Chem. J. Chinese Universities

Cover and Content of Chemical Journal of Chinese Universities Vol.33 No.9(2012)

2012, 33(09): 0-0.

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Synthesis and Function of Stimuli-responsive Polymer Systems

YAN Qiang, YUAN Jin-Ying

2012, 33(09): 1877-1885. doi:10.3969/j.issn.0251-0790.2012.09.001

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Stimuli-responsive polymer is a class of macromolecular system with smart behavior. Their macromolecular structure and state can be great changed in response to external stimuli, such as pH value, light, thermal, voltage, redox and gas. Then their physicochemical properties will be influenced and the functiona-lities will be realized. Stimuli-responsive polymers have shown wide prospective applications in the fields of nanomaterials, life science, medical science and so on. This review introduces the recent progress of the authors’ group on the synthesis, self-assembly, functionality and applications of stimuli-responsive macromolecular systems.

Inhibition Effect of NIR Photothermal Therapy Mediated by Gold Nanoflowers on Proliferation of Human Laryngocarcinoma Hep-2 Cells

SONG Wen-Zhi, JIANG Ya-Ping, JI Xiao-Hui, ZHAO Li-Li, YIN Wan-Zhong, YANG Wen-Sheng

2012, 33(09): 1886-1888. doi:10.3969/j.issn.0251-0790.2012.09.002

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Citrate-capped gold nanoflowers(GNFs) prepared by seeding approach were identified to show efficiently photothermal conversion under the irradiation of 808 nm near-infrared laser. MTT results demonstrate that the photothermal therapy mediated by GNFs inhibits the proliferation of Hep-2 cells effectively, and the inhibition effect increases with the increased concentrations of GNFs and power of the laser. The results of apoptosis and necrosis tested by flow cytometry demonstrate that the photothermal ablation play a predominant role in suppressing the proliferation of the Hep-2 cells. Such citrate-capped GNFs are expected to be a kind of materials potential useful in tumuor NIR photothermal therapy.

Synthesis, Structure and Luminescence Properties of Two 3D Interpenetrating Metal-organic Coordination Polymers of Mixed Ligands with Zn(Ⅱ) and Cd(Ⅱ)

XUE Ming, CHEN Si-Ru, GUO Li-Jia, QIU Shi-Lun

2012, 33(09): 1889-1894. doi:10.3969/j.issn.0251-0790.2012.09.003

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Two new metal-organic coordination polymers [Zn(BPDC)(BPE)·(DMF)₂](JUC-91) and [Cd(BPDC)(BPE)·(DMF)₂](JUC-92)[BPDC:4,4'-biphenyldicarboxylic acid,BPE:trans-bis1,2-二(4-pyridyl)ethylene,DMF:N,N'-dimethylformamide] were synthesized by self-assembly of mixed ligands and corresponding transition metal salts under mild conditions and characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, topology analysis and powder X-ray diffraction. X-Ray crystallography revealed that JUC-91 and JUC-92 exhibited three-dimensional structures with fivefold interpenetrating diamond network and twofold interpenetrating primitive cubic network, respectively. In addition, luminescence properties of JUC-91 and JUC-92 were characterized.

Preparation of Self-assembled Titanate Aggregates with Regular Structure

PAN Yan, GUO Yu-Peng, SONG Wen-Bo, LIU Zhi-Hui

2012, 33(09): 1895-1901. doi:10.3969/j.issn.0251-0790.2012.09.004

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Bird's nest-like self-assembly titanate nanoribbon aggregates, fluff sphere-like self-assembly titanate nanoribbon aggregates and urchin-like self-assembly titanate nanotube aggregates were prepared without template from Ti flake(or TiO₂ powder, P25) under hydrothermal conditions by adjusting NaOH concentration and cooling temperature. Cattail-like self-assembly titanate-sodium carbonate self-assembly complex aggregates were prepared with sodium carbonat as template. A possible two-stage growth mechanism involving the initial formation of primary 1D nanostructures that subsequently self-assemble was proposed. This method will provide a promising approach that the function materials are assembled into highly ordered structure in the ideal way and lend itself to the research on microdevice.

Controllable Reduction and Structural Characterizations of Graphene Oxides

YANG Xu-Yu, WANG Xian-Bao, LI Jing, YANG Jia, WAN Li, WANG Jing-Chao

2012, 33(09): 1902-1907. doi:10.3969/j.issn.0251-0790.2012.09.005

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Graphene with different reduction degree was prepared by controling the reduction time. The structures and properties of graphene were characterized systematically by Fourier transform infrared spectroscopy(FTIR), UV-Vis spectroscopy, Raman spectroscopy, X-ray diffrations(XRD), thermo-gravimetric analysis(TGA) and electrical conductivity measurements. Moreover, transmission electron microscopy(TEM), scanning electron microscopy(SEM) and atomic force microscopy(AFM) were employed to compare the morphologies of graphene oxide with those of graphene. The results showed that with the increase of reduction time, the oxygen-containing groups were removed gradually and the absorption peak of ultraviolet displayed a gradual red-shift, besides, the ratio of the Raman intensities(I_D/I_G) of graphene increased markedly, and the thermal stability was improved significantly. The characterization of microstructures reveals that graphene consists of thicker layer structures and more crumples than those of graphene oxide.

