    PENG Min, KONG Xu-Xin, YU Yi-Hua, CHEN Qun*
    2006, 27(5):  939-943.  doi:
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    The interactions of α-naphthylacetic acid(α-NAA) with α-cyclodextrin(α-CD) and β-cyclodextrin(β-CD) were studied by NMR diffusion measurements, 1H-1H ROESY and solid-state high-resolution 13C NMR spectroscopy. Both α-CD and β-CD are found to be able to form inclusion-complex with α-NAA. The complex formed by β-CD and α-NAA are more stable than that formed by α-CD and α-NAA, due to the effect of cavity size. The association constant of β-CD/α-NAA complex was calculated from the self-diffusion coefficients of α-NAA. The application of β-CD/α-NAA system in drug release was discussed.

    Preparation and Properties of Low Cerium Content Ce-Zr-Y Oxygen Storage Material with High Thermal Stability and High Specific Surface Area
    WANG Min, ZHANG Xiao-Yu, GONG Mao-Chu, CHEN Qing-Quan, CHEN Yao-Qiang*
    2006, 27(5):  944-947.  doi:
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    Low cerium content Ce-Zr-Y tenary compound was prepared with ammonia aqueous solutioncarbonate ammonia mixed solution as the precipitator. Its crystal structure, specific surface area, pore size distribution, oxygen storage capacity(OSC) and redox behavior were investigated by X-ray diffraction, BET, oxygen pulse adsorption and H2temperature programmed reduction(H2-TPR). The results show a high specific surface area of 116.8 m2/g and total pore volume of 0.30 cm3/g after calcining at 873 K for 4 h, and after aging at 1 273 K for 10 h, the specific surface area and total pore volume of 68.1 m2/g and 0.22 cm3/g were maintained. According to the results of XRD, there was only one tetragonal Zr 0.84 Ce 0.16 O2 in the mixed oxide, and its crystal structure was stable in the process of thermal treatment. The results of OSC and H2-TPR show that the oxygen storage capacities were maintained even after being treated at 1 073 K and 1 273 K indicating the durability of the materials.

    Influences of Substrate Materials on Properties of Nano-fibrous Polyaniline Film Prepared by Pulse Galvanostatic Method
    WEN Jing-Bang,ZHOU Hai-Hui,LUO Sheng-Lian,PANG Xin-Yu
    2006, 27(5):  948-950.  doi:
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    Effects of substrate materials on the properties of nanofibrous polyaniline(PANI) film prepared by the pulse galvanostatic method(PGM) were investigated. The chronopotentiograms of aniline polymerization in 0.3 mol/L aniline+1 mol/L HNO3 aqueous solution showed that the anodic potential on Pt and Ru electrodes rised to 880 and 850 mV quickly when the mean current density was 1.0 mA/cm2 . The potential turned to 750 mV after about 40 s and kept constant until the experiment was over. When the aniline polymerization occurred on stainless steel(SS) and Al electrodes, the anodic potential climbed to 1100 and 1700 mV respectively, and after about 55 and 250 s it turned to 750 mV. The scanning electron microscopic images demonstrated that the PANI films on Pt, Ru, SS and Al prepared by PGM all exhibited a similar fibrous morphology with a diameter of 80-100 nm. Therefore, it can be considered that the PGM polymerization of aniline on different substrate materials was markedly distinct when the surface of electrode was not covered by PANI completely. The cyclic voltammograms and electrochemical impedance spectroscopy results showed that PANI films on various substrates presented different electrochemical reactivities in an aqueous aniline free solution of 1 mol/L HNO3.

    Surface Tailoring of PET via Immobilization of Comb-shaped Poly(ethylene glycol) for Promoting Endothelial Cell Compatibility
    PU Ming, JI Jian*, LI Xiao-Lin, SHEN Jia-Cong
    2006, 27(5):  951-955.  doi:
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    The hydroxyl end groups of a comb-like poly(ethylene glycol) were transformed into aldehyde groups, which were further grafted onto PET substrate. Ligands including lysine and RGD peptide were tethered onto the reactive PEG end groups. Linear PEGs with different molecule weights(Mw=4 000 and 10 000) were also investigated as controls. The surface grafting process was characterized by means of FTIR, 1 H NMR, contact angle and XPS. The two systems were compared with regarding their abilities to prevent non-specific interaction and to promote cyto-compatibility. Owing to its high branched-arm structure, the comb-like PEG modified surface achieved stronger entropic repulsion than the linear PEG. Meanwhile, more ligands were tethered onto the comb-like PEG modified surface with a great amount of reactive end groups, which increased cell proliferation. The glycocalyx mimicking surface designed with comb-shaped PEG end-tethered by RGD peptide was proved to present non-specific resistance and excellent cyto-compatibility simultaneously.

