Chemical Research in Chinese Universities

Content of Chemical Research in Chinese Universities Vol.24 No.6(2008)

2008, 24(6): 0-0. doi:

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Cis- and Trans-Coordination Assembly of Nitrogen Heterocycle with Copper(II) and Silver(I)

TAN Di , TAN Gui-ping , HUANG Xiao-chun , TONG Shan-ling , YANG Ke-er , YAN Yan

2008, 24(6): 661-667. doi:

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After the preparation of 1,4-bis(4,5-dihydro-1H-imidazol-2-yl)benzene(bdib), a nitrogen heterocycle with potential coordination manners of both cis- and trans-configuration forms, three complexes, including cis-[Cu₂(bdib)₂(μ-OCH₃)₂]Cl₂·2MeOH(1), trans-[Cu(bdib)(AcO)₂]_n(2), and cis-[Ag₂(bdib)₂](NO₃)₂·2H₂O(3), were successfully self-assembled. Complexes 1 and 2 crystallized in the monoclinic system with P2₁/n space group and
complex 3 in the triclinic system with Pī space group.

Synthesis, Characterization, and Properties of Supported Tungstozincate Bridged by Co(II) Complex Fragment

LIU Kun , LI Jia , LIU Hong-bo , CHEN Ya-guang

2008, 24(6): 668-671. doi:

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[Co^II(phen)₃]₂[{(ZnW₁₂O₄₀)CoII(phen)₂(H₂O)}₂Co^II(trien)₂(NaH₂O)₂·3H₂O was synthesized via hydrothermal technique and characterized with elemental analyses, IR spectroscopy, TGA-DTA, and variable temperature magnetic susceptibility. The compound crystallized in the monoclinic system with the space group P2₁/n, a=1.8210 nm, b=2.3592 nm, c=2.2932 nm, β=110.31º, V=9.239 nm³, Z=2, R₁=0.0827. The compound consists of two coordination cations, three lattice water molecules, and a macroanion [{(ZnW₁₂O₄₀)Co(phen)₂(H₂O)}₂Co(C₆H₁₈N₄)₂(NaH₂O)₂]^4- in which each supported Keggin anion [(ZnW₁₂O₄₀Co^IIphen)₂(H₂O)]^4- acts as a ligand to coordinate to central bridging Co²⁺ ion via a terminal oxygen atom. Hydrogen bonds are responsible for the construction of 3D architecture of the compound. The compound is paramagnetic with a weak antiferromagnetic interaction(θ=-46.796 K).

Preparation and Magnetic Property of La_0.7Sr_0.3MnO₃ Nanorod by Combination Sol-Gel with Molten Salt

QI Shu-yan, FENG Jing , XU Xiao-dong, WANG Jing-ping, HOU Xiang-yu , ZHANG Mi-lin

2008, 24(6): 672-674. doi:

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La_0.7Sr_0.3MnO₃(LSMO) nanorods were synthesized by a method combining sol-gel with molten salts at 950 °C for 10 h, which employed KCl+NaCl(mass ratio 4:1) as eutectic molten salts. The morphologies and magnetic properties of the resulting LSMO nanorods were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and vibrating sample magnetometer(VSM) measurements. It was found that the obtained perovskite manganite LSMO was a uniform nanorod with a diameter of about 50 nm and a length of longer than 500 nm. The Curie temperature(T_c) of the LSMO nanorod used here was 262 K, much lower than that of bulky single crystal LSMO(360 K). The low Curie temperature might be a result of the great disorder near the grain boundary, which could be observed clearly from the TEM picture.

Synthesis and Structural Characterization of Manganese Carbonyl Incorporated Polyoxomolybdate (n-Bu4N)2[Mo6O16(OCH3)2{HOCH2C(CH2O)3}2{Mn(CO)3}2]

WANG Jing-ping, LI Ji-li , NIU Jing-yang

2008, 24(6): 675-678. doi:

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The polyoxoanion incorporated {Mn(CO)₃⁺} complex, (n-Bu₄N)₂[Mo₆O₁₆(OCH₃)₂{HOCH₂C(CH₂O)₃}²{Mn(CO)₃}₂](1), has been synthesized by the reaction of (n-Bu₄N)₄[Mo₈O₂₆] with Mn(CO)₅Br in methanol, in the presence of C(CH₂OH)₄. The complex 1 has been characterized by IR, UV-Vis, X-ray single crystal diffraction, and TG. Crystal data for the complex 1: C₂₅H₄₈MnMo₃NO₁₆(1), Triclinic P1, a=0.9405(3) nm, b=1.3351(4) nm, c=1.5455(4) nm, α=103.206(5)º, β=102.165(5)º, γ=100.784(5)º, V=1.7896(9) nm³, Z=2, R₁=0.0703, wR₂ = 0.1495. The structure analysis of complex 1 shows that the complex consists of two tetrabutylammonium cations and a polyoxomolybdate anion that incorporates two fac-Mn(CO)₃⁺ units. The anion of complex 1 can be considered as the dimer of two rhomb-like anions by sharing of two corners.

