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    24 February 2000, Volume 21 Issue 2
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    Articles
    Synthesis and Characterization of a New Tungsten Sulfide with a Lamellar Mesostructure
    WANG Ying, CHEN Jie-Sheng, YU Shao-Fang, XU Ru-Ren
    2000, 21(2):  165-168. 
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    Anew tungsten sulfide(designated as WS-L) with intercalated cetyltrimethylammonium surfactant cations was prepared under a mild hydrothermal condition, and the product was characterized by IR, ICP, SEM, TEM, XPSand TGA. Sodium tungstate and thioacetamide were used as the tungsten and sulfur sources respectively, whereas the template was cetyltrimethylammonium bromide. XRDand TEMresults reveal that the compound has a lamellar mesostructure with an interlayer distance of 2.925 nm. The empirical composition of the individual inorganic layer is [WS3.5]2-and the negative charges on the layer are balanced by the surfactant cations intercalated between two adjacent layers.
    Spin Trapping EPR Investigation on Rearrangement Reactions of Radicals Generated by Cleavage of Co——C Bonds of Three Aqua(butyl)cobaloximes Under Photolysis
    SONG Xin-Yi, CHEN Ying, CHEN Hui-Lan
    2000, 21(2):  169-171. 
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    The radicals formed from the anaerobic photolysis of aqua(alkyl)cobaloxime(R=n-C4H9, i4H9, sec-C4H9) are detected by the EPRspin trapping technique using 2-methyl-2-nitroso-propane as the spin trap. The rearrangement reactions are found in which the primary radicals produced by Co-Cbonds cleavage under photolysis are converted into the secondary ones.
    A Study of Preparing and Morphology of Tetrapod-like ZnO Whiskers
    CHEN Er-Fan, TIAN Ya-Juan, CHENG Yuan-Jie, ZHOU Ben-Lian
    2000, 21(2):  172-176. 
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    This paper dealt with the preparing conditions and morphology of tetrapod -like zinc oxide (T-ZnO) whiskers with an angle of 109° between any two legs, which were prepared by vapor-phase oxidation of zinc metal in the air and by introducing white carbon black as a reaction catalyst. The product was pure zinc oxide verified by EDSand XRDpatterns of T-ZnOwhisker, in which the peaks are sharp with narrow half-widths and can be identified as a wurtzite ZnOstructure. Morphology of T-ZnOwhiskers was affected greatly by white carbon black as mold catalyst and supersaturations ratio(the fractional pressures of zinc vapor vs pressed air).
    Synthesis, Crystal Structure and Characterization of Complex Cu(C14H9NO3)(C3H4N2)
    GAO Shan, SHI Zhan, HUA Jia, FENG Shou-Hua, XU Ru-Ren, LIU Shi-Xiong, HUO Li-Hua, CHEN Peng-Gang
    2000, 21(2):  177-180. 
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    The copper(Ê) complex with N-(2-carboxyphenyl)salicylidenamine and imidazole ligands, Cu(C14H9NO3)(C3H4N2) , was synthesized. The crystal belongs to orthorhombic, space group Pca21, with the crystal cell parameters: a=0.94453(12) nm, b=1.12278(9) nm, c=2.9123(4) nm, V= 3.0885(6) nm3, Mr=370.84, Z=8, R=0.036, wR=0.087, GOF=0.975. The copper(Ê) ion lies in a distorted square-planar environment composed of two oxygen atoms, one nitrogen atom of the tridentate Schiff base ligand and one nitrogen atom of the imidazole ligand. The complex was also characterized by elementary analysis, IR, UV-Vis, TGand cycle voltammetry measurement.
    Effects of Fe Doped on Properties of Synthetic Kaolinite in Hydrothermal Process
    LIU Su-Qin, HUANG Ke-Long
    2000, 21(2):  181-184. 
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    Kaolinite doped with iron was hydrothermally synthesized, and the relationship between the amount of impurity and white degree of synthetic kaolinite was determined by mathematical analysis. The synthesized kaolinite was characterized by X-ray diffraction(XRD) and differential thermal analysis(DTA), and states of iron in the kaolinite were discussed.
    Studies on Oriented Growth of KH2PO4Crystals Under Phospholipid Monolayer
    LI Bin, ZHANG Xi, BAI Yu-Bai, XU Ru-Ren
    2000, 21(2):  185-186. 
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    Using a Langmuir-Blodgett film of dipalmitoylphosphatidylcholine(DPPC), a model of biomembranes, as a template, we succeed in obtaining oriented KH2PO4(KDP) crystals toward crystal face (100) under well-compressed DPPCmonolayer. This is explicable in terms of the geometrical complementarity between KDPand the DPPCmonolayer. It is found that the distances between the closest K-K (0.416 nm) fit the d(100) network spacing of DPPCmonolayer(0.420 nm), which results in that the special activation energy for nucleation exists in the interface covered with DPPCmonolayer. DPPCmonolayer has a very strong selected catalysis on the crystallization of KDPcrystal face (100), and drives KDPrapid and oriented nucleation on the monolayer/solution interface. The oriented KDPcrystals show a good second harmonic generation(SHG) signal.
    Synthesis and Structure of the Coordination Polymer with One-dimensional Zigzag Chain Extended by Fe(Ⅲ)-CN-Cu(Ⅱ) Linkages
    LU Tong-Bu, XIANG Hua, LI Xiao-Yan, SU Cheng-Yong, MAO Zong-Wan, JI Liang-Nian, YU Kai-Bei
    2000, 21(2):  187-189. 
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    One-dimensional cyanide-bridged bimetallic coordination polymer [CuL(H2O)2]n[(CuL)·(μ-CN)2Fe(CN)4]2n·(H2O)2nwas synthesized and structurally characterized. The coordination polymer crystallizes in a monoclinic system of the space group C2/c with a=2.9831(5) nm, b=1.5274(3) nm, c= 1.7253(4) nm, β=107.68(2)°, V=7.490(3) nm3, Z=8, Dc=1.382 g/cm3, F(000)=3260, R=0.0593, wR2=0.1323, S=0.885. The one-dimensional zigzag chain extents through Cu-CN-Fe-CN-Cu linkages. The adjacent two polymer chains are linked by the O-H……NChydrogen bonding between [CuL(H2O)2]2+and [Fe(CN)6]3-ions to form hydrophilic channels in which water molecules are included.