    Synthesis and Self-assembly of Temperature- and pH-Sensitive Diblock Copolymer of Poly(acrylic acid)-b-poly(N-isopropylacrylamide)
    LI Gui-Ying, AN Ying-Li, HE Zhe-|Ping, MA Ru-Jiang, ZHANG Wang-Qing, SHI Lin-Qi*
    2006, 27(5):  956-960.  doi:
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    Diblock copolymer of poly(t-butyl acrylate)-b-poly(N-isopropylacrylamide)(PtBA-b-PNIPAM) with designed molecular weight and narrow molecular weight distributions was synthesized by sequential atom transfer radical polymerization(ATRP) of butyl acrylate and N-isopropylacrylamide using CuCl/(1,1,4,7,7-pentamethyl diethylenetriamine(PMEDTA) and CuCl/tris(2-dimethylaminoethyl)amine(Me6TREN) as the catalyst respectively in a mixture solvent of butanone and 2-propanol. Temperature- and pH-sensitive block copolymer of poly(acrylic acid)-b-poly(N-isopropylacrylamide)(PAA-b-PNIPAM) was realized after hydrolysis of PtBA-b-PNIPAM in toluene. PAA-b-PNIPAM existed as single molecules in aqueous solution at 25 ℃ and pH>pKa of PAA. Increasing temperature above LCST of PNIPAM or decreasing pH value lower pKa of PAA respectively formed PNIPAM-core micelles or PAA-core micelles.

    Analysis of Sequential Structure and Monomer Unit Ratio of Ethylene-propylene Copolymer by Spectroanalysis Method
    DONG Hui-Ru*, TAO Hong, WANG Nan-Nan, BI Peng-Yu
    2006, 27(5):  961-965.  doi:
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    The sequential structures and monomer unit ratio of ethylene-propylene copolymer(EPC)were analyzed by FTIR, 1 H NMR and 13 C NMR. The spectra of 1 H NMR, 13 C NMR and two-dimensional NMR of EPC were also analyzed in detail, the differential explanations of the NMR spectra for EPC with predecessors, and an analytical method of the relativity of the integrated areas of differential carbon atoms in the inverse gated decoupling 13 C NMR spectrum were proposed in this paper. The proposed method can be used to determine the main sequential structures in EPC simply. The theoretical calculated results of the main sequence distribution for three EPR samples proved that the proposed method is feasible.Compared 1 H NMR with 13 C NMR, it is accepted that 1 H NMR method can be used to calculate the monomer unit ratio of ethylene and propylene in EPC.

    A Fractal Model on the Diffusion of Small Molecule Penetrants in Dense Polymer Membranes
    XU Ye-Xin, SHANG Tian-Gang, CHEN Cui-Xian*, LI Ji-Ding
    2006, 27(5):  966-969.  doi:
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    The mechanism of small molecule penetrants in dense polymer membranes was described on the basis of free volume theory and the concept of diffusion path was presented. The statistical character of diffusion path was related with the size of penetrant molecules, the temperature and the free volume of membranes according to the percolation theory. Then a novel fractal model was developed to describe the diffusion of small molecule penetrants in dense polymer membranes. According to this fractal model, the diffusion of penetrant consisted of a series of active jumps in the diffusion path, and the diffusion behavior could be classified to three types: fractal diffusion, transition diffusion and normal diffusion. The fractal diffusion together with transition diffusion was called anomalous diffusion. The phenomenon was called fractal crossover that the diffusion of penetrants transformed from the fractal diffusion to the transition diffusion or the normal diffusion was analyzed.

    Rare Earth Compounds Assisted Melt Grafting of Maleic Anhydride onto Isotactic Polypropylene by Reactive Extrusion
    ZHU Lian-Chao1,2, TANG Gong-Ben1, SHI Qiang1,2, YIN Jing-Hua1*
    2006, 27(5):  970-974.  doi:
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    A series of rare earth compounds were employed for melt grafting of maleic anhydride(MAH) onto isotactic polypropylene(iPP) by reactive extrusion. Melt flow rate(MFR) of the graft copolymers and the grafting degree of MAH monomer were measured for determining the impact of rare earth compounds on the grafting reaction. It was shown that rare earth oxides, neodymium oxide as well as cerium oxide, promoted the grafting reaction. The increment of the grafting degree maximally were up to about 14% and 25% respectively compared with those of the related system without importing any rare earth compound, whereas MFR of the graft copolymers were enhanced by 36% and 56%. According to the correlation between MFR of the graft copolymers and the grafting degree of MAH under our experimental condition, a method that characterized the grafting degree by means of MFR was put forward and a calibration curve was also built up. The inhibition and synergism mechanisms that rare earth compounds having impact on grafting reaction were tentatively investigated.