Vacuum Ultraviolet Excited Photoluminescence Properties of Y₂O₂S:Eu³⁺,Bi³⁺ Phosphor

WANG Zhi-long, WANG Yu-hua , ZHANG Jia-chi

2008, 24(6): 679-682. doi:

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As an Hg-free lamp using phosphor, the Bi³⁺ and Eu³⁺ co-doped Y₂O₂S phosphors were prepared and their luminescence properties under vacuum ultraviolet(VUV) excitation were investigated. The VUV photoluminescent intensity of Y₂O₂S:Eu³⁺ was weak, however, considerably stronger red emission at 626 nm with good color purity was observed in Y₂O₂S:Eu³⁺,Bi³⁺ systems. Investigation on the photoluminescence reveals that the strong VUV luminescence of Y₂O₂S:Eu³⁺,Bi³⁺ at 147 nm is mainly because the Bi³⁺ acts as a medium and effectively performs the energy transfer process: Y³⁺-O^2-→Bi³⁺→Eu³⁺, while the intense emission band at 172 nm is attributed to the absorption of the characteristic ¹S₀-¹P₁ transition of Bi³⁺ and the direct energy transfer from Bi³⁺ to Eu³⁺. The Y₂O₂S:Eu³⁺,Bi³⁺ shows excellent VUV optical properties compared with the commercial (Y,Gd)BO₃:Eu³⁺. Thus, the Y₂O₂S:Eu³⁺,Bi³⁺ can be a potential red VUV-excited candidate applied in Hg-free lamps for backlight of liquid crystal display.

Preparation, Crystal Structure, and Thermal Analysis of Carbohydrazide Trinitrophloroglucinolate

LIU Zhen-hua , ZHANG Tong-lai , HU Xiao-chun , ZHANG Jian-guo , YANG Li , , QIAO Xiao-jing

2008, 24(6): 683-687. doi:

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A new compound (CHZ)(HTNPG)·0.5H₂O was synthesized by mixing carbohydrazide(CHZ) and trinitrophloroglucinol(TNPG) and characterized by elemental analysis and Fourier transform infrared (FTIR) spectrum. Its crystal structure was determined by single crystal X-ray diffraction analysis. The crystal belongs to triclinic system, Pī space group, with a=0.45578(9) nm, b=1.0142(2) nm, c=1.3041(3) nm, α=86.53(3)°, β=99.56(3)°, γ=81.94(3)°, V=0.5958(2) nm³, Z=2, D_c=2.008 g/cm³, R₁=0.0476, and wR₂=0.1139. The compound is a di-substituted salt of TNPG, which consists of a cation (CHZ)²⁺and an anion (HTNPG)^2–. The thermal analysis of the compound was studied by means of differential scanning calorimetry(DSC) and thermogravimetry-derivative thermogravimetry(TG-DTG). Under nitrogen atmosphere at a heating rate of 10 °C/min, the thermal decomposition of the compound contained one endothermic process of dehydrating stage and two intense exothermic decomposition processes in a temperature range of 140―232 °C on the DSC trace. The decomposition products of the title compound are nearly gaseous products. The existing complicated hydrogen bond networks and electrostatic attraction between (CHZ)²⁺ and (HTNPG)^2– enhance the thermal stability of the title compound.

Effects of Magnesium and Ferric Ions on Crystallization of Calcium Sulfate Dihydrate Under the Simulated Conditions of Wet Flue-gas Desulfurization

GAO Xiang , HUO Wang, ZHONG Yi, LUO Zhong-yang, CEN Ke-fa, NI Ming-jiang , CHEN Le-ming

2008, 24(6): 688-693. doi:

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The influences of magnesium and ferric ions in their different ratios on the rate of gypsum crystallization were studied under the conditions similar to those of wet flue-gas desulfurization(WFGD). The results show that addition of both Mg²⁺ and Fe³⁺ increased induction time and decreased the growth efficiency up to 50% compared with the baseline(without impurities) depending on the concentration and the type of impurity. The effects of Mg²⁺ and Fe³⁺ on the surface energy and the rate of nucleation were estimated by employing the classical nucleation theory. The surface energy decreased by 8% and 14% with the addition of 0.02 mol/L magnesium or ferric ions, respectively, compared to the baseline. Mg²⁺ and Fe³⁺ made the growth rate of the (020), (021) and (040) faces of gypsum crystal a much greater reduction, which leads to the formation of needle crystals compared to the baseline which favors the formation of plate or flakes. Furthermore, an edge detection program was developed to quantify the effects of impurities on the filtration rate of gypsum product. The results show that the inhibition efficiency of the presence of 0.02 mol/L Mg²⁺ and Fe³⁺ on the filtration rate of gypsum crystal ranges from 22% to 39%.