    Inverse Spinel LiNiVO4Synthesized by Moist Method at Low Temperature
    LAI Qiong-Yu, LU Ji-Zheng, LIANG Xing-Long, JI Xiao-Yang
    2000, 21(2):  190-192. 
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    In this paper, we report a new kind of moist chemical method for preparing LiNiVO4which can be used to prepare lithium ion battery for the cathode active materials with a very high battery voltage(48 Vvs. Li). Li2CO3, NiCO3and NH4VO3were used as row materials, and H2C2O4saturated solution was used both as a precipitate agent and as a complex agent. The precursor gel composed of (NH4)2(VO)2(C2O4)4·6H2O, NiC2O4·2H2Oand Li 2C2O4can be obtained, and after sintering the dry gel we got the products. The results of XRDshow that the product sintered at 400 ℃ for 2 h exists in a cubic crystal, single phase, inverse LiNiVO4and the average sizes (by Scherrer formula ) were 40-50 nm(400 ℃, 2 h ) and 65-70 nm(700 ℃, 2 h) , respectively, a=0.8223(1) nm. The TGand DTAcurves implied that the dry gel underwent water loss, decompositions of oxalates and complex oxalate, the solid state reactions finished at 377 ℃. The results of XPSproved that the valence in LiNiVO4would be Li+,V5+, Ni2+(in the main), respectively. From ICPanalysis we also knew that the sample corresponded basically to stoichiometry LiNiVO4.
    Using Elman Recurrent Neural Network Trained in Sections to Filter Noise of Chromatographic Spectrogram
    CHEN Feng, HU Shang-Xu, YU Meng-Huai
    2000, 21(2):  193-197. 
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    In this paper, the noise of chromatographic signal has been analyzed by fractal geometry, and the Elman neural network trained in sections has been used to filter noise. The proposed method has obvious advantages over other neural networks and median filter in filtering noise, and the precision of results are much higher.
    Studies and Application of Polarographic Catalytic Wave of Lysozyme in the Presence of KIO3
    GUO Wei, YANG Yia-Ni, SONG Jun-Feng
    2000, 21(2):  198-201. 
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    Apolarographic catalytic wave of lysozyme(LE) in the presence of KIO3is described. In 0.1 mol/L HAc-NaAc(pH4.7±0.1) buffer solution, LEyields a reversible wave with peak potential -0.51 V (vs. Ag/AgCl) due to the reduction of a disulfide bond between cys6-cys127. When KIO3is present in the acetate solution, LEproduced a polarographic catalytic wave at original potential. The mechanism of the catalytic wave was considered that the disulfide bond was regenerated through oxidation reaction of reduction product -SHgroup by KIO3and its derived species with intermediate valence state(including free radical IO-·, IO2-·). This is a new class of polarographic catalytic wave for protein. In01mol/L HAc-NaAc(pH4.7±0.1)-1×10-3mol/L KIO3supporting electrolyte, the sensitivity of the catalytic wave is two orders of magnitude higher than that of the corresponding reduction wave. The peak current of the catalytic wave was linearly proportional to LEconcentration in the range 2×10-7-1×10-6mol/L. 100-fold cystine and cystein do not interfere the determination of 1×10-6mol/L LE.
    Electrocatalysis of Osmium Poly-vinylindole Complex Modified Glassy Carbon Electrodes to Epinephrine Oxidation
    GONG Yi, YE Lei, JU Huang-Xian, CHEN Hong-Yuan
    2000, 21(2):  202-205. 
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    The electrocatalytic characteristics of osmium complex polymer [Os(bpy)2(PVI)10Cl]Cl· (Os-PVI10) and Nafion dual-layer membrane modified glassy carbon electrodes were studied. The modified electrodes show an excellent electrocatalytical activity for the oxidation of epinephrine(EP). Under the normal physiological condition, the catalytic current of EPvs. its concentration has a good linear relation in the range of 1.0×10-6-8.4×10-5mol/Lwith the correlation coefficient of 0.9987. Nafion membrane makes the modified electrodes eliminate efficiently the interference of ascorbic acid(AA). The modified electrodes exhibited a good reproducibility, sensitivity, and stability. The amperometric determination of EPconcentration can be performed at +250 mV. The kinetic research was performed with a rotating disk electrode, and the electrocatalytical rate constant kch was evaluated to be 3.53×103mol-1·L·s-1. At a high EPconcentration, the relationship between the catalytic current and its concentration exhibits a Michaelis-Menten kinetic mechanism for the electrocatalytical process, and the constant Km is about 147 mmol/L.
    Ultrasensitive Fluorometric Detection of Oligosaccharides as Their APTS Derivatives by Capillary Electrophoresis
    DANG Fu-Quan, CHEN Yi, GUO Qing, XU Gui-Yun
    2000, 21(2):  206-209. 
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    Reducing oligosaccharides, after reductive amination, were separated and detected as their APTSderivatives by capillary electrophoresis with laser-induced fluorescence. Brief optimization studies have also been performed with respect to CEseparation conditions of oligosaccharides. The oligosaccharide ladders were analyzed in an acidic phosphate-tris buffer(pH2.5) or in the alkaline borate buffer. Acid hydrolysis products of dextran T-40 labeled with APTSwere also successfully mapped.
    Newborn Screening of Phenylketonuria by LC/MS/MS
    QU Jun, WU Zhu-Ping, LUO Guo-An, LIU Mi-Xin, YANG Cheng-Dui
    2000, 21(2):  210-212. 
