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Table of Content

    24 July 2003, Volume 24 Issue 7
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    Preface
    Synthesis of Water-soluble Metalloporphyrins and Their Inhibiting Action on the Growth Metabolism of E. coli
    WANG Lei, ZHU Xun-Jin, FU Shi-Tao, LI Zao-Ying
    2003, 24(7):  1145-1149. 
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    Based on 5,10,15,20-(4′-pyridyl)porphyrin, a series of water soluble metalloporphyrins were synthesized. An LKB-2277 Thermal Activity Monitor was used to monitor the cell metabolic activity in vitro to produce thermogenesis curves. The growth rate constants k, maximum heat production rates Pmax and peak time of growth thermogenic curves t of E. coli in different metalloporphyrins at different mass concentrations were deduced from these thermogenesis curves. Metalloporphyrins 1a, 1b and 2a-2c showed an inhibiting action on the growth metabolism of E. coli, with 2c as the best one.
    Studies on Cluster-cracking Method for Synthesizing Dithiolate Complexes
    YAN Ze-Min, WANG Xin, BIAN Guo-Qing, DAI Jie, ZHU Qin-Yu, FAN Jian-Fen
    2003, 24(7):  1150-1153. 
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    Mononuclear complexes (Bu4N)2 [Cd(mnt)2], (Bu4N)2 [M(dmit)2](M=Cd, Zn) and binuclear complex (Me4N)2 [Zn2(Sph)2(S2TTF(SCH2)2)2] were synthesized by cluster-cracking reaction from precursors 2 [M4(SPh)10] and 4 [S4M10(SPh) 16](M=Cd, Zn). The net charge on mercapto sulfurs of these dithiolate ligands was calculated by the methods of quantum chemistry PM3 and resulted in the order: mnt 2->SPh ->dmit 2-> [(MeS)2TTFS2]2-≈ [(CH2S)2TTFS2]2-. Based on these theoretical and experimental results, the relationship between the charge on mercapto sulfurs and the reaction products was discussed.
    Preparation of Highly Pure Nano-sized t-BN Coating Al2O3 and ZrO2 Composite Powders by a Low-temperature Chemical Reaction
    LI Yong-Li, QIAO Guan-Jun, JIN Zhi-Hao
    2003, 24(7):  1154-1157. 
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    Al2O3 and m-ZrO2 powders with nanometers turbostratic-BN(t-BN) coating were prepared through chemical reaction in nitrogen with boric acid and urea as B source and N source, respectively. t-BN was obtained at 650 ℃ and turned into h-BN by heating the nanocomposite powder at 1 600 ℃ in argon. After being calcined in air at 450 ℃ for 5 h, the semi-finished compounds containing CH2 and CN groups in the reaction products decomposed and the powders were purified. The yield of BN in the composite powders is more than 99%.
    Synthesis, Photoluminescence and Electroluminescence of Beryllium(Ⅱ) Complex with 2-Naphthalene-substituted Oxadiazole
    WANG Guang, WANG Li-Xiang, JING Xia-Bin, WANG Fo-Song
    2003, 24(7):  1158-1160. 
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    A novel beryllium(Ⅱ) complex with 2-naphthalene-substituted oxadiazole was synthesized and its photoluminescent spectra(PL) and absorbance spectra were investigated. Double layer organic lighting diodes(OLEDs), ITO/NPB(80 nm)/complex A(80 nm)/Mg:Ag, were fabricated by using this complex as the emitting layer. Blue electroluminescence(EL) was observed, indicating that this complex was a good candidate as electroluminescence emitting materials.
    Synthesis, Crystal Structure and Magnetic Properties of Ni(Ⅱ) Complex with a New Thiazole-substituted Nitronyl Nitroxide
    WANG Li-Ya , YANG He-Ping, LIAO Dai-Zheng, JIANG Zong-Hui, YAN Shi-Ping
    2003, 24(7):  1161-1162. 
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    A new nickl(Ⅱ) complex containing the thiazole-substituted nitroxide radical with the formula Ni(NIT2-thz)2Cl2(NIT2-thz=4,4,5,5-tetramethyl-2-(2′-thiazole)imidazolin-1-oxyl-3-oxide) was synthesized and its crystal structure was determined. The magnetic property analysis indicates that there is strong antiferromagnetic interactions between Ni(Ⅱ) and radical(J=-71.82cm-1).
    Synthesis of Aligned Carbon Nanotubes on Ni Substrate at Low Temperature
    WANG Sheng-Gao, WANG Jian-Hua, WANG Chuan-Xin, MAN Wei-Dong, MA Zhi-Bin, ZHANG Bao-Hua
    2003, 24(7):  1163-1165. 
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    In this paper, under the catalytic effect of nickel particles electro-deposited on Ni substrate, self-aligned carbon nanotubes were synthesized by microwave plasma chemical vapor deposition with a mixture of methane and hydrogen gases at 510 ℃. During the process of nanotubes growth, the total pressure in the chamber was kept at 3 kPa, the microwave plasma input power was 500 W, and the flow rates of H2 and CH4 were 50 and 1 mL/min, respectively. The aligned features and hollow structure have been verified by scanning electron and transmission electron microscopic images. As the nanotubes grow, the nickel cap remains on the tip of the carbon nanotubes. The nanotubes′diameter is about 70 nm and they have bamboo structures. Because of the strong etching ability of hydrogen plasma and the low volume ratio of H2/CH4, no carbonaceous particles attached to the carbon nanotubes were found. It demonstrats that MWPCVD is a very efficient process for the synthesis of the aligned carbon nanotubes at a low temperature. The aligned CNTs grown on Ni substrate at such a low temperature are suitable for device fabrication.
    Hydrothermal Synthesis and Structure Characterization of a New Four-capped Metal-oxygen Cluster [NiMo12O40H10{Ni(H2O)3}4]
    SU Chang, XU Ji-Qing, ZENG Qing-Xin, CUI Xiao-Bing, LI Chuan-Bi, ZHANG Li-Juan
    2003, 24(7):  1166-1168. 