Determination of Acetonitrile Volume Fraction in Mobile Phase by HPLC

WU Yi , WANG Zhi-wu , GU Jing-kai , WANG Ying-wu

2008, 24(6): 694-696. doi:

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This paper reports the development and validation of an assay for the determination of acetonitrile in the recycled mobile phase using high performance liquid chromatography(HPLC). The method is based on that the retention in reversed-phase liquid chromatography increases with decreasing concentration of organic phase in the mobile phase. The natural logarithm of the capacity ratio for a given solute is linearly related to the volume fraction of the organic modifier in the mobile phase. For dimethylphthalate and diethylphthalate, the linearity range is 30%―60%, and for biphenyl and terphenyl, the range is 60%―95%. Precision values(RSD) were both <1% and the accuracy(RE) was in the range of ±1%. The assay was successfully applied to the determination of acetonitrile concentration of recycled mobile phase after the distillation of the column eluent in our laboratory.

Characterization of Hapten-Protein Conjugates for Immunoassay of Polycyclic Aromatic Hydrocarbons(PAHs)

ZHANG Yan-feng , GAO Zhi-xian , SUN Hong-wen , DAI Shu-gui

2008, 24(6): 697-700. doi:

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Preparation and characterization of the hapten-protein conjugates are fundamental to developing environmental immunoassays. As a hapten, 1-pyrenebutyric acid(PBA) was conjugated to the carrier protein of bovine serum albumin(BSA) or ovalbumin(OVA) by active ester method. Infrared spectra(IR) showed that PBA-BSA and PBA-OVA conjugates were successfully prepared. The number of the haptens conjugated to the carrier protein was determined by ultraviolet spectra(UV) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF-MS). The calculated average binding ratios of PBA/BSA and PBA/OVA were 18:1 and 10:1 by UV, and 31:1 and 22:1 by MALDI-TOF-MS, respectively. Although there was a discrepancy between the results determined by the two methods, both of them were useful for the characterization of the hapten-protein conjugates. The antibody was produced against the antigen of PBA-BSA, and the affinity was tested by the double agar diffusion method. The conjugates and the antibody could be used for developing a sensitive and selective immunoassay of polycyclic aromatic hydrocarbons(PAHs).

Electrochemical Study on the Interaction of Protein with Bromothymol Blue and Its Analytical Application

WANG Xue-liang, YANG Jie , JIAO Kui

2008, 24(6): 701-706. doi:

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The interaction of bromothymol blue(BB) with human serum albumin(HSA) was studied by electrochemical techniques and a sensitive method for proteins assay was developed. When BB interacted with HSA, the voltammetric peak current value of BB decreased linearly with the concentration of HSA in a range of 1.0―40.0 mg/L, and the peak potential shifted negatively. Based on the results, a sensitive assay method for proteins, such as HSA, bovine serum albumin(BSA), and egg albumin etc. was established. This method was further applied to determining the HSA in healthy human blood samples, and the results are not significantly different from those obtained by the classic Coomassie Brilliant Blue G-250 spectrophotometic method. The detecting conditions of this method were optimized and the interaction mechanism was discussed. The results show that the electrochemical parameters(formal potential E⁰, standard rate constant of the electrode reaction k_s, parameter of kinetic nα) of BB have no obvious changes before and after the interaction, which indicate that BB can interact with HSA, forming an electrochemical non-active complex. The equilibrium constant(β_s) and the binding ratio(m) for this complex were calculated. The m is 4 and β_s is 1.41×10¹⁹. This method is fast, simple, highly sensitive, and has good selectivity, which can be used in clinical measurements.

Determination of Seven Major Ginsenosides in Different Parts of Panax quinquefolius L.(American Ginseng) with Different Ages

ZHANG Kun , WANG Xiao , DING Lan , LI Juan , QU Chen-ling , CHEN Li-gang , JIN Hai-yan , ZHANG Han-qi

2008, 24(6): 707-711. doi:

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Ginsenosides Rg₁, Re, Rb₁, Rc, Rb₂, Rb₃, and Rd in different parts of the American ginseng plant were investigated. The extraction process was a pressured microwave-assisted extraction(PMAE). The seven ginsenosides were separated and determined by high-performance liquid chromatography(HPLC) with a ultraviolet(UV) detector, at 203 nm. The experiment results showed significant variations in the individual ginsenoside contents of the American ginseng in different parts and ages of the plant. The results demonstrated that the leaves, root hairs, and rhizomes of Panax quinquefolius L. contained higher ginsenoside contents, followed by the main roots and stems. The leaves contained dramatically higher levels of ginsenoside Rg₁, Rb₃, and Rd than the other four parts. Higher contents of Rb₁ and Re were present in the main roots, root hairs, and rhizomes. The amount of ginsenoside content in the stems was the lowest. The total content of the seven ginsenosides in main roots, root hairs and rhizomes increased with the age of the plant. In contrast, the ginsenoside contents in the leaves and stems decreased with a year of growth.