    Water-resistance Properties of the Semi-IPN Between Starch and Biodegradable PCL or PHBV
    WU Hang, RAN Xiang-Hai, ZHANG Kun-Yu, ZHUANG Yu-Gang, DONG Li-Song*
    2006, 27(5):  975-978.  doi:
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    The semi-IPN between starch and biodegradable PCL or PHBV was prepared by using HDI as the cross linking reagent under solution conditions. Their water\|resistance properties were investigated by comparing with cross-linked starch net works without PCL or PHBV. It was found that the water resistance of the Semi\|IPN can be further improved by means of heat treatment or solvent treatment methods, respectively.

    Synthesis of CdS Nanocrystals in Polymer-impregnated Sol-gel Silica Matrix
    TANG Jun 1* , LIN Hang 1,2 , WANG Ce 2*
    2006, 27(5):  979-981.  doi:
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    A new method for the synthesis of CdS nanocrystals in polymer-impregnated sol-gel matrix was described. The CdS nanocrystals were prepared by simply passing H2S in polymer/silica sol-gel composite matrix formed by the in situ polymerization of tetraethoxysilane in Cd 2+ containing polymer microgel. The synthesized CdS nanocomposite were characterized by means of X-ray diffraction(XRD), UV-Vis spectroscopy and TEM. X-ray diffraction and TEM results show that hexagonal CdS nanocrystals are well dispersed in polymer/silica composite matrix. The results of UV-Vis spectroscopy demonstrate that the size of CdS nanocrystals can be adjusted from 1.0 nm to 2.4 nm by changing the amount of H2S.

    Synthesis of Poly(ε-caprolactone) Catalyzed by Immobilized Porcine Pancreas Lipase on Narrow Distributed Micron Glass Beads
    WANG Ying-Xia, HE Feng*, LI Feng, FENG Jun, ZHUO Ren-Xi
    2006, 27(5):  982-984.  doi:
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    Porcine pancreas lipase(PPL) immobilized on narrow distributed micron glass beads was employed successfully for ring-opening polymerization of ε-caprolactone(CL). Different polymerization conditions such as enzyme concentration, reaction temperature and reaction time were studied. The results showed that Mn of the resulting PCL was significantly increased compared with that catalyzed by PPL. Higher temperature and longer reaction time both contributed to gaining PCL with a higher molecular weight, while the yield had almost no change. In addition, for evaluating the recyclibilty of immobilized PPL on narrow distributed micron glass beads for the ring-opening polymerization of CL, we adopted the most severe reaction conditions(180 ℃, 240 h) in the recycling experiments. It was found that the recovered immobilized PPL could be used again with a compatible high catalytic activity. The highest Mn of 21300 of PCL could be obtained at a mass fraction of 5.18% of the reused immobilized PPL at 180 ℃ for 240 h, which is the highest Mn of PCL catalyzed by PPL. The excellent recyclability of immobilized PPL on narrow distributed micron glass beads is very helpful to its further industry applications.

    Synthesis and Characterization of AB-Type Diblock Copolymer by Enzymatic Ring-opening Polymerization and ATRP
    SHA Ke, LI Dong-Shuang, LI Ya-Peng, LIU Xiao-Tian, AI Peng, WANG Wei, WANG Jing-Yuan*
    2006, 27(5):  985-987.  doi:
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    Mono-hydroxyl terminated polycaprolactone(PCL) was prepared by Novozyme 435 catalyzed ring-opening polymerization(ROP) of ε-caprolactone(ε-CL) initiated by methanol, and subsequently converted to bromine ended PCL by the esterification of the resulting macromolecules with α-bromopropionyl bromide. The macroinitiators containing α-bromoester group were employed in the atom transfer radical polymerization(ATRP) of glycidyl methacrylate(GMA) with CuCl/2,2-bipyridine(bpy) as the catalyst system to obtain amphiphilic diblock copolymer PCL-b-PGMA.

    Effect of Crosslinking Agent Amount on Uniaxial Piezoresistivity of Carbon
    Black Filled Poly(methyl vinyl siloxane) Conductive Composites

    CHEN Yong-Liang1, SONG Yi-Hu1, ZHENG Qiang1,2*, ZHANG Ming-Qiu3

    2006, 27(5):  988-990.  doi:
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    The effect of crosslinking degree on the piezoresistive behavior of carbon black (CB) filled poly(methyl vinyl siloxane) (PMVS) vulcanites under uniaxial compression was studied. The results reveal that increasing the amount of crosslinking agent could weaken the negative pressure coefficient of resistance (NPCR) effect at the late stage of compression and enhance the piezoresistivity intensity at a high stresses. The recovery property of resistance was related to the content of CB, the stress level and the degree of crosslinking. It was proved that repeated compression with the same maximum stress level could improve piezoresistive stability considerably.

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