Table of Content

24 April 2004, Volume 25 Issue 4

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Articles

Preparation of Lead Nanowires and Nanoparticles by Solution-based Method

XU Jian, LI Ya-Dong

2004, 25(4):  595-597. 

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A solution-based method was developed to obtain Pb nanowires in diameters of 70—120 nm and lengths up to~40 μm. Pb nanoparticles in diameter of 10—100 nm were also received under specific conditions. The products were characterized by XRD, SEM, and TEM. Based on the morphology and size evolution of products as varying reaction temperature, reactant concentration, as well as reaction time, the growth mechanism for Pb nanowires was suggested. Different reductants, such as diethyl glycol and hydrazine hydrate, were also compared.

Synthesis, Characterization and Electrochemistry Behavior of a Lower-symmetrical Alkylthioporphyrazine

LIU Yong-Zhou, WANG Hai-Chuan, PENG Zheng-He, ZHAN Hui, ZHOU Yun-Hong

2004, 25(4):  598-602. 

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A lower symmetrical alkylthioporphyrazine, 2,3,7,8,12,13-hexakis(methylthio)-17,18-mono(dithiin)porphyrazine, [H₂Pz(dtn)(mt)₆] , and their derivatives MPz(dtn)(mt)₆ [M=Cu, Zn, Co] were prepared and characterized by the methods of elemental analysis, mass spectra, ¹H NMR, IR and UV-Vis spectra. The electrochemical behavior of H₂Pz(dtn)(mt)₆ was studied in DMF solution with the method of CV. The results show that the electron transfer is quasi-one-electron chemical-electronic transfer process. The modification on the cathode materials MnO₂ in lithium ion battery was studied. The results shows that the initial charging and discharging capacity as well as the cyclic number are all increased.

Preparation, Characterization, Structure and Formation Mechanism of a Novel Layered Structural Nanosilicate Magadiite Host

PENG Shu-Ge, GAO Qiu-Ming

2004, 25(4):  603-606. 

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Stable layered structural silicate nanocomposites of TBAOH intercalated magadiite were obtained successfully by intercalation reaction methods. XRD, FTIR, SEM and HRTEM were used to characterize the structures of these nanocomposites. The XRD results and the approximate calculation of the interlayer distances show that a novel kind of structure with bilayer TBA⁺ ion intercalated magadiite was formed, further proved by HRTEM image and FTIR spectra. SEM image shows that the particle sizes exfoliated by TBAOH are about 10—100 nm. The reassembly of particles on the glass were also found after the solution evaporated. The self-assembly process of magadiite nanosheets was described on the basis of HRTEM analyses. These nanocomposites of layered magadiite are the potentional candidates of hosts of 2-dimensional host-guest nanocomposites and functional nanomaterials with open frameworks.

Synthesis of Nano-SnO₂ Through Pyrolysis Method and Its Gas Sensitivity Property

SHI Juan, WU Shi-Hua, ZHANG Shou-Min, HUANG Wei-Ping, WANG Shu-Rong

2004, 25(4):  607-609. 

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Nanosized SnO₂ powders were synthesized by using the direct pyrolysis means from SnC₂O₄ .The specimens were characterized by TEM, XRD, TG-DTA, FTIR and BET. TEM and XRD showed that the SnO₂ crystallines were less than 8 nm in diameter together with a narrow particle size distribution. BET showed that the surface area of SnO₂ was 115.2 m₂/g. FTIR spectra revealed that the absorptions of Sn—O and —OH bonds in SnO₂ ultrafine powders were red-shifted and broadened. According to the curve of TG-DTA, SnC₂O₄ transformed into SnO₂ completely after being calcined at 250 ℃. Further gas sensing experiments testified that the response and recovery times to C₂H₅OH were shorter than those obtained by the conventional precipitation method.

A Microfluidic Chip for Absorbance Measurements with Long Optical Path-length Based on a Liquid-core Waveguide Technique

DU Wen-Bin, FANG Qun, FANG Zhao-Lun

2004, 25(4):  610-613. 

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In this work, a system for high sensitivity absorbance measurements on microfluidic chips was developed with a detection volume of 240 nL. Long optical path-length(1.7 cm effective path length) was achieved on the chip by using an integrated liquid core waveguide(LCW) silica capillary coated with Teflon AF. The performance of the system was tested by using o-phenanthroline-Fe(Ⅱ) complex as a model sample with spectrophotometric detection, achieving a detection limit of 8 nmol/L for the complex. The absorbance of samples ranging from 0.03—50 μmol/L is linear(R 2=0.999 4) and showed good repeatability with a RSD of 0.8%(n=5). The sensitivity of the chip-LCW system was a factor of 1.7 higher than conventional spectrophotometry using a 1 cm cell. The present system can be applied in continous flow or flow injection analysis systems.

A Biosensor Based on Immobilizing Horseradish Peroxidase on SiO₂ Nanoparticles

ZHANG Juan, XU Jing-Juan, CHEN Hong-Yuan

2004, 25(4):  614-617. 

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Horseradish peroxidase(HRP) was immobilized on SiO₂(about 60 nm) nanoparticles. In this experiment, HRP can remain a higher bioactivity with the Michealis-Menten constant of 7.8 μmol/L . By means of catechol mediator in the solution, HRP/SiO₂ modified electrode displayed an excellent electrocatalytical response linearly to the reduction of H₂O₂ in the concentration range of 1.7×10^-7 —1.9×10^-5mol/L. The detection limit was 8.3×10^-8mol/L. The time for steady-state current reaching 95% is less than 10 s.

Capillary Electrophoresis On-line Coupled with Atomic Fluorescence Spectrometry and Its Application for Speciation Analysis

YIN Xue-Bo, JIANG Yan, YAN Xiu-Ping, HE Xi-Wen

2004, 25(4):  618-621. 

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The low cost, easy operation and high sensitivity of hydride generation atomic fluorescence spectrometer(HG-AFS) make it attractive as an on-line element-specific detector of capillary electrophoresis(CE) for speciation of hydride-forming elements. A few important practical aspects for the on-line coupling of CE to AFS are critically discussed. These include adaptation of conventional atomic fluorescence spectrometer for CE, design of an efficient interface, gas-liquid separator and AFS atomizer, and elimination of the effect of backpressure on CE separation. The application of the developed CE-HG-AFS for the speciation analysis of arsenic in water and urine samples is highlighted.

Applications of the Periphery of Projection in Studies of the Quantitative Structure-activity Relationship of Nitrobenzenes

ZHANG Qing-You, QI Yu-Hua, WANG Jun, LUO Cao-Cao, XU Lu

2004, 25(4):  622-626. 