Fluorescent Switch Behavior of 1,2-Bis(4-pyridyl) Ethylene Controlled by pH in Aqueous Solution

ZOU Wen-sheng , SHEN Qian-jin , WANG Yu , JIN Wei-jun

2008, 24(6): 712-716. doi:

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With the decrease of pH value from 8.45 to –1.0, the UV-Vis absorption and fluorescent spectra of 1,2-bis(4-pyridyl) ethylene(BPE) took on the same changing trend at four different successive pH stages: 8.45―7.20, 7.20―5.62, 5.62―2.60, and 2.60―−1.0, namely, no change, decrease, increase, and decrease again. Among these, in a range of 7.20―5.62, the fluorescence wavelength blueshifted from 418 to 359 nm, but the UV-Vis absorption wavelength, in contrast, redshifted from 285 to 298 nm. The fluorescence intensity of BPE had a drop even to quench upon a decline in the pH value from 2.60 to –1.0 probably owing to its cation-π interaction to reduce the π electron cloud density of BPE. Two dissociation constants, pK_a1(4.30±0.01) and pK_a2(5.65±0.04), were obtained based on fluorescence data. The changes of fluorescence spectra indicate that BPE has “off-on-off” switch behavior. The fluorescent spectra of BPE were nearly independent on the presence of α- and β-cyclodextrins.

Quantitative Analysis of Berberine in Processed Coptis by Near-Infrared Diffuse Reflectance Spectroscopy

ZHANG Yong , XIE Yun-fei , SONG Feng-rui , LIU Zhi-qiang , CONG Qian , ZHAO Bing

2008, 24(6): 717-721. doi:

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The near-infrared(NIR) diffuse reflectance spectroscopy was used to study the content of Berberine in the processed Coptis. The allocated proportions of Coptis to ginger, yellow liquor or Evodia rutaecarpa changed according to the results of orthogonal design as well as the temperature. For as withdrawing the full and effective information from the spectral data as possible, the spectral data was preprocessed through first derivative and multiplicative scatter correction(MSC) according to the optimization results of different preprocessing methods. Firstly, the model was established by partial least squares(PLS); the coefficient of determination(R²) of the prediction was 0.839, the root mean squared error of prediction(RMSEP) was 0.1422, and the mean relative error(RME) was 0.0276. Secondly, for reducing the dimension and removing noise, the spectral variables were highly effectively compressed via the wavelet transformation(WT) technology and the Haar wavelet was selected to decompose the spectral signals. After the wavelet coefficients from WT were input into the artificial neural network(ANN) instead of the spectra signal, the quantitative analysis model of Berberine in processed Coptis was established. The R² of the model was 0.9153, the RMSEP was 0.0444, and the RME was 0.0091. The values of appraisal index, namely R², RMSECV, and RME, indicate that the generalization ability and prediction precision of ANN are superior to those of PLS. The overall results show that NIR spectroscopy combined with ANN can be efficiently utilized for the rapid and accurate analysis of routine chemical compositions in Coptis. Accordingly, the result can provide technical support for the further analysis of Berberine and other components in processed Coptis. Simultaneously, the research can also offer the foundation of quantitative analysis of other NIR application.

Fabrication of Poly(4-vinylpyridine) Nanofiber and Fluorescent Poly(4-vinylpyridine)/Porphyrin Nanofiber by Electrospinning

SONG Yan , ZHAN Nai-qian , YU Miao , YANG Qing-biao , ZHANG Chao-qun , WANG Heng-guo , LI Yao-xian

2008, 24(6): 722-725. doi:

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Poly(4-vinylpyridine)(P4-VP) nanofiber and fluoresent poly(4-vinylpyridine)/porphyrin(P4-VP/TPPA) nanofiber were respectively prepared by electrospinning. The effect of the concentration of P4-VP/dinethylformamide (DMF) electrospinning solutions on the morphology of P4-VP nanofiber was investigated and it was found that the average diameter of the nanofiber of P4-VP/DMF increased with the increase of the concentration of the spinning solution. After the addition of TPPA to the P4-VP/DMF spinning solution, the diameter of P4-VP/TPPA nanofiber became even due to the increase of the conductivity of the P4-VP/DMF-TPPA solution. The photoluminescent(PL) spectral analysis indicates that the emission peak position of P4-VP/TPPA nanofiber is almost the same as that of pure TPPA at about 650 nm without peak shift, and when it was stored for 20 days, the emission peak of P4-VP/TPPA nanofiber is also at 650 nm, indicating that the fluorescent property of P4-VP/TPPA nanofiber is stable. Fourier-transform infrared(FTIR) spectrum confirms the chemical composition of the resulting P4-VP/TPPA composite nanofiber.

