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Table of Content

    24 November 1999, Volume 20 Issue 11
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    Articles
    Synthesis of Ruthenium Polypyridyl Complexes and the Steric Influence of the Intercalated Ligand on DNA-Binding
    ZHEN Qi-Xiong, YE Bao-Hui, LIU Jin-Gang, JI Liang-Nian, WANG Lei
    1999, 20(11):  1661-1666. 
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    Two structurally related ligands dmtatp(2,3-dimethyl-1,4,8,9-tetraazatriphenylene), dptatap(2,3-diphenyl-1,4,8,9-tetraazatriphenylene) and their ruthenium(Ⅱ) complexes [Ru(bpy)2dmtatp]2+(1) and [Ru(bpy)2dptatp]2+(2) were synthesized and characterized. Combined with the previous study data of [Ru(bpy)2tatp]2+(3, tatp=1,4,8,9-tetraazatriphenylene) the steric influence of the intercalated ligand of these complexes on DNA-binding were investigated by electronic absorption, steady state luminescence, CDspectra and viscosity measurement. All the data suggested that the complexes bind with DNA by intercalation and the order of binding affinities is 3>2>1, consistent with the reduced steric effect of the intercalated ligand.
    Synthesis of Large Single Crystals of Silica-sodalite and Silicalite-1 in the Presence of Pyrocatechol
    SHAO Chang-Lu, LI Xiao-Tian, QIU Shi-Lun, XIAO Feng-Shou, ZHANG Zong-Tao, WEI Bo, WANG Run-Wei, YUE Yong
    1999, 20(11):  1667-1670. 
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    To obtain large perfect crystals of zeolites, pyrocatechol as an additive was added into the two system: SiO2-NaOH-EG-R and SiO2-TPABr-NaOH-R-H2O (R: pyrocatechol, EG: ethylene glycol). Experimental results showed that the crystals synthesized in the presence of pyrocatechol have much larger size and better morphology than those synthesized in the absence of pyrocatechol. The role of pyrocatechol in the hydrothermal reaction mixture has been characterized by 29SiNMR, IR, and UV-V is spectroscopy, and it was shown that silicon pyrocatechol complex was formed in the reaction system.
    Crystal Structures and Magnetisms of Two Ni(im) Complexes Having Hydrogen-Bonded Networks
    NIU Shu-Yun, YANG Zhong-Zhi, YANG Qing-Chuan, HOU Yun-Yan, YANG Guang-Di, BU Wei-Min
    1999, 20(11):  1671-1676. 
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    The crystals of two complexes [Ni(im)6](NO3)(OH)(H2O)4(Ⅰ) and [Ni(im)4(H2O)2][C6H4(COO)2] (Ⅱ) were synthesized. The structures of single crystals were determined by X-ray diffraction. The crystal (Ⅰ) is of hexagonal system, space group P63/m with a=0.8985(10)nm, c=2.1002(4) nm, V=1.4685(4)nm3, Z=2, R=0.043, Rw=0.045.The crystal(Ⅱ) is monoclinic system, space group C2/c with a=2.2207(4) nm, b=0.7665(2) nm, c=1.6043(3) nm, β=120.60(3)°, V=2.3503(9) nm3, Z=4, R=0.056, Rw=0.079. The prominent feature of these two complexes is that they have various hydrogen bondings and thereby possess infinite three-dimensional networks. This not only increa-ses the crystal structure stability but also forms hydrogen bonded charged-transfer system, which modulates and promotes the electron transfer between the molecules. The temperature dependence of the magnetic susceptibility was measured and discussed.
    Studies on Self-assembly of Porphyrin Zinc with Adenine
    LI Ying, RUAN Wen-Juan, GUO Xian-Zhi, WANG Chuan-Zhong, ZHU Zhi-Ang, CHEN Rong-Ti, LI He-Xian, WANG Guo-Chang
    1999, 20(11):  1677-1681. 
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    Anew zinc porphyrin with an adenine substituted was synthesized and characterized by 1HNMR and IR spectroscopy and elemental analysis. The coordination of adenine substituted to the central zinc leads to self-assembly. The results of vapor pressure osmometry and visible spectroscopy and fluorescence spectrophotometry revealed the presence of a stable self-assembled complex.
    In Vitro Antitumor Activity of Titanocene Glycine Complex and Its Interaction with DNA
    ZHANG Zhi-Gang, YANG Pin
    1999, 20(11):  1682-1684. 
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    Titanocene glycine complex, Cp2Ti(O2CCH2NH3+Cl-)2, was found to have in vitro antitumor activity against Ethrlich ascites tumor cells. The interaction between Cp2Ti(O2CCH2NH3+Cl-)2and DNA was investigated by agarose gel electrophoresis. The results suggested that no intercalation bonding exists between the compound and DNA, and the compound does not induce nicking of DNA.