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In this paper, the periphery of projection of a molecule is described based on three-dimensional projection, and the new invariable was used for quantitative structure-activity relationship studies. Much better results were obtained, if Am indexes, indicated index and quantum-chemical parameters were combined with the new index. If on the new parameter, periphery of projection of a molecule, the correlation coefficient is 0.939; whereas the correlation coefficient is 0.954 because the addition of the new index. Artificial neural networks were performed to predict the toxicity of nitrobenzenes, and the satisfactory result, the correlation coefficient of 0.986, were achieved.

Influence of Auxiliary Electrode on Nanoliter Electrospray

XU Xue-Jiao, ZHAI Jian-Jun, SHUI Wen-Qing, XU Guo-Bin, YANG Peng-Yuan

2004, 25(4):  627-629. 

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An auxiliary electrode was used to improve the electric field distribution between the nESI emitter and the MS sampler. The results show an improvement in the ratio of signal to noise for nanoliter electrospray using a home-made nanoliter electrospray tip, evaluated by spraying a 25 pg/μL reserpine solution. In addition, the average ratios of signal to noise of reserpine acquired within 30 min at different concentrations were compared with those obtained with an auxiliary electrode. The experimental results suggest that an auxiliary electrode could dramatically improve the ratio of signal to noise and provide confident trends for future application of auxiliary electrode in nanoliter electrospray.

Spectroscopic and Electrochemical Studies on the Interaction Between DNAand the Product of the Enzyme-catalyzed Reaction of OAP-H₂O₂-HRP

ZHANG Shu-Sheng, NIU Shu-Yan, MA Li-Bo, JIAO Kui

2004, 25(4):  630-632. 

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The pure product of 2-aminophenoxazine-3-one was prepared by enzyme-catalyzed reaction and analyzed. The electrochemical behaviour of 2-aminophenoxazine-3-one on a glass carbon electrode was investigated. The interaction between DNA and 2-aminophenoxazine-3-one was investigated by cyclic voltammetry and UV-Vis spectroscopy. The peak potential of 2-aminophenoxazine-3-one in pH 6.8 phosphate buffer solution in the presence of DNA shifts positively, indicating that the bind of 2-aminophenoxazine-3-one with DNA is intercalation action. The influence of reacting time was also studied. The binding ratio of the complex of DNA and 2-aminophenoxazine-3-one at room temperature is calculated to be 1∶1, and the binding constant is to be 6.60×10⁴L/mol.

Studies on Highly Selective Thiocyanate Electrode Based on Bisbebzoin-semi-triethylenetetraamine Binuclear Cobalt Complex as Neutral Carriers

WANG Xiu-Ling, YUAN Ruo, XU Lan, CHAI Ya-Qin, SUN Zhi-Yong , HUANG Xiao-Jing, LI Qun-Fang, ZHAO Qin

2004, 25(4):  633-635. 

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A new highly selective thiocyanate PVC membrane electrode based on bisbebzoin-semitriethylenetetraamine binuclear cobalt(Ⅱ) metallic complex [Co(Ⅱ)₂-BBSTA] as neutral carrier is reported, which displays an anti-Hofmeister selectivity sequence. The electrode exhibits Nernstian potential linear range to thiocyanate from 1.0×10^-1 to 1.0×10^-6mol/L with a detection limit 8.0×10^-7mol/L and a slope of -52.0 mV/dec in phosphorate buffer solution of pH=5.0 at 25 ℃. The response mechanism is discussed in view of the a.c. impedance technique and the UV spectroscopy technique. The electrode based on binuclear cobalt(Ⅱ) compound was used to determine the thiocyanate content in waste water with satisfactory results.

Direct Electrochemistry of Cytochrome c at Nanoporous AluminaTemplates Modified Electrodes

QIN Yu-Hua, ZHOU Li-Heng, WANG Sheng-Tian, XU Hong-Ding, LI Jing-Hong

2004, 25(4):  636-637. 

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Electrochemical behavior of cytochrome c at a bis(4-pyridyl)disulphide modified gold electrodes covered with nanoporous alumina templates was investigated. The experimental results show that the nanoporous alumina templates promote further the direct electron transfer of cytochrome c on the modified gold electrode, resulting in a well-defined fast votammetric response.

Analysis of Vitamin B₆ Derivatives in Biological Samples with High Performance Liquid Chromatography

ZHANG Jian-Yun, HUANG Long-Quan, HAYAKAWA Takashi, TSUGE Haruhito

2004, 25(4):  638-640. 

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For the determination of vitamin B₆ derivatives, a high performance liquid chromatography(HPLC) system composed of a single reversed-phase octadecylsilane column and fluorescence detector with an isocratic elution was proposed. This HPLC system perfectly analyzed pyridoxine, pyridoxal, pyridoxamine, pyridoxine 5′-phosphate and pyridoxamine 5′-phosphate together with pyridoxic acid in biological samples. In this method, relatively low fluorescence intensity of pyridoxal 5′-phasphate was improved by converting it to pyridoxic 5′-phosphate with KCN. The analytical procedure is very simple and economical, it is a useful tool for studying vitamin B₆ in animal body.

Synthesis, Characterization and Crystal Structure of (Z)-1-Triphenylstannyl-3-p-chlorophenyl-1-butene-3-ol and Their Arylhalostannyl Derivatives

ZHU Dong-Sheng, LI Xing-Qi, MEI Ze-Min, L� Chun-Sheng, MU Ying

2004, 25(4):  641-645. 

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(Z)-1-Triphenylstannyl-3-p-chlorophenyl-1-butene-3-ol(1) was synthesized by the additive reaction of 3-p-chlorophenyl-1-butyne-3-ol with triphenyltin hydride. The phenyl groups in compound 1 were substituted by ICl, Br₂ or I₂ to yield mono- and dihalide derivatives(2—8). Compounds 1—8 were characterized by elemental analysis, ¹H NMR and FTIR spectroscopy. The crystal structures of compounds 1, 3 and 5 were determined by single crystal X-ray diffraction analysis. Sn atom in compound 1 exhibits a distorted tetrahedral structure due to a weak intramolecular interaction between Sn and the hydroxyl O atoms (0.281 and 0.283 nm), while the Sn atom in 3 and 5 adopts a trigonal bipyramidal geometry with a significant Sn1←O interaction [0.240 1(6) nm in 3 and 0.238 4(7) nm in 5]. The Lewis acidities of the Sn atoms are in the following order: PhSnX₂>Ph₂SnX>Ph₃Sn.

Studies on Ionic Organotin Compounds(Ⅱ)──The Reaction of Trialkyltin Chloride and Triphenyltin Hydroxide withMercaptoacetic Acid in the Presence of Organic Bases

SUN Li-Juan, SONG Xue-Qing, CHEN Jian-Xin, ZHONG Gui-Yun, XIE Qing-Lan

2004, 25(4):  646-650. 

