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Table of Content

    24 May 2001, Volume 22 Issue 5
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    Articles
    Sol-gel Derived Inorganic/Organic Hybrid Separation Membrane
    ZHANG Guo-Chang, CHEN Yun-Fa, WU Zhen-Jiang, XIE Yu-Sheng
    2001, 22(5):  713-716. 
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    Organic/inorganic hybrid separation membranes have been prepared on porous α-Al2O3 substrates (pore size, 1—10 μm). The effects of sol synthesis conditions, such as reaction temperature, solvent pH, sol viscosity, n (PTMOS)/ n (TEOS) and n (H2O)/ n (alkoxide) ratios, on the layer processing and its performance of the resulted membrane were characterized, and an optimum condition of the procedure was achieved. From FTIRspectra, it is found that the crack formation in the membrane is principally related to the structure of the Si—O—Si other than the solvent nature and any other factors. The thickness of the hybrid layer is about1-2 μm estimated by the SEMimage of cross section. The selectivity of O2/N2 and CO2/N2 as well as CO2/O2 is 2.30, 4.31 and 1.17 respectively, and the permeability is 75.81×10-17, 75.28× 10-17 and 72.78×10-17 m3(STP)·m/(m2·s·Pa) when the trans membrane pressure difference is 0.10 MPa and the n (PTMOS)/ n (TEOS) ratio is equal to 1.16.
    A New Way to Formation of Perthiocarbonate Ligand── Synthesis and Crystal Structures of [Me4N]n[Cu(CS4)]n(Ⅰ) and [Me4N]4[Cu4(CS4)4](Ⅱ)
    TANG Ka-Luo, JIN Xiang-Lin, LONG Yao-Ling, CUI Peng, TANG You-Qi
    2001, 22(5):  717-721. 
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    The solutions of tetranuclear copper cluster anionic complexes [Me4N]2[Cu4(SePh)6] or [Me4N]2[Cu4(SPh)6] in DMFor CH3CNreacted with CS2 in the presence of a small amount of S. From the resulting solutions brown-black block-shaped crystals Ⅰ or brown-red block-shaped crystals Ⅱ were formed, respectively. Crystal data: (Ⅰ) orthorhombic, space group Pbca, a=1.1385(4) nm, b=16683 (4) nm, c=10921(2) nm, V=20742(9) nm3. μ=2846 mm-1, F (000)=1136 e, Dc=1777 g/cm3, for Z=8, R=00544 for 1821 observed reflections; (Ⅱ) tetragonal, space group P421c, a=13952(2) nm, b=13952(2) nm, c=11350(2) nm, V=22094(6) nm3. μ=2677 mm-1, F (000)=1136e, Dc=1671 g/cm3, for Z=8, R=00645 for 1114 observed reflections.The X-ray crystal structure determination indicated that the molecule of the complex Ⅰ consists of a polymeric anion [Cu2(CS4)2]n2- and cations [Me4N]+. In the polymeric anion, the repeated unit is a dinuclear copper complex [Cu2(CS4)2]2-, which links to four surrounding aggregations through sulfur bridges to form a two dimensional layer structure. The cations [Me4N]+ locate between the layers. The molecule of complex Ⅱ consists of a tetranuclear copper cluster anion with four perthiocarbonate ligands [Cu4(CS4)4]4- and four cations [Me4N]+. The four copper atoms form a tetrahedron. One of the sulfur atoms in each CS2- 4 ligand forms the sulfur bridge with two Cu atoms while the other is coordinated to only one copper.
    Studies on Langmuir-Blodgett Films of Bilirubin and Its Amphiphilic Derivatives
    OUYANG Jian-Ming, LIN Wei-Han, HUANG Chun-Xiao, YAO Xiu-Qiong
    2001, 22(5):  722-726. 
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    Monolayer formation, LBfilm fabrication of bilirubin(1), its two kinds of amphiphilic derivatives, bilirubin dioctadecyl ester [B(COOC18 H37 )2, 2] and dioctadecyl bilirubinamide [B(CONHC18 H37 )2, 3] at an air water interface on subphases with different pHvalues and subphases containing different metal ions were investigated and compared with 1. Some information regarding the packing density in monolayers, molecular orientation and complexation by metal ions has been obtained by means of many physical measurements such as the π-Aisotherms, X-ray photoelectron spectroscopy, UV-visible spectroscopy and low angle X-ray diffraction. At the air water interface the amphiphilic ligands with their complexing head groups in contact with the aqueous phase can form metal complexes with many metal ions present in the aqueous phase. The formation of ligand-metal complexes leads to changes in the area per molecule and in the collapse pressure, as well as to changes in the XPS and UV-visible absorption spectra of the monolayer assemblies. Low-angle X-ray diffraction indicates that the LBfilms of 1, 2 and 3 were Y-type with bilayer spacing of ca. 2.50, 5.60 and 5.65 nm. The coordination in ordered molecular films are much different from that in bulk solution. It can help us to understand the formation and prevent and cure of gallstones.
    Encapsulation and Characterization of Co(AC)2-5,10,15,20-tetra-p-Hydroxyphenylporphyrin in Si-MCM-41 by the Method of Ship-in-bottle
    XU Qing-Hong, ZHAO Zhi-Xin, LI Lian-Sheng, LIU Guo-Fa, XU Ru-Ren, WU YI Qun, XIANG Qian, WANG Wei-Ling, YUN Zuo-Min
    2001, 22(5):  727-730. 
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    Co(AC)2-5,10,15,20-tetra-p-hydroxyphenylporphyrin was encapsulated in Si-MCM-41 by the method of ship in bottle. The content of the complex, thermal stabilities of the complex before and after encapsulation, coordination state between Co(AC)2 and 5,10,15,20-tetra-p-hydroxyphenylporphyrin in Si-MCM-41 and the hydrothermal stability of the complex in Si-MCM-41 were studied by the methods of ICP, DTA, XRD, EPR, XPSand UV-Vis spectra. It indicated that the Co(AC)2 was coordinated with 5,10,15,20-tetra-p-hydroxyphenylporphyrin completely in Si-MCM-41. The hydrothermal and the thermal stability of the complex after being encapsulated are higher than that of the pure complex.