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    A Hydrothermal reaction of MoO3, NiCl2·6H2O, WO3 and H2O with a molar ratio of 1:0.6:1:83.3 gives a rhombic-shaped black crystal [NiMo12O40H10{Ni(H2O)3}4]. It crystallizes in a tetragonal system with space group I41/amd and unit cell parameters a=b=1.518 4(2) nm, c=3.082 9(6) nm, Z=4, V=7.108(2) nm3, R=0.067 1, wR=0.217 8. The compound possesses a four-capped Keggin structure. The structure of the Keggin-[NiMo12O40H10]8- consists of twelve MoO6 octahedrons and a NiO4 tetrahedron on the center. Four [Ni(H2O)3]2+ at the cap positions are linked to Keggin-structure by three μ 3-O, respectively. The calculation of bond valence shows that the oxidation state of Mo in the compound is +5.
    Size-controlled Synthesis of Silicalite-1 Nanocrystals
    YIN Shuang-Feng, XU Bo-Qing
    2003, 24(7):  1169-1171. 
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    With careful control of the amount of tetrapropylammonium hydroxide(TPAOH) template, nanocrystals of Silicalite-1 zeolite with different morphologies and crystal sizes(80-600 nm) were obtained by hydrothermal synthesis in the presence of isopropanol. This seems to be the first example for the size-controlled synthesis of Silicalite-1 zeolite.
    Synthesis of CdS Nanorods with Chiral Template
    XUE Peng-Chong, LU Ran, Jin Ming, ZHANG Tie-Rui, SU Li-Hong, ZHAO Ying-Ying
    2003, 24(7):  1172-1174. 
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    In the paper, two kinds of CdS nanorods with diameter of 50-150 nm were synthesized by using amphiphilic alanine as the templating reagent. XRD, TEM and polarized light microscopy were used to examine the course of CdS growth. The nanorod with a hexagonal pore microstructure was fabricated when the mesophase exhibited hexagonal morphology of the polarized light microscopy image. The XRD pattern of the nanorods with hexagonal pore microstructure showed a clear peak in 2H=0.88° which suggested the existence of hexagonal pore. While the mesophase disappeared and isotropic polarized light microscopy image shows that CdS would propagate into nanorod without hexagonal pore. It was deduced that nanorods with hexagonal pore grow in the hole of hexagonal liquid crystal and those CdS growth without hexagonal pore are in isotropic solution by the absorption of amphilphilic alanine. It was suggested that different nanostructures could be generated under various chemical micro-environments to reveal their special functionalities.
    Preparation of Molecularly Imprinted Microspheres Against Acidic Indometacin and Its Chromatographic Characterization by Aqueous Micro-suspension Polymerization
    LAI Jia-Ping, LU Chun-Yang, HE Xi-Wen
    2003, 24(7):  1175-1179. 
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    The molecularly imprinted microspheres(MIMs) for high performance liquid chromatography were synthesized by aqueous micro-suspension polymerization. The acidic indometacin, one of the antidepressants, was used as the template and basic 4-vinylpyridine was used as functional monomer. The influences of pH of mobile phase on the capacity factor(k′), separation factor(α) and selection factor(β) of indometacin were investigated in detail. All the results showed that the MIMs exhibited specific recognition and affinity to indometacin only in pH<4.0 eluent; and the specific recognition of MIMs was lost gradually in pH>4.0 eluent. By comparing the retention behavior of indometacin and 4-aminopyridine (4-AP) on the MIMs column, it proved that the recognition of MIMs to indomeatcin synthesized by 4-vinylpyridine as a cross-linker mainly relied on the ion-pair interaction between the nitrogen atom on the pyridine ring and the carboxyl on the indometacin, and the π-π interaction between the pyridine ring and the template molecule. This was just contrary to that MIMs synthesized by methacrylic acid as the cross-linker.
    Fabrication of the Microfluidic Chips with Integrated Ultra-micro Electrodes and Its Application in On-chip Electrochemical Detection
    JIN Ya, LUO Guo-An
    2003, 24(7):  1180-1184. 
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    Microfluidic glass chips with integrated ultra-micro electrodes were fabricated. In pattern EC-1, a 13-μm-wide platinum electrode was located photolithographically at the end of separation channel and extended 30 μm into the 6 mm wide detection reservoir. The electrode system and separation voltage were optimized, and neurotransmitters were detected after electrophoretic separation. In pattern EC-2, a 7-μm-wide platinum electrode with a battlement-like membrane structure were integrated in the chips. With post-etching procedure, the membrane width was reduced to 10 μm. With good electric conductivity and heat dissipation capability, the porous membrane successfully shields the high electric field before the ultra-micro electrode, which shows great possibility to apply in the on-chip electrochemical detection.
    An Optical Biosensor Based on Surface Plasmon Resonance for Determination of Human Cardiac Troponin I
    SONG Da-Qian, LIU Xia, ZHAO Li-Wei, ZHANG Han-Qi, WEI Jing-Yan, MU Ying, LUO Gui-Min
    2003, 24(7):  1185-1188. 
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    A novel optical biosensor based on simultaneous multi-wavelength detection surface plasmon resonance(SPR) was developed for diagnosing acute myocardial infaction. The sensor was designed on the basis of fixing the angle of incidence and measuring the reflected intensities in the wavelength range of 400-800 nm. The SPR spectra are shown in terms of reflected light intensity verus wavelength of incident light. The intensity of the reflected light is the minimum at the resonant wavelength. On the sensing element of a right angle the glass prism is a thin(50 nm) metallic gold film coated by vacuum-deposition. Molecular self-assembling in solution is used to form the sensing membrane on the gold substrate. Human cardiac troponin I was determined in the concentration range of 5.0-50 μg/L. Under the selected experimental conditions, the sensor has a good sensitivity, repeatability, reversibility and selectivity.
    Separation, Purification and Structural Analysis of Polysaccharides from Aloe
    YAN Ji-Chang, CUI Chun-Yue, ZHANG Yi, CHU Ren-He
    2003, 24(7):  1189-1192. 
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    Two kinds of acid polysaccharides, PSA1 and PSA2, were extracted by hot water, precipated by ethanol with different concentrations from Aloe barbadensis miller, deproteinized by enzymolysis and Sevag method. Each of them was shown to be a single homogeneous component by paper and Sephadex column chromatography. TLC analysis of the acid hydrolyzed product and GC/MS analysis of the acetylized product show that PSA1 is composed of D-mannose and D-glucose in a molar ratio of about 1.3:1, and PSA2 is composed of D-mannose, which was confirmed by IR and 1HNMR techniques as the partially acetylized polymannose. Hakomori methylation, Periodic acid oxidation and Smith degradation of PSA1 and PSA2 show that they are all straight chain polysaccharied with more 1→4 linking, fewer 1→6 linking and few branches.