    Hydrothermal Synthesis and Characterization of PbTiO3Powders Derived from the Neutral Medium
    CHEN Dai-Rong, JIAO Xiu-Ling, XU Ru-Ren
    1999, 20(11):  1685-1687. 
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    PbTiO3with a perovskite phase has been hydrothermally synthesized without the alkaline mineralizer, and the characterization of PbTiO3powders by XRD, TEM and other techniques is also given in detail. Compared with other processes, this method can give the excellent ceramics powders free from the contamination by foreign materials.
    Determination of Pseudoephedrine in Human Plasma Using Capillary Zone Electrophoresis Coupled by Flow Injection on-line Solid Phase Extraction
    CHEN Heng-Wu, FANG Zhao-Lun
    1999, 20(11):  1688-1691. 
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    The previously developed hyphenated system of flow injection on-line solid phase extraction-capillary zone electrophoresis(FI-SPE-CZE) was adapted to the determination of trace pseudoephedrine in human plasma. Interference from the coexisting species was eliminated by off-line and on line sample cleaning-up, and by optimization of CZE separation conditions. The sensitivity of hyphenated system was improved by increasing of loaded sample volume and strengthening of field amplified stacking effect. Thus, plasma samples, after deproteinized by off-line precipitation, could be consecutively loaded onto the FI-SPE-CZE system, and trace amounts of pseudoephedrine be automatically preconcentrated, separated and determined by the system. The adapted FI-SPE-CZE system was successfully applied to determination of trace pseudoephedrine in volunteer s plasma samples for pharmacokinetic studies after administration of the drug with normal dosage.
    Atom Space Distance and Computing of Molecular Similarity
    YANG Jia-An, XU Lu
    1999, 20(11):  1692-1696. 
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    Amathematical model on computation of molecular similarity was suggested. The algorithmic techniques for measuring the degree of similarity between pairs of three-dimensional chemical molecules was represented by modified interatomic distance matrices. Current work was carried out on Indigo 2 work station with Sybyl software. Four groups of molecules were used to compute the molecules similarity to testing the mathematical model with satisfatory results.
    Studies on the Reaction Between Zincon and Bovine Serum Album in
    CHI Yan-Hua, ZHUANG Jia, LI Na, LI Ke-An, TONG Shen-Yang
    1999, 20(11):  1697-1702. 
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    The interaction of zincon(ZCN) with bovine serum albumin(BSA) and the changes of its spectrum were studied by UV spectra at pH4.1 buffer solution. The conditional constants, apparent molar absorptivity εP=1.3×106L·mol-1·cm-1, maximum binding number n=278 and apparent binding equilibrium constant Kc=8×107were obtained. It was considered that electrostatic force is the main binding force. The ion(sodium chloride) concentration of the solution has significant effect on binding reaction of BSAand ZCN. The effects of different denaturants were also examined. The Scatchard model is appropriate in the treatment of data obtained.
    Effects of Training of Operant Conditioned Reflex on Free Amino Acids in Hippocampus of Rats
    SHU Hong-Jun, HAN Hui-Wan, ZHAO Rui, CHEN Yi, LIU Guo-Quan
    1999, 20(11):  1703-1707. 
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    Changes of intracellular levels of free amino acids(FAA) in hippocampus of freely moving rats were measured using intracerebral microdialysis coupled to Orthophthaladehyde(OPA) pre-column derivatization reversed phase HPLC-fluorescence detection. The analytical method was systematically optimized and the real samples were determined. It was employed to analyze the trace level of free amino acids(FAA) and possible to qualitative and quantitative 18 kinds of amino acids in every 5μL microdialysate. The sensitivity and the linear relation between the amounts and the peak areas were satisfied. The recoveries were 82%-109% . The detection limits reached 0.5-5.7 pmol for each FAA. A significant decrease of 14 FAAafter training of OCRwas founded in comparison to basal condition(before training). In fore finds of neurotransmitter amino acids(NAA), excitatory NAA, glutamic acid and aspartic acid increased 19.12% and 53.40% respectively than before training. Inhibitory NAA, γ-aminobutyric(GABA), increased 138.17% than before training. The results confirm that metabolic increase of FAAin hippocampus can be induced by learning and memory in rats. The intracerebral microdialysis technique thus appears to be a useful tool to monitor changes in physiological activity of learning and memory during ongoing behavior.
    Preparation and Evaluation of 8-Quinolinol Derivatized β-Cyclodextrin Bonded Silica for High-performance Liquid Chromatography
    FENG Yu-Qi, XIE Min-Jie, DA Shi-Lu
    1999, 20(11):  1708-1713. 
