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25 July 2010, Volume 26 Issue 4

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Cover and Content of Chemical Research in Chinese Universities Vol.26 No.4(2010)

2010, 26(4):  0. 

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Articles

Synthesis, Structure and Luminescence of Zn_4.5Cu₃ Heteronuclear Coordination Polymer Comprising Macrocyclic Oxamide and 5-Sulfosalicylic Ion

SUN Ya-qiu*, WANG Jing, FAN Lan-lan and GAO Dong-zhao

2010, 26(4):  501-504. 

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The complex [Zn_4.5(SSA)₃(CuL)₃(H₂O)₆]_n was synthesized and structurally determined, where SSA is fully deprotonated 5-sulfosalicylic acid(CuL, H₂L=2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca- 7,13-dien). The title complex crystallized in the triclinic system with space group P1, a=1.19788(17) nm, b=1.4253(2) nm, c=2.2890(4) nm, α=90.211(2)°, β=93.076(2)°, γ=90.600(2)°. The complex displayed a 1D ladderlike chain. All these 1D chains were further interlinked via hydrogen bonds, resulting in a 2D architecture. The luminescent property of the compound was also discussed.

Hydrothermal Synthesis of AgLnMo₂O₈(Ln=La, Nd, Eu) Hierarchical Structures: Growth Mechanism and Photoluminescence Property

YUAN Rui-rui, WU Da-peng, JIANG Yi, LI Xia, ZHAO Min and JIANG Kai*

2010, 26(4):  505-508. 

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Uniform AgLnMo₂O₈(Ln=La, Nd, Eu) hierarchical architectures were firstly synthesized via a facile hydrothermal method. These three dimensional architectures were assembled from primary micro-rods and the average diameter was about 5 mm. According to the time-depend experiments, a possible growth mechanism was proposed to be a self-assembling process followed by an Ostwald ripening step. The concentrations of precursor and pH value were also found to have great influences on the final morphologies of the products. In addition, the photoluminescence properties of the products were investigated.

Structure and Antibacterial Activity of Modified Montmorillonite

XIE Yu-shan, TAN Shao-zao*, LIAO Ma-hua and LIU Ren-fu

2010, 26(4):  509-513. 

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Tetradecyldimethylbenzyl ammonium salt(TDMBA) cations were intercalated into sodium montmorillonite(Na-MMT) by an ion exchange reaction. The resulting TDMBA-MMT was characterized by Fourier-transform infrared spectroscopy(FTIR), thermogravimetric analysis(TGA), and X-ray diffraction(XRD). Moreover, the antibacterial activity and water-resistance of TDMBA-MMT were investigated. The results show that TDMBA cations are intercalated into the Na-MMT. The onset temperature of decomposition of TDMBA cations in TDMBA-MMT is raised about 60 °C higher than that of tetradecyldimethylbenzyl ammonium chloride(TDMBACl), and the d₍₀₀₁₎ spacing enlarged from 1.23 nm to 2.10 nm. 0.1 mg/mL TDMBA-MMT is fully enough to kill all the Staphylococci aureus(S. aureus) and more than 99.99% of the Escherichia coli(E. coli) in a sample solution within 6.0 h touch, and the TDMBA-MMT also shows long acting properties.

Synthesis of Novel Quaternary Selenide K₂CdSnSe₄

ZHANG Li-dan*, HAN Chun-ying, FENG Xiu-ling, WEI Yong-ge and GUO Hong-you

2010, 26(4):  514-516. 

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A novel quaternary metal selenide, K₂CdSnSe₄, was synthesized via a molten-salt reaction at 550 C. The compound has a one-dimensional structure containing a chain of ¹_∞[CdSnSe₄]^2– anions separated by K⁺ cations. The crystal belongs to the space group I-42m, with the unit cell parameters a=0.80298(11) nm, b=0.80298(11) nm, c=0.69217(14) nm, α=β=γ=90°. A reflectance spectroscopy study reveals the nature of the semiconductor with an energy gap of 1.7 eV for the compound and it has a strong optical absorption in a range of 2—5 eV.

Hydrothermal Synthesis and Characterization of Double Perovskites RSrMnFeO₆(R=La, Pr, Nd, Sm)

ZHANG Gang-hua, YUAN Hong-ming, CHEN Yan, LI Wei-juan, YANG Mei-qi and FENG Shou

2010, 26(4):  517-521. 

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A series of double perovskites RSrMnFeO₆(R=La, Pr, Nd, Sm) was synthesized under mild hydrothermal conditions. Crystal growths of the samples were sensitive to alkalinity, temperature, filling fraction, and composition of initial reaction mixture. The desired series of compounds belongs to the class of AA′BB′O6 perovskites with a random distribution of Mn and Fe atoms over the B-cation sub-lattice. Their structures show the distorted orthorhombic symmetry with space group Pnma. The shapes and sizes of the crystals were analyzed on a Rigaku JSM-6700F by scanning electron microscopy. Analysis done by XPS, M?ssbauer spectroscopy and iodometric titration reveals that Mn and Fe ions have +4 and +3 oxidation states, respectively.

