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Table of Content

    10 April 2007, Volume 28 Issue 4
    目次
    高等学校化学学报2007年第28卷第4期目次
    2007, 28(4):  0.  doi:
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    研究论文
    Hydrothermal Synthesis and Characterization of Nanometer Ce1-xCoxO2-δ Solid Solutions
    ZHANG Guo-Fang1,3, XUE Yan-Feng2, XU Jiao-Xing1, QIU Xiao-Qing1, LI Guang-She1, LI Li-Ping1*
    2007, 28(4):  603-607.  doi:
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    Using (NH4)2S2O8 and NH4OH as the oxidizer and chelating agent, respectively, Ce1-xCoxO2-δ solid solutions were synthesized under hydrothermal conditions and the optimum preparation parameters were explored. The obtained solid solutions had a cubic fluorite structure, and the average particle size was about 4 nm. The lattice parameter monotonously decreased with increasing the cobalt content. The solubility of x=0.06 was determined by combining XRD and Raman techniques. Cobalt ions are found to be in a mixed valence state of Co2+/ Co3+ in CeO2 lattice. Increasing the cobalt content resulted in a clear blue shift of the absorption threshold edge and an increase of bulk conductivity.
    Carbothermal Reduction Synthesis and Growth Mechanism of Antimony Doped Tin Oxide Solid and Hollow Spheres
    HUANG Zai-Yin1, 2*, CHAI Chun-Fang2, TAN Xue-Cai1, LIAO Dan-Kui2, WU Jian1, YUAN Ai-Qun1, ZHOU Ze-Guang1
    2007, 28(4):  608-613.  doi:
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    Antimony doped tin oxide(ATO) solid and hollow spheres were fabricated by reducing ATO nanoparticles with graphite as the reducer in the high temperature tube furnace. The phase, element composition, morphologies and crystalline structures of the as-synthesized sample were characterized by XRD, EDX, FE-SEM, TEM and HRTEM, respectively. The results show that the products are ATO solid and hollow spheres with the diameters of about 0.2—5 μm and 2—20 μm, respectively. The size and yield of the solid spheres could be controlled by adjusting the rate of Ar flow and deposition positions. Ostwald Ripening was employed to explain the growth of solid spheres. ATO hollow spheres were synthesized in alumina tube system which has a relatively high oxygen concentration, and its growth mechanism was also discussed. The reason for why the spheres with different morphologies were synthesized by using different tubes under the same conditions was analyzed.
    Preparation and Characterization of CoFe2O4/SiO2 Nano-composites
    LI Hai-Bo1,2*, CHEN Jing-Yan1, LIU Mei1, FENG Ming1, HUA Jie1
    2007, 28(4):  614-616.  doi:
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    CoFe2O4/SiO2 nano-composites were prepared by the sol-gel method. The changes of gels during the heat treatment and the structure, crystalline size, microstructure of CoFe2O4/SiO2 nano-composites were investigated by TG/DTA, XRD and Mössbauer Techniques. The results show that with the increase of the content of SiO2, the crystalline size of CoFe2O4 and internal magnetic fields decreased, while samples were transferred from magnetic order to superparamagneitc state.
    Synthesis and Characterization of Cerium Oxide Nanotubes Based on Carbon Nanotubes
    FU Hong-Xia1,2, ZHANG Deng-Song1,3, SHI Li-Yi1,2,3*, FANG Jian-Hui2
    2007, 28(4):  617-620.  doi:
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    A facile and novel method for synthesizing cerium oxide nanotubes is reported in this paper. Carbon nanotubes(CNTs) were firstly uniformly coated with CeO2 nanoparticles by a liquid deposition approach at room temperature and normal pressure and then CNT templates were removed by calcination at a suitable temperature. The characteristics of cerium oxide nanotubes were characterized by TEM, XRD and XPS. The results reveal that the face-centered cubic-phase CeO2 nanotubes with an average diameter of 40—60 nm and a length of 0.5—2 μm is synthesized.
    Radioiodination and Biodistribution of PEGy Lated YP13 Polypeptide
    SUN Li-Yan, CHU Tai-Wei*, WANG Yi, WANG Xiang-Yun
    2007, 28(4):  621-626.  doi:
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    A dodeca-peptide SVSVGMLPSHAP that targets human CL-187 tumor was identified in vivo by phage display technology. In order to evaluate the potency of YP13 as the imaging agent for diagnosis of tumor and to be easily radioiodinated, peptide YSVSVGMLPSHAP(YP13) with tyramine being added to the N-terminal was synthesized and chemically modified by conjugation with a low molecular weight monomethoxy polyethylene glycol(mPEG, Mw=5000). YP13, mPEG-YP13 and YR13(a nonspecific random 13 peptide as a control peptide) were labeled with 131I via Iodogen method. The labeled complex 131I-YP13, 131I-mPEG-YP13 and 131I-YR13 were isolated and purified by RP-HPLC. The radiochemical purity was estimated to be better than 95%. The RP-HPLC analysis of the supernatant of 131I-YP13 and 131I-mPEG-YP13 in serum collected for 60 min after injection shows that 131I-mPEG-YP13 in vivo was far more stable than 131I-YP13. The biodistribution of 131I-YP13, 131I-mPEG-YP13 and the control peptide 131I-YR13 in mice bearing human colon cancinoma was investigated. The experimental results indicate that there was higher uptake of 131I-YP13 and 131I-mPEG-YP13 in tumor than that of control peptide YR13 at 1 h and 2 h. The ratios of tumor to blood for 131I-mPEG-YP13 and 131I-YP13 increased as time prolonging. The longer serum half-life of mPEG-YP13 improved the uptake in tumor. Therefore, it can be expected that the radioiodinated YP13 and PEGylated YP13 may be a potential tumor-imaging agent.
    研究快报
    Preparation and Characterization of AucoreCoshell Nanoparticles and Their Surface-enhanced Raman Spectroscopy
    BAO Fang1, CUI Yan2, YAO Jian-Lin1, REN Bin2, GU Ren-Ao1*
    2007, 28(4):  627-629.  doi:
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    AucoreCoshell nanoparticles with different shell thicknesses were prepared by using chemical reduction method and characterized by scanning electron microscopy(SEM) and cyclic voltammetry(CV). The results reveal that the prepared core-shell nanoparticles were covered by Co shell and exhibited the similar electrochemistry property with the Co nanoparticles surface. Surface enhanced Raman spectroscopy(SERS) activities of these nanoparticles were studied by using pyridine as a probe molecule. It was found that the SERS intensity depended on the Co shell thickness of the core-shell nanoparticles and was weakened with the increasing shell thickness. The SERS intensity of these AucoreCoshell nanoparticles is found to be about twenty times higher than that obtained on an electrochemically roughened cobalt electrode.