    Well-aligned Carbon Nanotube Array Synthesized at Low Temperature by Microwave Plasma Enhanced Chemical Vapor Deposition
    CHEN Xin, HU Zheng, WANG Xi-Zhang, WU Qiang, CHEN Yi, YANG Shao-Guang, DU You-Wei
    2001, 22(5):  731-733. 
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    Well-aligned nanotubes with diameter of 30—50 nm have been synthesized on a porous alumina template by microwave plasma enhanced chemical vapor deposition (MW-PECVD). By this means, the control over either diameter or length of the nanotubes could be realized. The hollow structure and vertically aligned features have been verified by scanning electron and transmission electron microscopic images. In comparison with the reported fabrication methods, lower synthesis temperature (below 520 ℃) and simpler process (no negative dc bias applied) have been achieved, which could be of great importance for both theoretical research and pratical applications.
    Application of Rate Constant-Rank Analysis in the Process Analysis of Chemical Reaction
    ZHU Zhong-Liang, YU Ling, SONG Wei-Feng, MEI Yu, LI Tong-Hua
    2001, 22(5):  734-738. 
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    Two-way matrix of kinetic-spectroscopic data is obtained after measuring a series of absorption spectra during the process of chemical reaction. Amethod called Rate Constant Rank-Analysis(RCRA) is proposed in order to resolve such kind of two-way data matrix in this study. The method is based on the optimizing the reaction rate constant by annihilating two-way spectra of reactant and minimizing the residual standard deviation of residual matrix. Model of consecutive first-order reaction taken as an example, RCRAhas been employed to determine the rate constants. Due to the interdependence of kinetic spectra of three components, two results could be yielded by optimizing rate constant of the first step. It is found that the two results correspond to the first and the second step rate constants, respectively. After kinetic spectrum of each component has been obtained, the least square regression is applied to resolve the absorption spectrum of each component. Among them, the spectrum of intermediate is the most valuable because it can hardly be measured directly. RCRAhas been successfully applied to resolve simulated reaction data. Principal component analysis is employed to determine the number of absorptive components. Two-way data obtained in the electrochemical degradation of aniline has been resolved by RCRA. The result indicates that there exists an intermediate in the degradation and the reaction accords with consecutive reaction.
    Studies on the Binding Nature in Molecularly Imprinted Polymer Selective for 4-Aminopyridine
    GUO Hong-Sheng, HE Xi-Wen, JING Ying, LIANG Hong
    2001, 22(5):  739-743. 
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    Amolecularly imprinted polymer was prepared using 4-aminopyridine as template. The bulk polymer obtained was ground up, sieved and investigated in equilibrium binding experiments to evaluate the binding characteristics of the 4-aminopyridine imprinted polymer. Scatchard analysis showed that two classes of binding sites were produced in the polymer matrix and their dissociation constants were calculated to be 6.0 μmol/Land 1.2 mmol/Lrespectively, by utilizing the model of multiple independent classes of binding sites. The substrate selectivity of the polymer was investigated. The results showed that the imprinted polymer exhibited much higher affinity for 4-aminopyridine among the tested compounds. 1HNMR studies and the analysis of the resonance structure of 4-aminopyridine indicated that the selective binding interaction between the template and binding sites in the polymer arose from their ionic interaction.
    DNA-Modified Electrodes(Ⅸ)── Immobilization and Characterization of DNA Probes and the Molecular Hybridization on Gold Surfaces
    ZHAO Yuan-Di, PANG Dai-Wen, ZHANG Min, CHENG Jie-Ke, DAI Hong-Ping
    2001, 22(5):  744-748. 
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    Double stranded DNAwas covalently immobilized onto gold surfaces by layer-by-layer immobilization method, and the surfaces were characterized by electrochemical and XPSmethods. The surface molecular hybridization of DNAwas studied on these functionized surfaces. This work might be fundamental for electrochemical gene chips and genosensors for disease diagnosis.
    Electrochemical Studies of Mitoxantrone Interaction with DNA at a Ni/GC Ion Implantation Modified Electrode
    HU Jin-Bo, SHANG Jun, LI Qi-Long
    2001, 22(5):  749-753. 
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    The electrochemical behavior of mitoxantrone interaction with DNAat a Ni/GCmodified electrode was studied by linear sweep and cyclic voltammetry. In0.05 mol/L Tris-0.5mol/L NaCl solution (pH=7.1), the reaction of DNAwith MXformed an electrochemically nonactive complex, resulting in a decrease in the MXequilibrium concentration and its reduction current. The composition of the complex was n (MX): n (DNA)=2:1. The combining constant was 1.61×1012. The electrode reaction rate constant k0 and the electron transfer coefficient α were 0.33 s-1 and 0.41, respectively. The decrease in peak current was proportional to DNAconcentration and can be used to determine DNAconcentration.
    Preparation of Temperature-sensitive Polymer with Reactive End Carboxylic Group and Its Application in the Fluoroimmunoassay
    YANG Huang-Hao, ZHU Qing-Zhi, LI Dong-Hui, DING Ma-Tai, XU Jin-Guo
    2001, 22(5):  754-758. 
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    Atemperature sensitive polymer containing a terminal carboxyl group was prepared by copolymerization of N-isopropylacrylamide with mercaptoacetic acid. This polymer was conjugated to the IgGwith EDCIand used to develop a novel polymer mimetic enzyme competitive immunoassay method for determination of anti-IgGwith iron-tetrasulfonatophthalocyanine as a labelling reagent to catalyze the reaction of p-hydroxyphenyl acetic acid (HPA) and hydrogen peroxide in alkaline medium. The calibration graph for anti-IgGwas linear over the range of 0-1 500 ng/mLwith a detection limit of 2.0 ng/mL.