Microfluidic System for Synthesis of Trigonal Selenium Nanowires

BIAN Tian-bin, YIN Xue-feng* and LIU Jin-hua2

2010, 26(4):  522-526. 

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A microfluidic system was developed for the synthesis of trigonal selenium(t-Se) nanowires, which was composed of a glass microchip coupled with a poly(methyl methacrylate)(PMMA) microchip. In the glass microchip, amorphous selenium(a-Se) colloid was prepared by reducing selenious acid with an excess amount of hydrazine at a temperature of 100 °C. In the coupled PMMA microchip, a-Se was transformed into more stable t-Se seeds via sonication at room temperature. The residence time of the reactants in both microchips was optimized by varying the dimension and length of the microchannel each. The t-Se nanowires were formed by anisotropic growth of selenium crystallite during sonication and aging under the assistance of β-cyclodextrin(β-CD). Various stages of the nanowires’ growth were investigated. The as-synthesized products were characterized by powder X-Ray diffraction(XRD), Raman spectroscopy, scanning electron microscopy(SEM), transmission electron microscopy(TEM) and selected-area electron diffraction(SAED).

Analysis of Ginsenosides by SPE-HPLC and Its Application to Quality Control

QU Chen-ling*, ZHANG Han-qi, WANG Jin-shui, ZHANG Rui and YU Song-cheng

2010, 26(4):  527-531. 

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A rapid and effective method, solid phase extraction coupled with high performance liquid chromatography(SPE-HPLC), was applied to the separation and analysis of ginsenosides. Waters OASIS HLB was used for concentrating and purifying samples and Alltima C₁₈(53 mm×7 mm, 3 μm) chromatography column was used for separating ginsenoside Rg₁, Re, Rb₁, Rc, Rb₂ and Rd. These ginsenosides were analyzed within 20 min in our gradient elution process and the equilibrium time of the chromatography column cost only 5 min. Moreover, there was no obvious baseline drift in our experiment. This method was used to analyze the contents of ginsenosides in different ginseng products for quality control. Four ginseng products were studied, including two kinds of capsules, one kind of tablet and one kind of injection. The results show that the method developed in this paper had good accuracy, linearity and precision. Therefore, this method could be applied in quality control of ginseng products.

Evaluation of Retention Factors for Nine Solutes with Ionic Liquid Additives via Linear Solvation Energy Relationships

ZHU Tao, TIAN Ming-lei and ROW Kyung-Ho*

2010, 26(4):  532-536. 

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A linear solvation energy relationships(LSERs) model was used to examine the fundamental chemical interactions governing the retention of 9 organic compounds on a C₁₈ column by means of reversed-phase high performance liquid chromatography(RP-HPLC). Three ionic liquids, 1-hexyl-3-methylimidazolium tetrafluoroborate ([Hmin][BF₄]), 1-butyl-3-methylimidazolium tetrafluoroborate([Bmin][BF₄]) and 1-octyl-3-methylimidazolium   tetrafluoroborate([OMIm][BF₄]) as additives, were added to a methanol-water mobile phase. The effects of these three ionic liquids additives on the retention of nine organic compounds were investigated, and a comparison between the predicted and experimental retention factors was made via the LSERs model, which indicated that the LSERs model could be used to reproduce the experimental retention factors of the solutes under different mobile phase conditions. It is also a useful tool for modeling the interactions of the solutes between the stationary and mobile phases and evaluating the retention characteristics of HPLC.

Determination of Metamizole Sodium by Cyclic Voltammetry Under Microwave Activation

LI Li-jun*, CHENG Long-jun, CAI Zhuo, LAN Su-mei, GUO Xiao-fei and LI Yan-qing

2010, 26(4):  537-540. 

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Microwave radiation was applied to the detection of metamizole sodium by cyclic voltammetry. The electrochemical characteristics of metamizole sodium were studied by cyclic voltammetry at GC electrode under microwave radiation and a considerable current enhancement was observed for metamizole sodium in aqueous 0.05 mol/L H₂SO₄. Under the optional conditions, metamizole sodium was determined in the absence and presence of microwave activation. In the absence of microwave activation cyclic voltammogram of metamizole sodium shows good linear relationship in a concentration range of 8.0×10^–5―1.0×10^–3 mol/L in aqueous 0.05 mol/L H₂SO₄ with a detection limit of 6.75×10^–6 mol/L(S/N=3) and the equation of linear regression is I_p=12.973c–0.1905(R²=0.9996, n=6); in the presence of 80 W microwave activation cyclic voltammogram of metamizole sodiumin shows good linear relationship in a concentration range of 4.0×10^–5―1.0×10^–3 mol/L in aqueous 0.05 mol/L H₂SO₄ with a detection limit of 4.41×10^–6 mol/L(S/N=3) and the equation of linear regression is I_p=25.107c–0.1193(R₂=0.9973, n=7). The current in the presence of 80 W microwave activation increases to about 2 orders of magnitude compared with that in the absence of microwave activation. The proposed method in the presence of microwave activation showed high selectivity and sensitivity, and the sampling of the disposal method is simple. The method was verified by the determination of Metamizole Sodium tablet with satisfactory results.