    Rapid Fabrication of Monolithic PDMS Microchips and Highly Sensitive Chemiluminescence Detection for Amino Acids
    YAN Liu-Shui, LIANG Ning, LUO Guo-An, WANG Yi-Ming, WANG Jian-Yong
    2003, 24(7):  1193-1197. 
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    A novel and facile method for the fabrication of monolithic microfluidic chips in poly dimethylsiloxane)(PDMS) has been presented. The fabrication consists of two steps including channels definition and replica molding. Two micrometeric metal wires, previously welded in the cross section on a co-plane, were spanned over a templet to define microscopic channels. PDMS is then cast against the templet. After the metal wires removed and the templet peeled away, a monolithic replica with enclosed networks of channels is obtained. Scanning electron microscopy and CCD imaging demonstrated that the cross-section of two channels was complete contact and channel inner well is smooth. A microchip capillary electrophoresis system was constructed by integrating the monolithic microchip with a chemiluminescence detection, and its performances was demonstrated by the separation and the detection of two amino acids such as arginine and aspartic acid without derivatization procedures. Excellent separation with the resolution of 2.45 within 80 s was achieved with the concentration detection limit(S/N=3) of 3.50 μmol/L for arginine.
    Enzyme-linked Fluorescence Immunoassay for Human IgG by Using a pH-Sensitive Phase Separating Polymer as Carrier
    LIN Peng, ZHENG Hong, YANG Huang-Hao, YANG Wei, ZHANG Chang-Gong, XU Jin-Gou
    2003, 24(7):  1198-1200. 
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    Poly(N-isopropylacrylamide-N,N-dimethyl aminopropyl methacrylamide) [P(NIP-DMAPM)], a novel linear water-soluble pH-sensitive polymer whose phase transition pH is about 7.4 at 37 ℃, was synthesized. P(NIP-DMAPM) polymer precipitated out of water above a critical pH 7.4 at 37 ℃ and redissolved at pH below 7.4. P(NIP-DMAPM) was used as a novel separation carrier for the reactants in immunoassay and a enzyme-linked fluorescence immunoassay for human IgG was built. The linear range of determination was 0-1700 ng/mL and the limit of detection was 2.2 ng/mL. The sensitivity of this method was close to that of traditional ELISA by using same reactants. However, the assay was much faster. This method has been applied to the determination of the human IgG levels in human serum with satisfactory results.
    Spectroscopic Characteristic of the Gold Nanoparticle-fluorescein System
    JIANG Zhi-Liang, LIU Shao-Pu, WANG Li-Sheng, QIN Ai-Miao, LIANG Hong
    2003, 24(7):  1201-1203. 
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    There are an absorption peak at 485 nm and a synchronous fluorescence peak at 510 nm for fluorescein in the medium of 3.4×10-3 mol/L tri-sodium citrate. The gold nanoparticle system exhibits a characterization resonance scattering peak at 580 nm. In the coexisting system of gold nanoparticle and fluorescein, there are a synchronous fluorescence peak at 510 nm and a resonance scattering peak at 580 nm. It has been found that the fluorescence peak may be quenched by gold nanoparticle. When the concentration of fluorescein is higher, the A470nm nm affects the I470nm of gold nanoparticle. The I470nm decreases exponentially with the concentration of fluorescein.

    Preparation and the Recognition Property of Molecular Imprinted Polymer of Bisphenol A
    ZHAO Mei-Ping, LI Yuan-Zong, ZHANG Xin-Xiang, CHANG Wen-Bao
    2003, 24(7):  1204-1206. 
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    A molecular imprinted polymer of bisphenol A(PBPA) was prepared. The eluting efficiencies of different solvent systems for eliminating the template from the P BPA were investigated. The P BPA showed specific recognition characteristics for molecules with a bisphenolic structure such as bisphenol A, 4,4-bis(4-hydroxyphenyl)valeric acid and phenolphthalein. The possibility to use bisphenol A-imprinted polymer as a solid-phase extraction material was also studied. The best binding buffer was found to be acetonitrile containing 0.05%(volume fraction) of Tween 20, and acetonitrile-ethanol solution containing 0.5%(volume fraction) diethanolamine was found to be the optimal eluting solvent.

    Quantitative Characterization of Molecular Conformation of Lysozyme with Z in Liquid Chromatography
    WANG Yan, LI Min, GONG Bo-Lin, GENG Xin-Du
    2003, 24(7):  1207-1209. 
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    Different molecular conformations, i.e., native, urea-unfolded, guanidine hydrochloride(GuHCl)-unfolded, urea-reduced-unfolded, GuHCl-reduced-unfolded, of lysozyme was systematically studied by reversed-phase liquid chromatography(RPLC), and weak-cation exchange chromatography(WCX), and the stoichiometric parameters Z in stoichiometeric displacement model(SDM). The difference of molecular conformations of lysozyme with their disulfide bonds cleaved or could not be found in RPLC and WCX in terms of retention. However, they could not be used to distinguish their reduced states from non-reduced ones. Each difference of molecular conformations of lysozyme, caused by urea and GuHCl solution, can only be characterized with Z. The definition of the degree of the unfolded was introduced to characterize the change of conformation.

    Studies on the Synthesis and Mutagenicity of 2,8-Diamino-10-hydroxy-5-methyl-5,10-dihydrophenophosphazine-10-oxide
    YIN Zhi-Gang, JIN Kun, ZHAO De-Feng, PENG Qin-Ji, Freeman H. S.
    2003, 24(7):  1210-1215. 
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    Diphenylamine and phosphorus trichloride interacted on each other at slow-elevated temperatures and then the brown solution obtained was treated with H2O, followed by oxidization to produce a phosphinic acid, viz, 10-hydroxy-5,10-dihydrophenophosphazine-10-oxide(yield 45%) which could be converted to a methyl phosphinate in yield 70% by reacting with SOCl2 and then with MeONa in MeOH. After being treated with NaH in anhydrous DMF and then heating the reaction mixture to 120 ℃, the methyl phosphinate obtained above could also be transformed into N-methyl phosphinic acid with a yield of 62%. On nitrating the new phosphinic acid with 45 equimolar amount of nitrating agent, a dinitro compound will be obtained in a yield 59%. And this dinitro compound could further be reduced to 2,8-diamino-10-hydroxy-5-methyl-5,10-dihydrophenophosphazine-10-oxide with hydrogen over 5% Pd/C. The effect of the amount of 5% Pd/C on the hydrogenation was investigated and the title compound was ultimately synthesized in a yield 70% by using the optimum amount of catalyst. All five intermediates obtained from this study were identified by NMR and mass spectroscopy. The title compound was proved to be a nonmutagenic aromatic diamine via Salmonella/mammalian microsome assay.