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The study of ionic tin compounds is current attention owing to their diversified molecular structure and wide range of application. Three kinds of ionic organotin compounds were obtained by the reaction of trialkyltin chloride and triphenyltin hydroxide with mercaptoacetic acid in the presence of organic bases. When Ph 3SnCl was treated with HSCH₂COOH, a novel complex [Ph₂ClSn (μ²-SCH₂COO) ][R₃NH] was formed with the cleavage of Ph—Sn and the dephenylation mechanism was proposed and approved by Ph 3SnOH treated with HSCH₂COOH. All of the products were characterized by elemental analysis and ¹H, ¹³C, ¹¹⁹Sn NMR. Antitumor activities of some compounds were tested for Bel-7402 and KB. The results show that the activities of compound B are better than compound A.

Asymmetric Aminohydroxylation of Olefins Catalyzed by 1,4-Bis(9-O-quininyl)phthalazine-OsO₄ Complex

CHENG Si-Kun, KUANG Yong-Qing, LU Li-Hua, LI Xiao-Ye, ZHANG Sheng-Yong

2004, 25(4):  651-653. 

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Five olefins were aminohydroxylated enantiomerically catalyzed by 1,4-bis(9-O-quininyl)phthalazine-OsO₄ complex in the presence of benzyl N-chlorocarbamate(oxidant and nitrogen source). Excellent enantioselectivity(85%—99% e.e.) as well as specific regio and chemoselectivity were observed and isolated yield of the products 48%—68% was achieved. The results are comparable to those of the best catalyst reported for AA reaction.

Intake Transportation Function of Ginkgo-imitatedFungicide of 2-Allyl Phenol

ZHANG Long, LIU Xi-Li, LI Jian-Qiang, MENG Zhao-Li, QU Bao-Han, ZHANG Wen-Hua

2004, 25(4):  654-658. 

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The high performance liquid chromatography(HPLC) was applied to investigate the intake and distributional mechanism of 2-allyl phenol in wheat seedling. With a treatment level of 2-allyl phenol at 500 μg/mL, the intake reached 389.67 μg per gram of plant tissue in 72 h(standard deviation, SD= 9.5 ). In comparison with carbofuran(a typical intake reagent) as well as thiram(a typical non-intake reagent), it is for the first time found that 2-allyl phenol could be intaken into wheat seedling. It was transported in a high speed from the root to the top of the seedling. The accumulation levels of 2-allyl phenol in stem(Y₁) and leaves(Y₂) were positively correlated with treatment time(X) in linear relationships of Y₁=2.9586X+44.217 and Y₂=1.6281X-4.4412, respectively. The corresponding coefficients of determination(r²) were 0.848 6 and 0.859 1, respectively. 2-Allyl phenol was distributed in whole seedling at 72 h after the treatment. The accumulation levels at root, stem, and leaves were 99.70(SD=10.58), 243.8(SD=19.87), and 137.37(SD=12.44) μg per gram of plant tissue, respectively. CCCP, temperature, the properties of amino acid and sucrose, as well as the pH of solvents significantly affected the intake of 2-allyl phenol by wheat seedling, indicating that wheat tends to intake and transport 2-allyl phenol actively.

Synthesis, Structure and Photochemical Properties of Cyclobutanes Containing Four Different Aryl Groups

ZHUANG Jun-Peng, ZHANG Wen-Qin

2004, 25(4):  659-662. 

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Four cyclobutane derivatives, rctt-1-(2-benzoxazolyl)-2-(4-chlorophenyl)-3-(4-pyridinyl) -4-phenylcyclobutane, rctt-1-(2-benzoxazolyl)-2-phenyl-3-(4-pyridinyl)-4-(4-chlorophenyl)cyclo-butane, rctt-1-(2-benzoxazolyl)-2-(4-chlorophenyl)-3-[2-(5-phenyloxazolyl)]-4-phenylcyclobutane and rctt-1-(2-benzoxazolyl)-2-phenyl-3-[2-(5-phenyloxazolyl)]-4-(4-chlorophenyl)cyclobutane, containing four different aryl groups, were synthesized by the cross-photodimerization reactions of different heteroarylethene monomers in sulfuric acid solution upon the irradiation of medium-pressure mercury lamp. Three photodimers were detected in the reaction, two of them were the photodimer of the monomer itself and the other was the cross-photodimer. The photolysis of the cross-photodimer upon the irradiation of low-pressure mercury lamp was carried out in dilute methanol solution and the reactions were traced by UV and HPLC. It was found that the cross-photodimer photolysized into trans-monomers at first, which were then converted to cis-monomers by trans-cis isomerization.

Synthesis and Bioactivity of Pyridine Containing 1,3,4-Oxadiazole Derivatives

FAN Zhi-Jin, LIU Bin, LIU Xiu-Feng, ZHONG Bin, LIU Chang-Ling, LI Zheng-Ming

2004, 25(4):  663-666. 

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1,3,4-Oxadiazole containing heterocyclic compounds and pyridine containing compounds are associated with diverse biological activities of antiinflammation, antibacter and pesticide bioactivity. In order to find leading compound with an excellent fungicide activity, a series of 5-(pyridin-3′-yl- or 4′-yl-)-1,3,4 oxadiazole-2-thioacetamides were designed and synthesized according to the biological isosterism by introducing pyridine and 1,3,4-oxadiazole moiety and thioacetamide group in one molecule. The target compounds were synthesized by reaction of N-substituted chloroacetamide with 2-mercapto-5-(pyridin-3′-yl- or 4′-yl-)-1,3,4-oxadiazole which was prepared by the reaction of CS₂ and 3-pyridinoyl or 4-pyridinoyl. The structures of all compounds synthesized were determined by ¹H NMR , IR, MS and elemental analysis. Bioasscay indicated that, all compounds synthesized had no fungicidal activity, some compounds such as B1-6 possessed satisfactory activity of growth inhibition against Echinochloa crusgalli and Brassica napus. Pot examination of soil treatment revealed that, fresh weight inhibition of compound B1-4 and B1-6 against Brassica napus was not obvious, however, Brassica napus had distinct symptom of phototoxicity, leaf curl and marginal scorch were observed.

Reaction of 3-Thioformylindolizine(Thioaldehyde) with 1,2-and 1,4-Dimethylpyridinium Iodides

LIU Wei-Wei, OU Song, WANG Bing-Xiang, HU Hong-Wen

2004, 25(4):  667-672. 

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A series of 3-thioformylindolizines(thioaldehydes)were synthesized from 3-unsubstituted indolizines by the modified Vilsmeier reaction. The condensation reaction of these thioaldehydes with 1,2- and 1,4-dimethylpyridinium iodides in methanol solution in the presence of piperidine was investigated in detail, and the corresponding dimethine-cyanines dyes containing the indolizine ring were synthesized in excellent yields. The structures of them were established on the basis of their elemental analysis, IR, ¹H NMR and MS data. The fluorescence properties of these new compounds were studied in the solid state, and the results show that all of them have strong emission in the region above 400 nm, and may have potential application as luminescent materials.