Amperometric Hydrogen Peroxide Biosensor Based on Multiwall Carbon Nanotubes and Cadmium Sulfide Quantum Dots

ZHANG Jin-lei, TAN Xue-cai*, ZHAO Dan-dan, TAN Sheng-wei, HUANG Zeng-wei, ...

2010, 26(4):  541-545. 

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A novel third-generation hydrogen peroxide(H₂O₂) biosensor(Hb/CdS/MWNTs/GCE) was fabricated through hemoglobin(Hb) adsorbed onto the mercaptoacetic acid modified CdS QDs/carboxyl multiwall carbon   nanotubes’(MWNTs) films. Cyclic voltammogram of Hb/CdS/MWNTs/GCE showed a pair of well-defined and  quasi-reversible redox peaks with a formal potential(E⁰') of –0.230 V(vs. Ag/AgCl) in 0.1 mol/L pH=8.0 phosphate buffer solution(PBS), which was the characteristic of the Hb heme Fe(III)/Fe(II) redox couple. The biosensor shows an excellent electrocatalytic activity to the reduction of H₂O₂. The response time of the designed biosensor to H₂O₂ at a potential of –0.30 V was less than 2 s and linear relationships were obtained in the concentration ranges of 2.0×10^–6―2.7×10^–3 mol/L and 2.7×10^–3―7.7×10^–3 mol/L with a detection limit of 3.0×10^–7 mol/L(S/N=3). The  apparent Michaelis-Menten constant K_m was estimated to be 1.324 mmol/L that illustrated the excellent biological activity of the fixed Hb.

Synthesis and Complexation Properties of Novel Chiral Calix[4]-1,3-aza-crown and Calix[4]arene Hydrazone Derivative

YANG Fa-fu*, HUANG Zhi-sheng, GUO Hong-yu, HONG Bi-qiong and ZHANG Xiao-yi

2010, 26(4):  546-549. 

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Refluxing calix[4]-1,3-substituted benzaldehyde derivative(4) with glycine hydrazide derivative, we obtained a novel calix[4]arene hydrazone derivative(5) via “1+2” condensation in a yield of 78%. In the reaction of compound 4 with L-leucine hydrazide derivative at room temperature, lariat calix[4]-1,3-aza-crown(6) with chiral amino acid group as branched chain was synthesized via “1+1” addition in a yield of 70%. The preliminary extraction experiments suggested that hosting compounds 5 and 6 possessed good complexation abilities for α-amino acids.

Catalytic Synthesis of Methylene Diphenyl Dicarbamate in AcOH/H₂O Mixed Solvent

PEI Yi-xia, LI Hui-quan*, LIU Hai-tao, ZHANG Qin-hua and ZHANG Yi

2010, 26(4):  550-553. 

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In a mixed solvent of acetic acid(AcOH)/water, methylene diphenyl dicarbamate(MDC) was synthesized by the condensation of methyl phenyl carbamate(MPC) and formaldehyde in the presence of an inorganic acid catalyst. Based on the different solubilities to MPC and MDC, the mixed solvent showed higher catalytic performance than pure water. The mixed solvent not only promoted the condensation of MPC but aslo exhibited the advantage of the product separation with the reactants. Under the optimized conditions: a H₂SO₄ mass fraction of 31%, a reaction temperature of 95 °C and reaction time of 3.5 h, the yield of MDC reached 74.3%. In addition, the recycle of the solvent was also investigated.

[Bmim]OAc Catalyzed Michael Addition of Active Methylene to α,β-Unsaturated Carboxylic Esters and Nitriles

YANG Yu, WANG Li-bing, ZHANG Zhan, LI Cai-meng, FU Xian-lei and GAO Guo-hua*

2010, 26(4):  554-557. 

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Michael addition of active methylene compounds to α,β-unsaturated carboxylic esters and nitriles was effectively catalyzed by a basic ionic liquid, 1-butyl-3-methylimidazolium acetate([Bmim]OAc). The bis-addition products were selectively obtained in high yields under mild reaction conditions.

Synthesis and Cytotoxicity of Novel Diaryl Ureas Containing 2-Amino-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidinyl Group

YAO Peng, XUE Hao, LIU Qian, LIU Hong-tao, CHEN Ming-jia and GONG Ping*

2010, 26(4):  558-562. 

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A series of 2-amino-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidinyl substituted diaryl urea derivatives was designed and synthesized. Their in vitro cytotoxicities against two cancer cell lines(Bel-7402 and A549) were evaluated by standard MTT assay. Six of tested compounds 6, 8, 10, 17, 21 and 22 exhibited more potent cytotoxicity superior to sorafenib. The structure activity relationship(SAR) study indicates that 2-amino-5,6,7,8-tetrahydropyrido- [4,3-d]pyrimidinyl group was an option for cytotoxic potency.