    研究论文
    Sample Loops-valve Interface of Comprehensive Two-dimensional Liquid Chromatography(NPLC×RPLC) and Its Application
    TIAN Hong-Zhe, XU Jing, GUAN Ya-Feng*
    2007, 28(4):  630-634.  doi:
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    A comprehensive two-dimensional liquid chromatography(NPLC×RPLC) was developed. Normal phase liquid chromatography(NPLC) with a CN microcolumn was used as the first dimension, and reversed-phase liquid chromatography(RPLC) with a monolithic column was used as the second dimension. The interface was based on a ten-port, two-position valve with two storage loops. The first column was operated at a flow rate of 8 μL/min in isocratic mode, while the monolithic column flow rate was 4 mL/min and was operated in gradient mode. The sample loops had a volume of 12 μL each, and the analysis time in the second dimension was 1.5 min. The primary fractions were stored into the two storage loops alternately, and then were separated by the secondary column sequentially. AUV detector was used after the secondary column. The use of a monolithic column in the second dimension permits a very fast analysis operating at highter flow rates without loss of resolution, since the monolithic column has higher permeability than conventional packed columns. The incompatibility of the two dimensional mobile phases was avoided because the flow rate of the first dimension is only 1/500 of that of the second dimension. The performance of the system was evaluated by several standards mixture and Radix salviae miltiorrhiza bage extract and the advantage of using 2D-LC over one-dimensional chromatographic techniques is clearly demonstrated in the analysis of the extract.
    Application of HPLC-ICP-MS in Speciation Analysis of Selenium in Selenized Flammulina velutipes
    TIE Mei1, FANG Yu-Zhi2, SUN Tie-Biao1, LI Chuang1, FEI Jin-Yan1, LI Hua-Wei3, ZANG Shu-Liang1*
    2007, 28(4):  635-639.  doi:
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    The determination of selenium in different selenium-containing compounds extracted from selenized Flammulina velutipes was studied by SEC-DADICP-MS-ICP-MS. After hydrolyzation of the different compounds under special condition, selenium-amino acid in the leaching solution was confirmed by RPLC-DADICP-MS-ICP-MS. A new selenium-containing compound was detected and the content of selenium in differnt offspring by hydrolyzation was determined. It is shown that the soluble selenium was the main existing form in selenized Flammulina velutipes, and the content of selenium in compounds low molecular weight accounting for 71.87% of the total amount was much higher than that in compounds with a high molecular weight. Then the further results show that in selenized Flammulina velutipes there mainly are Se-Cys, Se-Met, peptide composed by the former two. The max content of selenium in the three main speciations accounted for 12.3%, 17.6%, 36.8%. This method combined by HPLC and better sensitive element detect technology can be successfully applied in the online determination of selenium in selenium-containing biological molecule.
    Electrogenerated Chemiluminescence of Ru(bpy)2+3 Incorporated in Highly Order Mesoporous SBA-15 Material
    LIU Yang1,2, YANG Xiu-Rong1*
    2007, 28(4):  640-644.  doi:
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    Highly ordered mesoporous SBA-15 was prepared and characterized by using TEM and N2 adsorption. The Ru(bpy)2+3 were incorporated into SBA-15 by electrostatic effect. The Ru(bpy)2+3 adsorbed on SBA-15 were immobilized on the surface of a glass carbon electrode and their electrogenerated chemiluminescence(ECL) were investigated. The oxidative current increased and the reductive currents decreased with the addition of tripropylamine(TPA), indicating that TPA presented an obvious catalysis to the oxidation of Ru(bpy)2+3. Meanwhile, the intensity of ECL increased sharply. The ECL intensity was decreased with the increase of scan rate which resulted from the large pore diameter and open pore structures of SBA-15 that improve the diffusion and electron transfer in the SBA-Nafion composite films on the electrodes. The modified electrodes of Ru(bpy)2+3 adsorbed on SBA-15 presented an excellent linear relationship between the ECL intensity and the concentration of TPA in the range of 5.0×10-5—1.0×10-2 mol/L with a linear equation of y=71.7+41.2x and showed a good stability in successive 10 cycles, which would be attributed to the high specific area and ordered mesoporous structures of SBA-15.
    Fourier Transform Mid-infrared Spectroscopy(FTIR) Used for the Rapid Intraoperative Diagnosis of Gallbladder Diseases
    XU Yi-Zhuang1*, ZHAO Ying2, LING Xiao-Feng3, YANG Li-Min1, XU Zhi3, ZHOU Xiao-Si3, ZHANG Yuan-Fu1, GONG Rong-Ye4, PAN Qing-Hua5, WANG Bing-Bing1, SHI Jing-Sen6,
    2007, 28(4):  645-648.  doi:
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    Identification of gallbladder cancer rapidly at the time of surgery would allow the appropriate resection to be completed at the original surgery. The aim of this study was to assess the sensitivity and specificity of FTIR in the rapid detection of gallbladder cancer, via an attenuated total reflection(ATR) accessory with a ZnSe window. This allowed the edges of the surgically resected specimens to be examined rapidly. The results indicate that there are a series of differences between the spectra of normal and malignant tissues, and subtraction technique is helpful to identify cholecystitis and gallbladder cancer. Compared with pathological diagnosis results, one benign specimen was classified as a malignant and 6/6 malignant specimens and 39 cases of benign specimens were correctly classified. The sensitivity was 100%(6/6), specificity 97%(39/40), and accuracy was 97%(45/46). We can conclude that mid-infrared ATR FTIR spectroscopy is highly accurate and rapidly allows appropriately tailored resection at the time of initial surgery.
    研究简报
    Piezoelectric Immunosensor Detection of IgG Based on Nanoprobe Immunoagglutination
    MO Zhi-Hong*, HUANG Hong-Ji, QIAN Jun-Zhen, ZHU Li-Hua
    2007, 28(4):  649-651.  doi:
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    A piezoelectric immunoassay based on nanoprobe immunoagglutination was proposed for rapid and sensitive detection of IgG. The nanoprobes were prepared by labeling gold nanoparticles with anti-IgG antibody. And a piezoelectric sensor was used to monitor the changes in solution density and viscosity caused by the immunoagglutination of IgG and anti-IgG nanoprobes. The effects of pH and ionic strength were investigated. It is found that the developed immunoagglutination assay is sensitive to IgG with the detection limit of 1.12, 0.72, 0.70 nmol/L to the detection time of 10, 20, 30 min, respectively, and it is unnecessary for immobilization of immunoactive entities.