Preparation of 2-(1,2-Ethylene/1,3-Propylenedithio)methylene-3-oxo-butyryl Chloride and Their Acylation Reaction with Arenes

YU Hai-Feng, XIAO You-Ping, LIU Qun, CHI Ying-Nan, ZHANG Qian

2004, 25(4):  673-675. 

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As the α-elaboration strategy of the versatile α-oxo ketenedithioacetals, 2-(1,2-ethylene/1,3-propylenedithio)methylene-3-oxo-butyryl chlorides(3) were prepared via the sequential base-catalyzed hydrolysis of ethyl 2-(1,2-ethylene/1,3-propylenedithio)methylene-3-oxo- butyrate (1) and followed chlorination by sulfur oxychloride. 2-(1,2-Ethylene/1,3-propylenedithio)methylene-1-aryl- butane -1,3-diones(4) were synthesized by the Friedel-Crafts acylation of selected arenes with compound 3.

Quantum Chemical Studies of Absorption and Emission SpectrocopicProperties for Oglimeric Fluorenes and Its Derivatives

WANG Ji-Fen, FENG Ji-Kang, REN Ai-Min, LIU Xiao-Dong, MA Yu-Guang

2004, 25(4):  676-680. 

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We have fully optimized the structures of the oligomers of (PF)_2n and (PFDBO)_n (n=1—4) using DFT/B3LYP method and calculated their P_I(v,a), E_A(v,a), E_HP , E_EP . The absorption spectra data were calculated at ZINDO and TD-DFT levels of theory. We analyzed the rules to the variation of their HOMO-LUMO energy gap with n rising and how the energy gap reflected the spectral properties of the oligomers to deduce the spectral properties of their polymers. We optimized the S₁ excited geometries and studied the emission spectra. Moreover, in the excited geometries all the framework atoms in a molecule are apt to coplanar. Above all, the dramatically twisted segment of seven-membered-ring in PFDBO(dihedral angel between it′s two phenyl ring is 42.5°±0.5°), because of CH₂OCH₂ caused the conjugated backbone broken. So the energy gap of it is broader, which makes in the max absorption and emission wavelengths of PFDBO shorter than PF′s.

Theoretical Study on Mechanism of Cycloaddition Reaction Between Difluorovinylidene and Formaldehyde

LU Xiu-Hui, WU Wei-Rong, BU Yu-Xiang, LIU Cheng-Bu

2004, 25(4):  681-684. 

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The mechanism of cycloaddition between singlet difluoro-vinylidene and formaldehyde was investigated with MP2/6-31G^* method, including geometry optimization, vibrational analysis, and energetics for the involved stationary points on the potential energy surface. The results show that the title reaction has two major channels. The first one brings about a three-membered ring product(P1) via a, b and c paths, of which c is the leading path that consists of two steps: (Ⅰ) an intermediate (INT1c) is formed between difluoro vinylidene and formaldehyde through a free barrier exothermic reaction of 219.18 kJ/mol; (Ⅱ) the intermediate then isomerizes to a product, difluoro-methylene ethane oxide, with an energy barrier of 134.71 kJ/mol. The reaction path of channel 2 consists of three steps: (Ⅰ) an energy-rich intermediate (INT1b) is firstly formed between difluoro-vinylidene and formaldehyde through a free barrier exothermic reaction of 142.77 kJ/mol; (Ⅱ) the intermediate(INT1b) then isomerizes to the other one intermediate(INT2), with an energy barrier of 22.31 kJ/mol; (Ⅲ) the intermediate(INT2) isomerizes to one 4-membered ring products (P2), with an energy barrier of 11.98 kJ/mol.

Theoretical Studies on Kinetics Reaction for the Reaction ofNCS Radical and NO

Liu Peng-Jun, PAN Xiu-Mei, ZHAO Min, SUN Hao, SU Zhong-Min, WANG Rong-Shun

2004, 25(4):  685-688. 

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DFT-B3LYP was used to calculate the geometries of reactants, intermediates, transition states and products for NCS + NO reaction on the 6-31+G^* level. The transition states and intermediates of the reaction were verified by frequency analysis. The intrinsic reaction coordinate(IRC) calculations at the same level were also carried out to check the connection between all the critical structures located on the potential energy surface. Single point energies were calculated on the CCSD(T)/6-311+G^* level. The energy barriers, rate constants and thermodynamic quantities of the reaction were also calculated. The results show that the reaction system of the title reaction involves four paths, producing OCS+N₂(1), CS+N₂O(2), NS+OCN(3) and ONCNS(4) products, respectively. The NCS+NOOCS+N₂ is the dominant reaction path.

Theoretical Studies on the Intermediate Complex Mechanism ofthe Energy Transfer Reaction of O(¹D)+CO₂(¹∑_g⁺)→O(³P)+CO₂(¹∑_g⁺)

YANG Guang-Hui, ZHANG Xin, MENG Qing-Tian, HAN Ke-Li, SUN Chia-Chong

2004, 25(4):  689-692. 

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The reaction mechanism of spin-forbidden energy transfer reaction O(¹D)+CO₂(¹∑_g⁺)→O(³P)+CO₂(¹∑_g⁺) was investigated by ab initio quantum chemistry methods. The conical intersection of the two surfaces of CO₃ intermediate complex with multipl-spin electronic states was searched by using CASSCF(6,8) /6-311G^* method. The intermediate complex channel are supported by the calculations of spin-orbit coupling and transition probability.

Systematic-dynamical Analysis of Pt Electrode BZ Reaction System

WEI Guo-Ying, JIANG Wen, LUO Jiu-Li

2004, 25(4):  693-696. 

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A Pt electrode is usually used as a probe to observe and measure the dynamic behavior of the classical BZ reaction. Due to the coupling of electrode process with pure BZ reaction, a special kind of electrochemical oscillatory system arises. It is no doubt that the quantitative study of the dynamic behavior of electrode BZ reaction system will be helpful to qualify the accuracy and reliability of the detection of pure BZ reaction monitored by an electrode. Therefore, this work will be of great theoretical and practical value. In this article, the systematic-dynamical analysis of a Pt electrode BZ reaction system has been established on the basis of FKN mechanism and Oregonator Model. Under certain conditions, the coupled system of high dimensions involving six variables is reduced to a three-variable dynamical system. Furthermore, by means of linear stability analysis of three-variable system, regimes of dynamic behavior in bulk phase and in electrode reaction phase have been calculated numerically, respectively. Meanwhile, electrochemical oscillations in the electrode reaction phase have been simulated numerically. It is shown that when the bulk phase keeps to be a homogeneous steady state, the electrode reaction phase can enter the oscillatory regime by changing the externally controlled parameters of this coupled system. It turns out that the dynamical behavior of the two subsystems is not always synchronous.