New Chemical Compound from Caragana jubata (pall.) Poir.

SONG Ping*, YANG Xin-zhou and YU Jun

2010, 26(4):  563-566. 

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A new pterocarpan glycoside, (–)-maackiain 3-O-6'-O-acrylyl-β-D-galactopyranoside(1) was isolated from the whole parts of Caragana jubata(pall.) Poir., together with three known pterocarpan glycosides, (–)-maackiain 3-O-6'-O-acetyl-β-D-glucopyranoside(2), (–)-maackiain 3-O-β-D-glucopyranoside(3) and (–)-maackiain 3-O-β-D-galactopyranoside(4). All the compounds were isolated from the title plant for the first time. The structure of the new compound was established on the basis of detailed 1D, 2D NMR and circular dichroism spectroscopic analyses. All the compounds were evaluated for their cytotoxic activities against three tumor cell lines, A549, HL-60 and P388.

Preparation and Inhibitory Effects of 20(S)-Ginsenoside Rh₂ on Hep-A-22 Cells

ZHOU Hong-yu, JIN Yong-ri, WEI Wei, SHI Xiao-lei, YANG Rui-jie, YANG Shi-jie,...

2010, 26(4):  567-571. 

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A modified method of preparing 20(S)-ginsenoside Rh₂(G-Rh2) and the inhibitory effect of 20(S)-ginse- noside Rh₂ on Hep-A-22 cells were investigated. The total saponins and strong alkali were dissolved in glycerol at the atmospheric pressure, and the degradation was performed at a high temperature. After G-Rh₂ had been isolated and purified, MTT(methyl thiazolyl tetrazolium) assay was applied to evaluating the effect of 20(S)-ginsenoside Rh₂ on the cells viability and morphological changes were observed. It was shown that 20(S)-ginsenoside Rh₂ can reduce Hep-A-22 cells viability in dose-dependent manner and the cells took on cell shrinkage, membrane blebbing, chromosomal condensations, especially under the higher concentrations of it. In conclusion, 20(S)-ginsenoside Rh₂ can be prepared effectively that not only decreases viability but also induces the apoptosis of Hep-A-22 cells.

Syntheses and Crystal Structures of Calix[4]arene Dithiocarbazate Schiff Bases

SUN Jing, LIU Dong-mei, WANG Jin-xiang and YAN Chao-guo*

2010, 26(4):  572-577. 

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The regioselective syntheses of novel p-tert-butylcalix[4]arenes with functional aldehyde and dithiocarbazate Schiff base groups were carried out. p-tert-Butylcalix[4]arene was alkylated with o-, p-(ω-chloroalkoxy)-benzaldehydes in the system of K₂CO₃/KI/CH₃CN to give calixarene 1,3-dialdehydes. Then the condensation reactions of active calixarene aldehydes with S-methyl and S-benzyldithiocarbazate, calixarene sulfur-containing Schiff bases were efficiently obtained in satisfied yields. The single crystal analysis of the four representative products shows that calixarene aldehydes and Schiff bases exist in cone conformation and there are interesting intermolecular hydrogen-bands and π···π interaction in the crystals.

Expression and Emmprin Regulated Function of Aquaporin1 in SMMC7221 Cells

LI Jiang, ZHANG Ai-li, TONG Qian, ZHANG Jun-fang, LI Hai-jing, ZHAO Bing, ...

2010, 26(4):  578-582. 

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Herein lie the crosstalk and regulation between AQP1 and Emmprin in SMMC7221 cells by means of siRNA technology and deglycosylation method. Firstly, HAQP1, rather than hAQP3, was selectively upregulated in SMMC7221 cells by FBS, flollowed by the upregulated expression of Emmprin. Emmprin gene silencing caused a remarkable change in the expression of AQP1 gene, just like its downstream gene, MMP9, meanwhile the water permeability and cell migration were also descended prominently. Furthermore, when treated with tunicamycin, Emmprin was deglycosylated, which made the expression of AQP1 significantly declined, followed by remarkably decreased cell membrane water permeability and cell migration. Taken together, all the data indicates the expression level and the modification of Emmprin by glycosylation are the key factors in regulating the expression of AQP1.

Isolation and Characterization of Two Novel Gene Encoded Alkaline Esterases from an Alkaline Soil Metagenomic Library

LU Yang, LIU Xiang-guo, YU Ying, QU He-zhi, YANG Shuo, NING Bo, ...

2010, 26(4):  583-590. 