    Colorimetric Detection of cis-Pt with Gold Nanoparticle Probes
    SUN Lin-Lin, LIU Dian-Jun, WANG Zhen-Xin*
    2007, 28(4):  652-654.  doi:
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    A novel method of colorimetric assay for determining cis-Pt (cis-diammino-dichloroplatinum Ⅱ) was found by the binding affinities between cis-Pt and DNA based on the change of surface plasmon resonance band of gold nanoparticles. The red-shift of the maximum band of the surface plasmon resonance band of gold nanoparticles increased linearly with the logarithm of the cis-Pt concentration from 40 to 2000 nmol/L and the detection limit is 40 nmol/L when the concentration of gold nanoparticles is 4 nmol/L. The colorimetric readout can be visualised with the naked eyes.
    研究论文
    Glycol-unit Structure Identification of a Kind of Exopolysaccharide from a Lactic Acid Bacterium
    LI Quan-Yang1*, XIA Wen-Shui2, XU De-Ping2
    2007, 28(4):  655-657.  doi:
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    The structure of exopolysaccharide EPS03-1gm was identified by the technology of GC, UV spectrophotometric analysis and NMR. The EPS03-1gm was separated and purified before analysis which was secreted from S. thermophilus. The results show that the mono-glycos of EPS03-1gm were glucose and galactose and there are no glycol-aldehudic acid or protein ingredient. The 1H NMR made it clear that there were four glycol-cells in each repeat glycol-unit. The DEPT reveals there were four CH2 in every repeat glycol-unit. The positions of H were confirmed by analyzing the TOCSY spectrum. The positions of H and the order of glycol-cell were confirmed by analyzing the HMQC and HMBC spectra. Finally, the glycol-unit structure were fixed on as follows: →3)-α-D-Galp-(1→3)-β-D-Galf-(1→3)-β-D-Glcp-(1→6)-β-D-Glcp-(1→.
    Effects of Novel Fungicide Flumorph on Synthesis and Distribution of the Components of Cell Wall of Phytophthora melonis
    ZHU Shu-Sheng1, LIU Xi-Li1*, LIU Peng-Fei1, LI Jian-Qiang1, SI Nai-Guo2, WANG Hui-Ming1
    2007, 28(4):  658-662.  doi:
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    The effects of flumorph on the synthesis and distribution of cell wall materials of Phytophthora melonis were investigated by the biochemical methods of isotopic trace and histological fluorescent staining. The synthesis of cellulose and noncellulose glucan was significantly inhibited by flumorph from 1 h to 4 h after the germling suspensions of P. melonis exposure to flumorph and the inhibition was dose-dependent. The rate of inhibition reached 22.78% and 34.67% after exposure to 25 μg/mL flumorph for 1 h and 4 h later, respectively. Subsequently the synthesis of cellulose increased from 4 h to 8 h, and then was inhibited again after 16 h treatment. The change of inhibition of flumorph on cell wall synthesis was consistent with the alteration of hyphal morphology. Flumorph can significantly inhibit the diameter of colony, but it also can cause stunting of hyphae and stimulate the formation of short lateral branches after exposure to flumorph for 4 h to 8 h. The other most characteristic effect of flumorph treatment was that the development of the periodic expansion along hyphae yielded a "beaded" morphology. These data above show that flumorph did not inhibit the synthesis of cellulose and other cell wall materials, the hyphae can grow continually, but its morphology was abnormal. After being stained with calcofluor, it was observed that the synthesis of new cell wall was going on, but they uniformly deposited throughout the diffuse expanded cell walls, in contrast to their normal polarized patterns of deposition. These may be the result of that the disruption of cell polarity, because the change of hyphae morphology and patterns of deposition of newly synthesized cell wall after exposure to flumorph were similar to the characteristics of disrupted process of the polarity growth of cell in other eukaryotic cells. Thus, the results obtained in this study suggest that flumorph might cause the disruption of establishment of cell polarity. Subsequently, the newly synthesized cellulose lost their normal polarized patterns of deposition, but the synthesis of cell wall materials was not interfered.
    Isolation and Kinetic Properties of Dioscin-α-L-rhamnosidasefrom Sheep Liver
    WANG Hong-Ying*, QIAN Si-Ri-Gu-Leng, YU Hong-Shan, ZANG Shu, JIN Feng-Xie
    2007, 28(4):  663-667.  doi:
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    Dioscorea nipponica is a popular herb in China. It has been wildly used to prevent bronchial and other respiratory infections as well as viral infections to treat rheumatic diseases, to improve cardiovascular conditions, to treat and reduce the risk of heart disease and to protect against cancer. The enzymatic transforming generally improves the bioactivity of natural productions. In this paper, dioscin-α-L-rhamnosidase hydrolyzing α-L-rhamnoside from dioscin was found and purified from sheep liver by means of centrifugation, ammonium sulfate precipitation and ion-exchange chromatography on DEAE-cellulose column, and its partial cha-racteristics were studied. A 19.9-fold purification factor was achieved by DEAE-cellulose column. The enzyme showed the highest activity under the reaction condition of pH=6.8, 42 ℃, 8 h, and 23 mmol/L of substrate concentration. In the concentration range of 10—250 mmol/L, ions Fe3+, Cu2+ strongly inhibited the enzyme, Mg2+ and Zn2+ slightly activated the enzyme, but Ca2+ activated strongly the enzyme. The molecular weight of the enzyme estimated by SDS-PAGE was about 71000. In the comparative examination with rutin-α-L-rhanmosidase, ginsenoside-α-L-rhamnosidase, and α-L-rhamnosidase on the substrates such as dioscin, ginsenoside Re, rutin, it was found that the enzyme has a narrow substrate specificity.
    Design, Synthesis of Unnatural Amino Acids with Chelating Functional Groups and Their Application in Bio-active Peptide
    ZHOU Ning1, FU Hui-Jun1, RONG Di2, CHENG Mao-Sheng2, LIU Ke-Liang1*
    2007, 28(4):  668-671.  doi:
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    In order to synthesize long acting bio-active peptides, some novel unnatural amino acid with chelating functional group were designed and synthesized, and were used in the solid phase synthesis of LHRH analogues. The purity of peptide was analyzed by HPLC and the structure of peptide was confirmed by ESI-MS. The experiment result shows that these unnatural amino acids could be successfully used in the solid phase synthesis of peptides as novel monomers. LHRH antagonists with functional groups show a longer duration of action and half-lives than that of model peptide in vivo and in vitro respectively.