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    8-Quinolinol derivatized β-cyclodextrin bonded silica(QCDS) has been prepared for high-performance liquid chromatography. The resulting bonded silica was characterized by using elemental analysis, thermal analysis and solid state NMR. The separation performance of QCDS for positional isomers, dansylamino acids, phenylpropionic acids and nucleosides was investigated. It was found that the retention of p-nitroaniline and p-nitrophenol was much smaller on the QCDS than on β-cyclodextrin bonded silica(CDS), whereas the retention of their ortho-and meta-isomers was similar on the both bonded stationary phases.
    The Electrochemistry Analytical Method of Iodine Ions at the Self-assembled Monolayers of Mercapto Methoxy Poly(ethylene glycol) Gold Electrode
    HOU Shi-Feng, WANG Hong-En, FANG Hui-Qun, CHEN Hong-Yuan
    1999, 20(11):  1714-1716. 
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    Self-assembled monolayers(SAMs) of mercapto methoxy poly(ethylene glycol)(MPEG) on gold electrode surface was formed. The SAMs of MPEG had molecular recognition characteristics. The iodine ions could permeate through the SAMlayer to approach the electrode surface. This MPEG film electrode can be used to detect iodine ions with lower interference.
    New Anionic Surfactant Two-phase Extraction Systems and Their Applications to Porphyrins and Dyes
    TONG Ai-Jun, DONG Jian-Jun, YIN Mu-Sheng, LI Long-Di
    1999, 20(11):  1717-1719. 
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    In this paper, two anionic two-phase systems, sodium dodecyl sulfate(SDS)-dodecyl triethylammonium bromide(C12NE) and sodium perfluorooctanoate (SPFO)-C12NE, were established. A two-phase system with a clear interfacial boundary formed spontaneously under certain surfactant concentrations and molar ratios, respectively for the above two mixtures. Phase separation conditions and their properties were studied. Extractions of dyes and porphyrin compounds were performed. The results show that hydrophobic molecules are easily extracted into the surfactant-rich phase of SPFO-C12NE or into the "aqueous phase" of SDS-C12NE. Positively charged porphyrins are extracted with higher extraction efficiencies than negatively charged porphyrins. The extraction results for charged porphyrins are opposite to those extracted with cationic two-phase of C12NE-SDS mmixture, indicating that anionic two phase systems are complementary to the cationic two-phase systems.
    Studies on the Substitution Reactions of (CH3CN)2Mo(Cl)(CO)3(GeCl3) with Poly(pyrazol-1-yl)alkanes
    TANG Liang-Fu, WANG Zhi-Hong, JIA Wen-Li, XU Yu-Ming, WANG Ji-Tao 
    1999, 20(11):  1720-1724. 
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    Mo_Ge bimetallic complexes containing poly(pyrazol-1-yl)alkanes have been synthesized by means of the replacement of CH3CN ligand in (CH3CN)2Mo(Cl)(CO)3·(GeCl3) by poly(pyrazol-1-yl)alkanes. Due to the weaker donating ability, the replacement of bis(3,5-dimethyl-4-halopyrazol-1-yl)methane with (CH3CN)2Mo(Cl)(CO)3(GeCl3) requires heating to start the reaction. All new compounds were characterized by 1HNMR, IR, mass spectra and elemental analyses.
    Synthesis of Glucosyl Esters of N,N-Di[O-nitrophenylamino)ethyl]glycine
    CHEN Hong, DAI Zhi-Qun, QU Fan-Qi, HUANG Xiao-Ling
    1999, 20(11):  1725-1728. 
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    Four new glucosyl esters of N,N-di[O-nitrophenylamino)ethyl]glycine were synthesized by the reaction of N,N-di[O-nitrophenylamino)ethyl]glycine with O-acetylglucopyranosyl bromide or O-acetylgalactopyranosyl bromide, O-acetyllactopyranosyl bromide, O-acetylxylopyranosyl bromide in the presence of Bu4NBr. Their structure are confirmed by IR, 1HNMR, MS and elemental analysis.
    Purification and Determination of the Structure of Pulullan Polysaccharide
    CAO Hai-Shi, SUN Hong, LIANG Fang, GUO Hui-Yun, LIU Lan-Ying 
    1999, 20(11):  1729-1732. 
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    Pullulan polysaccharide was purified by the procedure including Savage method, DEAE-cellulose column chromatograph and Sephadex G-100gel filtration. The structure of the polysaccharide purified has been determinated by the methods of TLC, IR and NMR.
    An Investigation on Synthesis and Spectroscopic Properties of Hantzsch Type1,4-Dihydropyridine Derivatives
    ZHAO Bing-Jun, ZHU Xiao-Qing, HE Jia-Qi, XIA Chi-Zhong, CHENG Jin-Pei 
    1999, 20(11):  1733-1737. 