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The development of industrial biotechnology has created an increasing demand for alkaline lipolytic enzymes with functional diversity. In this study, an alkaline soil metagenomic library was constructed to search for new lipolytic enzymes. Two novel gene encoded alkaline esterases(designated as estA and estB) were isolated by functional screening from the library. The estA gene consisted of 834 bp and coded for 277 amino acids with a molecular mass of 29998. Amino acid sequence homology analysis indicates that EstA belongs to α/β hydrolase fold family 4.4(abH4.4), with EstA being the smallest member of that family yet reported. The estB gene consisted of 1185 bp and encoded 394 amino acids with a theoretical molecular mass of 40090. Its conserved domain analysis shows that EstB belongs to the GDSL hydrolase superfamily. Both EstA and EstB exhibit only moderate identity(<38%) in amino acid sequence to the known lipolytic enzyme genes in the database. The two genes were respectively expressed in Escherichia coli and the protein products were purified for functional characterization. While the expressed EstA did not exhibit the functional properties that were superior to those of other esterases previously reported, the EstB was stable at temperature up to 45 °C and its maximum activity was measured to be 53.6 U/mg at pH=10. Both the enzymes have further enriched the diversity of the lipolytic enzymes database and also appear to be promising biocatalysts for potential biotechnological application.

Purification and Characterization of Protein Tyrosine Phosphatase MEG1 and Preparation of Anti-PTPMEG1 Antibody

ZHANG Xiao-ping, XING Shu, WU Xiao-xia, LIN Fan, FU Xue-qi and LI Wan-nan

2010, 26(4):  591-595. 

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PTPMEG1 is an intracellular protein tyrosine phosphatase(PTP), which contains FERM and PDZ domains. This study focuses our attention on the expression, purification and characterization of catalytic domain of PTPMEG1(DMEG1) and preparation of its polyclonal antibody. A cDNA fragment encoding DMEG1 protein(amino acid residues 643―926) was amplified by PCR and then cloned into the pT7-7 vector. Both soluble and insoluble recombinant DMEG1 proteins were observed after induction by IPTG. Soluble DMEG1 was purified via two chromatographic steps, and the purified enzyme was characterized. With para-nitrophenylphosphate(pNPP) as a substrate, DMEG1 exhibited typical enzymatic characteristics of classic PTPs and classical Michaelis-Menten kinetics. Insoluble DMEG1, which was mainly distributed in the inclusion body of E. coli cells extracts, was purified by preparative electrophoresis gel for the preparation of the polyclonal antibody. A rabbit was immunized with DMEG1 purified by preparative electrophoresis to generate anti-DMEG1 antibody. Anti-serum was collected on 28th day after initial injection and purified via affinity chromatography. The purified polyconal antibody displayed a satisfactory titer and sensitivity.

Differential Expression of Molecular Chaperones in PC12 Cells Treated with PSI

LIU Tao, JIN Ying-hua, ZHANG Yu, CHANG Ming, WANG Dan-ping and HU Lin-sen*

2010, 26(4):  596-603. 

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Parkinson’s disease(PD) is a common neurodegenerative disorder whose primary pathology features are the degeneration of dopaminergic neurons in the substantia nigra pars compacta(SNc) and the presence of eosinophilic inclusions called Lewy body in the cytoplasm of the remained neurons. Growing evidence suggests that dysfunction of the ubiquitin-proteasome system(UPS) is involved in the etiopathogenesis of PD. In order to investigate the pathogenetic mechanism of ubiquitin-proteasome dysfunction in PD, 2D-differential gel electrophoresis(2D-DIGE) and MALDI-TOF Pro MS were used to determine the proteins, which were differentially expressed, in PC12 cells that had undergone a synthetic proteasomal inhibitor PSI(10 μmol/L) treatment for 24 h. Forty-six protein spots were differentially expressed in response to PSI administration, of which 34 were increased and 12 decreased. Six of these were identified as molecular charperones: endoplasmin precursor(GRP94), heat shock protein 105(HSP105), HSC-70-psl, glucose ruglated protein 75(GRP75), glucose ruglated protein 58(GRP58) and heat shock 27000 protein 1(HSP27). The results suggest that the molecular chaperones play an important role in the PD model induced by proteasomal inhibitor.

Screening and Identification of a Targeting Peptide to nGLP-1R from Phage Display Peptide Library

REN Hui, XIONG Xin-hui, JIANG Tao, ZHANG Yang-de*, WEI Zhong-hang, ...

2010, 26(4):  604-607. 

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In order to provide the structure information for designing new exendin-4 analogues, a phage display peptide library was screened by targeting the N-terminal extracellular domain of GLP-1R(nGLP-1R). After four rounds of selection, nine sequences were obtained, four of them have higher affinity for nGLP-1R than the others. We chose two of them named X and Y peptides. Islet β-cell proliferation assay suggested that X and Y peptides didn’t have any activity to increase islet β-cell proliferation. In other words, X and Y peptides were not agonists to GLP-1R. However, the conservative motifs of X and Y peptides provided us useful information to design new exendin-4 analogues.

Effect of CC Coherent Vibration on Relative Raman Scattering Cross Sections of All-trans β-Carotene

2010, 26(4):  608-611. 