    Design, Synthesis and Hypoglycemic Activity of 3-Methyl-1-phenyl-4-{4-[(5-methyl-2-phenyloxazol-4-yl)methoxy] benzylene(benzyl)}-2-pyrazol-5-one
    LIU Xing1, WANG Ya-Lou1*, WU Guan-Zhong2, LI Jiang-Chuan1, WU Xiao-Yan1
    2007, 28(4):  672-677.  doi:
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    Based on the SAR of TZDs, 3-methyl-1-phenyl-2-pyrazoline-5-one was selected as a substitute for TZD, 3-methyl-1-phenyl-4-{4-[(5-methyl-2-phenyloxazol-4-yl)methoxy]benzylene(benzyl)}-2-pyrazol-5-one compounds were designed and synthesized in order to find some more hypoglycemic active agents and further investigate the SAR of this class of compounds. The butanedione monoxime reacted with(substituted ) benzaldehyde via cyclization and chlorination to give 4-(chloromethyl)-5-methyl-2-phenyloxazole derivatives, which condensed with 4-hydroxybenzaldehyde or vanillin, and then followed by Knoevenagel reaction with 3-methyl-1-phenyl-2-pyrazol-5-one to give compounds Ⅰa—Ⅰh. Compounds Ⅰa—Ⅰh were hydrogenated with Pa-C to give Ⅱa—Ⅱh, and their hypoglycemic activity were evaluated with glucose oxidase kit and insulin load test on normal mouse. Sixteen new target compounds were synthesized. All the compounds were characterized by 1H NMR, IR, MS and elemental analysis. The preliminary pharmacological test shows that the compounds have a good hypoglycemic activity and can enhance the action of insulin, especially Ib, Id and If.
    Synthesis and Photophysical Properties of Tris(pinene-2-phenylpyridine) Iridium Complexes with Alkoxy Groups
    HE Jian1,2, WANG Peng-Fei1, LIU Hong-Mei1,2, ZHANG Xiao-Hong1*
    2007, 28(4):  678-682.  doi:
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    Heavy metal complexes as the highly efficient phosphorescent emitters in organic light emitting diodes(OLEDs) have been extensively studied in recent years. The complexes containing Ir(Ⅲ) have usually been modified to further improve electroluminescence(EL) efficiency. In our previous work, Ir(pppy)3[tris(5-phenyl-10,10-dimethyl-4-aza-tricycloundeca-2,4,6-triene)iridium]was synthesized by introducing pinene group as a spacer to decrease concentration quenching and showed good EL performances. In the present work, we studied the modified Ir(pppy)3 by attaching side alkoxy group to the pinene-2-phenylpyridine ligand, which is hoped to improve the chemical compatibility with host and further inhibit phase segregation in polymer matrix. The new series of Ir(Ⅲ) complexes [Ir(RO-pppy)3] were synthesized and the photophysical properties were investigated. Strong triplet emission peak at around 496 nm was observed with phosphorescence quantum yield ΦF=0.4—0.6, emission lifetimes τ=2—4 μs. Complex 8 [Ir(C16H33O-pppy)3] has special photophysical properties: no blue-shift on going from room temperature(298.15 K) to 77 K was observed and with relatively less part of long-lifetime in decay process. The results indicate that the complex with long side chains can reduce the aggregation between molecules, thus can be used as promising efficient phosphorescent emitter in OLEDs.
    研究简报
    Stability of Synthetic Exendin-4 in Human Plasma in Vitro
    CHEN Jie, LI Wei, YU Ling, WANG Li-Ping*
    2007, 28(4):  683-685.  doi:
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    Synthetic exendin-4 exhibits dose-dependent glucose-regulatory activity similar to that of native glucagon-like peptide-1(GLP-1). Moreover, exendin-4 is resistant to degradation by dipeptidyl peptidase-Ⅳ(DPP-Ⅳ) while GLP-1 is degraded by DPP-Ⅳ with a half-life of less than 2 min in mammals. In this study the stability of exendin-4 in human plasma was evaluated in vitro. Exendin-4 was incubated in plasma at 37 ℃, extracted and subsequently analyzed by using high performance liquid chromatography(HPLC). Exendin-4 was slowly broken down in plasma. Its half-life time is 9.57 h. The degradation products were identified by mass-spectrum(MS). According to natural sequence of exendin-4, we deduced that the cleavage were between the Thr5 and Phe6 bond, Phe6 and Thr7 bond, and Thr7 and Ser8 bond of the N-terminus region of the peptide, and the results of ESI-TOF-MS prove that our primary conclusion was correct.
    Isolation of New Polyhydroxylated Sterol from Soft Coral Sarcophyton crassocaule Mosre
    ZHANG Cui-Xian1,2, YAN Su-Jun1, ZHANG Guang-Wen3, SU Jing-Yu1, ZENG Long-Mei1*
    2007, 28(4):  686-688.  doi:
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    In our continuing search of discovering bioactive substances from marine organisms, a sample of soft coral Sarcophyton crassocaule Mosre collected off the Sanya bay, China, was investigated. Two polyhydroxylated sterols 1 and 2 were isolated from the 95% ethanol extract of the sample by chromatography over silica gel. Compound 1, named sarcrasterol, was a new compound, its structure was established as(22R*,24ξ)-methyl-cholest-5-en-3β,22α,25,28-tetraol by spectroscopic methods. Compound 2, a known compound, was first obtained by Kobayashi, however, the relative configuration of C24 has not been determined yet. This paper reports the stereochemistry of compound 2 established as (24S*)-methyl cholest-3β,5β,6α,25-tetraol by means of X-ray single crystal diffraction analysis. Bioassay results show that compound 2 has a moderate activity against human tumor cell lines MGC-803 with an IC50 value of 23.0 μg/mL.
    A Concise Synthesis of C2'—C7' Fragment of Aigialomycin D
    ZHANG Hong-Kui*, CHEN Wei-Qiang
    2007, 28(4):  689-691.  doi:
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    Aigialomycin D(1) possesses a potent antitumor activity and anti-malarial activity. In this paper a concise route for the synthesis of the key C2'—C7' fragment of aigialomycin D by using D-(-)-ribose was described. The fragment was synthesized in six steps in 37.2% overall yield, including protection of the vicinal diol, Wittig reaction of the lactol, hydrogenation, oxidative cleavage of the diol, terminal olefination and selective reduction of the ester. This work lays a good foundation for the total synthesis of aigialomycin D.
    研究论文
    Photoluminescence Spectroscopy of NaTaO3 and NaTaO3∶Bi3+ Photocatalysts
    SHI Jian-Ying, CHEN Tao, ZHOU Guo-Hua, FENG Zhao-Chi, YING Pin-Liang, LI Can*
    2007, 28(4):  692-695.  doi:
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    NaTaO3 and Bi3+ doped NaTaO3 were prepared by conventional high temperature solid state reactions and characterized by the photoluminescence spectroscopy. The luminescence characterization of NaTaO3 is sensitive to its preparation condition. Under the condition of Na scarcity, two luminescence bands of 515 nm and 745 nm are observed in the photoluminescence spectra, which are ascribed to the antisite defects of TaNa.... and VNa` defects, respectively. Under the condition of Na enough, the luminescence band shifts to about 460 nm, which are originated from the intrinsic tantalate groups. The introduction of Bi3+ causes the emission band shifts from 515 to 455 nm, namely, the TaNa.... defects are replaced by BiNa.. defects and the luminescence characterization of NaTaO3 is shift to the direction of a higher n(Na)/n(Ta) ratio. The present work also demonstrates that the photoluminescence spectroscopy is a powerful technique to characterize the defect chemistry in semiconductor materials and it is especially useful in the study of photocatalysts.