Preparation of Highly Active Pt-K/γ-Al₂O₃ Catalyst for o-Phenylphenol Synthesis from o-Cyclohexenyl-cyclohexanone Dehydrogenation

DING Jie-lian , LIN Ling, XU Jian-dong , ZENG Chong-yu

2008, 24(6): 726-730. doi:

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0.5%Pt-K/γ-Al₂O₃ catalysts for the synthesis of o-phenylphenol(OPP) from o-cyclohexenyl-cyclohexanone (dimer) dehydrogenation were prepared by means of a two subsequent impregnation method. The effects of catalyst preparation parameters, such as K promoters, calcination, and reduction conditions, were investigated. The results showed that the addition of K₂SO₄ to Pt/γ-Al₂O₃ catalyst notably promoted the selectivity of OPP, and its optimum content was found to be 6% in mass fraction. The higher activity was obtained when Pt/γ-Al₂O₃ catalyst was calcined in nitrogen atmosphere at 400―500 °C and then reduced at the same temperature for 3 h in hydrogen atmosphere. The conversion of the dimer and the selectivity of OPP were always above 99% and 90%, respectively, over 0.5％Pt-6％K₂SO₄/γ-Al₂O₃ catalyst during the pilot scale test of 8000 h.

Synthesis of an Anti-AIDs Drug Delavirdine Derivate, Resdelasu

GUAN Qing-xiang , HE Li-peng , WANG Xi , ZHANG Wen-yan , WANG En-si , YU Xiang-hui

2008, 24(6): 731-734. doi:

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In view of the anti-HIV activities of delavirdine and resveratrol, a novel anti-AIDs drug Resdelasu, 1-{3-[(1-methyl-ethyl)amino]-2-pyridinyl}-4-{[5-(4-{5[(1E)-2-(hydroxyphenyl)ethenyl]-1,3-benzenedioyl-carbonylbu-
tanoyl}amino)-1H-indol-2-yl]carbonyl}-piperazine was synthesized by linking the delavirdine derivative and resveratrol with succinic anhydride as the conjugated compound via two different routes. Its structure was confirmed by means of ¹H NMR, ¹³C NMR, IR, MS, and elemental analysis. The route of esterification followed by amidation for synthesizing Resdelasu was simpler and gave a higher yield(46%) than that of amidation followed by esterification. It was proved that the method was efficient and convenient to prepare Resdelasu. The results of HIV-1 Reverse Transcriptase Assay and quantitative titration of HIV-1 via MAGI assay showed that a novel anti-AIDs drug, Resdelasu, had been synthesized.

Regioselective Deprotection of 1,3-Dibenzyl-5-(N,N-dimethylamino)-6-phenylethyluracil

LI A-min , WANG Xiao-wei , ZHANG Zhi-li , CHENG Zhi-jian , LIU Jun-yi

2008, 24(6): 735-738. doi:

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The deprotection of 1,3-dibenzyl-5-(N,N-dimethylamino)-6-phenyl-ethyluracil I was investigated. A practical, regioselective N₃ deprotection of compound I was performed with excellent yield using cyclohexene as a hydrogen donor.

Synthesis of Heterocycle Compounds Containing Two Pyridazinone Units

XIN Bing-wei

2008, 24(6): 739-742. doi:

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Four novel compounds containing two pyridazinone units attached to one benzene or pyridine ring, protected and deprotected 1,5-di[3(2H)-pyridazinon-6-yl]benzene and 2,6-di[3(2H)-pyridazinon-6-yl]pyridine were synthesized in eight steps, which provided a useful method for the preparation of pyridazinone derivatives via the Stetter and cyclization reactions. Their structures were characterized by ¹H NMR, ¹³C NMR, and HRMS.

Preparation of Nicotinic Acid from Oxidation of 3-Picoline with Oxygen Under Catalysis of T(o-Cl)PPMn

BAI Jin-quan , WANG Qi-chang, HU Yun , GUO Feng-yan

2008, 24(6): 743-746. doi:

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The oxidation of 3-picoline to nicotinic acid took place efficiently in an ethanol solution with O₂ as the oxidant under the catalysis of T(o-Cl)PPMn at 40―150 °C and 0.5―3.0 MPa oxygen pressure. The influences of temperature, oxygen pressure, reaction time, concentration of 3-picoline, concentration of sodium hydroxide, and concentration of T(o-Cl)PPMn catalyst, etc. on the production of nicotinic acid were investigated. The results show that T(o-Cl)PPMn presented excellent catalytic activity in the oxidation of 3-picoline to nicotinic acid and the yield of nicotinic acid varied greatly with the reaction temperature, oxygen pressure, T(o-Cl)PPMn concentration, etc.