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We have determined the Raman scattering cross sections(RSCSs) of β-carotene for C=C and C―C stretching modes, with the 1444 cm^–1 Raman band of cyclohexane as internal standard, in different solvents at low concentrations by measuring Raman intensity. The results show that RSCSs of β-carotene were 10⁶―10⁷ times larger than the general RSCSs, we analyzed that this enhancement was caused not only by the resonance Raman effect but also by nonlinear coherent CC vibration in aqueous β-carotene. Moreover, overtone and combinations of it were also observed and their intensities were 10%―20% of those of their fundamentals when β-carotene was dissolved in non-polar solvents, respectively.

Colloid of Delaminated Layered Double Hydroxides: a Novel Type of LDH-based Catalyst

LIU Shi-yong

2010, 26(4):  612-616. 

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The colloid of delaminated layered double hydroxides(LDHs), a new LDH-based catalyst, is described. The semi-heterogeneous delaminated colloidal MgPdAl-LDH, in which the total surface of catalytic site-bearing lamellae was rendered accessible for chemical reactivity, showed excellent catalysis toward Suzuki reaction. The turnover frequency of this catalyst for Suzuki reaction between bromobenzene and phenylboronic acid is about 8000 h^–1.

Self-assembly of Liposomes Loading Hinesol by Rapid Expansion from Supercritical to Surfactant Solution

WEN Zhen*, YOU Xin-kui, LIU Bo, ZHENG Zong-kun, PU Yi-tao and LI Qiong

2010, 26(4):  617-621. 

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To improve the encapsulation efficiency and minimize particle agglomeration of liposomes, rapid expansion from supercritical to surfactant solution(RESSS) was applied to self-assembly of liposomes entrapping hinesol in supercritical carbon dioxide(SC-CO₂) medium. In the process, the solution of liposomal materials and hinesol dissolved in the mixture of SC-CO₂/ethanol was sprayed into a surfactant solution. The surfactant provided stabilization for liposomes by preventing bubbles overflowing and liposomes agglomeration during the spraying process. The encapsulating performance and particle size distribution of liposomes could be controlled by changing expansion processing conditions. When the solution was sprayed into a 5.0% Poloxamer l88 solution at a flow rate of 2 L/min, the entrapment efficiency and average particle size of liposomes were found to be 88.26% and 124 nm, respectively, which came to the standards of Chinese pharmacopoeia. The results show RESSS process provides an innovative method for formation of liposomes incorporating valid compositions extracted from the Chinese traditional medicines in SC-CO₂ medium.

Co,K-Supported Hexagonal Mesoporous Silicas for Catalytic Oxidation of 4-t-Butyltoluene

YU Wei-hua*, ZHOU Chun-hui, TONG Dong-shen, FANG Mei and ZHANG Bo

2010, 26(4):  622-625. 

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Co,K-Supported hexagonal mesoporous silicas(HMS) have been prepared by incipient wetness impregnation with cobalt acetate tetrahydrate and potassium acetate as metal precursors, and ethylene glycol as impregnation solvent. The products have been characterized via powder X-ray diffraction, N2 adsorption-desorption isotherms and diffuse reflectance UV-Vis spectroscopy. The divalent cobalt with a tetrahedral oxygen coordination exists mainly in the calcined samples. The catalytic properties have been tested for the oxidation of 4-t-butyltoluene with dioxygen in liquid phase at mild conditions. The products offered good catalytic activities in the oxidation reactions. Co-K-HMS catalyst with loading 4% Co and 2% K(mass fraction) affords a higher yield(22.4%) of 4-t-butylbenzaldehyde at a conversion of 28.3% under the reaction conditions. Adding a proper amount of potassium in Co-HMS results in an improvement catalytic activity and stability.

Evaluation of Thermal Hazard of Composite Modified Double-base Propellant by Microcalorimetery Method

XUE Liang, ZHAO Feng-qi*, XING Xiao-ling, XU Si-yu, PEI Qing, GAO Yin and HU Ron

2010, 26(4):  626-629. 

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The thermal decomposition behavior of composite modified double-base(CMDB) propellant containing cyclotrimethylene trinitramine(RDX) was studied via a Calvet microcalorimeter at five different heating rates. The activation energy(E) and the pre-exponential factor(A) of two obvious exothermic processes were obtained by Kissinger’s method and Ozawa’s method. The entropy of activation(ΔS^≠), the enthalpy of activation(ΔH^≠), and the free energy of activation(ΔG^≠) of the first stage were calculated. To evaluate the thermal hazard of the RDX-CMDB propellant, the critical temperature of thermal explosion(T_b), the self acceleration decomposition temperature(T_SADT), the adiabatic decomposition temperature increment(ΔT_ad) and the time-to-explosion of adiabatic system(t) were presented as 145.3 °C, 138.15 °C, 1634 K and 583.71 s(n=0) and 586.28 s(n=1), respectively.

Electrochemical Oxidation of Chlorimuron-ethyl on Ti/SnO₂-Sb₂O₅/PbO₂ Anode for Waste Water Treatment

YU Shi-jun, XUE Bin, WANG Jian-ya*, SUN Jian and SHEN Zhi-qiu

2010, 26(4):  630-635. 