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    Preparation of the Hantzsch type 1,4-dihydropyridine derivatives, i.e. 1,2,6-trimethyl-4-aryl-3,5-dicarbethoxy-1,4 dihydropyridines 2a_2f, 4-aryl -2,6-diphenyl-3,5-dicarbethoxy-1,4-dihydropyridines 3a_3f and their Nmethylated compounds 4a_4f was described(aryl: p-RC6H4-; R=OCH3, CH3, H, Cl, CN, NO2). The 4-aryl-2,6-dimethyl-3,5-dicarbethoxy-1,4-dihydropyridines 1a_1f show a relative strong fluorescence, whereas under the same conditions, compounds 3a_3f give a weak fluorescence. No fluorescence was observed for N-methylated compounds 2a_2f, 4a_4f. In 1HNMR spectra the methyl protons at the 1-position in 4a_4f are shifted unfield by δ= 0.6～0.7 compared to those in 2a_2f. The above observations were rationalized in terms of the conformational changes resulting from the steric interactions among the substitutents in the dihydropyridine ring.
    Studies of Pollen Peptide Antagonising Effect on Calmodulin
    QU Ze-Chuan, SONG Yan-Ling, YAN Hu-Sheng
    1999, 20(11):  1738-1742. 
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    The interactions of the buckwheat pollen peptide and its analogues with dansyl labeled calmodulin(D-CaM) were studied in the presence of Ca2+. All peptides except BP-1 can associate with D-CaM to form complexes peptide-calmodulin. The dissociation constants Kdfor the complexes were determined using the fluorescence spectra. Among the tested peptides, BP-13 showed a stronger inhibitory effect on CaM, with IC50of 2.2 μmol/Land Kdof 4.6×10-2μmol/L. The effects of the hydrophobicity and the behavior being predicated to have a higher α-helical propensities on their affinities were further studied. We have found that D-alanine substitution in BP-1 results in affinity enhancement. The result will be helpful to improving our ability to design peptides possessing anticalmodulin activity.
    Preparation, Structure Characterization and Bioassay of Tris(2-methyl-2-phenylpropyl)tin Carboxylates
    ZHANG Shu-Kui, CHEN Xue-Ren, LI Zhi-Chun, XIE Qing-Lan, ZHANG Zhao-Gui, DENG Feng-Jie
    1999, 20(11):  1743-1745. 
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    Fifteen tris(2-dimethyl-2-phenylpropyl)tin carboxylates were synthesized and characterized by IR and 1HNMR. The results showed that these compounds may be four-coordinated and there are a linear relationship between ΔνCO2 and the Hammett constants (σ) of the para-substituents of the corresponding substituted benzoates. The bioasay tests show that neophyltin derivatives have a good acaricidal activity and may provide an acaricide for the better activity and economy.
    Picosecond Energy Transfer Between Choromophores in Allophycocyanin Terminal Emitters
    WANG Hui, ZHAO Jing-Quan, JIANG Li-Jin 
    1999, 20(11):  1746-1749. 
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    Ultrafast time-resolved fluorescence spectra were used to study the energy transfer kinetics of API and APB from Cynobacteria Spirulina platensis. The same fast lifetime component(38 ps) was found in API and APB monomers which was attributed to energy transfer between αAP/βAP, another two lifetimes(198 ps,141 ps) observed describe the energy transfer processes of βAP→ αAPBand αAP/ β18. In trimers, we also found the excited energy transfer between αAP/βAP in API and APB with 29-32 ps constants. The substitution of αAPBin AP Iand β18in APB gives rise to a heterogeneity in the chromophore-conformations and chromophore chromophore interactions, another fast lifetimes(68 ps and 50 ps) was also found and attributed to the excited energy transfer between βAP/ αAPB and αAP/β18in the same monomers.
    Theoretical Studies on the C-H Bond Insertion Reaction of Carbenes with Ethers(Ⅰ)--Insertion Reaction of Carbene with Dimethyl Ether
    LIN Qi-Jun, FENG Da-Cheng, WANG Huan-Jie, CAI Zheng-Ting
    1999, 20(11):  1750-1753. 
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    The insertion reaction of singlet CH2with C-H bond in dimethyl ether has been calculated at MP2/6-31G(d) and MP4/6-31G(d)//MP2/6-31G(d) levels by using ab initio molecular orbital theory. The potential barrier of the reaction is an early one and only 8.1 kJ/mol. The process of the reaction is electrophilic-nucleophilic one in connection with carbene. The empty p orbital and the occupied σ orbital by a lone electron pair of carbene point towards Hatom and Catom of the C-H bond respectively.
    A ZINDO-SOS Study on Nonlinear Second-order Optical Properties of Amino-and Nitro-substituted Pyridine Derivatives
    ZHANG Suo-Qin, FENG Ji-Kang, REN Ai-Min, SU Zhong-Min
    1999, 20(11):  1754-1758. 
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    On the basis of ZINDO methods, according to the sum-over-states(SOS) formula, the program for the calculation of nonlinear second-order optical susceptibilities βijkand βμ has been devised. The structures and nonlinear second-order optical properties of pyridine and pyridine derivatives have been studied. It is concluded that the substitutes have a great influence on the nonlinear second order optical properties of pyridine derivatives. The calculated results have been explained micromechanically.