Asymmetric Synthesis of (R)- and (S)-Moprolol

WANG Zhao-yang , WANG Yan , SUN Li-wen , ZHU Jin-tao

2008, 24(6): 747-751. doi:

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A simple and effective procedure for the enantioselective synthesis of (R)- and (S)-moprolol was described. The key step was the asymmetric synthesis of enantiopure (R)- and (S)-guaifenesin, which were synthesized from enantioenriched (R)-3-chloro-1,2-propanediol and (S)-epichlorohydrin via kinetics of hydrolysis resolution of racemic epichlorohydrin by chiral Salen-Co^III complex. The e.e. values of both the optical compounds were above 98%, and the chemical structures of the target compounds were confirmed by ¹H NMR, ¹³C NMR, IR, and MS.

Cloning, Expression and Purification of Wheat Acetyl-CoA Carboxylases CT Domain in E. coil

WANG Rui-jian , YANG Xue-ying , ZHENG Liang-yu , YANG Ye , GAO Gui , CAO Shu-gui

2008, 24(6): 752-755. doi:

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The entire gene of carboxyltransferase(CT) domain of acetyl-CoA carboxylase(ACCase) from Chinese Spring wheat(CSW) plastid was cloned firstly, and the 2.3 kb gene was inserted into PET28a⁺ vector and expressed in E. coil in a soluble state. The (His)₆ fusion protein was identified by SDS-PAGE and Western blot. The recombinant protein was purified by affinity chromatography, and the calculated molecular mass(M_r) was 88000. The results of the sequence analysis indicate that the cloned gene(GeneBank accession No. EU124675) was a supplement and revision of the reported ACCase CT partial cDNA from Chinese Spring wheat plastid. The recombinant protein will be significant for us to investigate the recognizing mechanism between ACCase and herbicides, and further to screen new herbicides.

Functional Mechanism of Resveratrol in Inhabiting Growth of Cells ls174t and Its Mechanism in Subcutaneously Transplanted Tumor of Nude Mice

CHEN Jie, DONG Xin-shu , GUO Xing-gang

2008, 24(6): 756-761. doi:

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To explore the functional mechanism of Resveratrol against colon cancer cells ls174t and the growth of colon cancer tissue of tumor-bearing mice, MTT method was used to observe the functions of resveratrol for inhibition against cells ls174t in vitro. Transmission electron microscope was used to observe the cell apoptosis. FCM assay was performed to measure the change of the cell apoptosis rate and of cell cycle. RT-PCR method was used to detect the expressions of bcl-2 and bax mRNA. Western blot method was used to detect the expressions of bcl-2 and bax protein. Cells ls174t were transplanted subcutaneously to nude mice to observe the effect of resveratrol on the growth of subcutaneously transplanted tumor. RT-PCR method was used to detect the expressions of bcl-2 and bax mRNA in the tumor tissue. Western blot method was used to detect the expressions of bcl-2 and bax protein in the tumor tissue. Resveratrol has an effect of inhibiting proliferation of cells ls174t in vitro(P<0.01). It is able to induce the apoptosis of cells ls174t, causing the decrease in the expression of bcl-2 and the increase in the expression of bax. Resveratrol could inhibit the growth of subcutaneously transplanted tumor of nude mice(P<0.05), causing the decrease in the expression of bcl-2 and the increase in the expression of bax. Resveratrol can inhibit the growth of cells 174t and the growth of subcutaneously transplanted tumor. The mechanism is possibly related to the induction of the cell apoptosis and the regulation of bcl-2/bax expression.

Lethal Effect of Benzene Nitrogen Mustard Glucoside Derivate on K562 Cells

LIU Tie-mei , ZHU Guang-ze , ZHOU Jin-song , SUN Zhi , XIE Feng

2008, 24(6): 762-766. doi:

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A new synthesized benzene nitrogen mustard was converted into glycosyl donor-trichloroacetimidate that was glycosylated with p-nitrophenol(glycosyl donors) to form β-lactosyl p-nitrobenzene under the protection of acetyl in a stereoselective manner, was prepared and evaluated for its cytotoxicity towards cultured K562 cell line. Methylthiazoy tetrazolium(MTT) assay, transmission electron microscopy(TEM), flow cytometry(FCM) and immunohistochemistry were utilized to explore the mechanisms of how the compound arrests the growth of HCT-T cells. This new synthesed benzene nitrogen mustard glucoside derivate(BNMGD) presented a lower toxicity to normal cells, but is significantly more toxic to K562 cells compared with nitrogen mustard, meanwhile it can induce the apoptosis of K562 cells. These results indicate that the new synthesized BNMGD can inhibit the growth of K562 cells and induce the apoptosis, and its cytotoxicity towards cultured K562 cell line is much more effective than that of nitrogen mustard.