    DFT Study and Quantitative Structure-activity Relationship for Cephalosporin Derivatives
    SUN Qin-Chao, FENG Da-Cheng*
    2007, 28(4):  696-699.  doi:
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    The molecular structures of nine kinds of cephalosporin derivatives were optimized by using density functional theory(DFT)B3LYP method of quantum chemistry, and the quantitative structure-activity relationship of these cephalosporin derivatives was systematically studied. The structure-activity model of cephalosporin derivatives was found: QC8, QC7, dipole had positive correlation on the activities of cephalosporin derivatives.
    Theoretical Study on the Mechanism of Reaction of Pentafulvenone with Hydrocyanic Acid
    PAN Xiu-Mei1,2, LIU Ying2, YUAN Hui-Juan2, LI Ze-Sheng1*, SUN Chia-Chung1, WANG Rong-Shun2
    2007, 28(4):  700-703.  doi:
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    The reaction mechanism of pentafulvenone with hydrocyanic acid is studied theoretically at the MP2/6-311+G**//B3LYP/6-311+G** level. We found a complex, two intermediates, thirteen transition states and eight products. Our results show that the reaction has two attacking forms, which are HCN attacking CO double bond and CC double bond of pentafulvenone. Each kind of attacking form includes two reactive paths. The tautomerizations of the products include two kinds of processes, which are the tautomerizations of the same kind and the different kinds of cyclopentadienyl acetonitrile acids. In the process, the b kind of cyclopentadienyl acetonitrile acids is the most stable products.
    Electrooxidation of 2-Picoline in Different Organic Compound/Water Mixed Solvents
    LI Fei, CAO Xue-Jing, ZHANG Heng-Bin*, ZHANG Yu-Min, LI Ke-Chang
    2007, 28(4):  704-708.  doi:
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    In an electrolytic cell with proton exchange membrane as the diaphragm, the electrooxidation conditions of 2-picoline at a PbO2 electrode were studied by using cyclic voltammetry, linear scan voltammetry and potentiostatic electrolysis in acetone/H2O, acetonitrile/H2O and 2-butanone/H2O mixed solvents respectively, and after comparison of the selectivity, the current efficiency and the current density, it was found that in acetone/water mixed solvents the selectivity and the current efficiency of electrooxidation from 2-picoline to 2-pyridinecarboxylic acid were the highest , the current density of anode oxidation was also obviously increased. The electrooxidation from 2-picoline to 2-pyridinecarboxylic acid in acetone/water mixed solvents can completely replace to that in pure water.
    Theoretical Calculation of pKa for Ammonium Ions in Aqueous Solution
    YU Ao1, LIU Yuan-Hai1, CHENG Jin-Pei1,2*
    2007, 28(4):  709-713.  doi:
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    The conductor-like polarizable continuum model(CPCM) combined with UAKS cavity was applied to calculating the solvation free energy of 11 ammonium ions in aqueous solution at HF/6-31+G* and B3LYP/6-31+G* levels. The computational values were consistent with the experimental values, the mean errors and standard deviations were 0.17, 12.04 and 0.96, 10.96 kJ/mol, respectively. Using the calculated gas-phase proton-transfer free energies of the ammonium ions at the B3LYP/6-31+G* level of theory, the absolute pKa values in aqueous solution were obtained and agreed well with the experimental values, the relevant mean errors and standard deviations were only 0.05, 1.50 and 0.45, 1.40 pKa units, respectively. In order to validate the practicability of CPCM-UAKS model, the absolute pKa value of noradrenalin was also calculated. The result shows that CPCM-UAKS method can be used to calculate the absolute pKa values of ammonium ions compounds in aqueous solution accurately.
    Study of Surface Dilational Elasticity and Viscosity of Nonylphenol Polyoxyethylene Ethers
    ZHANG Chun-Rong1,2, SONG Xin-Wang3, CAO Xu-Long3, LUO Lan1, ZHANG Lu1, LI Zhen-Quan3, ZHAO Sui1*, YU Jia-Yong1
    2007, 28(4):  714-718.  doi:
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    The surface dilational viscoelasticity properties of nonylphenol polyoxyethylene ethers solutions, NP-8, NP-10 and NP-12, were investigated by Langmuir trough method. The influences of concentration and the number of polyoxyethylene groups on the surface dilational properties were expounded. It is shown that the surface dilational elasticity increased with the increase of frequency, while dilational viscosity passed through an indistinctive maximum. Surface dilational elasticity and viscosity passed through the distinctive maximum with the increase of bulk concentration and changed little with the increase of the number of polyoxyethylene groups from 8 to 12. The mechanisms responsible for the experimental results were discussed based on the relaxation processes existed in or near the surface. It showed that the arrangement of polyoxyethylene chain at the surface played an important role in film properties.
    Equilibrium Thermodynamics Analysis of Underpotential Deposition of Bi-Te Substrate System Thermoelectric Material
    ZHU Wen*, YANG Jun-You, ZHOU Dong-Xiang, BAO Si-Qian, FAN Xi-An, DUAN Xing-Kai
    2007, 28(4):  719-722.  doi:
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    Based on the general Nernst equation, thermodynamics model of the submonolayer equilibrium potential was set up. Both the underpotential-coverage and the underpotential-electrosorption valency relationships were analyzed, and the interactional properties between the deposit and substrate were obtained. By mean of the theoretical model, the thermodynamic properties of underpotential deposition of Bi-Te compound were obtained. The mechanism of variation of work function with UPD coverage was elucidated via analyzing the system of Bi UPD on several different substrates. The coverage and underpotential of UPD Bi as a function of Bi ion concentration were studied. The results show that the electrosorption valency remains invariant over all underpotential range for Bi UPD in Pt system. However, for Bi UPD in Te-covered Pt system, the electrosorption valency decreases with increasing the Bi coverage. These features will be helpful to explain theoretically the negative shift of Bi UPD on Te-covered substrate.
    Palladium Complex Catalyzed Heck Coupling Reaction in Synergic Functionalized Ionic Liquid System
    LIU Ye, LI Min, LU Yong*, WU Hai-Hong, GAO Guo-Hua
    2007, 28(4):  723-726.  doi:
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    In the functionalized ionic liquid (FIL) system of [BMIM][TPPMS] and [BMIM][OAc], PdCl2(CH3CN)2 efficiently coupled bromobenzene and ethyl acrylate to ethyl cinnamate with a yield of 60% (Heck reaction) and without the activity loss even after eleven recycling uses. The favourable impacts of this ionic liquid system on the activity and the stability were explained in terms of synergic ligand effects of [BMIM][TPPMS] and [BMIM][OAc], no formation of sodium or ammonium bromides as slurry mixtures by using [BMIM][OAc] as base, and the positive effect of [BMIM]Br by forbidding the formation of palladium black. The generality of this FIL system to the substrates with different electronical effects also gave out the pleasing results.