    Electrochemical Synthesis and Characterization of Soluble C60Derivative
    ZHENG Ning, YU Zhan-Jun, LI Lin-Song, ZHOU Shi-Hong, HAN Li, LI Tie-Jin
    1999, 20(11):  1759-1762. 
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    A new C60derivative was synthesized by means of electrochemistry, which exhibits greater water-solubility and remains stable in water and air. And very broad white light spectrum from this derivative has been observed. The bright white light emission of the new material results from a perturbation to the normal C60molecule due to the Jahn-Teller distortion of symmetry structure and the interaction between C60and -OH . And negative charges related to electrolysis product have been proved by using of electrophoresis. According to the infrared and Near-infrared spectrum the derivative contains hydroxyl groups. And XPS spectrum, 13CNMR spectrum prove the derivative contains ester carbons.
    Calculation of Solvent Self-diffusion Coefficient in Polymer Solution by Percolation Theory
    LIU Hua, JIANG Wen-Hua, HAN Shi-Jun
    1999, 20(11):  1763-1766. 
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    According to the percolation theory, a new model which is used to describe the solvent self diffusion in polymer solution has been established. The solvent self diffusion coefficient of PS-toluene, PS-benzene, PS-ethylbenzene and PS-THF systems has been correlated by using the new model at different temperatures and concentrations and the critical volume fraction of solvent self-diffusion at different temperatures has been estimated. The results show that below the glass temperature of PS, the new model not only has a satisfactory correlated accuracy, but it is suitable for a large range of temperature and concentration.
    Kinetics and Mechanism of Oxidation of Tetrahydrofurfuryl Alcohol by Diperiodatoargenate(Ⅲ) Complex Ion in Aqueous Alkaline Medium
    SONG Wen-Yu, LI Wen-Kui, JIA Chun-Ping
    1999, 20(11):  1767-1771. 
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    The kinetics of oxidation of tetrahydrofurfuryl alcohol by diperiodatoargenate(Ⅲ) complex ion was studied spetrophotometrically in alkaline medium in a temperature range of 27-42 ℃. The reaction rate showed the first order dependance both in oxidant and tetrahydrofurfuryl alcohol. It was found that the pseudo first order ([THFA]》[Ag(Ⅲ)]) rate constant, k obs, increases with the increase in [OH-] and decrease with the increase in [IO4-]ex. Aweak positive ionic strength effect was observed. No free radical was detected. Amechanism of an inner-sphere two-election transfer reaction involving a preequilibrium is proposed. The rate equation derived from the mechanism can be used to explain all the experimental observations. The preequilibrium constants and rate constants of the rate-determining step along with the activation parameters were evaluated.
    GC-MS and GC-IR in Studies on Catalytic Oxidation of Cyclohexene in the Presence of Molecular Oxygen
    WANG Rong-Min, YU Tian-Zhi, HE Yu-Feng, WANG Yun-Pu, XIE Bao-Han, XIA Chun-Gu, SUO Ji-Shuan
    1999, 20(11):  1772-1775. 
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    Based on the GC, MS and IR spectra, the analysis of the products of the reaction process of the catalytic oxidation and its mechanism can be elucidated. In the paper, the analysis of the aerobic oxidation products of cyclohexene catalyzed by the polymer Schiff base complex through G-MS and GC-IR were performed. The main products are 1,2-epoxy cyclohexane, 2-cyclohexen-1-ol, 2-cyclohexenone and 2-cyclohexen-1-hydroperoxide. 2-Cyclohexen-1-hydroperoxide is an unexpected result. From the analysis, the radical reaction mechanism were presumed.
    Transient Interfacial Tension of Crude Oil/Alkali/ Surfactant/Polymer Flooding Systems
    MU Jian-Hai, LI Gan-Zuo, LI Ying, CAO Xu-Long, ZENG Sheng-Wen
    1999, 20(11):  1776-1780. 
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    The effect of each component of two alkali/surfactant/polymer flooding systems which use a low-price natural mixed carboxylate as the major surfactant on transient and minimum interfacial tension is discussed in this paper. It is found that each component of the ASPflooding systems has an optimum concentration making the minimum interfacial tension on O/W interface lowest: alkali 1.0%, surfactant 0.5%, polymer 0.1%. We also probe into the mechanism of interaction in each component and their adsorption on O/W interface initially.
    σπ Model in the Atom-bond Electronegativity Equalization Method and Its Applications
    YANG Zhong-Zhi, CONG Yao, WANG Chang-Sheng
    1999, 20(11):  1781-1783. 