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    The application of MS/MSin newborn screening is one of the most important branches of MS/MS's current clinical applications. In this paper, we firstly reported a new method of newborn screening for Phenylketonuria(PKU) by coupling LCwith MS/MS, which was relatively cheap, fast, sensitive, and accurate. In this method, only a few steps of sample preparation were required and no isotopically labeled internal standard was required. Phe and Tyr were extracted from dry blood spots with 0.1 mol/L HCl-methanol and reacted with 2.8 mol/L HCl-butanol at 68 ℃ for 35 min. MS/MSwas used as a detector for LCand multi reactions monitoring (MRM) scan mode was employed to determine phenylalanine and tyrosine in blood samples. Among the product ions of Phe and Tyr butyl esters, [M+H-102]+was the most abundant in intensity and unique to α-amino acids, therefore the precursor-daughter ion pairs of m/z 222-120 and m/z 238-136 were selected as MRMion pairs. The contents of these two amino acids in blood samples were determined by calculating the areas of their ionic flow peaks. Finally, the molar ratios of Phe to Tyr in blood samples were calculated as the basis of PKUdiagnosis. The curve for Phe showed excellent linearity over the concentration range of 24_1 152 μmol/L(r2=0.999). As to Tyr, the range of linearity was 22_1 056 μmol/L(r2=0.998). The average analytical recoveries of added Phe and Tyr from blood were 98% and 96%, respectively. The limits of detection for Phe and Tyr were respectively 0.5 pg and 2.0 pg , which were 103times lower than that of reported MS/MSmethod. About 40 blood samples were analyzed by this method, and the results proved that this method could successfully discriminate between normal infants and PKUpositive ones. Each sample's analysis time was about 4 minutes; therefore it was capable for large-scale screening.
    Synergistic Effect of Dibenzo-18-crown-6 and Resorcarene Derivative Mixed Stationary Phase in Gas Chromatography
    YUAN Li-Ming, LING Yun, FU Ruo-Nong
    2000, 21(2):  213-215. 
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    The synergistic effect is investigated in mixed gas chromatographic stationary phase containing dibenzo-18-crown-6 and resorcarene derivative, with benzene/cyclohexane, halogenated hydrocarbon, aromatics, ketone, phenol, alcohol and aniline derivatives as the sample compound pairs. This separation effect is affected by temperature, mixing ratio of stationary phases and linear velocity of carrier gas.
    Application of Genetic Programming Coupling with Genetic Algorithm
    ZHOU Xiang-Dong, LI Tong-Hua, BIAN Fang, QIAN Jun-Lü
    2000, 21(2):  216-218. 
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    GA-GPis an algorithm for dealing with all kinds of nonlinear function relationships and fraction relationships, which use GP(Genetic programming) to create new individuals and GA(Genetic algorithm)to optimize them at the same time. In this way we make full advantage of GAand GP. We discuss the application of this algorithm in quantitative structure-activity relationships(QSAR) in the medicinal field. The result shows that GA-GPis better than ANNand mathematical expressions could be obtained. Expressions clearly express and explain QSARof the medicine. All can show GA-GPhas very wide applications in the medicinal field of the molecule design.
    Structure-activity Relationships for Antiplasmodial Activity Among Aminoquinolines
    QI Yu-Hua, XU Lu, LIU Zhong-Ying
    2000, 21(2):  219-221. 
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    The extended gravitational index GQ and quantum-chemical descriptors were calculated for the relationship analysis of aminoquinolines. An evolutionary algorithm was described for variable selection and building QSARmodels. And the quasi-newton neural networks were employed with better results.
    ansa-Metallocene Complexes(Ⅳ)——Synthesis, Structure and Application in Ethylene Polymerization of Sila-bridged Substituted Cyclopentadienyl Titanium and Zirconium
    SUN Xiu-Li, WANG Bai-Quan, XU Shan-Sheng, ZHOU Xiu-Zhong, ZHAO Jian, HU You-Liang
    2000, 21(2):  222-226. 
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    Tetramethyldisilane-bridged substituted cyclopentadienyl ligands react with n-butyl lithium and MCl4·2THFto give tetramethyldisilane-bridged substituted cyclopentadienyl metallocene dichlorides(Me2SiSiMe2)(C5H4R)(C5H4R')MCl2[R=H, R'=t-Bu, M=Ti(1), Zr(2), Hf(3); R=H, R'=Me, M=Ti(Ê); R=R=Me, M=Ti(5), Zr(6)]. Complexes 16 were characterized by 1H NMR, mass spectra and elemental analyses. The crystal structure of 1 was determined by X-ray diffraction analysis. The complexes 1_3 and 6 were used for the polymerization of ethylene after activation with methyl aluminoxane(MAO).
    Synthesis of Glycoconjugated Metalloporphyrins and Their Catalysis for Cyclohexane Oxidation Under Mild Conditions
    GUO Can-Cheng, ZHANG Xiao-Bing, OUYANG Yu-Zhu, LI He-Ping
    2000, 21(2):  227-232. 
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    Two glycoconjugated porphines, tetra[2-acetylglucosyl-oxo-phenyl]porphine (T(o-glu)PPH2) and tetra[3-acetylglycosy-oxo-phenyl]porphine(T(m-glu)PPH2), were synthesized from the reaction of pyrrole with ortho-acetylglycosylate benzaldehyde and meta-acetylglycosylate benzaldehyde, respectively, by Lindsey's method. Four glycoconjugated metalloporphyrins, chloro[tetra(o-2,3,4,6-O-acetylglucose-1-O-phenyl)porphinato] iron(T(o-glu)PPFeCl), chloro[tetra(o-2,3,4,6-O-acetylglucose-1-O-phenyl)porphinato]manganese, (T(o-glu)PPMnCl), chloro[tetra(m-2,3,4,6-O-acetylglucose-1-O-phenyl)porphinato]iron(T(m-glu)PPFeCl) and chloro[tetra(m-2,3,4,6-O-acetylglucose-1-O-phenyl)porphinato]manganese(T(m-glu)PPMnCl) were prepared from these glycoconjugated porphines. The newly synthesized compounds were characterized by UV-Vis spectroscopy, 1H NMRand elemental analysis. Cyclohexane oxidation catalyzed by four glycoconjugated metalloporphyrins with PhIOat room temperature and atmospheric pressure were studied. In contrast with metalloporphyrins without sugar groups, the acetylglycosylated metalloporphyrins raised the ratio of cyclohexanol to cyclohexanone and increased the reaction rates and the yields of cyclohexane oxidation. The results of study indicated that the selective catalysis of these acetylglycosylated metalloporphyrins for hydrocarbon oxidation was more close to cytochrome P-450 monooxygenase, and that the kinetics of cyclohexane oxidation catalyzed by acetylglycosylated metalloporphyrins was in consistent with cytochrome P-450 monooxygenase.