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The electrochemical oxidation of chlorimuron-ethyl on Ti/SnO₂-Sb₂O₅/PbO₂ electrode was studied by cyclic voltammetry. The electrochemical behaviour of the electrode in a sodium sulfate solution and in the mixture solution of sodium sulfate and chlorimuron-ethyl was studied. The experimental results of cyclic voltammetry show that the acidic medium was suitable for the efficient electrochemical oxidation of chlorimuron-ethyl. Some electro-generated reagent was formed in the electrolysis process and chlorimuron-ethyl could be oxidized by the electro-generated reagent. A Ti/SnO₂-Sb₂O₅/PbO₂ electrode was used as the anode and the electrolysis experiment was carried out under the optimized conditions. The electrolysis process was monitored by UV-Vis spectrometry and high performance liquid chromatography(HPLC), and the chemical oxygen demand(COD) was determined by the potassium dichromate method. The mechanism of chlorimuron-ethyl to be oxided was studied primarily by the cyclic voltammetry and UV-Vis spectrometry. The results of electrolysis experiment demonstrate the possibility of the electrode to be used as an anode for the electrochemical treatment of chlorimuron-ethyl contained in waste water.

Determination and Correlation of 1-Octanol/Water Partition Coefficients for Six Quinolones from 293.15 K to 323.15 K

ZHANG Cong-liang* and WANG Yan

2010, 26(4):  636-639. 

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A shake-flask method was used to determine 1-octanol/water partition coefficients of ofloxacin, norflo- xacin, lomefloxacin, ciprofloxacin, pefloxacin and pipemidic acid from 293.15 K to 323.15 K. The results show that 1-octanol/water partition coefficient of each quinolone increased with the increase of temperature. Based on the fluid phase equilibrium theory, the thermodynamic relationship of 1-octanol/water partition coefficient depending on the temperature was proposed, and the changes of enthalpy, entropy, and Gibbs free energy for quinolones partitioning in 1-octanol/water were determined, respectively. Quinolones molecules partitioning in 1-octanol/water was mainly an entropy driving process, during which the order degree of system decreased. The temperature effects of 1-octanol/water partition coefficient were investigated. The results show that its magnitude is the same as the values in the literature.

Electrochemical Synthesis and Magnetic Studies of Ni-Fe-Co-Mn-Bi-Tm High Entropy Alloy Film

YAO Chen-zhong, ZHANG Peng, TONG Ye-xiang*, XIA Dao-cheng and MA Hui-xuan

2010, 26(4):  640-644. 

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Amorphous Ni-Fe-Co-Mn-Bi-Tm high entropy alloy films were firstly prepared by potentiostatic electrodeposition. The results indicate that the six elements can be co-deposited in an organic system of DMF (N,N-dimethylformamide)-CH₃CN. The surface of the film is composed of compact and uniform particles with triangular cone shape and a particle size of 100—200 nm. A simple face-centered-cubic structure is identified by XRD patterns after the films were annealed under Ar atmosphere. The annealed alloy film shows soft magnetic properties and the magnetization decreases with Fe content decreasing.

Manipulation and Separation of Particles of Metal Oxides by Dielectrophoresis

CHEN Hui-ying* , ZHU Yue-lin, LIU Yan, ZHANG He-teng, YU Le and LI Di

2010, 26(4):  645-648. 

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With the development of nanotechnology, the separation and manipulation of micro-nano-particles have become a research focus in the field of nano-materials. Dielectrophoresis(DEP) is a non-contact technology for the separation and manipulation of micro-nano-particles. Here is reported the design and fabrication of a DEP based microchip with microelectrode arrays for capturing micro-particles of inorganic oxides in petroleum. The DEP behavior of micro-particles of inorganic oxides in oil media was explored via this microchip. The microchip shows relatively a good DEP response to inorganic oxides in oil media. Furthermore, much more factors were explored such as frequency(Hz), and particle size(μm), as well as metal valence. As a conclusion, the best frequency is 50 Hz. It is expected to capture particles with different sizes or separate different oxide particles by regulating DEP conditions. Thus, a new method could be established for the separation and purification particles of different oxides, as well as the separation and manipulation of an oxide with different particle sizes.

Fabrication and Photoelectrochemical Properties of [Ru(bpy)₂dppz]²⁺ on ITO Electrode Associated with the Oxidation of Guanine

GUO Qing-yu, LI Hong*, YANG Hui-yi and SHAO Jiang-yang

2010, 26(4):  649-655. 