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    Based on density functional theory and electronegativity equalization principle, a σπ model, which considers the structure of double bond for the first time, is developed. In this model the double bond is partitioned into one σ bond region and four π bond regions. The atom-bond electronegativity equalization method plus σπ model(ABEEM σπ ) is then proposed for the calculation of charge distribution and charge polarization in large molecules. It has been shown that the results of charge distribution in large molecules obtained by ABEEM σπ model agree with those obtained by ab initio method very well. In addition, the model can be used to explain the region-selectivity of Diels-Alder reaction successfully. All these indicate that ABEEM σπ model is reasonable and reliable.
    Theoretical Calculations of the Tautomeric Equilibrium in 3-X-2(1H)-Pyridones
    ZOU Jian-Wei, LI Jiang-Bo, ZHU Long-Guan, YU Qing-Sen, LIN Rui-Sen
    1999, 20(11):  1784-1786. 
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    The geometries of 3-X-2(1H)-pyridones(X=NO2, NH2, COOH) and their tautomers in the gas phase and DMSO solution(SCRF) have been obtained at HF/6-31G**and MP2/6-31G**levels. The influences of intramolecular hydrogen bond on the tautomeric equilibrium have also been investigated. In the gas phase, the calculated results show that the enol form is more stable than the keto form for 3-NO2-2(1H)-pyridone, and the keto?enol equilibrium shift right due to the formation of intramolecular hydrogen bond between 3-nitro and 2-hydroxyl group, while for the amino and carboxyl-derivatives, the keto forms are favored over the enol forms because of the stronger intermolecular hydrogen bonds in keto-tautomers. However, owing to the polarization effects of solvent, it can be predicted that the keto-tautomers are dominant for all of the title compounds in DMSO solution, which are in good agreement with the experimental results.
    Effect of Surface State Properties of TiO2Nanoparticle Film on Its Photocatalytic Activity
    CAO Ya-An, DING Lan, MA Ying, GUAN Zi-Sheng, XIE Teng-Feng, ZHANG Xin-Tong, WU Zhi-Yun, BAI Yu-Bai, LI Tie-Jin, YAO Jian-Nian, WU Yue
    1999, 20(11):  1787-1789. 
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    TiO2nanoparticle film catalysts with different thicknesses were prepared by plasma-enhanced chemical vapor deposition(PECVD) method and the surfaces were subsequently treated by TiCl4or O2plasma. Two kinds of TiO2films with different surface properties were obtained. Their surface microstructures and energy levels of surface states were tested by AFM, XRD, SPS. The photocatalytic activities of the catalysts were determined via photodegradation experiments of phenol. The results demonstrated that photocatalytic activities of samples whose surface was treated by O2plasma were greater than those treated by TiCl4plasma. Moreover, photodegradation ratio of phenol during the first hour catalyzed by 0.17 μm thickness TiO2nanoparticle film was greater than other samples. Especially, the difference of photocatalytic activities of TiO2nanoparticle films treated by TiCl4or O2plasma was respectively explained by energy band theory.
    Flocculation Mechanism of Cationic Polyelectrolyte to Oily Sludge
    LI Gang, XU Tao, ZHANG Song-Mei, YU Cui-Yan
    1999, 20(11):  1790-1792. 
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    Acationic polyelectrolyte with a high density charge, its average molecular weight was 2.60×106and cationic character reached 45%, adsorbed on the particles with the adsorption pattern of static electricity gravitation between the cationic groups and the clay surface with negative charges. It could be neutralize the ζpotential of clay particle surface to 0mV and keep with 0 mV, and make the capillary suction time of oily sludge reduce to 100～200 s and finally make it chemical destabilization, but also make the fine grains(diameter under 20μm) be effectively flocculated and swept away. The flocculating reaction kinetics of cationic polyelectrolyte to solid particles of oily sludge was made certain as second order reactions.
    Preparation of Thermostable Silica-pillared Layered Niobic Acids with Different Interlayer Distance, Surface Area and Pore Size
    HOU Wen-Hua, WANG Xue-Guang, YAN Qi-Jie, CHEN Jing
    1999, 20(11):  1793-1794. 
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    By varying the concentration of APS aqueous solution, reaction time and temperature, a series of silica-pillared layered niobic acids with different interlayer distances, surface areas, pore sizes and thermostability were successfully prepared. It was shown that increasing the concentration of APS aqueous solution under a certain level(from 2.1% to 10%) led to the formation of silica-pillared layered niobic acids with a gradually increased interlayer distance, surface area and silica pillar density, and therefore a gradually decreased pore size, but the same thermostability. On the other hand, reducing reaction time from 3 days to 1 day caused the decrease of the interlayer distance, surface area and thermostability, but the increase of pore size due to lower pillar density. Furthermore, the reaction at room temperature gave rise to the silica pillared layered niobic acid with a smaller interlayer distance and pore size, a slightly larger specific surface area and a lower thermostability.