    Synthesis of 1,4-Bis(9-O-quininyl)phthalazine and Its Application as a Ligand to the Catalytic Asymmetric Dihydroxylation of Olefins
    SUN Xiao-Li, KUANG Yong-Qing, NAN Peng-Juan, ZHANG Sheng-Yong
    2003, 24(7):  1216-1218. 
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    An improved procedure for the preparation of 1,4-bis(9-O-quininyl) phthalazine[(QN)2PHAL] and the rudimentary application of (QN)2PHAL to the catalytic asymmetric dihydroxylation of olefins were described. (QN)2PHAL was synthesized in a good yield by the reaction of quinine with 1,4-dichlorophthalazine in the presence of K2CO3 and KOH in refluxing toluene. The asymmetric dihydroxylation of four olefins with (QN)2PHAL as the chiral ligand showed an excellent enantioselectivity and activity.

    Total Synthesis of (±)-19-Norabieta-4(18),8,11,13-tetraen-7-one
    BIE Ping-Yan, ZHANG Cheng-Lu, PENG Xuan-Jia, CHEN Bo, YANG Yi, PAN Xin-Fu
    2003, 24(7):  1219-1221. 
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    (±)-19-Norabieta-4(18),8,11,13-tetraen-7-one(8) was first synthesized starting from m-isopropylbromobenzene(1). After bromination of alcohol(2), coupling reaction of bromide(3) with Hagemann′s ester in the presence of t-BuOK and hydrolysis of compound(4) with KOH, compound (5) was obtained in a high yield. Intramolecular cyclization of coupling compound(5) with BF3·Et2O afforded a trans-fused key intermediate(6). After structural modification by Wittig reaction with Ph3P +CH3I-and oxidation with CrO2, the target molecule was obtained in a good yield.
    Studies on the Condensation Reaction of α,α-Diacetyl Ketene Dithioacetals with Arylaldehydes
    AI Lin, LIU Qun, LI Xiao-Fang, WANG Mang
    2003, 24(7):  1222-1224. 
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    The condensation reactions of α,α-diacetyl ketene dithioacetals with arylaldehydes catalyzed by sodium tert-butoxide were performed. These reactions were affected by the alkylthio groups. The deacylation-condensation products α-cinnamoyl ketene dibenzylthioacetals 4 were obtained by the reaction of α,α-diacetyl ketene dibenzylthioacetals 1 with arylaldehydes 3. α,α-Dicinnamoyl ketene cyclic dioacetals 5 was formed when the reaction was performed between α,α-diacetyl ketene cyclic dioacetals 4 and arylaldehydes 3.
    Synthesis and Herbicidal Activity of Substituted Phenyl Pyrazole Derivatives
    ZHOU Yu-Han, MIAO Wei-Rong, CHENG L-Bai, WANG Da-Xiang, BAI Zai-Su
    2003, 24(7):  1225-1230. 
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    Herbicides inhibiting protoporphyrinogen oxidase are one of the most important class of herbicides. Targeting the porphyrin pathway, these herbicides show high activity and low toxicity, and have been a hot-point of novel pesticides research. A series of novel substituted phenylpyrazole derivatives were prepared from 1′-(4-chloro-2-fluoro-5-methylphenyl)-4′,4′,4′-trifluoro-1,3-dibutanone via a ring closure reaction, methylation, chlorination, oxidization reaction and so on. The conditions of key steps were discussed. Their structures were confirmed by 1HNMR, IR, CIMS and elemental analysis. Preliminary bioassay shows that these compounds have good herbicidal activity to latifoliate weeds, and their activity is better in soil treatment than in stem and leaf treatment.
    Effect of Functional Groups on the Activity of Water-soluble β-Alanine C60Derivatives for Superoxide Anion Radical Scavenging
    SUN Tao, XU Zhu-De, JIA Zhi-Shen
    2003, 24(7):  1231-1233. 
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    Three water-soluble β-alanine C60 adducts with different addition numbers, C60(NHCH2CH2COONa) nH n(n=1,5,9), were synthesized. The products were characterized by FTIR, 1HNMR and elemental analysis. The antioxidant activity of these C60 adducts as the quencher for superoxide anion radical O2-· was evaluated by chemiluminescence in the system of pyrogallol-luminol. The results indicate that the three C60 derivatives are all excellent quencher for superoxide anion radical O2-·. The concentrations of 50% inhibition are 252, 140, 112 μmol/L respectively. This high efficiency should be attributed to many factors such as the numbers of remaining double bonds, donor effect of amino group and steric effect. However, the above results also suggest the effect of the adducted β-alanine groups is predominated in this system.
    Studies on the Dehydro-rearrangment Reaction of Eudesma-4, 11-en-3,9-diones′ Analogues with DDQ
    CHEN Jin-Chun, ZHANG Chen, ZHENG Guo-Jun, LI Yu-Lin
    2003, 24(7):  1234-1236. 
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    14-Noreudesma-4,11-dien-3,9-diones′ analogues were treated with DDQ in dioxane and afforded the rearranged aromatic products. The similar compounds to eudesma-4,11-dien-3,9-diones had no reaction. 9-Actoxy-14-noreudesma-4,11-dien-3-ones, 9-actoxy-eudesma-4,11-dien-3-ones and their analogues yielded the normal 1,2-dehydro-products. The mechanism of the rearrangement was discussed.
    Raman Spectroscopy of Titanium Dioxide Photocatalyst
    WANG Jian-Qiang, XIN Bai-Fu, YU Hai-Tao, XIE Yu-Tao, ZHAO Bing, FU Hong-Gang
    2003, 24(7):  1237-1240. 