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Electrochemical assembly of [Ru(bpy)₂dppz]²⁺{bpy=2,2′-bipyridine, dppz=dipyrido[3,2-a:2′,3′-c]phena- zine} on an ITO electrode in the presence of guanine and photoelectrochemical properties of the assembled layer were investigated. It has been found that [Ru(bpy)₂dppz]^3+/2+ can be assembled onto the ITO electrode by the method of repetitive voltammetric sweeping, and the assembly is enhanced by guanine. The peak currents of prewaves increase linearly up to a guanine concentration of 0.25 mmol/L. More importantly, upon illumination with 470 nm light source and at an applied potential of 0.2 V, cathodic current for the fabricated layer on the ITO electrode indicate a linear enhancement with the rise of guanine concentration. Meanwhile, [Ru(bpy)₂dppz]²⁺ can be served as an excellent mediator to prompt the oxidation of guanine, and the mediated peak current increases linearly with added guanine concentration from 0.01 to 0.25 mmol/L. In addition, the assembly mechanism of [Ru(bpy)₂dppz]²⁺ on the ITO electrode associated with the oxidation of guanine and the assistance of light irradiation were discussed.

Ab-initio Investigation on Ion-associated Species and Association Process in NaNO₃ Solution

ZHANG Hao, FENG Bo, YU Jian-kang* and SUN Chia-chung

2010, 26(4):  656-661. 

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Some ion-associated species existed possibly in NaNO₃ solution were investigated via the ab-initio method. The hydrated ion parings, triple and multiple ion clusters in NaNO₃ solution are all analogous to those in Mg(NO₃)₂ system except that the bi-dentate structures can not be formed. Only one solvent-shared ion paring has larger v₁-NO₃^-  frequency than the hydrated NO₃^- ion. And all triple clusters with two hydrated Na⁺ ions and one NO₃^- have larger v₁-NO₃^-  frequency than the hydrated NO₃^- ion. The ion association process in NaNO₃ solution is predicted as free ions→solvent-separated ion pairings→solvent-shared ion pairings→solvent-shared triple ion clusters→contact triple ion clusters→contact multiple ion clusters→amorphous NaNO₃, which is not analogous to that in MgSO₄ but those in Mg(NO₃)₂ and Mg(ClO₄)₂ systems.

Fabrication of Novel Scaffolds Containing Collagen-I/Polylactic Acid/Nanohydroxyapatite via Co-electrospinning Methods

ZANG Jun-ting, QI Xin, LI Shu-qiang, LI Dong-song, GONG Yu-bao, YANG Chen, ...

2010, 26(4):  662-666. 

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A novel scaffold containing collagen-I/polylactic acid(PLA)/nanohydroxyapatite(nHA) was prepared via co-electrospinning method. Different target substrates were used to improve the collection efficiency of this scaffold. The properties of the novel scaffold were compared with those of conventionally prepared ones. Compared to conventional method, the modified method was more efficient in producing the scaffold. Moreover, the porosity, thickness, and morphology of the novel scaffold were better than those of scaffolds prepared by conventional methods. The properties of collagen-I, collagen-I/PLA and collagen-I/PLA/nHA scaffolds were also compared. Diameters of the electrospun fibers ranged from 180 to 405 nm, and roughness was present on the surface of the fibers due to the deposition of crystals of nHA along the long axis of the fibers. The fibers of the collagen-I/PLA/nHA scaffold and the fibers of natural bone tissue had similar structure.

Isolation of Hemicellulose from Wood Chips via Extraction with Kraft Green Liquor

SUN Hui*, XU Ying-kai and XU Guo-zhi

2010, 26(4):  667-671. 

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The present paper covers the extraction of hemicelluloses from woods, i.e., Eucalyptus Globulus, white fir and Douglas fir via green liquor pretreatment and alkali post-treatment with sodium hydroxide. The effects of such extraction conditions as extraction time, temperature on the yields of hemicellulose and the degree of deliginification were investigated. Sugar analyses using Dionex indicate that xylose, glucose and mannose are the main sugar types present in the hemicellulose from Eucalyptus. Other sugar components such as arabinose and galactose were also found in Dogulas fir hemicellulose. The highest yield of hemicellulose was 8.4% for Eucalyptus extracted with green liquor at 130 °C for 3.5 h. Further sodium hydroxide extraction for 5 h gave a hemicellulose yield of about 20%. The use of green liquor for the extraction of wood hemicellulose is believed to be the first attempt.

Letter

Synthesis and Characterization of Fluorine-containing Poly(ether ether ketone)s

ZHANG Pei, ZHAO Yun, TANG Xin-liang, ZHOU Ming-ji and JIAO Qing-ze*

2010, 26(4):  672-674. 

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The fluorine-containing poly(ether ether ketone)s (FPEEK) were prepared from o-fluorine hydroquinone and 4,4-difluorobenzophenone to introduce fluorine atom via nucleophilic aromatic substitution polymerization. o-Fluorine hydroquinone was synthesized through Elbs reaction. Fourier transform infrared spectra (FTIR) and nuclear magnetric resonance (1HNMR) were used to determine the structure of the monomer and polymer. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) as well as scanning electron microscopy (SEM) were used to characterize the properties of the polymer. The polymer exhibits good solubility, excellent thermal stability, low dielectric constant and low water absorption.