    Influence of Temperature and Flow Rate on Enantioselectivity About Derivative β-Cyclodextrin Bonded Stationary Phase in Normal-Phase Liquid Chromatography
    CHEN Hui, LU Xian-Yu, GAO Ru-Yu, WANG Qin-Sun
    2000, 21(2):  233-236. 
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    Apartially phenyl carbamate derivative β-cyclodextrin bonded phase(CSP1) has been prepared to achieve two aims: firstly, we want to add more interaction sites to enhance the selectivity; secondly, we attend to increase hydrophobic effect to make it easy for the compound to get into the cone. The effect of structure of enantiomers, temperature and flow rate on enantioselectivity of a series of O,O-diethyl(p-methylbenzenesulfonamido)aryl (or alkyl)methylphosphonates has been investigated in order to obtain a better understanding of the separation mechanism. The results reveal that the substituent on the chiral carbon is a decisive factor for the separation. When the substituent is an aryl group, the enantiomer can get a good separation. On the contrary, the enantiomer cannot be recognized when the substituent group is an alkyl. It is obvious that the aryl group gives a dipole-dipole stacking interaction which contributes to the separation. Plots of lnα against 1/Tyields linear relationships under the conditions studied which can be used to determine the Gibbs-Helmholtz parameters Δ (R,S)ΔH° and Δ (R,S)ΔS°. The good linear relationships indicate that the same recognizing mechanism exists. According to the value of thermodynamic parameters, the separation mechanism is believed to depend on weak π-π interactions or weak hydrogen bonding. There is no great influence on enantioselectivity when the flow rate varied from 0.5 to 2.0 mL/min . The kinetics of the mass transfer suggests that inclusion complex formation may be slower than simple external cyclodextrin interaction. That the enantioselectivity does not decrease with the increase of the flow rate shows that the inclusion mechanism does not control the separation. More interaction sites have been added to the derivative cyclodextrin bonded phase which can afford π-π interactions, hydrogen bonding and dipole-dipole stackings. Dipole stacking contributes to the enantioselectivity between the aryl group connected to chiral carbon and the benzene group of CSP1.Hydrogen-bonding interactions can be involved between the N_H of the carbamate function of the CSP1 and the oxygen atom of the PO. Each glucose unit contains five chiral centres. Two of these chiral centres are on the C-2 and C-3 atoms. The carbamate groups on C-2 are located at the entrance of the cone and point in a clockwise direction whereas the hydroxyl groups on C-3 are located outside the cyclodextrin molecule and point in a counter-clockwise direction. In this way, the third chiral repulsive interaction can be involved. In conclusion, the chiral recognizing model involves one hydrogen-bonding interactions, stronger dipole stacking and repulsive interaction.
    Syntheses and Herbicidal Activity of Ether Analogues containing 1,2,4-Triazo-[1,5-a]-pyrimidine or3,5,6-Trichlorosalicylate and Pyrimidine Derivative
    FEI Xue-Ning, SONG Hong-Hai, WANG Xiang, YANG Xiu-Feng, YANG Hua-Zheng
    2000, 21(2):  237-240. 
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    Six kinds of intermediums of pyrimidine derivatives and twelve kinds of new ether analogues containing1,2,4-triazo-[1,5-a]-pyrimidine or 3,5,6-trichlorosalilate were synthesized, whose structures were confirmed by 1H NMRand elemental analysis. Biological test showed that all of the ether analogues synthesized displayed a herbicidal activity to some extent. The herbicidal activity of particular compound is good enough for the grass family.
    Interaction of Peptides with Pollen Camodulin and Their Effects on Cellular Functions
    SU Jing, SONG Yan-Ling, YAN Hu-Sheng
    2000, 21(2):  241-245. 
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    The interaction between dansyl-labeled pollen calmodulin(D-pCaM) and buckwheat pollen peptide analogs was studied in the presence of Ca2+. Most peptides in our research can associate with D-pCaMand form peptide-pCaMcomplexes, which changed the fluorescence spectra of D-pCaM. The dissociation constants Kdfor these complexes were determined using fluorescence titration. Peptide BP-13, AMALALKKTGNH2, had the smallest Kdvalue 4.0 nmol/L, demonstrating the highest affinity for pCaM. In addition to studying the influence of hydrophobicity, propensity of secondary structure and chain length on these peptides abilities to bind pCaM, we have also found that Gly/L-Ala→D-Ala substitution in peptide chains caused great changes in their affinity for pCaM. These results suggest a potentially useful approach to improving the binding ability of peptidic antagonist to CaM. Furthermore, our data provided evidence on the dissimilarity of different CaMs although they have highly-conserved structures. Aprimary study was carried out on the effects of CaM-binding peptides on cellular signal transduction, cell proliferation and growth, showing the participation of CaMin this important cellular life process.
    Synthesis and Properties of Triphenylgermanium Derivatives of Unsaturated Alkylphosphonic Acid
    YIN Han-Dong, MA Chun-Lin, ZHANG Ru-Fen, WANG Yong
    2000, 21(2):  246-248. 
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    Fourteen new triphenylgermanium derivatives of alkynyl or alkenyl phosphonic acid were synthesized by the reaction of corresponding triphenylgermanium chloride with alkynyl or alkenyl phosphates. All compounds were characterized by elemental analysis, IR, 1H NMRand MS. The results showed that bis(triphenylgermanium) alkynyl or alkenyl phosphonates are both four- and five-coordinated germanium and triphenylgermanium alkynyl or alkenyl phosphonates are five-coordinated germanium.