    Studies on Emulsifier-free Emulsion Polymerization Mechanism of MMA/BA--Three stage Mechanism for Particle Formation
    ZHANG Mao-Gen, WENG Zhi-Xue, HUANG Zhi-Ming, PAN Zu-Ren
    1999, 20(11):  1795-1799. 
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    The particle formation mechanism of monodispersed particles in MMA/BA emulsifier free emulsion polymerization was investigated with Coulter LS230 laser particle size analyzer. The nucleation mechanism of the system is homogeneous nucleation by theoretical and experimental analyses. Athree stage mechanism of the particle formation mechanism of emulsifier-free emulsion polymerization is proposed. Stage 1 is a homogeneous nucleation coagulation stage. The particle number density, N, increases rapidly in this stage, but the particle size changes less. Stage 2 is a nucleation=-coagulation-propagation-aggregation stage. When N begins to decrease rapidly, it marks the end of stage 1 and beginning of stage 2. Stage 3 is a propagation-aggregation stage. When the particle nucleation process ends, it marks the beginning of stage 3. Particle size increases remarkably through propagation and aggregation. Ntends to level off gradually. The precedent aggregation of smaller particles during the propagation leads to produce monodispersed particles.
    Particle Formation Mechanism in the Emulsifier-free Emulsion Polymerization of MMA/BA/Sodium Polyethylene Glycol Maleate
    ZHANG Mao-Gen, WENG Zhi-Xue, HUANG Zhi-Ming, PAN Zu-Ren
    1999, 20(11):  1800-1803. 
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    The particle formation mechanism of MMA/BA emulsifier-free emulsion polymerization in the presence of small amount of ZA-6 comonomer(sodium polyethylene glycol 600 maleate) was investigated with Coulter LS230 laser particle size analyzer. After the primary particles of the early stage have vanished, new small particles were twice found periodically. It is believed to be formed by new nucleations by theoretical and data analyses and is called periodic nucleation phenomenon. It is suggested that the nucleation processes do not end really at the middle and later stages of the polymerization, and it is in the dynamic equilibrium of nucleation and aggregation.
    Studies on Emulsifier-free Emulsion Polymerization Using Emulsifierable Reactive Monomer AGES
    TANG Guang-Liang, HAO Guang-Jie, SONG Mou-Dao, ZHANG Bang-Hua
    1999, 20(11):  1804-1807. 
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    In this article, allylglycerdyl ether sulfosalt(AGES), a novel copolymerizable monomer containing not only the reactive vinyl bond, but also groups of sulforous and hydroxyl having the role of emulsifier was synthesized and used in the MMA/BA emulsifier-free emulsion polymerization. Particle size and flowing behavior of the latexes, as well as dynamic mechanical properties of the resulted copolymers were investigated. The results show that with the addition of AGES, the latex particles are about 0.5 μm in diameter and are evenly distributed; stable latexes of high solid content(60%), low viscosity with the characteristic of plastic Non-New ton flowing behavior is obtained. In addition, all the polymerization systems undergo a typical random copolymerization.
    Synthesis and Characterization of C60-Containing Styrene and Acrylamide Copolymers
    TAO Zheng-Hong, WANG Chang-Chun, YANG Wu-Li, FU Shou-Kuan
    1999, 20(11):  1808-1810. 
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    Aseries of styrene/acrylamide copolymers were synthesized. The PAm molar fraction in copolymers varies from 18% to 33%. Then the C60-containing copolymers were obtained by the reaction of St/Am copolymer with C60in toluene at 30 ℃ and 80 ℃, respectively. The products are orange or brown powders and soluble in common solvents, such as CH2Cl2, CHCl3, toluene, THF etc .. The C60moiety in copolymers varies from 0.49% to 1.45%(weight percentage ratio). The results also show that with the increase of mole percentage of amide group in copolymers, the weight percentage of C60increases while the C60/amide mole ratios in copolymers decline. In addition, raising the reaction temperature enhances the reactivity. The UV-V is spectra show that C60containing copolymers have a stronger adsorption from 400 nm to 500 nm than pure C60and C60doped copolymers have. Increasing the C60content in those samples, the characteristic peak of C60at 330 nm was suppressed gradually by a strong wide adsorption band from 290 nm to 350 nm, which reveals that amide group can react with C60and the C60is chemically bonded to the copolymers.
    Effect of Electron Radiation on Crystal Structure Transition of trans-1,4-Polybutadiene
    CAI Jia-Li, LI Gao, YANG Xiao-Niu, SU Feng-Yu, DONG Wei-Min, ZHOU En-Le
    1999, 20(11):  1811-1812. 
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    trans 1,4-Polybutadiene(PTBD) was synthesized by rare earth catalyst system. The effect of electron radiation on phase transition from monoclinic phase to hexagonal phase was observed by TEM. Electron diffraction patterns of monoclinic phase, hexagonal phase and two coexistent phases were recorded. The mechanism of phase transition was also discussed in this paper.