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    Nano-size TiO2, Fe3+-TiO2, TiO2/SiO2, and Fe3+-TiO2/SiO2 were prepared by sol-gel method. The structural change of TiO2 caused by different calcining conditions, Fe3+-doped contents, and formation of film on silica were studied by FT-Raman and confocal Raman technologies. The experimental results show that the different crystalline phases were observed at different calcinating temperatures. The titanium dioxide powder heated at 350-550 ℃ for two hours forms an anatase phase. The anatase phase materials transforms to rutile phase at 600 ℃ and transits completely to rutile phase calcining for two hours at 750 ℃. After doping Fe3+, the FWHM at 144cm-1 of Fe3+-TiO2 and Fe3+-TiO2/SiO2 is broadened apparently compared with that of TiO2 and TiO2/SiO2, respectively. Some peaks of TiO2/SiO2 coating film has some shift and broadening compared with those of TiO2.
    Hydrolysis of Methyl Acetate Under Near-and Supercritical Conditions
    YUAN Pei-Qing, CHENG Zhen-Min, LIU Tao, YUAN Wei-Kang
    2003, 24(7):  1241-1245. 
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    Near-and supercritical water is an excellent medium for conducting chemical reactions, and is especially propitious to the development of environmentally benign techniques for acid/base catalyzed organic reactions. The work presented in this paper focuses on experimental investigation on noncatalytic hydrolysis for methyl acetate, trying to overcome high energy consumption and other defects of conventional ones. Hydrolysis of methyl acetate(5%) in this work was carried out in a tubular reactor under near-or supercritical conditions(523-673 K, 23-32 MPa), and characteristic of hydrolysis was investigated via combining various reaction conditions. The experimental results show that under the optimized operating condition conversion of methyl acetate achieves thermodynamic equilibrium within 150 to 300 s, the selectivity of which process closes to 1, with no acid catalyst added. Due to phase transition resulted from broad experimental range and singularity of supercritical zone, the influence of temperature and pressure on the reactivity takes on a complicated trend, transition-state theory and cluster theory were adopted to interpret experimental phenomena, also reaction kinetics was established based on SN2 mechanism. Conclusion drawn from this work indicates the promising prospect of applying near-and supercritical reaction technology to the industrial practice of hydrolysis of methyl acetate.
    Studies on Methanol-tolerant Cathode Electrocatalysts Cobalt Tetracarboxylic Phthalocyanine Supported on Carbon Black(CoPcTc/C) in Direct Methanol Fuel Cell
    LI Xu-Guang, XING Wei, LU Tian-Hong, JI Yi-Ping, LIANG Hong-Ying, SHAO Yun
    2003, 24(7):  1246-1250. 
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    The electrocatalytic performance of Pt/C and cobalt tetracarboxylic phthalocyanine supported on carbon black(CoPcTc/C) for oxygen reduction were compared. The results showed that the presence of methanol reduced seriously the electrocatalytic activities of Pt/C for the oxygen reduction, while it had no effect on that of heat-treated CoPcTc/C at 800 ℃(CoPcTc/C-800). And the electrocatalytic activity of CoPcTc/C-800 for the oxygen reduction was higher than those heat-treated at other temperatures. Therefore, CoPcTc/C-800 was a promising candidate of methanol-tolerant cathode electrocatalyst in DMFC. XPS result reveals that active site of CoPcTc/C-800 may be the composite of CoN4 and Co0.
    Research on Preparation and Properties of CNx Thin Films with High Nitrogen Content by Electrodeposition in Liquid Phase
    ZHANG Jia-Tao, CAO Chuan-Bao, Qiang, LI Chao, ZHU He-Sun
    2003, 24(7):  1251-1255. 
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    CNx thin films with a high nitrogen content were prepared on ITO conductive glass substrates by cathode electrodeposition, using dicyandiamide(C2H4N4) in acetone as the precursors. The surface morphologies of CNx thin films were observed by thermal field emission scanning electron microscopy(SEM). The size of CNx got a nanometer level, with about 80 nm minimum size. The N/C atomic ratio and bond state in the films were studied by X-ray photoelectron spectroscopy(XPS). The maximum value of the N/C atomic ratio was 1.08. Carbon and nitrogen existed mainly in the form of C-N bond, with little CN bond. Fourier transform infrared(FTIR) spectroscopy supports the existence of C-N covalent bond. Through the UV-Vis absorption phenomenon, the ultraviolet radiation(200-280 nm) could be transmitted. The electrical resistivities of the films were in the range of 1012-1016 Ω·cm.
    Structure of Phosphatidylethanolamine Liposome and Langmuir-Blodgett Films in Liquid Crystalline State
    SUN Run-Guang, ZHANG Jing
    2003, 24(7):  1256-1261. 
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    The structure of phosphatidylethanolamine in Langmuir-Blodgett films and liposome in liquid crystalline state was investigated by means of the atomic force microscope(AFM), small angle X-ray scatting(SAXS) and 31P nuclear magnetism resonance( 31P NMR). By the atomic force microscope, some large and small lipid vesicles and a coexistent structure of cubic phase and bilayer phase of PE liposome were observed. The coexistent structure of the two phases is closely related to the structure of phospholipid, concentration, medium and pH. It was found that sodium salt solutes induce the formation of an Im3m(Q229) cubic phase in DEPE dispersions. The phase transition of DEPE with the change of temperature was investigated. The Lβ→Lα transitions are at 37.5 ℃ and the Lα→HⅡ transitions are at 63.5 ℃.
    Effects of Substrate Temperature on the Chemical Structure of Diamond-like Carbon Films Deposited by High-intensity Pulsed Ion Beam Ablation
    MEI Xian-Xiu, MA Teng-Cai
    2003, 24(7):  1262-1265. 
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    Diamond-like carbon(DLC) films have been deposited on the silicon(Si) substrate at different substrate temperatures by using high-intensity pulsed-ion-beam(HIPIB) ablation with graphite as the targets. Raman and XPS spectroscopies were used to study the relationship between the chemical binding state of DLC thin films and substrate temperature. The analysis result of the XPS of the C1s core level of DLC thin films obtained at different substrate temperatures was presented. These spectra are deconvoluted into different contributions at 285.5 and 284.7 eV, which are respectively attributed to sp3 and sp2 hybridized carbon atoms. XPS spectra show when the substrate temperature is lower then 573 K, the content of sp3 carbon in the films is about 40%; when the substrate temperature is increased, the content of sp3 carbon in the films decrease; when the substrate temperature is 573 K, the transition from sp3C to sp2C occurre. Raman spectrum shows that with the increase of substrate temperatures, the G peak position shifted to the peak position of graphite the full width at half-maximum decreased from 176 to 122cm-1 and the ratio of ID/IG increased from 1.56 to 3.62. The content of sp3 carbon in the films may be related with the G peak position, the full width at half-maximum of G peak and the ratio ID/IG.