    Mpolecular Rexognigion Studies on Supram olecular Systems(ⅩⅩⅩ)——Syntheses of Organoselenium Modified β-Cyclodextrins and Their Inclusion Complexation with L- and D-Tryptophan
    YOU Chang-Cheng, LIU Yu
    2000, 21(2):  249-251. 
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    Mono(2-phenylseleno-2-deoxy)-β-cyclodextrin(2) and mono[2-(p-methoxyphenylseleno)-2-deoxy]-β-cyclodextrin(4), were newly synthesized and characterized by combustion analyses, IR, 1H NMRand 13C NMR. Spectrofluorometric titrations have been performed in aqueous phosphate buffer solution(pH7.20, 0.1 mol/L) at 25 ℃ to give the complex KSand -ΔG° for the stoichiometric 1∶1 inclusion complexation of mono(6-phenylseleno-6-deoxy)-β-cyclodextrin(1), mono[6-(p-methoxyphenylseleno)-6-deoxy]-β-cyclodextrin(3) and the novel cyclodextrin derivatives 2 and 4 with L- and D-tryptophan. The molecular binding ability and selectivity for L- and D-tryptophan of modified β-cyclodextrins(1_4) are discussed from the size/shape-fit and geometrical complement relationships between the host cavity and the guest molecule. The results obtained indicate that van der Waals force and hydrophobic interactions dominate the complexation of 1-4 and the aromatic substituents introduced extend the original hydrophobicity of cavity and the molecular binding ability, but reduce the enantioselectivity for L/D-tryptophan guests.
    Synthesis and Spectrum Study of 4P-Hydroxymethyl- 2,6,7-trioxa-1,4-diphospha-bicyclo[2.2.2]-chlorooctane
    HAN Jia-Xiang, LIU Jun, PU Min-Li, YUAN De-Kai, ZHANG Zhong-Wei, LI Yu-Gui
    2000, 21(2):  252-254. 
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    Using THPCas the initial substrate, 2,6,7-trioxa-1,4-diphospha-bicyclo[2.2.2]-octane was gotten in strong basic environment by an indirect way. And then, after a series of reaction, the target Caged-diphospha-bicyclo compounds were synthesized using a new method. The whole procedure was reported in detail. Furthermore, the molecule structures and some spectra of the target compounds were also systematically described in this paper. Some valuable phenomena were discovered in 13P NMRspectra, such as the chemical shift from 2 to 5a and 5b, and the increase of 3JP_Pfrom 2 to 5.
    Quantum Chemical Study of Silicon-sulfur Clusters(SiS2)n+(n=1-3)
    WANG Su-Fan, FENG Ji-Kang, CUI Meng, SUN Chia-Chong, LIU Peng, GAO Zhen, KONG Fan-Ao
    2000, 21(2):  255-259. 
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    The possible geometrical structures and relative stability of silicon-sulfur clusters(SiS2)n+(n=1-3) are explored by means of density functional theory(DFT) quantum chemical calculations. The effects of polarization functions and electron correlation are included in these calculations. The electronic structure and vibrational spectrum of the most stable geometrical structure of (SiS2)n+are analyzed by the same method. As the result, the regularity of the (SiS2)n+cluster growing is obtained, and the calculation can be used to predict the mechanism of the (SiS2)n+cluster forming.
    Theoretical Studies of Lead-sulfur Binary Pb5S4+Clusters
    CUI Meng, FENG Ji-Kang, WANG Su-Fan, SUN Chia-Chung, LIU Jian-Bo, GAO Zhen, KONG Fan-Ao
    2000, 21(2):  260-262. 
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    The possible structures and properties of Pb5S4+clusters were studied by using Density Functional Theory (B3LYP) method. The result shows that the most stable isomers is Pb5S4+(Cs) which has a cage structure. Our forecast to the properties of the clusters is agreement with experimental results.
    Studies on the Preparation of Cr Nanometer Powder
    CHENG Qi-Lin, ZHAO Bin, GU Hong-Chen
    2000, 21(2):  263-264. 
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    Cr nanometer powder with mean diameter 50 nm was prepared in an organic solution of CrCl3, using sodium triethylborohydride as a reducing agent, toluene as a solvent, PVPas a dispersant, PdCl2as a nucleator. The temperature, the concentration of reactants and the addition of dispersant and nucleator were the main factors affecting the particle size. Also the mechanism and thermal stability of Cr nanometer powder were discussed.
    A Study on the Dynamic Response of Precipitate-based Ion-selective Electrodes to Interfering Ions
    SHI Sheng-Hua, WANG Zhong-Wen, SUO Zhi-Rong, YU Shu-Ping, GAO Hong
    2000, 21(2):  267-272. 