    Porous Aligned Carbon Nanotube Films for Ultrahydrophobic Surfaces
    LI Huan-Jun, WANG Xian-Bao, SONG Yan-Lin, LIU Yun-Qi, LI Qian-Shu, JIANG Lei, ZHU Dao-Ben
    2001, 22(5):  759-761. 
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    The porous aligned carbon nanotube(ACNTs) films prepared by pyrolysis of metal phthalocyanines show an ultrahydrophobic property. The contact angle for water of the films is 161°. The films modified with fluoroalkylsilane show a better hydrophobic property. The contact angle for water of the modified films is as high as 172°. The alignment structure of the films and large fraction of air on the films are considered to be responsible for the ultrahydrophobic property.
    Application of Adaptive Stochastic Resonance Algorithm in Weak Signal Detection
    WANG Li-Ya, YIN Chun-Sheng, CAI Wen-Sheng, PAN Zhong-Xiao
    2001, 22(5):  762-763. 
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    An adaptive algorithm for extracting weak signal based on the theory of stochastic resonance(SR) was proposed. It was implemented by investigating the self correlation of the outputs of the bistable system(with different μ). The results show that the self-correlation will reach maximum when a sudden change of output occurs, and hence prove that SRis sensitive sharply to the change of the parameters μ, and also provide one novel method to express the outputs which hasn't been solved till now. The adaptive algorithm was also applied to analyze the weak Laser-Raman spectrum of a CCl4 sample(liquid in capillary) which was measured with SPEX-1403 Laser-Raman spectrometer from250 cm-1 to 418 cm-1 on5 mW(output power of laser). The spectrum was analyzed with the adaptive algorithm by varying the data to (-413, 350) and declining μ from20 with step 001. The results obtained show that the adaptive algorithm was able to detect the weak signal automatically and correctly.
    Studies on Transition Metal Complexes Containing the Scorpionate Ligand(Ⅱ)── Synthesis and Characterization of Zinc and Cadmium Complexes with Scorpionate Ligands
    DENG Yuan, WANG Ru-Ji, SUN Su-Qin, FENG Yu-Ping, DING Ting-Zhen
    2001, 22(5):  764-767. 
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    Two scorpionate ligands KTpAn and KTpAn were prepared and reacted with MX2(M=Zn, Cd; X=Cl, OAc) affording some new complexes, which were characterized by elemental analysis, IRand 1HNMR. The single crystal structure of TpAn ZnCl has been determined by a four-circle X-ray diffractometer, which shows that the coordination environment about the Zn center is distorted tetrahedral. The crystals are monoclinic, space group P21 /n, with dimensions a=1.005 5(2) nm, b=1.6890(3) nm, c=1.7760(4) nm, β=102.16(3)° and Z=4, with final residuals R=0.0500 and wR=0.1202.
    New Method for Synthesis of 4-Substituted Benzamido-2-thioxo-2,4-thiazolidindiones
    CHU Chang-Hu, XU Peng-Fei, HUI Xin-Ping, ZHANG Zi-Yi, LIAO Ren-An, LI ZhI Chun
    2001, 22(5):  768-770. 
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    Eight 3-substituted benzamido-2-thioxo-2,4-thiazolidindione derivatives 2a-2h were synthesized and the reaction mechanism was also discussed. The structures of these compounds were confirmed by elemental analyses and spectra data. The preliminary biological test showed that the representative compounds exhibited moderate antifungal and plant growth regulatory activities.
    Characterization of the Adsorption of Bovine Serum Albumin on Hydroxylapatite
    YIN Gang, ZHAN Jin, LIU Zheng, YUAN Nai-Ju
    2001, 22(5):  771-775. 
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    Experimental studies on the effects of the concentration of PO43- and Ca 2+, ion strength and pHof buffer on the polarity and magnitude of F-potential of hydroxylapatite(HAP) were carried out in present study to characterize the surface physicochemical properties of hydroxylapatite. Adsorption of bovine serum albumin(BSA) on HAPwas carried at different conditions in terms of pH, ionic strength, and the concentration of PO43- to establish the knowledge of adsorption mechanism. A Langmuir adsorption isotherm was obtained and the apparent activation energy and adsorption heat were interpreted. The low magnitude of the apparent activation energy and the adsorption heat indicated the fast adsorption of BSAon hydroxylapatite was a physical adsorption in nature.
    Structure and Characterizations of the Inclusion Complex of Acylferrocene-2-furoylhydrazone with β-Cyclodextrin
    LIAO Zhi-Xin, ZHANG Yan-Ling, MA Xue-Yi, CHEN Yao-Zu, SHI Zhi-Xian
    2001, 22(5):  776-778. 
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    Inclusion complex of acylferrocene-2-furoylhydrazone(AFH) with β-Cyclodextrin( β-CD) has been prepared by using kneading method. Elemental analysis and the solubility determination proved that1:1 inclusion complex is formed. Characterizations of the inclusion complex were studied by UV, FTIRand X-ray diffractometry. The association constant to be 227.3 L·mol-1 was calculated from the straight portion of the phase solubility diagram. The structure of the inclusion complex was investigated by NMRspectroscopy.
    Asymmetric Addition of Diethyl Zinc to Aldehyde Catalyzed by Chiral Ti(Ⅳ)/Schiff Base Polymer
    DONG Chun-E, ZHANG Jun-Long, ZHENG Wei-Zhong, ZHI Yong-Gang, ZHANG Liang-Fu, YU Zuo-Long
    2001, 22(5):  779-782. 