    Preparation and Properties of the Nanometer Composite Oxide TiO2-SiO2
    ZHOU Ya-Song, FAN Xiao-Hu
    2003, 24(7):  1266-1270. 
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    In this paper, the nanometer TiO2-SiO2 composite oxide, which has a higher surface area and better thermal stability, was prepared by sol-gel and supercritical CO2 fluid drying method. The effects of feed composition and calcinations temperature on the specific surface area, thermal stability and acidity of the composite oxide were examined. Through hydrodesulfurization(HDS) reactions, the feasibility of the composite oxide as the support of hydrofining catalyst was also examined. The results indicate that nanometer particles of the composite oxide were obtained. When n(Ti)/n(Si) ratio was equal to 1, the specific surface area and pore volume of the composite oxide were maximum. Compared with pure TiO2, the addition of SiO2 obviously improved the thermal stability and crystal stability of the composite oxide. The source of producing Brnsted acid sites was Ti-O-Si bonds, coming from the composite oxide. That the surface of the composite oxide was rich in Ti was conducive to improve the intensity of Lewis acid. The hydrofining catalyst supported on this composite oxide had a better HDS activity at a low temperature. The acidic characteristics of TiO2-SiO2 support has influence on the HDS activity of the catalyst.
    Molecular Recognition and "on-off" Switching of Calix[4]arenes to Monosaccharides and Pyrimidine Derivatives
    WU Shi, TENG Qi-Wen, CHEN Xiao-Fei, ZHOU Rong-Hui
    2003, 24(7):  1271-1273. 
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    The AM1 and INDO/SCI method were used to study supra-molecular complexes composed of octahydroxy calixarenes and monosaccharides and pyrimidine derivatives. It was shown that the host performs a better molecular recognition to mono-saccharides especially to the erythrose by the CH-π interaction but there is almost no π-π interaction between the host and the pyrimidine which exists in the pyrimidine derivative when H is substituted by-COOH, and the "on-off" molecular switching can be designed by this. The reason of red-shift for UV absorption peaks of the complexes compared to that of the host was discussed.
    Time-dependent Wave Packet Theoretical Study for D+HCN Reaction with SVRT Model
    MA Wan-Yong, YANG Guang-Hui, ZHOU Jian-Hua, HAN Ke-Li
    2003, 24(7):  1274-1276. 
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    Time-dependent wave packet calculation for the D+HCN reaction is carried out of employing potential energy surface with the semirigid vibrating rotor target(SVRT) model. We calculated the total reaction probabilities from the initial ground rotational-vibrational state for various values of total angular momentum J. The rate constants are obtained by using Uniform J-shifting approach. The results show that the SVRT model is a valid and reasonable model for the quantum dynamics calculations of polyatomic molecule systems. The reaction cross sections and rate constants are compared with the previous results for the isotopic reaction H+HCN on the same potential energy surface.
    Studies on Synthesis of Methyl N-Phenylcarbamate by Reaction of Aniline and Methyl Carbamate
    LI Qi-Feng, WANG Jun-Wei, DONG Wen-Sheng, WANG Xin-Kui, PENG Shao-Yi
    2003, 24(7):  1277-1280. 
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    In the presence of methanol, a new non-phosgene route for the preparation of methyl N-phenylcarbamate(MPC) was studied based on the reaction between aniline and methyl carbamate. The effects of reaction temperature, reaction time, catalyst content and the molar ratios of aniline to methyl carbamate and methanol on the reaction were studied, and the reaction mechanism over zinc chloride catalyst was proposed. Under the optimum reaction conditions, the MPC yield reached 89.90% and selectivity of MPC is 99.76%.
    n-Heptane Isomerization over Ni Doped MoOx Catalyst
    WANG Ying-Jun, WANG Xin-Ping, CHAI Song-Hai, CAI Tian-Xi
    2003, 24(7):  1281-1284. 
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    The Ni doped molybdenum oxide(Ni-MoOx) as the catalyst for n-heptane isomerization has been studied in a conventional fixed bed reactor. It is indicated that addition of mass fractions 2%-5% Ni to MoO3 can markedly shorten the reduction period of H2 which is necessary for the formation of active phase Ni-MoOx catalyzing n-heptane isomerization. The relative activity for n-heptane isomerization in terms of unit surface area of the catalyst can be enhanced greatly by addition of Ni as well. On the Ni-MoOx catalyst, the apparent activation energy for n-heptane isomerization is ca. 35.3 kJ/mol, which is obviously lower than 49.3 kJ/mol obtained on MoOx. And it is 1/3-1/4 as low as those of zeolite-based bifunctional catalyst for the n-heptane isomerization.
    SERS Study of Single-walled Carbon Nanotubes on Silver Films Deposited on Different Substrates
    YU Miao, LIU Bing-Bing, LI Dong-Mei, LI Ming-Hui, YAO Ming-Guang, WANG Lin, WANG Hui, ZOU Guang-Tian, WANG Xu, ZHAO Bing, Sundqvist B.
    2003, 24(7):  1285-1288. 
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    Surface-enhanced Raman Scattering of single-walled carbon nanotubes(SWNTs) on silver films deposited on various substrates, including sapphire, quartz and glass, has been studied systematically. The characteristic features of Gband and Dband have been analyzed and compared with arc discharge and laser ablation samples. Dband is much more sensitive than Gband. The position and the intensity of the Gband in SERS spectra depend on substrates. The peakshift and absolute intensity of Gband on sapphire is obviously larger than that on glass. The contribution of high frequency vibrations to the Dband is also dependent on substrates. Compared to the SWNTs sample with high semiconducting tube concentration, the sample with high metallic tube concentration has a stronger interaction with silver films.
    Theoretical Studies on Effect of the Interaction Between Metal and Ligands on Frontier Molecular Orbitals and Nonlinear Optical Properties Within BeQ2 and Its Derivatives
    LIAO Yi, SU Zhong-Min, QIU Yong-Qing, KAN Yu-He, CHEN Ya-Guang, WANG Rong-Shun
    2003, 24(7):  1289-1292. 