    Electrochemical Detection of C606- and C706- in Toluene at Room Temperature
    ZHANG Mei-Qin, LIU Hui, HU Hu, XIE Shu-Bao, JING Ping, LI Mei-Xian, GAN Liang-Bing, ZHU Zhi-Wei, KOU Yuan, SHAO Yuan-Hua*
    2007, 28(4):  727-730.  doi:
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    The complete set of six one-electron reductions of C60 and C70 was observed for the first time in a single organic solvent, toluene, at room temperatures (25±1) ℃ by cyclic voltammetry and differential pulse voltammetry on a Pt disk ultramicroelectrode(UME). A type of room-temperature ionic liquid(RTIL), tetrahexylammonium bis(trifluoromethylsulfonyl)imide(THA-Tf2N), was found to have an excellent solubility in toluene, and was employed as the supporting electrolyte to increase the conductivity of toluene. This electrochemical system presents a wide potential window down to -3.7 V vs. ferrocenium/ferrocene(Fe+/Fe), which essentially allows electrochemical detection of C606-and C706-at room temperature. We also discussed the reasons why does this RTIL dissolve well in toluene, and the future applications of such system.
    Effects of SO2 on Cathode Performance of Proton Exchange Membrane Fuel Cell
    YANG Dai-Jun1,2, MA Jian-Xin1,3*, MA Xiao-Wei3, ZHOU Wei1,3, XU Lin4, WU Min-Zhong4, WAN Gang1
    2007, 28(4):  731-734.  doi:
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    SO2 with volume fractions from 5×10-8 to 3.2×10-6 was introduced into the cathode of a single Proton Exchange Membrane Fuel Cell(PEMFC) to investigate the effect of SO2 on the performance of the PEMFC. Voltage-time(V-t) curve and polarization(V-I) curves show that 5×10-7 SO2 can cause significant and irreversible effect on the cell performance, and the performance decay increases with SO2 volume fraction increasing. Using electrochemical impedance spectroscopy(EIS), it was found that after being poisoned by 5×10-7 SO2 for 130 h, the charge transfer resistance(Rct) was reversible after cathode purging for 20 h and cyclic voltammetry(CV) test, however the surface state of the cathode was permanently changed. A reduction of the electrochemical active surface(EAS) of the cathode, which contributed to the irreversible cell performance decay, was confirmed by cyclic voltammograms.
    Spatio-temporal Symmetry-breaking of Temperature Field and Temperature Wave in a Nonisothermal Single-Molecule Chemical Reaction System
    HAN Yu-Min, LI Zhi, LUO Jiu-Li*
    2007, 28(4):  735-738.  doi:
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    Spatio-temporal symmetry-breaking of temperature field in a small spatially distributed Lindemann single-molecule chemical reaction-diffusion-heat conduction system is studied by both the linear stability analysis and the computer numerical simulation. It is shown that the temperature wave can appear beyond spatio-temporal symmetry-breaking bifurcation at a certain constraint controlled externally and a fixed boundary condition for the model system.
    Study of Oxidative Desulfurization of Thiophene by Phase Transfer Catalysis

    ZHAO Di-Shun*, REN Hong-Wei, LI Le

    2007, 28(4):  739-742.  doi:
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    As the oxidative desulfurization by phase transfer catalysis tallies with the principle of Starks, the cycling model of oxidative desulfurization of thiophene by phase transfer catalysis was developed. The essencial processe was the transportation of active component from water phase to organic phase. The extraction constant of Q+, nucleophilicity of X-, and r(Q+) were calculated to investigate the process of oxidative desulfurization of thiophene. When thiophene was oxidized by peroxyformic acid with TBAB as the phase transfer catalyst, the desulfurization rate was up to 86.36%. From the kinetics study, it was shown that the reaction was first-order reaction.
    Effect of Fe on Electrocatalytic Activity of Pt-Fe/C Catalyst for Oxygen Reduction
    WANG Yan-En1, TANG Ya-Wen1, ZHOU Yi-Ming1, GAO Ying2, LIU Chang-Peng3, LU Tian-Hong1,3*
    2007, 28(4):  743-746.  doi:
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    In this paper, the carbon supported Pt-Fe(Pt-Fe/C) cathodic catalyst in the direct methanol fuel cell was prepared. The results of the energy dispersive X-ray(EDX) analysis, X-ray reflection spectroscopy(XRD) and electrochemical measurements indicate that in the Pt-Fe/C catalyst, Fe exists as the three forms. About 20%(mass fraction) Fe enters the crystal lattice of Pt, forming the alloy with Pt. About 80%(mass fraction) Fe does not enter the crystal lattice of Pt and exists as Fe and Fe2O3. After the Pt-Fe/C catalyst being treated with acid , non-alloying Fe and Fe2O3 in the catalyst are dissolved. Therefore, the electrochemically active specific surface area of the Pt-Fe particles in the Pt-Fe/C catalyst after the acid treatment is 30% larger than that of the Pt-Fe/C catalyst before the acid treatment. Thus, the electrocatalytic activity of the Pt-Fe/C catalyst after the acid treatment for the oxygen reduction is higher than that of the Pt-Fe/C catalyst before the acid treatment. It illustrates that the electrochemically active specific surface area of the Pt-Fe particles in the Pt-Fe/C catalyst can significantly affects the electrocatalytic activity of the Pt-Fe/C catalyst for the oxygen reduction. In addition, it also demonstrates that only alloying Fe can increase the electrocatalytic activity of the Pt for the oxygen reduction and non-alloying Fe has no such effect.
    Study on Electronic Structures and Spectra Properties of 3-Phenly-6-aryl-1,2,4-triazolo [3,4-b]-1,3,4-thiadiazole with Time-dependent Density Functional Theory
    LI Hui-Xue1*, XIAO Tai2
    2007, 28(4):  747-750.  doi:
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    Theoretical studies on a series of 3-phenyl-6-aryl-1,2,4-triazolo [3,4-b]-1,3,4-thiadiazoles were carried out by using the Time-dependent Density Functional Theory(TD-DFT) at B3LYP/6-31G(d) level to obtain the optimized equilibrium structure. The effects of 6-aryl molecular charge transfer, energies of frontier molecular orbitals and the electronic absorption spectra were investigated. On this basis, the electronic transition energy of the excited state was calculated by using time-dependent density functional theory, and λmaxcalcd. was obtained. The computed results indicate that the predicted characteristics accord quite well with the available experimental ones and the relative deviation is in the range from 0.071 to 0.041.