Studies on the Relaxivities of Novel MRI Contrast Agents──Two Water-soluble Derivatives of Gd@C₈₂

LU Xing, XU Jian-Xun, SHI Zu-Jin, SUN Bao-Yun, GU Zhen-Nan, LIU Hong-Dong, HAN Hong-Bin

2004, 25(4):  697-700. 

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The water proton relaxivities of two water-soluble derivatives of Gd@C₈₂ [Gd@C₈₂ (OH)₂₂ and Gd@C₈₂ (OH)₆(NHCH₂CH₂SO₃H)₈] were determined to be r₁=42.3 mmol^-1 ·L·s^-1 , r₂=90.9 mmol^-1 ·L·s^-1 ; r₁=4.5 mmol^-1 ·L·s^-1 , r₂=8.9 mmol^-1 ·L·s^-1 , respectively at (37±1) ℃ by a 1.5 T spin-echo method. The relaxation mechanism was discussed and the reason why the relaxivities of Gd@C₈₂ (OH)₂₂ is an order of magnitude higher than that of Gd@C₈₂ (OH)₆ (NHCH₂CH₂SO₃H)₈ were explained.

Influence of Cation Distribution of ZnFe₂O₄ on Its Catalytic Activityof Phenol Hydroxylation with H₂O₂

LIU Qing-Sheng, YU Jian-Feng, YANG Piao-Ping, WANG Zhen-Lü, YANG Xu-Wei, WU Tong-Hao

2004, 25(4):  701-704. 

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The spinel ferrite exhibits a good catalytic performance in phenol hydroxylation by H₂O₂ to dihydroxybenzene. ZnFe₂O₄ was synthesized by co-precipitation and hydrothermal methods. The catalysts were characterized by means of Mossbauer spectroscopy, XRD and ESR techniques.The results of Mssbauer spectra, XRD and ESR all indicate that ZnFe₂O₄ synthesized from hydrothermal processing is the normal spinel structure, while ZnFe₂O₄ synthesized from co-precipitation method is partly inverse spinel with a substantial displacement of Fe³⁺ cations to A sites and Zn²⁺ cations into B sites of the cubic close-packed anionic sublattice. We found that the distribution of cations on tetrahedral and octahedral sites in zinc ferrites was different between the catalysts prepared by hydrothermal and co-precipitation methods, and the catalytic activity was influenced by the distribution of cations.

Adsorption Sites And Adsorption States for Hydrogen Atom on Ru(1121) Stepped Surface

WANG Ze-Xin, PANG Xue-Hui, ZHANG Xiao-Ming

2004, 25(4):  705-709. 

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Using the five-parameters Morse potential theory about the interaction between an atom and the surface cluster(shortened form 5-MP),the H- Ru(1121) stepped surface adsorption system was studied. At the same time , the 2H- Ru(1121) system and the interaction between the surface adsorption states were researched by means of the extended LEPS potential theory. The theoretical data indicate that there are four kinds of different surface adsorption states that are 3-fold adsorption states. In the meantime, there are two kinds of inner adsorption states, which have direct diffused channels. The theoritical analysis proclaims that α state is the strong repulsion adsorption state which interacts deeply with the inner adsorption states, β state is the weak repulsion adsorption states and γ state is the surface adsorption states which doesn′t interplay with the inner adsorption states. The presumption that the α state has assigned to the 4-fold adsorption state by Fan et al. according to their experimental result doesn′t obtain the support of our theoretical data.

Electrooxidation of Bromide Anion at a PbO₂ Electrode

WANG Hai-Tao, ZHANG Heng-Bin, CAO Xue-Jing, YU Jian-Guo

2004, 25(4):  710-712. 

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By determination of the polarization curves and the current efficiency, the electrolytic conditions and the reaction mechanism of the anodic oxidation of Br^- at a PbO₂ electrode were explored. It is indicated that the electrooxidation of Br^- is a first order reaction and the apparent activation energy is 8.53—8.81 kJ/mol in the potential range of 1.16—1.26 V. The current efficiency of Br^- oxidation at a PbO₂ electrode does not change basically with the change of pH values in the pH range of 2.0—10.2, decreases slightly with increasing temperature, and increases with increasing the concentration of bromide anion, but when the concentration of bromide anion increases up to a certain extent, the current efficiency keeps fixed.

Studies on Relationship Between Structure and Antioxidant ActivityUsing Eigen Value Method

KONG De-Xin, JIANG Tao, YAN Zuo-Wei, GUAN Hua-Shi

2004, 25(4):  713-716. 

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Antioxidants are of great interest because of their involvement in important biological and industrial process. It′s meaningful to study the quantative structure-activity relationship (QSAR) and design novel, efficient, low-toxicity antioxidant. In this article, using eigen values (EVA) method, the QSAR of a group of antioxidants was firstly studied. Without any experimental parameters, we got a QSAR model that is as good as the one reported earlier. Moreover, it′s the first time to use EVA method to study the relationship between the structure and antioxidant activity. And also we believe that EVA will be an efficient approach to study the relationship of QSAR of antioxidants.

Hydroformylation of 1-Dodecene Catalyzed by Water Soluble Rhodium-Phos-phine Complexes in Micellar System with Cationic Gemini Surfactant

LI Min, XU Bin, CHEN Hua, HE Yu-E, HUANG Xue-Yuan, LI Li-Bo, LI Yao-Zhong, LI Xian-Jun

2004, 25(4):  717-720. 

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The promotion of 1,2-bis(dimethylcetyl ammonium bromide) ethane[G(Et)] cationic gemini surfactant for the hydroformylation of 1-dodecene in the oil/water biphasic catalytic system is reported. The critical micelle concentration(cmc) and solubilization of laurylbenzene in G(Et) solution were determined. The cmc of G(Et) was 3.8×10^-5 mol/L, which was much lower than that 9.6×10^-4 mol/L of CTAB. The influences of the concentration of G(Et) and the stirring rate on 1-dodecene hydroformylation were studied. The results show that in the biphasic system containing the catalyst RhCl(CO)(TPPTS)₂ and TPPTS[TPPTS=tris(sodium-m-sulfonatophenyl) phosphine], the hydroformylation of 1-dodecene in the presence of gemini surfactant G(Et) occured with a higher turn over frequency(TOF=1 066 h^-1 ) and higher selectivity for normal aldehyde[n(normal)/n(iso)=5.7] than that using conventional monomeric surfactant CTAB[TOF=901 h^-1 , n(normal)/n(iso)=3.7]. The phenomena could be attributed to that G(Et) has a lower cmc and could form more compact and spherocylindrical micelle in the solution. The lower cmc and good surface tension reduction ability of G(Et) would be favorable for decreasing phase transfer energy barrier of 1-dodecene from the core of micelle to the interface of two phases where 1-dodecene coordinated with rhodium catalysts, and thereby the reaction rates was accelerated greatly. The more compact structure of the spherocylindrical micelle of G(Et) would be favorable for the formation of linear aldehyde.