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    New Schiff base chiral polymers was synthesized. The asymmetric addition of diethyl zinc to aldehyde was achieved catalyzed by Ti(Ⅳ)/polymer which was formed in situ from chiral polymer and Ti(O-i-Pr)4. Optical alcohols were obtained in a high yield with e.e. up to 84.5%. The effects of temperature, complex time, structure of substrate etc. on the catalytic activity and enantio selectivity were studied in detail. The reaction mechanism was proposed.
    Crystal Structure of a Novel Supramolecular Calix[4]arene Derivative with 1D Structure
    XING Yan-Jun, DU Chen-Xia, ZHOU Zhi-Xian, WU Yang-Jie
    2001, 22(5):  783-784. 
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    Anew calix[4]arene derivative, 5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-bis[2-(methoxycarbonyl)benzyloxy]calix[4]arene was synthesized. The X-ray crystal structure of the title compound has been determined. It crystallizes in the monoclinic with space group C2/c, a=1.2628(3) nm, b=2.5350(5) nm, c=2.0957(4) nm, β=103.36 (3)°, V=6.528(2) nm3, Z=4, Dc=1.203 g/cm3, F (000)=2488, R=0.1143, wR2=0.2979, Δ ρmax=0.329× 103 e/nm3, Δ ρmin=-0.256× 103 e/nm3. The crystal structure of the title compound shows that in the molecule there are hydrogen bonds between proximal hydroxyl and ether functional groups [O(H)—O: 0.3004 nm ]. The benzoic ether site in the title molecule may be considered as a π-conjugated system, therefore, the intermolecular π-π interaction exists between two benzoic ether site of the adjacent molecules, which caused the formation of a one dimensional saw-toothed supramolecule.
    The Factors Influencing the Peptide Affinity for Pollen Calmodulin——Peptide Conformation Study by CD and 2D-NMR
    CHENG Yuan, SU Jing, LI Er-Cheng, SONG Yan-Ling, WANG Jin-Feng
    2001, 22(5):  785-797. 
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    Synthetic buckwheat pollen peptide BPP-1(A-P-V-L-Q-I-K-K-T-G-S-N) and its analogues BPP-2[(D)A-P-V-L-Q-I-K-K-T-G-S-N-NH2], BPP-3(A-P-A-L-Q-L-K-K-N-G-S-Q-G-NH2) showed different binding behavior to rape pollen calmodulin(pCaM). Fluorescence titration experiments demonstrated that BPP-1 had no affinity for pCaMwhile its Cterminal amide, BPP-2, had fair affinity for pCaM(dissociation constant of pCaMpeptide complex, Kd=2.9× 10-1 μmol/L) due to the decrease in C-terminal polarity. But compared with BPP-3( Kd=8.1× 10-2 μmol/L), which was also a peptide amide, BPP-2 had a much lower binding ability. In order to investigate other factors influencing peptide affinity for pCaMbesides polarity(or hydrophobicity), CDand 2D-NMRspectroscopes were used to study the conformations of BPP-1 and BPP-3. It revealed that molecular flexibility could affect peptide's ability to bind pCaM. BPP-1 displayed rigid extended peptide bonds in the middle region where the basic amino acid pair Lys7-Lys8 is located, flanked by flexible peptide segments on both terminals; while the middle five residue region of BPP-3 exhibited as very flexible segment. Such a structural character might facilitate BPP-3 to adopt a conformation contributive to the interaction of two Lys residues with the acidic residues of pCaMin its peptide binding site and resulted in higher affinity. As this study revealed, both of the two peptides showed the lack of ordered structure in the aqueous solution. It seemed that there was no relationship between peptide affinity for CaMand the propensity of peptide chain to form α-helix. This contradicted what most previous researches approved that α-helix was an important character of peptide with high affinity for CaM.
    Lipophilicity Determination of Some 1-1, 2, 4-Triazole Compounds by Reversed-phase Thin Layer Chromatography
    JIANG Zheng-Jin, ZHANG Zhi-Chao, YIN Biao-Lin, ZHAO Guo-Feng, WANG Qin-Sun
    2001, 22(5):  788-790. 
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    Astudy has been carried out of evaluating lipophilicity of some 1-1, 2, 4-triazole compounds by RP-HPTLC. An equation that reasonably correlates partition coefficients( c lg P ) with RM0 values for 23 1-1,2,4-triazole compounds was derived and its predictive capability was tested with five 1-1,2,4-triazole compounds. It has been found that RP HPTLCcan be extensively applied to determining lipophilicity of 1-1,2,4-triazole compounds.
    A Study of LSM-YSZ Composite Cathodes by AC Impedance and Polarization
    LU Zi-Gui, JIANG Yi, DONG Yong-Lai, ZHANG Yi-Huang, YAN Jing-Wang
    2001, 22(5):  791-795. 
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    Aseries of composite cathodes with various YSZadditions were investigated by ACimpedance, polarization and conductivity measurement. The electrochemical performance of the cathodes was improved by increasing the YSZaddition, and the optimal YSZaddition for the lowest electrode resistance(1.18 Ω/cm2) was found to be 40%. The rate determining step of the cathode reaction varied when YSZwas added into the LSMelectrode. The contact resistance increased as YSZaddition increased. By applying a layer of platinum on the cathode as a current collecting layer, the contact resistance decreased significantly, and the electrode resistance at1223 Kdropped remarkably from 1.18 Ω/cm2 to 0.41 Ω/cm2.
    Studies on EPR Spectra of Gd(Ⅲ) Ternary Complexes
    CHENG Yi-Xiang, ZHANG Zheng-Lin, XU Yuan-Zhi
    2001, 22(5):  796-799. 