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    The dynamic response of precipitate-based ion-selective electrodes to a sudden step change in the activity of interfering ions (Y±) is studied in this paper. In this case the responses of AgIelectrode to Cl-,Br-and SCN-, AgBr electrode to Cl-and SCN-, CuSelectrode to Pb2+, Zn2+, Cd2+, Co2+, Ni2+and Mn2+, PbSelectrode to Cd2+and CdSelectrode to Pb2+are all nonmonotonic overshoo-type transient signals in the presence of certain concentration of primary ion(X±) in the solution, while all the other transient signals in the absence of primary ion in the solution are monotonictype, except the response of AgBr electrode to Cl-. For the responses of a certain electrode to different interfering ions, the experiment discovers that both the smaller solubility product Ksp(MY) of ionexchange product (MY) and difference [ΔHh(X±)° -ΔHh(Y±)°] of hydration enthalpies of ions in ionexchange process, the larger the peak height ΔEPof transient signal responded to sudden increase in the activity of interfering ion by electrode, and the effect of [ΔHh(X)°-ΔHh(Y±) °] on ΔEPislarger than the KSP(MY). For the responses of AgIelectrode to Br-and SCN-, although pKsp(AgSCN)≈pKsp(AgBr), ΔEP(SCN-)>ΔEP(Br-). This is probably related to [ΔHh(I-)°-ΔH h(SCN-)°]<[ΔH h(I-)°-ΔHh(Br-)°]. For CuSelectrode, pKsp(PbS) <pKsp(CdS) , pKsp(MnS)<pKsp(CoS)and pKsp(NiS), but ΔEp(Pb2+)>ΔEp(Cd2+), ΔEp(Mn2+) >ΔEp(Co2+ )and ΔEp(Ni2+). These are the same due to [ΔHh(Cu2+)°-ΔHh(Pb2+)°]<[ΔHh(Cu2+)°-ΔHh(Cd2+)°], [ΔHh(Cu2+)°-ΔHh(Mn2+)°]<[ΔHh(Cu2+)°-ΔH(Co2+)°] and [ΔH(Cu2+)°-ΔHh(Ni2+)°]. The relative magnitudes of differences of hydration enthalpies in positive and reverse reactions in ionexchange can also be used to explain the relative magnitudes of peak heights ΔEpand ΔE of transient signals in the positive and negative activity steps. Therefore, on the basis of the above facts, we believe that the peak potential of the transient signal responded to the interfering ion by an electrode is determined not by the velocity of ion diffusion but by that of ionexchange because the thickness of diffusion layer is infinitely thin when the solution is sprayed on the surface of electrode at a high velocity .The smaller the difference in hydration enthalpies, the larger the velocity of ionexchange, then the larger the peak height of transient signal may be. Besides, for other electrodes, except Cu Selectrode, the selectivity coefficients Kxyedetermined on the basis of the equilibrium potentials in nonmonotonic overshoottype transient signals all conform to the Ksp(MX) /Ksp(MY) values.
    Volumetric Properties of1-Butanol in N,N-Dimethylformamide+Water Mixed Solvents
    BAI Tong-Chun, HAN Shi-Jun
    2000, 21(2):  273-277. 
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    Densities of ternary mixture (1-butanol+N,N-dimethylformamide+water) at 298.15 Khave been measured. The apparent molar volumes of 1-butanol in DMF+water mixed solvents have been evaluated from density data. Asimilar feature between Φ20,E～fm and VDMFE～fmcurves, and opposite feature between B 1 ～fmand Φ20,E～fmcurves have been observed, where Φ20,Eis the excess apparent molar volume of 1-butanol at infinite dilution, VDMFE is the excess partial molar volume of DMFin DMF+water binary mixture, B 1 is the second volumetric virial coefficients and fmis the mole fraction of DMFin DMF+water mixed solvents. These relationships reflec the interplay between solute solvation and solutesolute interactions. For hydrophobic solutes such as 1butanol, the stronger the solute was hydrated, the weaker the solutesolute interactions become. By using the special particle theory, the effect of cavity volume and interaction volume on the features of B1～fmand Φ20～fmcurves have been discussed.
    Improved Mathematical Model of APA Microcapsules
    HE Yang, XIE Yu-Bing, WANG Yong, LIU Qun, MA Xiao-Jun
    2000, 21(2):  278-282. 
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    It is essential to investigate the diffusion characteristics of alginate-polylysine-alginate(APA) microcapsule system for its broad applications. An advanced mathematical model for protein diffusion in APAmicrocapsules is established, which presents the resistance coefficient of microcapsule membrane and distribution coefficient in microcapsule matrix. These two parameters as the important basis of optimizing preparation and directing application of microcapsule are determined by the measurement of the protein concentration in the extracapsular solution. With assistance of mathmatical model, membrane diffusion characteristics affected by reaction time in membrane forming are analyzed: (1) microcapsule shows greater resistance constant and distribution constant to the diffusion of protein with greater molecular weight, (2) prologation reaction time results in increase in resistance constant and distribut constant of microcapsule.
    The Photoelectrochemistry of Au/PATP/PANI Film Electrode and Au/PATP/PANI/TiO2Film Electrode
    HUANG Huai-Guo, LUO Jin, ZHANG Hong-Ping, WU Ling-Ling, LIN Zhong-Hua
    2000, 21(2):  283-285. 
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    Au/PATP/PANI (polyaniline) film electrode was prepared by voltamometry in0.5mol/Laniline/0.5 mol/L HClO4from -0.2-0.8 Vat 100 mV/s after selfassembling PATP(4aminothiophenol) on bare Au. The potential dependence of photocurrent and the photocurrent spectra of Au/PATP/PANIfilm electrode were obtained. The potential dependence of photocurrent showed that all of the three forms(oxidized/partiallyoxidized/reduced) of PANIfilm had both anodic photocurrent and cathodic photocurrent. The halfoxidized PANIfilm had a great photoelectrochemical response. The photocurrent spectra of Au/PATP/PANIfilm electrode showed both half oxidized and reduced PANIfilm had the characteristics of subbandgap photocurrent spectra and followed Fowler rule(IPCE1/2 =Ethreshold+ bhν). Aphotoelectrochemical model on internal photoemission at insulator covered metal was presented to interpret it, which agreed with the model of granular metal island. The model assumed metallic polymer particles embedded in the nonmetallic matrix, while, Au/PATP/PANI/TiO2film electrode was prepared by electrodeposition in TiCl3solution (pH≈2.2). The photocurrent spectra of Au/PATP/PANI/TiO2film possessed the photoelectrochemical characteristics of both TiO2and PANI. The Au/PATP/PANI/TiO2film was expected to improve the efficient absorption of solar light.
    Double Carbonylation of Benzyl Chloride to Substituted Phenylpyruvic Acid Catalyzed by Cobalt Pyridine-2-carboxylate
    LI Guang-Xing, HUANG Han-Min
    2000, 21(2):  286-288. 