Construction and Expression of Human Survivin and Preparation of Its Polyclonal Antibody

ZHANG Hai-hong, ZHANG Xi-zhen, ZHAO Dong-hai, SHI He-liang, YU Yong-hui, WU Yong-ge, YU Xiang-hui , KONG Wei

2008, 24(6): 767-770. doi:

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Survivin, a novel member of inhibitor of apoptosis(IAP) protein family, is aberrantly expressed in cancer but undetectable in normal, differentiated adult tissues. The cancer-specific expression of survivin, coupled with its importance in inhibiting cell death and in regulating cell division makes it a useful diagnostic marker of cancer and a potential target for cancer treatment. Survivin cDNA amplified from the total RNA of 293 cells through RT-PCR was cloned into prokaryotic expression vector pRSET-B. The recombinant plasmid pRSET-B-Surv was expressed in E.coli BL21, and the relative molecule mass(M_r) of expressed fusion protein was approximately 21000. The recombinant protein was purified through Ni²⁺ affinity chromatography column and characterized by SDS-PAGE and Western blot. The purified recombinant protein was then injected into rabbits, and antisurvivin polyclonal antibody with a high titer was obtained.

Effects of Temperature and Energy on Stability of Oligomeric Enzyme Probed on Electrospray Ionization Mass Spectrometry

LI Zhi-li

2008, 24(6): 771-779. doi:

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Escherichia coli 3-Deoxy-D-manno-octulosonate 8-phosphate(KDO8P) synthase catalyzed the condensation reaction between D-arabinose 5-phosphate(A5P) and phosphoenolpyruvate(PEP) to form KDO8P and inorganic phosphate(P_i). The noncovalent tetrameric association of KDO8P synthase was observed and dissociated in gas phase by means of electrospray ionization mass spectrometry under the very “soft” conditions. The results indicate that PEP-bound enzyme generated abundant tetrameric species as well as monomeric species at the “soft” conditions, whereas, the unbound enzyme favored the formation of a dimeric species. The mass spectra of the mixture of the enzyme with one of substrates, PEP, and A5P or one of products, KDO8P and P_ishow that the complex of the unbound enzyme with PEP or P_iwas prone to the formation of a monomeric species, whereas, that of the unbound enzyme with A5P or KDO8P was similar to the unbound enzyme. The intensity of the dimeric species increased with the increase of temperature at a collision voltage of 10 V. Taken together, the results presented here suggest that mass spectrometry will be a powerful tool to explore subtile conformational changes and/or subunit-subunit interactions of multiprotein assembly induced by ligand-binding and/or the changes of environmental conditions.

Inhibition Mechanism of Cholinesterases by Carbamate: A Theoretical Study

YAO Yuan , LI Ze-sheng

2008, 24(6): 778-781. doi:

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The density functional theory at the B3LYP/6-311G(d, p) level was applied to exploring the inhibition mechanism of cholinesterases by carbamate. The results indicate that the inhibition reactions with or without the catalytic effect of the catalytic triad in cholinesterases underwent a two-step addition-elimination mechanism, which is in good agreement with the proposed mechanism. The solvent has a strong effect on the inhibition reactions and the reaction with the catalytic triad in the solvent phase is close to the real reaction under biological condition.

Electrochemical Oxidation of Ammonia on Ir Anode in Potential Fixed Electrochemical Sensor

HAN Yi-ping , LUO Peng , CAI Chen-xin , XIE Lei , LU Tian-hong

2008, 24(6): 782-785. doi:

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Ir catalyst possesses a good electrocatalytic activity and selectivity for the oxidation of NH₃ and/or NH₄OH at Ir anode in the potential fixed electrochemical sensor with the neutral solution. Owing to the same electrochemical behavior of NH₃ and NH₄OH in a NaClO₄ solution, NH₄OH can be used instead of NH₃ for the experimental convenience. It was found that the potential of the oxidation peak of NH₄OH at the Ir/GC electrode in NaClO₄ solutions is at about 0.85 V, and the current density of the oxidation peak of NH₄OH is linearly proportional to the concentration of NH₄OH. The electrocatalytic oxidation of NH₄OH is diffusion-controlled. Especially, Ir has no electrocatalytic activity for the CO oxidation, illustrating that CO does not interfere in the measurement of NH₄OH and the potential fixed electrochemical NH₃ sensor with the neutral solution, and the anodic Ir catalyst possesses a good selectivity. Therefore, Ir may have practical application in the potential fixed electrochemical NH₃ sensor with the neutral solution.