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    Gd(Ⅲ) ternary complexes of the solid powder and THFsolution have been investigated by EPRspectra. The EPRspectra of Gd(Ⅲ) ternary complexes have many differences due to the change of the coordinated synergic agents. Resonance peaks of the solid powder complexes don't show an obvious difference between room temperature and liquid nitrogen, but solution EPRspectra of Gd(Ⅲ) ternary complexes in the liquid nitrogen shows a superfine splitting, fine splitting and super-hyperfine splitting. Most Gd(Ⅲ) complexes show prominent “U” spectrum feature. It results from the EPRspectra that the strength of crystal field of Gd(Ⅲ) ternary complexes belongs to the intermediate CFcategory, the asymmetry parameter λ ' is changed with the variation of the synergic agents.
    Studies on Thermodynamics and Kinetics about Pyrolysis Mechanism of Carbon Matrix Precursor CH3ArCH2NH2
    WANG Hui, ZHAI Gao-Hong, YANG Hai-Feng, WEN Zhen-Yi, SHI Qi-Zhen, RAN Xin-Quan, LUO Rui-Ying, YANG Yan-Qing
    2001, 22(5):  800-804. 
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    Based on the experiment, the pyrolysis mechanism of carbon matrix precursor CH3ArCH2NH2 was further studied by quantum chemistry computation. Using the AM1 and DFT UB3LYP/321G * method in Gaussian98 program package, thermodynamic and kinetic data were calculated for 5 designed pyrolysis paths of the compound. The calculation result shows that the reaction producing CH3ArCH2·and NH2·is the main pyrolysis reaction path and the calculated activation energy is Ea=230.78 kJ/mol by AM1 method and is Ea=321.18 kJ/mol by DFTmethod, which could be understood by analyzing the geometry parameters, spin densities and charges of some atoms in reactants and free radicals produced. Compared with experimental data of bond enthalpy, the calculated results by DFTcoincide well. The geometry parameters of the produced free radicals also shows that, after the compound CH3ArCH2NH2 as carbon matrix compound are pyrolyzed, the plane orientation of the produced free radicals will benefit the formation of a fused aromatic ring structure.
    Describing Hydrogen-Bond Acidity with Quantum Chemical Parameters
    FU Xu-Chun, YU Qing-Sen, LIANG Wen-Quan
    2001, 22(5):  805-809. 
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    The correlations between the overall hydrogen bond acidities ∑A2H of 137 diverse compounds and their quantum chemical parameters have been studied. For the compounds having hydroxyl or carboxyl, ∑A2H=-0.027 7+3.826 QH-0.0273 ELUMO -0.0654 EHOMO +3.085 QO( n=70, r=0.982 ). The quantum chemical parameters QH, ELUMO, EHOMOand QOare the net charge of the hydrogen atom in the hydroxyl or carboxyl of the compounds, the energy of the lowest unoccupied molecular orbital, the energy of the highest occupied molecular orbital and the net charge of the oxygen binding with the hydrogen atom in the hydroxyl or carboxyl, respectively. For the compounds having amino group, ∑A2H=-1.569+3.637 QH-0.1235 EHOMO ( n=49, r=0.985). QHis the net charge of the hydrogen atom having greater positive net charge in the amino group. For the compounds having imino group, ∑A2H=-0.472+3.676 QH( n=18, r=0.993). QHis the net charge of the hydrogen atom in the imino group.
    Dynamic Study of the Electron Transfer Reaction for Non-metal Redox Couples of 0/1-Type
    ZHANG Dong-Ju, ZHUANG Bing-You, LIU Yong-Jun, HU Hai-Quan, LIU Cheng-Bu
    2001, 22(5):  810-813. 
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    Atheoretical scheme is presented to study the dynamics of the self exchange reactions and cross-reactions for the several bent triatomic species of 0/1-type (NO2/NO2-, SO2/SO2-, ClO2/CLO2-). The values of the inner-sphere reorganization energy and activation energy are calculated by using Nelson's reoganization model with the results of density functional calculations. The values of the solvent reorganization energy are obtained by the dielectric continuum model of the Marcus Thery and by requesting a gas phase molecular volume calculation in Gaussian94 program package. The rate constants of the three self exchange reactions (NO2/NO2-, SO2/SO2-, ClO2/CLO2-) and six cross reactions (NO2/SO2-, NO2-/SO2, SO2-/CLO2-, SO2/CLO2-, NO2/CLO2-, NO2-/ClO2) are obtained by the relative and absolute Marcus Hush theories. The theoretical results are compared with the experimental findings or the values from literature and better agreements are fornd.
    Metal-Support Interaction in Na-W-Mn/SiO2 Catalyst
    CHEN Hong-Shan, NIU Jian-Zhong, ZHANG Bing, LI Shu-Ben
    2001, 22(5):  814-816. 
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    The interaction of metal components with silica support in Na-W-Mn/SiO2 was studied. The inducing effect of sodium makes amorphous silica transferred to α-cristobalite during calcination, and the specific surface area decreases enormously as a consequence. When sodium alone is loaded, the silica has almost no micropores retained after calcination. When tungsten is loaded together with sodium, quite regular pores at the size of micron can be formed in silica during the phase transition.
    Studies on Methanation of CO2 Under Synergism Plasma with Catalyst
    DAI Bin, GONG Wei-Min, ZHANG Xiu-Ling, ZHANG Lin, HE Ren
    2001, 22(5):  817-820. 
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    At atmospheric pressure and ambient temperature, converting CO2/H2 into CH4 under synergism pulse corona plasma with catalyst was studied for the first time. Anew route of CO2 activation was opened up in the comprehensive utilization of carbon resources. Effect of catalyst loading on conversion of CO2, the parameters of plasma discharge and the process parameters were studied. Additionally, the mechanism of activation and transformation of CO2 under discharge plasma was discussed. Experimental results showed that CO2/H2 were converted into CH4, the conversion of CO2 was increased with increasing catalyst loading. The peak value of pulse voltage, discharge frequency, discharge polarity, the way of gas input and space velocity were important to conversion of CO2. Under the same conditions, Plasma catalysis are better than conventional catalysis and plasma methods.