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    The complex cobalt pyridine-2-carboxylate Co(Pyca)2·4H2Ocatalyst is found to have a good activity and selectivity for double carbonylation of benzyl chloride to a substituted phenylpyruvic acid, β-benzyl-αphenylpyruvic acid, in CaO/CH3OH/H2Oreaction system. After stirring 10h in3.0 MPa and 333 Kwith the PhCH2Cl to CaOratio of 1.33 and catalyst of 5.5 mmol, the yield of the substituted phenylpyruvic acid is 40%, the selectivity is 80%, and the conversion of benzyl chloride is 51%. The substituted phenylpyruvic acid is characterized by IR, NMR, MSand microanalyses. The strong IRbands at 3453-3554 cm-1are assigned to the -COOH , and the sharp bands at 1706 and 1729 cm-1are assigned to the two C=Ogroups stretch, respectively. In the 13C NMRspectra, two characteristic strong peaks at δ 193.2 and 159.2 are assigned to C=Oand COOH. The MSspectra shows that the main characteristic peaks are m/z=254(M+), 236, 209, 181(basic peak), 91 and 77. The melting point of the phenylpyruvic acid is 87-89 ℃. Further study of the double carbonylation reaction over this new catalyst system is being carried out.
    Studies on Efficiency of Water-proof Layer in Soil
    CUI Xiang-Hao, ZON Won-Lk, WEI Chang-Ping
    2000, 21(2):  289-291. 
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    The water-saving technique, which prevents water from downward seepage and salts from upward, was proposed on the basis of analysis of the two major processes of material differentiation in the desertification process of semiarid zone. The organic-inorganic complex materials are water emulsion, which are composed of the polymer and clay, possesses a clay penetrability and can penetrate coarse sand to react with calcium ions from soil to form a gel waterproof layer, which can prevent water from seepage.
    A New Method for Preparing Porous Ti-Si Dioxide Composite with High Surface Area
    ZHAO Jing-Zhe, YANG Shao-Feng, WANG Zi-Chen, SHA Xiao-Xiang, ZHAO Mu-Yu, SHAN Zhi-Jun, DING Shi-Zhou
    2000, 21(2):  292-294. 
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    Anew method named peptizinggelation method was used to synthesize TiSi dioxide composite, whose surface area is above 1000 m2/g. The character of this method is that Ti exists in the form of ion and ion cluster during the hydrolysis of Si(OC2H5)4. This is the progress on the cohydrolysis of Si(OC2H5)4and Ti(OC4H9)4.During the calcination of gelation, Ti-O-Si was formed with Ti element in the situation of SiO2crystal cell. This is confirmed by FTIRanalysis. TiSi dioxide composite with Ti molar fraction of 13.1% is mainly in the form of amorphous based on XRDanalysis, which reveals that TiSi dioxide composite is uniform in structure. Furthermore, extra Ti element presents on the surface layer of TiSi dioxide composite examined by Raman and EESanalysis. Owning to these two characters, TiSi dioxide composite prepared by peptizinggelation method becomes a good catalyst in the field of catalysis.
    Effect on the Property of the Photoinduced Carrier Transport of CdS as Sensitizer for TiO2Nanoparticulate Thin Films
    QIAN Xin-Ming, SONG Qing, BAI Yu-Bai, LI Tie-Jin, TANG Xin-Yi, DONG Shao-Jun, WANG Er-Kang
    2000, 21(2):  295-297. 
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    The TiO2nanoparticle thin films have been sensitized in situ with CdSnanoparticles. The SPSmeasurement showed that large surface state density was present on the TiO2nanoparticles and the surface state can be efficiently decreased by sensitization as well as selecting suitable heat treatment. Both the photocurrent response and the charge recombination kinetics in TiO2thin films were strongly influenced by trapping/detrapping of surface states. The slow photocurrent response of TiO2nanoparticulate thin films upon the illumination was attributed to the trap saturation effects. The semiconductor sensitization made the slow photoresponse disappeared and the steadystate photocurrent value increased drastically, which suggested that the sensitization of TiO2thin films with CdScould get a better charge separation and provide a simple alternative to minimize the effect of surface state on the photocurrent response.
    Hexaaluminate Oxides LaMAl11O19-δCatalyzing CO2Reforming of Methane to Synthesis Gas
    XU Zhan-Lin, CUI Xiang-Hao, BI Ying-Li, ZHEN Kai-Ji
    2000, 21(2):  298-300. 
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    In this paper, a series of hexaaluminate oxides, LaMAl11O19-δ(M=Fe, Co, Ni, Mn and Cu), were prepared using transition metals Mto substitute Al in the hexaaluminate lattices. XRDanalyses indicated that the series of hexaaluminates had almost the same magnetoplumbite crystal structure, however, they exhibted different reducibility and catalytic activities for CO2reforming of methane to synthesis gas. Among the LaMAl11O19-δ samples, LaNiAl11O19-δ showed the best catalytic activity for the reaction at 1053 Kfor 2 h, the conversion of CH4and CO2was 98.8% and 97.6%, respectively, and the catalytic activities of rest Msubstituted catalysts were extremely lower than that of LaNiAl11O19-δ . The sequence of affection on catalytic activity of transition metal Mfor the topic reaction was Ni>>Co>Fe> Mn> Cu.
    The Pervaporation Properties of the Interpenetrating Network Membrane of Poly(vinyl alcohol) and Poly(vinyl pyrrolidone)(Ⅱ)
    ZHOU Ji-Qing, YE Yun-Fen, HU Xiao-Hua, PING Zheng-Hua
    2000, 21(2):  301-305. 
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    Anovel interpenetrating network(IPN) membrane of PVA/PVPcrosslinked by chemical crosslinking agent glutaraldehyde and water soluble photocrosslinking agent 4,4′diazostilbene2,2′disulfonic acid disodium salt(DAS) was prepared and the membrane performance in dehydration of some organic solvent by pervaporation as a function of IPNcomposition was investigated. It was found that the IPNmembrane possesses better separation properties compared with noncrosslinking blend. For a majority of organic solvents, the permeation increases with the increasing of PVPcontent in IPNwhile the selectivity to water decreases. In case of THF, both the selectivity and the permeation flux of IPNmembrane are obviously better than that of PVAmembrane, no matter what the PVPcontent is in IPNmembrane. The tension test showed that the mechanical properties of IPNare also remarkably improved.
    Coordination Structure and Higher Order Structure of Cu(Ⅱ)-Silk Fibroin Protein(Bombyx Mori) Complexes
    CHEN Wen-Xing, SHEN Zhi-Quan, LIU Guan-Feng, SHIRAI Hirofusa
    2000, 21(2):  306-310. 