Thermal Decomposition of Ammonium 3-Nitro-1,2,4-triazol-5-onate Monohydrate

LI Ji-zhen , FAN Xue-zhong , ZHANG Jiao-qiang , ZHANG Guo-fang , WANG Bo-zhou

2008, 24(6): 786-789. doi:

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The thermal decomposition of ammonium 3-nitro-1,2,4-triazol-5-onate monohydrate[NH₄(NTO)·H₂O] was studied by means of thermal analysis-MS coupling and the combination technique of in situ thermolysis cell with rapid-scan Fourier transform infrared spectroscopy. The results show that there are two endothermic steps and one exothermic step in the decomposition process of NH₄(NTO)·H₂O. The detected gas products consist of NH₃, H₂O, N₂, CO₂, CO, and NO₂.

DFT Study on Intermolecular Cleavage Reaction of N-(2-Hydroxyphenyl)-phthalamic Acid

ZHAO Chu-feng, TANG Ming-sheng , WANG Hong-ming , WEI Dong-hui, ZHAO Jing, ZHANG Shou-ren , CAO Shu-xia

2008, 24(6): 790-792. doi:

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The reaction mechanisms of intermolecular cleavage reaction of N-(2-hydroxyphenyl)-phthalamic acid were studied via the density functional theory(DFT). All geometries of the reactant, transition states, and products were optimized at the B3LYP/6-31G(d, p) level. Vibration analysis was carried out to confirm its identity as transitions’ structure, and the intrinsic reaction coordinate method(IRC) was used to search the minimum energy path. Two possible reaction channels are reported in this article. The calculated results indicate that O-cyclization reaction channel has the lower activation barrier, and therefore, it occurs more easier than the other.

Effective VTeO/SBA-15 Catalyst Prepared by Precursor Method for the Selective Oxidation of Propane to Acrolein

FENG Mao-ying, HUANG Chuan-jing, WENG Wei-zheng, WAN Hui-lin , XU Qin , ZHOU Zhao-hui

2008, 24(6): 793-797. doi:

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Precursor decomposition was used for the preparation of VTeO/SBA-15 catalyst for the selective oxidation of propane to acrolein. The catalyst shows a better performance compared with those prepared by conventional impregnant method. A yield of 9.3% of acrolein was achieved with 2% V loadings at 500 oC. XRD, N₂-adsorption, H₂-TPR, Py-IR and XPS measurements were used to unclose the relationship between the structure and performance of the catalyst.

Synthesis, Crystal Structure, Physical Properties, and Application of a Series of Functional Dibenzo[d,f][1,3]dioxepine Derivatives

ZHANG Hai-quan , ZHANG Cheng-bo , ZHENG Yan , YANG Bing , MA Yu-guang

2008, 24(6): 798-804. doi:

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The twisted aromatics, functional dibenzo[d,f][1,3]dioxepine derivatives were synthesized in high yields from reactions of 5,5′-dibromo-2,2′-biphenol with corresponding ketal or ketone compounds under acid catalysis. The structures of these compounds were characterized by ¹H NMR, elemental analysis, UV-Vis absorption spectrum and X-ray diffraction analysis. The conformation of O―C―O bridged biphenyl derivatives with varied substitute groups on 6,6′-position was studied by X-ray crystallography and force-field simulation. The result of calculations by UNIVERSAL 1.02 force field in Cerius² package(4.6) indicates that dibenzo[d,f][1,3]dioxepine derivatives show twisted conformations and the twisted angle between the phenyl rings is about 40°, which is accordant with the result from crystal structure determination, though the obtained angles in the crystal of dibenzo[d,f][1,3]dioxepine derivatives with the varied substitute groups on 6,6′-position are shown to be slightly shifted to 40° owing to intermolecular interactions in crystal stacking. DSC studies exhibit that the substitute groups on 6,6′-position can induce a large variation of endothermic peaks ranging from 80 to 135 °C. The conjugated polymers based on dibenzo[d,f][1,3]dioxepine derivatives, which have ultraviolet emitting with a quantum efficiency of 10%, were obtained by Yamamoto coupling.

Preparation of 5-Fluorouracil Loaded Polylactide-co-glycolide-co-methoxy Poly(ethylene glycol)(PLGA-mPEG) Nanoparticles via High Speed Shearing

LIN Hang , REN Hui , WANG Xi-shan , TANG Qing-chao , TANG Jun , WANG Ce

2008, 24(6): 805-808. doi:

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5-Fluorouracil(5-FU) loaded nanoparticles(NPs) were prepared by a high speed shearing double emulsion method with polylactide-co-glycolide-co-methoxy poly(ethylene glycol)(PLGA-mPEG) as loading material. The prepared NPs possess a negative zeta potential and their loading efficiency is about 15%(mass fraction). The result of in vitro release shows that the release behavior of 5-FU from NPs is coincident with Zero-level release from the second day.

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