    Studies on Photoconductivity of a Difunctional Photorefractive Model Molecule
    LI Feng, WANG Jing-Yuan, YANG Qing-Xin, WEI Zhen-Qian, TANG Xin-Yi
    1999, 20(11):  1813-1814. 
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    Anew difunctional photorefractive model molecule, 3-azo-4′-nitro-9-ethyl-carbazole was synthesized and its structure was characterized by 1HNMR and UVspectra. The results from Time-of-Flight experiment show that the sample exhibited good photoconductivity not only by hole transport but also by electron transport, which may be due to the reason that the molecule formed not only a delocalized system but also charge-transport complex, and contributed to its charge carrier mobility.
    Cationic Ring-opening Polymerization of 3-Methyl-3-oxetanemethanol
    HOU Jian, YAN De-Yue, ZHU Xin-Yuan, FANG Ya-Peng
    1999, 20(11):  1815-1816. 
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    This work developed the cationic ring opening polymerization of 3-methyl-3-hydroxymethyleneoxetane initiated by BF3·OEt2directly. The resulted polymer was easily dissolved in polar solvents such as CH3OH, C2H5OH, DMSO and N-methyl pyrrolidone, but not dissolved in water, tetrahydrofuran and other non-polar solvents. The TGA study of sample 1 indicates that the polymer starts to pyrolyze at 360 ℃. There is a melting endotherm at 125.9 ℃ in the DSCcurve of sample 1, and the melting peak enlarged with decreasing the amount of catalyst added, which means that sample 1 is essentially linear, and with increasing the amount of catalyst the resulted polymer becomes slightly branched.
    Synthesis and Liquid Crystalline Properties of Mesogen-Jacketed Polymers with Different Polymer Backbone
    MI Qi-Ding, ZHANG Hai-Liang, ZHOU Qi-Feng
    1999, 20(11):  1817-1819. 
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    Two monomers of 2,5-bis[(p-methoxyphenoxy)carbonyl]benzyl acrylate and 2,5-bis[(p-methoxyphenoxy)carbonyl] benzyl methacrylate and their corresponding polymers were successfully synthesized. The mesomorphic behavior of both polymers was examined by using differential scanning calorimetry(DSC) and polarized optical microscopy(POM). It was found that both polymers are noncrystalline with a glass transition temperature of 67.1 ℃ for poly-{2,5-bis[(p-methoxyphenoxy)carbonyl]benzyl acrylate} and 95.1 ℃ for poly-{2,5-bis[(p-methoxyphenoxy)carbonyl]benzyl methacrylate}, above which the former can form liquid crystalline state and the clearing temperature is 97.8 ℃ while the latter can not. This indicates that main chain rigidity will affect the liquid crystallinity of mesogen-jacketed polymers.
    Morphological Transition of Molecular Aggregates in Aqueous Solution Formed by Amphiphilic Diblock Copolymers Containing Glycopolymer Segments
    LIANG Yu-Zeng, LI Zi-Chen, LI Fu-Mian
    1999, 20(11):  1820-1822. 
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    Amphiphilic diblock copolymers containing glycopolymer segments, polystyrene block-poly[2-(-D-glucopyranosyloxy)ethylacrylate](PS-b-PGEA), were synthesized by atom transfer radical polymerization. The morphologies of the crew-cut aggregates of PS-b-PGEA in water were studied by TEM. It has been found that for one specific diblock copolymer, the morphological transformation from spheres to vesicles was controllable by changing solvents. Spheres, rods and vesicles were found to be the dominant morphologies for PS55-b-PGEA9when the solvents were DMF, DMF/1,4-doxane and 1,4-dioxane respectively. When same solvent, e.g . 1,4-dioxane, was used, sphere to vesicle transition of crew-cut aggregates was also obtainable by using diblock copolymers of different compositions. The copolymers with a higher hydrophilic segment content tend to form spheres, while those with a lower content yield predominated vesicles.
    Effect of Multihole Silicon Dioxide on Crystallization Behavior of Poly(ethylene oxide)
    WANG Li-Wei, HUANG Li, WANG Gui-Bin, WANG Zi-Chen, JIANG Zhen-Hua, MA Rong-Tang
    1999, 20(11):  1823-1825. 
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    The effect of multihole silicon dioxide on the melting and crystallization behavior of poly(ethylene oxide) was investigated by means of DSC. It has been found that the melting temperature and enthalpy of poly(ethylene oxide) seem not to be affected by multehole silicon oxide, whereas the temperature of crystallization from melt is increased somewhat and the isothermal crystallization is accelected obviously. The Avrami exponents of poly(ethylene oxide)/silicon dioxide composite approach to that of pure poly(ethylene oxide). This suggests that the crystallization mechanism of poly(ethylene oxide) does not change after blending.
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