Hydrolysis of COS over Rare Earth Oxysulfides

ZHANG Yi-Qun, XIAO Zhong-Bin, MA Jian-Xin , ZHOU Wei, WU Min-Zhong

2004, 25(4):  721-724. 

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The hydrolysis of carbonyl sulfide was studied over a novel type of rare earth oxysulfides catalyst. The order of catalytic activity of the rare earth oxysulfides was in the sequence: La≈Pr≈ Nd≈ Sm>Eu>Ce>Gd≈Ho>Dy>Er. The analysis of XRD reveals that the catalytic activity could be well related to the easiness of the sulfidation from their oxides to the corresponding oxysulfides and the rare earth oxysulfide is the active phase for the hydrolysis of COS. The effect of the presence of O₂ or SO₂ in the feed was investigated over La₂O₂S and Nd₂O₂S, respectively. At the O₂ volume fraction below 1.5% there was not any effect on the COS conversion and at 2% a COS conversion of higher than 90% was obtained at temperature over 150 ℃. The catalytic activity of COS hydrolysis decreased in the presence of SO₂ at a temperature below 300 ℃. The poisoning effect of SO₂ was reversible and may be caused by the competitive adsorption between SO₂ and COS on the surface of rare earth oxysulfides.

Studies on Cefazolin Salt Inhibitor and Its Inhibiting Mechanism

ZHAO Di-Shun, LIU Hui-Ru, XU Zhi-Ce, PANG Deng-Jia, WANG Chun-Fang

2004, 25(4):  725-728. 

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A new type of inhibitor was selected on the basis of the study of cefazolin salt inhibitor in zinc-manganese battery. The polarization curves of the inhibitor were measured. The experimental results show that this new inhibitor has an efficient inhibiting effect, which in creases with its concentr-ation. The inhibiting mechanism was studied through the impedance curve and cycle volt-ampere curve. The results show that the inhibiting effect is mainly due to the physical absorption.

Effects of Electrolyte Composition on the Electrochemical Properties of Graphitized Mesocarbon Microbeads

ZHENG Hong-He, ZHUO Ke-Lei, WANG Jian-Ji, XU Zhong-Yu

2004, 25(4):  729-732. 

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Coal-tar pitch based mesocarbon microbeads, graphitized at the maximum heat treatment temperature of 2 800 ℃, were employed as the negative electrode materials in lithium ion batteries. Electrochemical performances of the graphitized mesocarbon microbeads(MCMBs) in different electrolyte systems were examined. Chemical composition and relative content of surface electrode inhibition(SEI) film formed on the carbon electrode was determined. The influences of co-solvents on the SEI formation, composition and the film texture were discussed. The results show that, the SEI film consists mainly of the reduction products of EC molecules in EC-based electrolytes despite a certain difference exists in the onset of the SEI formation potential. The texture of SEI film is a deciding factor on the compatibilities of the electrolytes with the carbon electrode in lithium ion batteries.

A Study of Loaded Photocatalysts with Precious Metal on the Photocatalytic Hydrolysis Reaction of Propyne(Ⅲ)

ZHANG Jin-Long, Masakazu Anpo

2004, 25(4):  733-736. 

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Three different loaded methods were used to prepare photocatalysts with different precious metals. Their photocatalytic reactivities and selectivities were measured by XPS spectra. It was found from the experimental results that the precious metals existing on TiO₂ photocatalysts could promote of hydrogenation reaction in photocatalytic hydrolysis of propyne, and made the yield of propene product increasing. Among the titanium oxides loaded with Pt, Ru, Rh, Pd and Ag, the photocatalyst loaded with Pd had the highest photocatalytic reactivities under UV light(λ>270 nm) irradiation. The photocatalytic reactivities are closely related to the oxidation state of precious metals and it is necessary to make the valence of precious metals be reduced to 0 valence for increasing photcatalytic reactivities.

Preparation and Catalytic Properties of Tetra-n-butylphosphonium Hydroxide(TBPH)

WU Tong-Hao, YANG Xu-Wei, YANG Hong-Mao, JIANG Yu-Zi

2004, 25(4):  737-739. 

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Quaternary phosphonium hydroxide(TBPH) is a very effective catalyst for rearrangement polymerization of organosloxanes. Such as octamethylcyclotetrasiloxane, may be polymerized to a linear dimethylsiloxane polymer by TBPH. In this paper it was found that this kind of catalysts exhibited a stronger basicity than quaternary ammonium hydroxides for a transient reaction. Methyltetramer polymerized at 90—100 ℃ with about 0.01% of the silanolate of TBPH. TBPH was synthesized and applied in the production of smell-less silicone oil.

Preface

Thermodynamic Studies on a New Type of Carboxamide Metal Complexes

GAO Dong-Zhao, GUO Yan-He, ZHU Shou-Rong, LIN Hua-Kuan, XU Xin-He

2004, 25(4):  740-742. 

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N,N-Bis(2-pyridylmethyl)-amine-N-ethyl-2-pyridine-2-carboxamide was synthesized and characterized according to the literature. At 25 ℃, I=0.1 mol/L KNO₃, the stability constants of the binary system formed by the ligand with metal ions in ethanol aqueous solution were studied by pH potentiometric titration and the appropriate structures with respect to the titration species were proposed. The results show that the stability order of divalent metals binding to the ligand is Co<Ni>Cu<Zn which does not conform to the order of the Irving-Williams series. Then the abnormal property of copper complex is discussed.

Articles

Characterizations of Photovoltaic Devices Based on Novel Acceptors of Perylenetetracarboxylates

YANG Mu-Jie, LU Sheng-Li

2004, 25(4):  743-745. 

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The perylenetetracarboxylates were used as electron acceptors and electron transport materials in the preparation of plastic solar cells for the first time. Bulk heterojunction photovoltaic devices were fabricated with conjugated polymer of poly(3-hexyl thiophene) (P3HT) as the donor and perylenetetracarboxylates as the acceptors. Their photovoltaic performance parameters were measured. It is found that the open circuit voltage of the device is closely related to the acceptor strength of perylenetetracarboxylate acceptors.

Mathematical Model of Dispersion System Consisting of Oil, Water and Surfactant

WANG Hai-Bo, LIU De-Shan, LI Yan-Mei

2004, 25(4):  746-748. 

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After the careful analysis on the factors affecting the emulsification of the dispersion system consisting of oil, water and surfactant, and investigation on the mechanism for the formation of emulsions, a mathematical model to be used in the emulsification was derived finally. By comparing the results of experiments with the results concluded from the mathematical model, it was found that the model was reasonable and useful in the investigation of emulsifications.

Grafting and Coating of Collagen Type Ⅰ on Poly-L-lactic Acid (PLLA) Membrane Surface to Enhance the Growth of Chondrocytes

MA Zu-Wei, GAO Chang-You, GONG Yi-Hong, SHEN Jia-Cong

2004, 25(4):  749-752. 