    DFT Study and NBO Analysis of Chemisorption of Acrylonitile on Cu(111)
    XIA Shu-Wei1*, XU Xiang1,2, YU Hong1, ZHANG Hui-Ling1
    2007, 28(4):  751-754.  doi:
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    Adsorption of acrylonitrile(AN) on different sites of Cu(111) surface was studied by using model copper cluster Cu16 with density functional theory (DFT). AN adsorbed perpendicularly to the surface and bonded to the metal sites via a nitrogen-metal interaction, i.e., a weak chemisorption. Such chemisorption led to electron transfer between the AN molecule and the cluster. In complexes Cu16—AN, the σ-binding via the lone-pair electrons of N atom and Cu atom was observed. Adsorption on bridge site was preferred with binding energy of 40.16 kJ/mol. The backbone of AN changes a lot due to adsorption, which can be indicated by the variety of bond lengths, bond orders, bond angles, IR spectroscopy and hybridization of chemical bonds. NBO analysis was uesed to explain these changes and why AN was activated by the chemisorption.
    Theoretical Study on Hydrocarbon Molecule(Acetylene, Ethylene, Ethane) Doped Armchair Single-Walled Carbon Nanotube
    JIN Lian-Ji, ZHANG Min, SU Zhong-Min*, SHI Li-Li, ZHAO Liang
    2007, 28(4):  755-759.  doi:
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    Recently, many scientists have been making appointments to encapsulate atom(s) or molecule(s) inside fullerenes. We calculated the structure and electronic properties of the endohedrally acetylene, ethylene and ethane doped(5,5) armchair single-walled carbon nanotube(SWNT) theoretically using B3LYP level of Density Functional Theory(DFT) on 6-31G(d) basis sets. The calculation results suggest that the formations of C2H2@(5,5)SWNT, C2H4@(5,5)SWNT and C2H6@(5,5)SWNT are endothermic; the frontier molecular orbital analysis shows that doping of hydrocarbon molecule made the increment of the HOMO-LUMO gap; the insertion of the hydrocarbon molecule in the center of the nanotube enlarge the diameter of the nanotube and the nanotube outside made the C—C and C—H bond lengths of hydrocarbon molecule compressed slightly and the bigger the dopant is, the tighter the compression is; a small quantity of electron transfer happens from(5,5) SWNT to the hydrocarbon molecule and the amount of the electron transfer in the three compounds is in the following sequence of C2H2@(5,5) SWNT<C2H4@(5,5) SWNT<C2H6@(5,5) SWNT.
    Structural and Electronic Properties of 1,2-C2B10H12 Isonitrile Derivatives Used in Boron Neutron Capture Therapy
    CHEN Bao-Guo1,2, ZHANG Ming-Yu1*, ZHAO Yuan-Yuan1, SUN Chia-Chung1
    2007, 28(4):  760-763.  doi:
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    A density functional investigation on 1,2-C2B10H12 isonitrile derivatives, as 10B-enriched compounds used in clinical trials for boron neutron capture therapy(BNCT), was reported. The structural and electronic properties of 1,2-C2B10H12 isonitrile derivatives were studied at B3LYP/6-31G(d) level. The calculated results show that the 1,2-C2B10H11NC is the most active among the considered compounds. For compounds 1,2-C2B10H11NC and 1,2-C2B10H11CH2NC, the C4 atoms can be linked with some of transition metal atoms by the coordinate function, respectively. The molecular polarities of compounds 1,2-C2B10H11NC and 1,2-C2B10H11CH2NC were less than that of the 1,2-C2B10H12, indicating that there is disadvantage for these isonitrile derivatives used in boron neutron capture therapy.
    Theoretical Studies on Electron Structures and Spectroscopic Properties of Complex [OsN(mnt)2]-
    ZHANG Yu-Hua1, XIA Bao-Hui2, ZHANG Hong-Xing1*
    2007, 28(4):  764-767.  doi:
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    Electronic structures and Spectroscopic properties of nitridoosmium(Ⅵ) complex ion, [OsN(mnt)2]- were studied theoretically, and the influence of interaction of the ligand[three bond N and dithiolene S2C2(CN)2] and the metal(Os) on the character of photochemistry was investigated. The structures of the complexes were fully optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels for the ground states and excited states, respectively. The bond length of Os≡N bond is shorted by ca. 0.066 nm in the A3A2 excited state in comparison with the X1A1 ground state, which is consistent with a higher vibration frequency of ν(Os—N) in the excited state than that in the ground state. We obtain the excited energy and the character of the charge transition of the absorption and emission under TD-DFT calculation. The intense absorptions at 300 nm and 262 nm were attributed to SC→Os≡N+CN and N+SC→Os≡N+CN, respectively. The lowest energy absorptions at λmax=446 nm were assigned as N→Os and N+SC→CN. The calculated phosphorescence emissions at λmax=678 nm(A3A2X1A1) were originated from N→Os and S→Os, the emission properties does not alter in the solvent acetonitrile. However, the emission blue-shifted to 625 nm.
    研究快报
    Preparation of Zinc Oxide Nanostructure Thin Films via Chemical Vapour Deposition and Its SERS Activity Research
    RUAN Wei-Dong, WANG Chun-Xu, JI Nan, XU Wei-Qing, ZHAO Bing*
    2007, 28(4):  768-770.  doi:
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    Zinc oxide nanostructure thin films were prepared on quartz slides via chemical vapour deposition(CVD). Various nanostructures such as nanorod, nanowires and surface-rough nanocubes, could be obtained under carefully tuning experimental conditions. The surface-enhanced Raman scattering(SERS) character of these films was investigated by using 4-mercaptopyridine(4-MPY) as the probing molecule.
    Novel Preparation Method for Keggin Type of Molybdophosphoric Blues——Glow Discharge H2-Plasma Solid-State Reduction Method
    LI Yang, CHU Wei*, CHEN Mu-Hua
    2007, 28(4):  771-773.  doi:
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    A novel glow discharge plasma solid-state reduction route was developed to synthesize molybdophosphoric heteropoly blues(MB). The glow discharge plasma played a role of activating hydrogen mole-cules and generated a lot of active species which rapidly induced molybdophosphoric heteropoly acid(PMo12) to form four-electron MB within several minutes. Analyses of the heteropoly blues via UV-Vis, FTIR, XRD and Py-IR confirmed that the materials retained not only the similar Keggin structures of their oxidized parents, but also exhibited more surface acidity due to protonation.