    Enhanced Photoluminescence of Eu, Ag-doped SiO2 gel Based on AAO
    SHI Yan-Li, ZHANG Xiao-Gang, LI Hu-Lin
    2001, 22(5):  821-823. 
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    Porous alumina covered with europium doped silica sol-gel film exhibited strong Eu 2+ related photoluminescence at 396 nm at room temperature( λex=310 nm). The intensity of the photoluminescence can be increased by using porous matrix, thicker gel film and lower annealed temperature due to more photoactive species on the surface. Ag particles can improve the photoluminescence by affecting the surrounding electron field of Eu 2+.
    Photochromic Properties of MoO3 and Au Nanoparticles Composite Thin Films
    HE Tao, YIN Yan-Hua, MA Ying, JIANG Peng, CAO Ya-An, YAO Jian-Nian
    2001, 22(5):  824-826. 
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    1-Nonanethiol capped gold nanoparticles were firstly used to modify the surface of MoO3 thin films in order to fabricate the MoO3/Au composite thin film. Absorption experiments and XPSmeasurements were used to investigate the effect of Au nanoparticles on the photochromic properties of the composite thin film. According to the XPSmeasurements, the binding energy for the valence band(O2p ) of the composite thin films decreased. The experimental results of absorbance showed that the photochromic efficiency for the composite thin films became at least as two times as that of MoO3 thin films. The mechanism of enhancement can be explained by the band energy theory of semiconductor. The Schottky barrier formed at the interface prolonged the electron hole pair separation lifetime and resulted in the enhancement of the photochromic efficiency.
    Researches on Photocatalytic Activities and Photovoltaic Properties of TiO2 Nanoparticles
    ZHU Lian-Jie, WANG De-Jun, XIE Teng-Feng, SHANG Jing, XU Zi-Li, DU Yao-Guo
    2001, 22(5):  827-829. 
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    We investigated the photovoltaic properties of series of TiO2 photocatalysts by means of SPS and found that the thresholds of TiO2 particles blue shift with their particle sizes decreasing and crystal phases changing from rutile TiO2 to anatase TiO2. Combining with the photodegradation activities of TiO2 on C7H16, it was concluded that the photocatalytic activities of TiO2 increase with their thresholds increasing,which can be explained using energy band theory. We also investigated the relationship beween the photovoltaic properties and photocatalytic activities of B TiO2 before and after photooxidation on C7H16, SO2 and C7H16 +SO2, respectively and found adsorbates at the surface of TiO2 affect their photocatalytic activities and conduction types of surface layer.
    Preparation and Photochromic Properties of Keggin Type Tungstophosphate Acids Based on Polyvinyl Pyrrolidone
    FENG Wei, ZHANG Tie-Rui, LIU Yan, LU Ran, ZHAO Ying-Ying, Yao-Jian-Nian
    2001, 22(5):  830-832. 
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    Anew photochromic complex of Keggin type tungstophosphate acid/polyvinyl pyrrolidone system was prepared, and its thin films was made by the dipping method. Their photochromic properties were investigated by FTIR, UV-Vis spectra. The salts were formed by the combination of the ion based on the Natoms in the polymeric molecules and H+ of the acids. The UV-Vis spectra showed that this type of system had an excellent photochromic behavior. The g values of ESRspectra for the one electron blues were the characteristic of tetragonal W(Ⅴ) complex in colored thin film. It was indicated that the charge could be transferred between the anion and cation under irradiation of UVlight and the result in the oxidation of the cation and the reduction of the anion.
    Studies on the Roles of Laser Stimulated Methane Partial Oxidation on the Surface of CaF2 Supported H3PMo12O40
    GAO Feng, ZHONG Shun-He
    2001, 22(5):  833-835. 
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    Solid materials PMo12 and PMo12 /CaF2 were prepared, and the surface structure, chemisorption to methane and the behavior of LSSRfor the materials have been investigated by using IR, XRD, BETand laser stimulated surface reaction techniques. With different amounts of PMo12, the distribution of PMo12 can be controlled from less than one layer to multi layer on the surface of CaF2. There exist Lewis base sites O2- in MoOand Mo—O—Mo bonds as well as Lewis acid site —Mo 6+ — on the solid surfaces. Methane can be adsorbed on the surface MoOand Mo—O—Mo bonds with the molecular adsorption state, and the adsorption amount on Mo=Obond is greater. With 960 cm-1 laser to excite the surface Mo=Obond, the partial oxidation of methane occurred obviously at normal pressure and 200 ℃. Methanol is the direct product of methane oxidation, while HCHO, CH3OCH3 and hydrocarbons are the products of methanol reacted continuously on the solid surface. As CaF2 doesn't adsorb 960 cm-1 laser, PMo12 /CaF2 can utilize the laser energy more efficiently than that of PMo12. According to the characterization and reaction results, a mechanism of LSSRfor methane partial oxidation to methanol is given.
    Studies on Interface Structure of BBDMS-PPV/ITO System Using ADXPS Technique
    SONG Wei-Jie, ZHU Yong-Fa, CAO Li-Li, LI Zhan-Ping, WANG Dao-Yuan, Huang-Wei
    2001, 22(5):  836-838. 
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    We analyzed the structure of buried interface of BBDMS-PPV/ITOsystem using a high resolution ADXPStechnique. Atransitional layer structure, whose chemical composition, state and valence band changed gradually from BBDMS-PPVsurface of film to substrate ITO, was observed. It was found that O2- ion from ITOdiffused into polymer film, interacted with back bone carbon and formed the carbonyl bonding which could possibly constructed the channel of the carrier on the heterointerface. Indium of ITOalso diffused into BBDMS-PPVlayer and In(OH)3 was formed during diffusion. The diffusion and reaction between PPV/ITOinterface may affect the performance of PLEDsignificantly.
    Role of Electron Transfer of Quinones in Hydroxylation of Phenol
    MEN Yong, LIU Yu, LI Jing, YANG Xiang-Guang, WU Yue
    2001, 22(5):  839-840. 