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Stable type Ⅰ collagen layer was formed on PLLA membrane surface by using the grafting-coating method. First, polymethacrylic acid (PMAA) was grafted on the PLLA membrane to yield carboxyl groups on the PLLA surface. Then, water-soluble carbodiimide was used as condensing agent to catalyze the reaction between the carboxyl groups and the amino groups to graft the collagen covalently on the PLLA-g-PMAA surface. Meanwhile, the collagen solution physically coated on the PLLA membrane surface was preserved to form coated collagen layer. XPS spectroscopy was used to verify the occurrence of the grafting reaction. The density of the carboxyl groups on the PLLA-g-PMAA surface was determined by colorimetric method. The surface density of the collagen coated on the PLLA surface was determined by ninhydrin method. The stability of the collagen layer was studied by incubating the collagen-coated membrane in phosphate buffer saline (PBS, pH=7.4). The surface density of the collagen decreased very slightly after the incubation, indicating the good stability of the coated collagen layer. The cell culture results showed that the growth rate of chondrocytes increased significantly on the collagen-coated PLLA membrane compared with that under the control. On the control of PLLA membrane, the cells were round shaped and easy to accumulate with each other, while on the collagen-coated PLLA membrane, the cells were spread out and evenly distributed. In conclusion, using grafting-coating method, stable collagen layer can be produced on the hydrophobic PLLA surface to improve the cytocompatibility obviously.

Preparation of Polymer Spherical Symmetry GRIN Microsphereby SDC and Controlling Its Gradient Index Distribution

XIA Ru, ZHANG Yu-Chuan, YI You-Min, DONG Liang-Wei, SHI Shi-Wei

2004, 25(4):  753-756. 

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A polymer spherical GRIN sphere lens was prepared by the suspension-diffusion-copolymerization(SDC) technique by using MMA as monomer M₁ and 3FEA as M₂. The radial distribution of refractive index of the lens was measured by the shearing interference method, which demonstrated that the quadratic refractive-index distribution was formed in the sphere lens, and its Δn=0.019.

Chemical Mechanism of the Anti-hyperlipoidenmia Effect of Water-soluble Chitosan(Ⅰ)──Capacities of Water-soluble Chitosan and Its Derivativesto Bind Taurocholate and Glycocholate as Bile Salts

WU Yan, WANG Yi-Nong, MA Jian-Biao

2004, 25(4):  757-761. 

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Chitosan in a range of molecular weight has the anti-hyperlipoidenmia effect owing to its ability to bind bile salt in gastrointestinal tract. Water-soluble chitosan with molecular weight of 8 000 was prepared and reacted with diethylaminoethyl chloride and dimethylamino(1-methyl)ethyl chloride to afford diethylaminoethyl chitosan(DEAE-chitosan) and dimethylaminoisopropyl chitosan(DMAIP-chitosan) respectively. DEAE-chitosan was methylated with methyl iodide to give the ammonium-containing chitosan(DEMAE-chitosan). The binding capacities of the water-soluble chitosan and its derivatives to taurocholate and glycocholate as bile salts were investigated in vitro. Through changing the factors of bile salts concentration, medium pH value, deacetylation degrees of the soluble chitosan and so on the influence of the binding capacity was studied on soluble chitosan to bile salts. The results indicated that the binding capacity of the soluble chitosan to bile salts was mainly depended on its cationic structure. The taurocholate binding capacities of chitosan, DEAE-chitosan at an initial taurocholate concentration of 10 mmol/L are 2\^04 and 2.83 mmol/g. The binding capacities are increased about 40% by the latter. The glycocholate binding capacities of chitosan, DEMAE-chitosan at an initial glycocholate concentration of 10 mmol/L are 1.65 and 3.34 mmol/g. The results indicated that the introduction of amino or ammonium groups onto chitosan could increase the binding capacity to bile salts.

Preparation of Uniform-sized Molecularly Imprinted PolymerMicrospheres Using N-Cbz-L-Trp as Template

GUO Tian-Ying, ZHANG Li-Ying, HAO Guang-Jie, SONG Mou-Dao, ZHANG Bang-Hua

2004, 25(4):  762-765. 

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Uniform-sized molecularly imprinted polymer microspheres were prepared by using N-benzyloxycarbonyl-L-tryptophane(N-Cbz-L-Trp) as the template via a multi-step swelling and suspension polymerization method in which 2-vinylpyridine(2-VP) was used as the functional monomer and diethylene glycol diacrylate(DEGDA) was used as the cross-linker. The surfaces of nonporous micropheres were rough. The average diameter of polymer micropheres was 6.3 μm, and its distribution coeffiene was 1.03. It was found that the baseline chiral separation of the template enantiomer was achieved on a shorter column. Moreover, the removing of the template molecule and the thermal stability of MIP micropheres were also discussed.

High Resolution Transmission Electron Microscopy Studies onNano-sized Crystals of Polyethylene and Polypropylene

CHEN Jian-Feng, YIN Li, ZHOU Yun-Chun, ZHOU En-Le

2004, 25(4):  766-769. 

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When polymer crystallized from its dilute solution, the formation of small crystallites is difficult because of the balance between the favorable energy decrease as the more stable crystal formed and the unfavorable interface energy increasing with the forming of crystallites, thus the crystallites smaller than a minimum critical size are unstable and will be disappear or grow to larger size crystals. In this paper, High Resolution Transmission Electron Microscopy(HRTEM) technology was used in the study of polyethylene(PE) and polypropylene(PP) nano-sized crystals obtained from their dilute solution of xylene. The results showed that the molecular packing in these crystals was far from perfect one. There were many defects such as distortion, branches, and dislocation in the crystals. After isothermal crystallization at the temperature of 413 K, the crystallinity was improved greatly. All these proved that the high resolution transmission electron microscopy technique was very powerful in the study on polymer crystal at the level of molecules, and the nano-sized crystals were another stable crystal state of PE and PP.

Preface

Synthesis and Characterization of 8-Hydroxy Quinoline Chemically Modified Macromolecule Chitosan and Its Ferrous Complex

LANG Hui-Yun, ZHANG Xiu-Jun, WEI Yong-Feng

2004, 25(4):  770-773. 

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In order to enhance biologic applicability of medicament and to reduce their medicial toxicity, chitosans ramification was derived from chitosan and 8-hydroxy quinoline through covalently binding between amido in chitosan and 5-chloromethyl-8-quinolinol hydrochloride, and its complex of ferrous were synthesized. Their compositions and structures were characterized by elementary analysis, IR spctra, UV-Vis spectra, fluorescence spectrophotometry and thermal analysis. It was found that the coordination was realized through binding of N, O in 8-hydroxy quinoline with the Fe(Ⅱ) in the ferrous complex. The optimizing coordination condition of ferrous complex that the reaction was carried out under stirring at 40 ℃ and pH=4 for 8 h. The sorption isotherm and sorption kinetics of CTS-HQ for ferrous ions were investigated and the results were satisfied with the Langmuir-single-molecule-layer adsorption mechanism. The apparent adsorption velocity constant K is 1.474 J/mg and the saturated sorption capacity Q is 86.96 mg/g at 293.15 K.