    研究论文
    Controlled/Living Photopolymerization of Methyl Methacrylate in Miniemulsion Mediated by HTEMPO
    LIU Xiao-Xuan1,2*, JING Yan-Ni2, BAI Ying-Kun2, WU Guang-Guo2
    2007, 28(4):  774-778.  doi:
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    Controlled/living photopolymerization of methyl methacrylate(MMA) in miniemulsion mediated by 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy(HTEMPO) was carried out at ambient temperature. MMA miniemulsion was prepared by using anionic surfactant SDS with cetyl alcohol as a costabilizer. The photopolymerization led to stable latices and they were obtained with neither coagulation during synthesis nor destabilization over time. It was found that the obtained MMA homopolymers exhibited relatively narrow molecular weight distributions(PDI=1.27—1.36), which was characterized by GPC. The plots of number-average molecular weight(Mn) vs. conversion and ln([M0]/[M]) vs. time were linear respectively, indicating that the reaction was a controlled/living free radical polymerization.
    Preparation, Composition and Structures of Reactive Nonionic Surfactants
    LI Li-Li1,2, CAI Chuan-Lun1, XIN Zhi-Rong1, SHI Qiang1, YIN Jin-Hua1*
    2007, 28(4):  779-782.  doi:
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    Three reactive nonionic surfactants with 1-olefinic bond were synthesized. Glycerol monostearate(GMS), glycerol monooleate(A300), and sorbitan monooleate(Span 80) were adopted as the starting materials to react with acrylic acid(AA) separately, p-toluene sulfonic acid as the catalyst and hydroquinone as the inhibitor. The conversion of the products was determined by means of AA adding level and the amount of the residual AA in the system. It was shown that the conversion of AA got to about 91%, and the yields of three different products, AGMS, AA 300 and ASpan 80 are over 80% respectively. Spectra of FTIR, 1H NMR and FTICR-MS were used to further confirm the formation of the three target products and their chemical structures. Then they were grafted with LLDPE, the Tc of the grafted LLDPE is higher than the plain, and the contact angles of the water on the grafted LLDPE film decrease. The terms of antifogging were prolonged when the grafted LLDPE was used as the agriculture films.
    Synthesis of Phthalimido Methyl Polystyrene Using Chloromethylated Polystyrene as Start Substance via Phase-transfer Catalysis
    LI Gang, GAO Bao-Jiao*, QI Chang-Sheng
    2007, 28(4):  783-788.  doi:
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    Chloromethylated polystyrene was transformed into aminomethylated polystyrene via Gabriel reaction using potassium salt of phthalic imidine as the reagent of nucleophilic substitution. The reaction process for preparing the precursor of aminomethyl polystyrene, phthalimido, methyl polystyrene, via phase-transfer catalysis system was mainly studied. The effects of various factors on the phase-transfer catalysis reaction were examined, and the phase-transfer catalysis mechanism was explored. The experiment results show that the functional transformation reaction of polymers can also be conducted via phase-transfer catalysis successfully. In this study system, the phase-transfer catalysts transfer the anions of phthalic imidine from water phase into organic phase, resulting in more easily performing the nucleophilic substitution reaction between chloromethylated polystyrene and the anions of phthalic imidine, and the successful transform of the chloromethyl groups on the macromolecular chains of chloromethylated polystyrene into methylated phthalimido groups. There are some factors which exert influences on the phase-transfer catalysis reaction, such as the species and the used amount of the catalysts, the polarity of the solvents, the ratio of oil phase to water phase and the reaction temperature. For this reaction system, cetyl trimethyl ammonium bromide is a suited catalyst, and the conversion of chloromethyl groups can reach 87% when toluene is used as solvent at a temperature of 50 ℃ for 8 h.
    Synthesis of Elastin Graft Copolymer via ATRP and Its Properties
    WANG Xiao-Li1, GAN Tian-Tian1, ZHANG Min2*, HOU Xin1, YAO Kang-De1
    2007, 28(4):  789-793.  doi:
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    Elastin was modified with 2-bromoisobutyryl bromide to prepare macro-initiator and subsequently poly(2-hydroxyethyl methacrylate) was synthesized by atom transfer radical polymerization(ATRP) method initiated by the macro-initiator. The graft copolymers were examined by using FTIR, XPS, TGA, SEM, ion chromatography and dynamic contact angle test. The results show that PHEMA has been covalently bound to the elastin. Although SEM suggested the surface of ATRP-modified elastin was much smoother than that of the unmodified samples, the thermal stability of modified samples was slightly lower than that of unmodified samples, and the initial temperature of thermal decomposition changed from 307 ℃ to 265 ℃. The dynamic contact angle test shows that the modified elastin was hydrophilic and after polymerization for 72 h, the advancing angle of elastin decreased from 130.45° to 29.80° and contact angle hysteresis reduced from 70.42° to 29.80°.
    Energy Levels of Novel 1,3,4-Oxadiazole Derivatives(OXDs) and Device Performance Using Blends of MEH-PPV and the OXDs as Emissive Layers
    ZHANG Xiao-Bing1, TANG Ben-Chen1, TIAN Wen-Jing2, ZHANG Peng1,2, LI Min1*
    2007, 28(4):  794-797.  doi:
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    The energy levels, band gaps of new oxadiazole derivatives with different lengths of alkyl chain attached either lateral or terminal to the central phenylene ring were obtained based on the results of CV and UV-Vis spectroscopy. HOMO energy levels(-5.75—-6.20 eV) of the alkoxyl-substituted derivatives are much higher than that of the unsubstituted one, especially the one with lateral alkyoxyl groups. In contrast, the LUMO energy levels are in the range of -2.78—-2.89 eV. The quasi-reversible redox behavior of the compounds indicates that they could be used as an active material for a light-emitting device. The light-emitting device using blends of MEH-PPV and the derivatives as emissive layers with brightness up to 11810 cd/m2(8.5 V), 40 times brighter than that with MEH-PPV was fabricated. The result of the devices suggests that oxadiazole derivatives studied can be used as the electron-transporting materials and thus to enhance the efficiency of LEDs.
    研究简报
    Synthesis of Hyperbranched Polymer by Enzymatic Ring-opening Polymerization and SCVCP
    LIU Xiao-Tian1, LI Ya-Peng1, WANG Shu-Wei1, SHA Ke1, WANG Wei1, CHEN Liang2, WANG Jing-Yuan1*
    2007, 28(4):  798-800.  doi:
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    This work was directed to develop a novel method for the synthesis of hyperbranched polymers by combining enzymatic ring-opening polymerization(ROP) with self-condensing vinyl copolymerization(SCVCP). Functionalized PCL was prepared by ROP of ε-CL with HEMA as the initiator and catalyzed by Novozyme 435, and subsequently converted to AB* macroinimer by the esterification with 2-bromoisobutyryl bromide. The target polymer was obtained by SCVCP of AB* macroinimer with styrene via ATRP.