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    The calculations of stable structures and binding energies for BeQ2 and its substituted derivatives have been performed at HF and B3LYP levels. On this basis, changes in frontier molecular orbitals as well as nonlinear optical coefficients have been analysed systematically. It is shown that the interaction between metal and ligand could increase the value of the third order NLO susceptibility γ more significantly than that of the second order NLO susceptibility β; either electrondonor CH3 or electron acceptor CN can lower the binding energy, which increases the delocalization of electrons in the calculated systems, thus can contribute to improving in NLO properties.
    Studies on Interaction Between CdTe Nanocrystals and Proteins
    LI Jun, YUAN Hang, ZHAO Kui, HONG Xia, LIU Yan-Mei, MA Lan, BAI Yu-Bai, LI Tie-Jin
    2003, 24(7):  1293-1295. 
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    Thiol-capping of CdTe nanocrystals were prepared in aqueous solution. The emission wavelengths of CdTe nanocrystals could be tuned by the refluxing time. Bioinorganic conjugates between CdTe nanocrystals and BSA were formed via electrostatic/coordinate self-assembly. The photoluminescence intensity of the bioinorganic conjugates was improved obviously. BSA could stabilize the CdTe nanocrystals, and the bioinorganic conjugates at room temperature were stable for a long time. We also demonstrated that CdTe nanocrystals could be blocked with BSA and avoid the nonspecific adsorption.
    Preparation of High Performance Cu/ZnO/Al2O3 Catalyst for Methanol Synthesis from CO2 Hydrogenation by Coprecipitation-reduction
    CAO Yong, CHEN Li-Fang, DAI Wei-Lin, FAN Kang-Nian, WU Dong, SUN Yu-Han
    2003, 24(7):  1296-1298. 
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    A novel coprecipitation-reduction process has been proposed for preparing highly selective Cu/ZnO/Al2O3 catalysts for methanol synthesis from CO2 hydrogenation. Compared to the catalysts prepared by the conventional method, the new catalysts prepared via the new method exhibit much higher BET surface area and pore size, much smaller crystallite size and higher catalytic activity and selectivity in CO2 hydrogenation to methanol. It is also found that the molar ratio of Cu+ to Cu0 on the surface of the catalyst obtained by coprecipitation-reduction is much higher than that on the reduced catalyst obtained by the conventional method, which could be crucial for its high activity and selectivity for catalytic hydrogenation of CO2 to methanol.
    Dynamical Lie Algebra Method for Highly Excited Vibrational State of Quasi-linear Tetraatomic Molecules
    FENG Dong-Tai, DING Shi-Liang, WANG Mei-Shan
    2003, 24(7):  1299-1301. 
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    The highly excited vibrational states of quasi-linear tetraatomic molecule HCNO are studied in the framework of U(4) algebra. By using symmetric group with which the tetraatomic molecules satisfy, we construct the algebraic Hamiltonian that not only includes Majorana operator M12 but also M13 and M23 which are very useful for getting potential energy surface and force constants in Lie algebra method. And the eigenvalue of the Hamiltonian are obtained by Lie algebra treatment.
    Conformation of Polyelectrolyte Chains with Sulfonate Groups Observed with Fluorescent Nonradiative Energy Transfer
    SUN Qi-Long, WANG Chao-Yang, REN Bi-Ye, TONG Zhen, LIU Xin-Xing, ZENG Fang, LIU Ping
    2003, 24(7):  1302-1306. 
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    Strong polyelectrolytes were prepared by copolymerization of 2-acrylamido-2-methylpropane sulfonic acid(AMPS) from 5% to 99%(charge densities) with N,N-dimethylacrylamide and lightly labeled by naphthalene and pyrene, respectively. The overlap mass concentration ρ* determined by intermolecular nonradiative energy transfer(NRET) decreased from 0.55 to 0.25 g/L with increasing the charge density of the samples and was about one order of magnitude smaller than that determined from the relative excimer emission. With increasing the charge density in dilute aqueous solution, the intermolecular NRET was first weakened till the charge density of about 30% and then enhanced. This phenomenon can be qualitatively interpreted in the framework of Manning′s theory for counterion condensation and aggregation of highly charged polyelectrolytes.
    MN as a Rate-accelerating Additive for Styrene Polymerization Mediated by TEMPO
    LIN Jian, ZHENG Shu-Ying, LI Wan-Li, YAN Ming-Fa, HUANG Jian-Ying, LIN Ming-Hua, ZOU You-Si
    2003, 24(7):  1307-1310. 
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    Styrene polymerization mediated by TEMPO was distinctly accelerated by the addition of small amounts of malononitrile(MN). The polymerization proceeded in a living fashion as indicated by the increase in molecular weight with time and conversion and relatively low polydispersities. It was found that the polymerization rate was so quick that the conversion reached 70% within 1 h at 125 ℃ when n(MN): n(TEMPO) equaled to 4:1. Moreover the molecular weight could be controlled to 105 and the reaction temperature could be reduced to 110 ℃. Analysis of 1HNMR showed that MN only acted a catalyst to enhance the polymerization rate and reduce clearly the temperature by weakening the bond of C-O.
    Synthesis and Characterization of Thermoassociating Graft Copolymer PAM-g-PNIPAm
    GUO Rui-Wei, LU Xian-Dong, FANG Dao-Bin
    2003, 24(7):  1311-1314. 
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    The graft copolymers polyacrylamide-graft-poly(N-isopropylacrylamide) were synthesized by polymerization of acrylamide and macromonomers poly(N-isopropylacrylamide) with acrylamide end group in aqueous solution. The macromonomers with different molecular weights were prepared by 2 steps: (1) synthesis of amino-end functionalized poly(N-isopropylacrylamide) macromonomer by radical polymerization of NIPAm with 2-aminoethanethiol hydrochloride as chain transfer agent; (2) conversion of amino-end group to acrylamide-end group by reaction with acryloyl chloride. In aqueous solution this graft copolymer shows thermoassociating characters, and its associating temperature is determined by the cloud point of the side chain polymer, independently with the content and length of the PNIPAm side chain. The results show that these graft copolymers have thermothickening effect, i.e. the viscosity of PAM-g-PNIPAm aqueous solution increases with the increasing of temperature above its cloud point.
    Studies on Assembly and Structure of Supramolecular Glyphosate Intercalated Magnesium-Aluminum Layered Double Hydroxide
    MENG Jin-Hong, ZHANG Hui, Evans D. G., DUAN Xue
    2003, 24(7):  1315-1319. 