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    It was found that at neutral pHthe hydroxylation reaction rate of phenol was accelerated with an increase of the amounts of 1,4-quinone (1,4-BQ). This acceleration was ascribed to the formation of semiquinone from 1,4-BQ. The semiquinone and 1,4-BQwere suggested to play a role of actual oxidant (electron transfer) in the catalytic cycle. With further reaction, most 1,4-BQwas converted into 1,4-hydroquinone (HQ) and the corresponding mechanism was proposed.
    Studies on Characterization of Sulfided Tertiary NiMoP/γ-Al2O3 Catalysts by TPR Technique and Their Thiophene HDS Activity
    QI Xing-Yi, XU Chun-Ming, LIU Zhi-Chang, LI Wen-Zhao, XIN Qin
    2001, 22(5):  841-843. 
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    Aseries of sulfided tertiary NiMoP/ γ-Al2O3 catalysts with different contents of MoO3 were prepared by using molybdophosphoric acid of Keggin structure(H3PMo12 O40 ) and nickel nitrate as origins of active phase components of molybdenum, phosphorus and nickel, and characterized by TPRtechnique, with their HDSactivity being investigated with thiophene as a model substrate. For the sulfided Mo-0 catalyst containing no nickel as promoter, the only hydrogen sulfide evolution peak Ⅰ is observed at 462 Kand attributed to the hydrogenation of the so-called edge sulfur atoms chemisorbed on coordinatively unsaturated(cus) Mox+ sites on the MoS2 phase(MoS2 slab). With the introduction of nickel into the active phase of the sulfided Mo-0 catalyst and with the increase of the molybdenum loading, a new hydrogen sulfide evolution peak Ⅱ gradually develops at the low temperature side of the peak Ⅰ, at the same time accompanied by both the increase of the area ratio of the peak Ⅱ to the peak Ⅰ and the shift of the hydrogen sulfide evolution maximum rate to lower temperatures, which may imply the existence of two kinds of active centers related to molybdenum and nickel respectively and the synergic action between the two centers above. It should be noted that for the sulfided NiMoP/ γ-Al2O3 catalysts, the thiophene HDSrate and the quantity of hydrogen sulfide evolved during TPRprocess increase monotonously with the atomic ratio of molybdenum to nickel in the form of [n(Ni)+n(Mo)]/n (Ni). On the basis of the results here, the conclusion may be reached that the two kinds of vacancies can be formed on the edge of Ni-Mo-S slab due to the loss of Sduring TPRprocess and vacancies or sites related to the H2Sevolution peak IIshould be regarded as the mainly active reaction centers of thiophene HDS.
    Hydrogen Bonding in Thermoplastic Polyurethane Elastomers── Dynamic Mechanical Analysis
    CHEN Da-Jun, LI Yao-Jun
    2001, 22(5):  844-846. 
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    Arelatively high degree of physical crosslink was inferred from the superior mechanical properties of thermoplastic polyurethane elastomers(TPU). For the most part, this has been assumed due to hydrogen bonding. In this paper hydrogen bonding effects in some thermoplastic polyurethane elastomers, consisting of poly(tetramethylene oxide) of Mn=2000, 4,4'-diphenyl methane diisocyanate and extenders: N-methyl diethanol amine,1,4-butandiol and 1,2-ethylene diamine, have been studied by using dynamic mechanical analysis. The activation energies of hydrogen bonding dissociation and the physical crosslink densities have been evaluated from the elastic modulus temperature relation of the TPUsamples.
    Carrier Transport Characteristics of the Soluble PPV Polymer with Main Chain Containing Electron-Transporting Group
    YANG Xiao-Hui, YIN Shou-Gen, WANG Zhen-Jia, HOU Yan-Bing, XU Xu-Rong
    2001, 22(5):  847-850. 
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    Akind of novel PPVderivative containing electron transporting group on the main chain(O-PPV), was synthesized according to the WITTIG-HORNER mechanism. This oligo polymer( Mw=1000, Tg=470 K) is soluble in chloroform and tetrahydrofuran. Single layer device ITO/O-PPV( 70 nm )/Al was fabricated, the electroluminescent(EL) spectra are essentially identical to photoluminescene(PL) spectrum. Compared with the quantum efficiency of the analogous single-layer device constructed with PPV(ITO/PPV/Al), the device ITO/O-PPV/Al is about five to eight times higher, which can be associated with the balanced carrier injection and transport owing to the attachment oxadiazole segment onto PPVmainchain. Two types of double layer devices were fabricated to study the carrier transport characteristic of OPPV. Our result showed O-PPVhas function both as electron transport layer and hole transport layer in double layer device, in other words OPPVhas obvious bipolar transport characteristic.
    Progress in the Chemistry of Spirodilactone and Its Derivations
    QU Jian-Qiang, WANG De-Qiu, HAN Fu-She, DING Meng-Xian, GAO Lian-Xun
    2001, 22(5):  851-859. 
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    Spirodilactones are a series of compounds with the structures of spiro-carbon and lactone which result in the special physical and chemical characters of Spirodilactones. In this paper the advance in the methods of synthesis, derivative reaction, chrial resolution, polymer synthesis of the most representative aspects for spirodi-γ-butylactone and its derivations, were summarized described.
    The Effect of Metal Ions on the Conformation Transition of Silk Fibroin
    LI Gui-Yang, ZHOU Ping, SUN Yao-Jun, YAO Wen-Hua, MI Yong, YAO Hui-Ying, SHAO Zheng-Zhong, YU Tong-Yin
    2001, 22(5):  860-862. 