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    The copper(Ⅱ) complexes of silk fibroin protein of Bombyx mori are prepared by homogeneous and heterogeneous phase coordination reaction at different pHvalues, and their coordination structures and aggregated structures are investigated by means of spectroscopy, electron spin resonance(ESR) and X-ray diffraction(XRD) measurements. Under the basic condition (pH=10.60), one type of complex is formed which contains four nitrogens from peptide main chain at the corners of a square in which the copper(Ⅱ) occupies the center, and while under the acid condition(pH=4.30, 5.88), other complex is obtained, which is mainly formed by the carboxyl of peptide side or end groups binding copper(Ⅱ) as Cu(Ⅱ)· (-COO-) (H2O)3and Cu(Ⅱ)(-COO-)2.The higher order structures of Cu(Ⅱ)-silk fibroin protein complexes prepared under various conditions are also discussed and described.
    Investigation of the Electrocatalytic Effect of Polyaniline on the Redox Reaction of 2,5-Dimercapto-1,3,4-thiadiazole by Cyclic Voltammetry
    YU Lei, WANG Xian-Hong, LI Ji, JING Xia-Bin, WANG Fo-Song
    2000, 21(2):  311-314. 
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    Electrochemical polymerized polyaniline(PAn) film electrode was used to investigate the electrocatalytic effect of PAn on the electrochemical redox reaction of 2,5-dimercapto-1,3,4-thiadiazole(DMcT). PAn film electrode was electrochemically treated or immersed in DMcTsolution before it was scanned in1.0 mol/L HCl electrolyte. The cyclic voltammograms of PAn film electrode in1.0 mol/L HCl solution changed with the above treatment, implying the electrocatalytic effect of PAn on the redox reaction of DMcT. The formation of electron-donor-acceptor adducts through the interaction between thiol or disulfide groups of DMcTand amine or imine groups of PAn during the treatment was probably the reason of the catalysis. The electrochemical properties of the adduct were different from those of PAn and DMcT. The adduct possessed a higher electrochemical activity and a better electrochemical reversibility than DMcTor PAn used alone.
    The Synthesis of Phenyl-capped Trianiline and Teraaniline by A Modified-pseudo-high Dilution Technique and Their UV-Vis Spectral Studies
    GAO Jun-Bo, LI Ke, SUN Hui, YU You-Hai, WANG Ce WU Zhong-Wen, ZHANG Wan-Jin, JI Yi-Ping
    2000, 21(2):  315-320. 
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    Phenylcapped trianiline and tetraaniline in the leucoemeraldine oxidation state were synthesized through a modified-pseudo-high-dilution technique. The chemical oxidation process of these compounds were studied by UV-Vi s spectra. It was found that phenyl-capped trianiline in the leucoemeraldine oxidation state was oxidized to its EBform and then decomposed. Phenyl-capped tetraaniline was oxidized to its EBform and then to the pernigraniline oxidation state.
    The Dissolution Mechanism of Polyelectrolyte Complex in Surfactant Aqueous Solution
    LUO Hao, ZHENG Xiao-Liang, CAO Wei-Xiao
    2000, 21(2):  321-323. 
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    Polyelectrolyte complex formed from diazoresin(DR) as cationic polyelectrolyte and alkaline hydrolysate of styrenemaleic anhydride copolymer(PSMNa) as anionic polyelectrolyte does not dissolve in water or organic solvents due to its ionic crosslinking structure. It was found that the solubility of this complex was greatly enhanced in aqueous solution of sodium dodecyl sulfate(SDS). The solubility of DR-PSMNa complex in0.1 mol/Land 0.15 mol/L SDSaqueous solution was determined to be 0.024 g/mLand 0.033 g/mLrespectively. It was also confirmed that the complex from DR and SDS, which does not dissolve in water, can also dissolve in SDSaqueous solution. The decomposition temperature(Td) of diazonium groups for different complexes was determined by DSCand shows that the Tdof DR-PSMNa after dissolution in SDSaqueous solution changes to 146 ℃ from the original value of 133 ℃. It was proposed that during the dissolution of PECin surfactant aqueous solution, the complex is separated to its two components via the interaction between PECand surfactant molecules at first, then the components dissolve in water.
    Atom Transfer Radical Polymerization of Vinyl Monomers in the Presence of1,4-Bis(α-chloroacetyloy)benzene/CuCl/bipyridyl
    DONG Jian-Hua, TAO Zhi-Qiang
    2000, 21(2):  324-326. 
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    Anew kind of initiation systems of "Atom Transfer Radical Polymerization" (ATRP) for vinyl monomers is presented. The 1,4-bis(α-chloroacetyloxy)benzene has been prepared by typical esterification. The vinyl monomers such as styrene can undergo radical polymerization via ATRPmechanism in the presence of the initiators as titled. It has been observed that the molecular weight of polymer increases in linear proportion with monomer conversion to polymers and the polymerization is controllable. The enlargement of molecular weight of polystyrene formed by ATRPcan be achieved via second round polymerizations of styrene monomers and the initiators. Prelimenary experiments on the block copolymerization of styrene methyl acrylate or butyl acrylate in the presence of polystyrene with chloro end groups obtained via ATRPhave been successfully performed.
    Effects of the Hydrophilic Composition PEG Content in the Emulsifier Molecules on Phase Inversion Process
    ZHU Yan, YANG Zhen-Zhong, ZHAO De-Lu
    2000, 21(2):  327-329. 
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    The effects of emulsifier molecular architecture on phase inversion process including the critical water content at phase inversion point as well as the particle size are investigated. It is found that the water content at phase inversion point reaches a maximum when the molar ratio of the hydrophilic component PEG10000 to the hydrophobic component bisphenol Aepoxy resin E20 is equal to 1:1, meanwhile, the particle size reaches a minimum (about 100 nm). From the experimental results, it can be seen that to alter the molecular architecture of the emulsifier is an effective method to control the size of the waterborne particles prepared by phase inversion emulsification technique.
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