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    A novel design of controlled-release glyphosate with a supramolecular structure has been proposed, according to the shortage of traditional pesticide and controlled-release pesticide at present. On the basis of the concept of intercalation and assembly, glyphosate anion intercalated magnesium-aluminum layered double hydroxides(abbreviated as MgAl-LDH-gly) has been prepared by coprecipitation. According to the crystal structure, the interaction between host and guest anion, and chemical composition of MgAl-LDH-gly, orientation of glyphosate anion between the layers of MgAl-LDH-gly are given.
    Synthesis and H-aggregation of a Novel Polyelectrolyte Bearing Branched Azo Side Chains
    DENG Yong-Hong, TUO Xin-Lin, CHENG Hao, WANG Xiao-Gong
    2003, 24(7):  1320-1324. 
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    A novel polyelectrolyte bearing branched azo side chains, MAPB6P-AA, was synthesized and characterized. H-aggregation of the azo chromophores of MAPB6P-AA in N,N-dimethylformamide(DMF)/H2O mixed solvent was studied by UV-Vis spectroscopy. The experimental results show that the critical volume fraction for MAPB6P-AA to form H-aggregates in the mixture of DMF and H2O is 11%. It is van der Waals force associated with the delocalized electrons of azobenzene chromophores that provides a driving force for the aggregation. Compared with low-molecular-weight azo molecules such as MAPB6 and MAPB6P, polymer MAPB6P-AA has a stronger aggregation tendency, which suggests that hydrophobic interaction and polymeric linkages also play a significant role in the formation of H-aggregation. In addition, the influence of H-aggregation of the azo chromophores on their photoresponsive behavior was also studied. A significant decrease of the trans-to-cis isomerization rate and the cis isomer content at photo-stationary state was observed.
    Chemical Reaction of PHBV/Sol-gel Bioglass Foams for Born Tissue Engineering in Simulated Body Fluid
    ZHENG Yu-Dong, WANG Ying-Jun, CHEN Xiao-Feng, REN Yao-Bin, WU Gang
    2003, 24(7):  1325-1328. 
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    A new kind of porous composites prepared from poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) and sol gel bioactive glass(SGBG) are used for born tissue engineering scaffolds. In this work, the chemical reaction and in vitro degradation of PHBV/SGBG porous materials was assessed in simulated body fluid(SBF). The changes in components and structures of the porous materials were investigated before and after immersion in SBF. It was found that the ion concentrations of SBF changed with immersing time because of ion exchange reaction and degradation reaction of PHBV/ SGBG in SBF solution. FTIR and XRD analysis indicated that hydroxyl carbonate apatite(HCA) had formed on the surface of PHBV/SGBG after the porous scaffold was exposed to SBF solution for 12 h.
    Synthesis of Crosslinkable Fluorinated Poly(ether ether ketone)
    LIU Bai-Jun, HU Wei, MA Xiao-Ye, RAO Xian-Hua, LI Ting, JIANG Zhen-Hua, WU Zhong-Wen
    2003, 24(7):  1329-1331. 
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    A novel crosslinkable fluorinated poly(ether ether ketone) with acetylenylbenzene end groups was prepared by solution condensation. The chemical structure of such polymer was confirmed by FTIR and 1HNMR. The crosslinking behavior and thermal stability were investigated by DSC and TGA respectively. The DSC thermogram for the first heating run shows a glass transition of 6F-PEEK at about 395 K and a exothermic peak correspongding to the self-crosslinking reaction of fluorinated poly(ether ether ketong) at about 700 K. For the second heating run, the exothermic peak disappered and the glass transition shifted to a higher temperature. The crosslinked polymer shown excelent thermal stability and solvent-resistence. The temperature for 5% weight loss was 774 K and the self-crosslinked polymer was no more disolved by polar solvents, which disolved in before crosslinking, such as DMF, DMAc and NMP. This kind of polymer may be a potential material used as electro-optical devices.
    Relationship Between Mean-square Radius of Gyration and Degree of Branching for Highly Branched Copolymers
    YU Min-Qiang, ZHOU Zhi-Ping, YAN De-Yue, LI Ze-Sheng
    2003, 24(7):  1332-1334. 
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    This work deals with the dependence of the z-average mean-square radius of gyration (<R2> z) on the degree of branching(DB) for highly branched copolymers made from the one-pot cocondensation of AB2 and AB monomers. A new expression of the degree of branching has been derived. The DB monotonously increases with increasing A group conversion and the fraction of AB2 monomers. The value of DB calculated in accordance with our formula is lower than that given by Frey and coworkers. Howerver, when the reaction approaches completion, our expression of the degree of branching degenerates into the equation reported by Frey. Furthermore, the z-average mean-square of gyration of the resulting copolymer in the Θ state has been derived on the basis of the classical work developed by Stockmayer, Gordon, Li and Ba. The relationship between DB and <R2> z is illustrated by numerical results. The z-average mean-square radius of gyration of the copolymer with a certain weight-average molecular weight monotonously decreases with increasing the degree of branching.
    Syntheses of a Novel Intermediate Polyphosphazene and C60-contained Polyphosphazenes
    LI Zhen, QIN Jin-Gui
    2003, 24(7):  1335-1337. 
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    In this paper, a novel synthetic strategy was developed to prepare functional polyphosphazenes. This strategy was successfully applied to synthesize the first C60-contained polyphosphazenes. Thus, polyphosphazene that contains azido groups as the side groups was obtained by a direct reaction. And then the azido groups reacted with C60 moieties to yield the C60-contained polyphosphazenes. The polymers were well characterized and exhibit an excellent solubility in common organic solvents.
    Studies on Grafting Kinetics of Bulk Copolymerization of Styrene onto Rubber(Ⅰ)──Grafting Behavior
    HUANG Yuan, CAO Kun, LI Bao-Fang, LI Bo-Geng
    2003, 24(7):  1338-1340. 
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    The difference between apparent grafting ratio and true grafting ratio in bulk graft copolymerization of styrene onto rubber and the change of rubber particle size during the overall polymerization processes were studied. The results show that, the apparent grafting ratio increased mutationally at the phase inversion and trended to level off after the phase inversion, but the true grating ratio increased gradually with the increase of conversion. At the same time, the particle size of rubber phase in the original polymerizing mixtures almost kept constant after the phase inversion. On the contrary, the size increased with the increase of conversion when the samples were dealt with multi-solution-centrifugation.
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