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    How the silkworm spins out such an excellent silk fiber has been a hot topic. The issue here is to know how the coil chains in the gland of silkworm transform to β-sheet in silk fiber. We used the regenerated silk fibroin to imitate the silk fibroin of the gland to investigate the effect of metal ion(Ca 2+. Cu 2+ ) on the silk spinning process of Bombyx mori silkworm. The solutions or gel obtained from hte mixture of regenerated silk fibroin and metal ions were dried for mimicking the gradual loss of water in the spinning process. The 13C NMRspectrum simulation for Cβnucleus of alanine quantitatively demonstrated that the conformation of the regenerated silk fibroin is dominantly of silk Ⅰ, whereas the fibroin with metal ions has more silk Ⅱ conformation. Raman spectroscopies show the consistent results with that of NMR. The binding of metal ion with carbonyl and amide in protein backbone allows the protein chain to array regularly, therefore leading to the β-sheet formation.
    Accurate Measurements of Heteronuclear 13C- 1H Coupling Constants by Phase-sensitive HMQC and HSQC Spectra
    DING Ke-Yang
    2001, 22(5):  863-865. 
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    Phase sensitive HMQC(Heteronuclear Multiple-Quantum Coherence) and HSQC(Heteronuclear Single-Quantum Coherence) experiments with t1 noise reduction are proposed for the accurate measurement of heteronuclear one bond 13C1Hcoupling constants. The resulting 2D spectra give anti-phase splittings of heteronuclear one-bond couplings along ω2-dimension, so that the precision of coupling constant measurement is less subject to the residual t1-noise. By combining use of data-fitting procedure on a spectrum with enough digital resolution and signal-to-noise ratio, a precision of about 0.03 Hz can be achieved in the measurement of heteronuclear one-bond coupling constants. The proposed method can be very useful for the study of residual dipolar couplings caused by the alignment in high magnetic field and the dynamic frequency shift caused by the cross correlation between chemical shift and spin dipolar interactions.
    Living Radical Polymerization of Methyl Methacrylate with a New Initiation System
    QIN Dong-Qi, QIN Shu-Hui, QIU Kun-Yuan
    2001, 22(5):  866-868. 
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    Living radical polymerization of methyl methacrylate was investigated using a new initiation system, i. e. DCDPS/Fe(DC)3, in which diethyl-2,3-dicyano-2,3-diphenyl-succinate(DCDPS) is a hexa substituted ethane thermal iniferter and ferric tri(diethyldithiocarbamate)(Fe(DC)3) is a ligand-free catalyst. The polymerization was successfully controlled in bulk at 95 ℃, PMMAwith high molecular weight and quite narrow polydispersities( Mw/Mn=1.20-1.29) were obtained. End group analysis by 1HNMRspectroscopy shows that the resulting PMMAis ω-functionalized by a DC group.
    Self-assembled Monolayers of New Dendron-thiols——Manipulation of Patterned Surface and Wetting Property
    ZHANG Li, ZOU Bo, DONG Bin, HUO Feng-Wei, WANG Zhi-Qiang, ZHANG Xi
    2001, 22(5):  869-871. 
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    Self-assembled monolayers(SAMs) based on a novel dendron-thiols system, which maintain the alkanethiols' active site, but the —SHgroup connected with independently variable groups by a dendron linker, showed the controllable surface pattern and wetting property. The precisely tailored structure of dendron-thiols with local controlled hydrophobic and hydrophilic peripheries allow the formation of designed surface structures on gold surface, e.g. nano-stripes, honeycomb and homogeneous structure.
    Self-assembly Behavior in PS/ Montmorillonite Nanocomposite
    CHEN Guang-Ming, MA Yong-Mei, QI Zong-Neng
    2001, 22(5):  872-874. 
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    A shear-induced ordered structure in an exfoliated polystyrene(PS)/clay nanocomposite is reported. Self-assembly behavior was reported for the first time of a shear induced ordered structure in the nanocomposite. The self assembly behavior was measured by X-ray diffraction(XRD) patterns, transmission electron microscopy(TEM), and FTIRdichroism technique. Compared with the broad amorphous peaks of the PS, a series of sharp XRDpeaks were observed for the exturded PS/clay nanocomposite pellet sample, showing that an ordered sructure occurred under shear flow. The intensities of the four sharp XRDpeaks of the ordered sructure decreased significantly with temperature. However, at 95 ℃, the XRDpeaks increased significantly, the FTIRdichroism showing that and the phenyl ring of PSchanged its orientation from parallel to perpendicular to the monmorillonite primary particles, whereas no obvious orientation of the alkyl chain of PScould be found. At110 ℃, a disordered structure occurred for the phenyl ring. TEMimages confirmed directly that the origin of the ordered structure was mainly due to the planar orientation of the primary particles of silicate layers as well as local ordered microsructure of the primary particles, induced by shear flow. Basd on these investigations, a possible mechanism was deduced for the formation of the ordered strucure induced by shear flow in the exfoliated PS/clay nanocomposite.
    Computer Simulation on Recognition of Chiral Hexahelicenes
    SUN Kai, LI Ting, LIANG Tai-Ning, YANG Xiao-Zhen
    2001, 22(5):  875-877. 
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    Molecular interactions are the key to understanding the structure and properties of materials. Also, it is critical of chiral recognition. Since the molecular interactions at play in chiral discrimination is difficult to investigate under traditional experiment conditions. We have undertaken a computer experiment of van der Waals interaction between chiral molecules and a polymer, which works for chiral separation. Building molecular models, choosing proper force field and Monte Carlo method, we have calculated the difference of interaction energy between isotactic poly-(triphenylmethyl methacrylate) and (+)-hexahelicene or (-)-hexahelicene. It is finally found about 1.3794 kJ/mol between the polymer and the two chiral hexahelicenes. Reasonably, this difference is regardd as the main reason which induced chiral separation. Furthermore, we compared the results from computer smulation with that from experiment. It can be seen that some details during chiral separation process, such as trailing effect, can also be predicted, and be consistent with the experiment results. Finally, the effective structureal characteristics of the recognition site are pointed out.
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