Articles

Studies on Acrylate Thermoplastic Elastomer with Latex Interpenetrating Polymer Network Structure

DONG Han-Peng, LI Xiao-Yu

2004, 25(4):  774-777. 

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The conditions of the multistage emulsion polymerization were investigated. The structure of the latex particles obtained under different polymerization conditions was observed by using TEM. An inverse core-shell structure was generated when 75% light crosslinked xPEA combines with 25% xPSt or xPSAN, whereas a pure core-shell structure was formed when xPEA was heavily crosslinked. DSC analysis showed that the two polymers formed IPN. The relationship between the mechanical properties and the interpenetrating networks was discussed based on the recombination model of the domains. The role of the recombination of the domains was investigated. The optimum values of TEGDA in the xPEA and DVB in the xPSt are 0.5% and 0.15%, respectively.

Preface

Nonisothermal Melt Crystallization Kinetics Studies on Thio-ether-contained Poly(ether ether ketone ketone) Copolymer

ZHAO Xiao-Gang, CHEN Chun-Hai, LIU Xin-Cai, ZHANG Wan-Jin 

2004, 25(4):  778-780. 

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Nonisothermal melt crystallization kinetics of thio-ether-contained poly(ether ether ketone ketone) copolymers was studied by DSC. The result shows that the crystallization activation energy was increased accompanied by the introduction of thio-ether structure. The random copolymer possesses a higher crystallization activation energy than the block one at the same thio-ether ratio.

Articles

Electrochemical Study on Poly-3-(4-fluorophenyl)thiophene/Carbonized Polyacrylonitrile Foam Composite Electrodes

ZHANG Qing-Wu, ZHOU Xiao

2004, 25(4):  781-783. 

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The carbon foams were prepared by carbonization of polyacrylonitrile membrane with carbon paper. After modified by CO₂, the BET specific surface area of the carbon foam increased from 14.3 to 290.2 m₂/g and there are more electrical double layer capacitance than that in the unmodified carbon foams. Composite electrodes were fabricated by electrochemical polymerization of 3-(4-fluorophenyl)thiophene on carbon foams in 0.2 mol/L tetraethylammonium tetrafluoroborate in acetonitrile solution. Cyclic voltammetry of PFPT/carbon foam electrodes show that they have two type of capacitance: one is quasicapacitance originated from PFPT doping/undoping in electrolyte solution; the other is electrical double layer capacitance belonging to high specific area of the composite electrodes. The performance of electrochemical capacitors, such as energy density, would be improved by adopting this carbon foam with a high specific area as electrodes in polymerization of conducting polymers.

Preface

Synthesis, Structure and Fluorescence Properties of a Novel Two-dimensional Inorganic-organic Framework Material Zn₃(PTC)₂(H₂O)₈·4H₂O

TIAN Ge, LIU Xiu-Jie, FANG Qian-Rong, ZHU Guang-Shan, XIN Ming-Hong, SHI Xin, WU Gang, QIU Shi-Lun

2004, 25(4):  784-786. 

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A novel two-dimensional coordination polymer Zn₃(PTC)₂(H₂O)₈·4H₂O was formed by Zn(CH _{3,/sub>COO)2·2H2O and 2-pyridine-1,3,5-tricarboxylate(H3PTC) under the hydrothermal condition at 417 K and characterized by fluorescence. The crystal structure of the compound was determined by single-crystal X-ray diffraction analyses. The six-coordinated Zinc(Ⅱ) center displays an octahedral geometry . The crystal is monoclinic and space group is P2(1)/c with a=0.722 70(14) nm, b= 1.866 7(4) nm , c=1.072 6(3) nm, α=90°, β=103.198(19)°, γ=90°, V=1.408 7(6) nm³, Z=4, Dc= 2.474 Mg/m³, Mr=828.536, μ=3.099 mm^-1 , F(000)=1 060, GOF=0.892, R=0.061 3, wR= 0.133 9 .}

Articles

Novel pH and Ionic Strength-sensitive Vesicles Composed of Alkyl Phosphates with 2-Hydroxy-3-chloropropyl or Epoxy Propyl on Their Membrane Surface

SONG Xi-Ming, ZHANG Guo-Lin, WU Qiu-Hua, LIU Feng-Qi, TIAN Peng, LIU Zhen-Rong, ZHANG Xiang-Dong, ZHANG Feng, WANG Jun, LIU Qi-Tao

2004, 25(4):  787-789. 

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Amphiphilic alkyl (dodecyl and hexadecyl)-2-hydroxy-3-chloropropyl phosphates (C₁₂ - and C₁₆ -AHCP) were synthesized, and then alkyl glycidyl phosphates (C₁₂ - and C₁₆ -AGP) were quantitatively obtained by the treatment of AHCP with NaOH in order to prepare a novel vesicle which has reactive and polymerizable epoxy group on its membrane surface. The bilayer vesicles were formed by ultrasonication of aqueous dispersion of C₁₆ -AHCP or C₁₆ -AGP, but the vesicles composed of C₁₂ -AHCP and C₁₂ -AGP were not obtained by the same treatment. Both of C₁₆ -AHCP and C₁₆ -AGP bilayer vesicles are only stable at pH₅—10 or the ionic strength below 0.15. The gel-filtration chromatography and the UV-Vis absorption spectroscopic studies on Co(Ⅱ) tetrakis(propyloxycarbonyl)phthalocyanine as a lipophilic probe indicated that the phthalocyanine was effectively incorporated into the C₁₆ -AHCP bilayer membranes and predominantly present in a monomeric state in the membranes, which is much different from its leading diameric state in SDS micelle and ethanol.

Synthesis and Thermal Properties of Emulsion Copolymers ofN-p-Tolylmaleimide, Methyl Methacrylate and Acrylonitrile

YANG Li-Ting, WU Wei-Hong, GAO Jun-Gang

2004, 25(4):  790-792. 

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Terpolymers of N-p-tolylmaleimide(NPTMI), methyl methacrylate(MMA) and acrylonitrile(AN) were synthesized by emulsion polymerization. The thermal properties of the terpolymers were investigated by torsional braid analysis, differential scanning calorimetry, thermogravimetric analysis and vicat softening point tester. The results showed that the glass transition temperature(T_g) and vicat softening point of the terpolymers increased with the increase of NPTMI content but decreased with the increase of AN content. The initial decomposition temperature(T₀) and the half weight-loss temperature(T₅₀) increased both with increasing NPTMI and AN content. The weight and number average molecular weights were also determined by gel permeation chromatography. The results showed that there was a maximum value at mass ratio 10∶85∶5 of NPTMI/MMA/AN.