Hydrothermal Synthesis of Ordered Mesoporous Silicas with Extraordinarily Ultra-low Dielectric Constants

LIU Fu-Jian, HAN Bing, CAO Yang, ZOU Yong-Cun, MENG Xiang-Ju, XIAO Feng-Shou

2012, 33(09): 1908-1914. doi:10.3969/j.issn.0251-0790.2012.09.006

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Ordered mesoporous silica samples with extraordinarily ultra-low dielectric constants(k) were hydrothermally synthesized at different temperatures(150—200℃) via soft-templates including amphiphilic triblock polymers of P123(PEO₂₀-PPO₇₀-PEO₂₀) and F127(PEO₁₀₆-PPO₇₀-PEO₁₀₆). The characterizations of XRD and N₂ adsorption-desorption isotherms show that these samples have ordered mesostructure, high BET surface area, large pore volume and uniform pore size.²⁹Si MAS NMR spectra show that the samples have much higher silica condensation degree than the ones synthesized at relatively low temperatures. More importantly, these samples exhibit extraordinarily ultra-low dielectric constant(k). For example, ordered mesoporous silica of SBA-15 synthesized at 200℃ gives k value as low as 1.31, which is interpreted by a collaborative effect of large pore volume with high silica condensation degree. These samples with extraordinarily ultra-low dielectric constants would be potentially important for applications of superior insulators in electronic industry.

Preparation, Characterization and Gas Sensing Performance of Ag-supported α-Fe₂O₃ Hybrid

MA Xiao-Dong, GUO Hong-Wen, LÜ Lu, HE Xuan, FENG Xi

2012, 33(09): 1915-1919. doi:10.3969/j.issn.0251-0790.2012.09.007

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α-Fe₂O₃ nanoparticles were synthesized by a simple hydrothermal treatment of FeCl₃ solution, followed by a calcination process, without templates or pore-directing agents. The as-prepared α-Fe₂O₃ nanoparticles were further employed as support to obtain Ag/α-Fe₂O₃ hybrid. The hybrid was characterized by XRD, TEM and XPS techniques and its gas sensing performance was investigated for several volatile organic compounds(VOCs) including methanol, ethanol, ether, acetone, butanol and hexanol at an operating temperature of 260℃. The Ag/α-Fe₂O₃ sensor presented a high sensitivity and fast response-recovery to these VOCs. Meanwhile, the Ag/α-Fe₂O₃ sensor exhibited a much higher response than the pure α-Fe₂O₃ sensor at the operating temperature of 260℃, which may be related to the unique porous structure on the surface of the Ag/α-Fe₂O₃ hybrid and the catalytic action of active Ag nanoparticles for the sensing reactions.

Light Induced Cellular Cytotoxicity of Rich Arginine Peptide Modified Ferric Oxide Core Gold Shell Nanoparticles

LIU Gui-Feng, GAO Zhong-Li, YU Qiong, ZHANG Hui-Mao, WANG Zhen-Xin

2012, 33(09): 1920-1925. doi:10.3969/j.issn.0251-0790.2012.09.008

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The laser induced cellular cytotoxicity of rich arginine peptide RRRRRRRR(R₈) modified ferric oxide core gold shell nanoparticles(R₈-Fe₂O₃@Au NP) was studied. Although R₈-Fe₂O₃@Au NP has a low cytotoxicity, the viability of nanoparticles internalized HeLa cell can be decreased by laser irradiation. The experimental result indicates that the R₈-Fe₂O₃@Au NPs have significant cellular phototoxicity under laser irradiation. In addition, the cellular phototoxicity of R₈-Fe₂O₃@Au NPs is dependent on the wavelength of irradiation laser, and increased by the irradiating time and light intensity.

NaNO₂ Biosensor Based on Hollow Nano-nickel Oxide Microsphere and Ionic Liquid Composite Film Immobilizing Hemoglobin

GU Guang-Zhe, DONG She-Ying, HUANG Ting-Lin, TANG Hong-Sheng, ZHENG Jian-Bin

2012, 33(09): 1926-1931. doi:10.3969/j.issn.0251-0790.2012.09.009

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Hollow nano-nickel oxide microsphere (NiO) was fabricated by microwave hydrothermal process and characterized by SEM. The prepared NiO was used to immobilize hemoglobin(Hb) on the surface of the carbon paste electrode with 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF₄). The structure of Hb in the composite film was still maintained native-like demonstrated by FTIR spectra and UV-visible spectra. Moreover, the functions of different components in the modified electrode were studied by electrochemical impedance spectroscopy. A pair of stable and quasi-reversible redox peaks was observed in phosphate buffer solution which indicating that heme-proteins could achieve its direct electron transfer effectively. The modified electrode displayed an excellent and rapid electrocatalytic response to the oxidation of NaNO₂. The proposed biosensor exhibited a good linear response to the concentration of NaNO₂ in the range of 10-170 μmol/L, with a detection limit of 4.57 μmol/L(S/N=3). The apparent Michaelis-Menten constant was estimated to be 2.4 mmol/L. Furthermore, the biosensor possesses satisfactory stability and good reproducibility.

Effect of Acarbose on Urine Metabolic Profiling of Type Ⅱ Diabete Rats

LIU Yue-Qin, PI Zi-Feng, SONG Feng-Rui, LIU Zhi-Qiang, LIU Zhong-Ying

2012, 33(09): 1932-1937. doi:10.3969/j.issn.0251-0790.2012.09.010

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An ultra performance liquid chromatography-mass spectrometry(UPLC-MS) method was developed for the metabonomics study of effect of acarbose on type Ⅱ diabete rats. Urine from three groups of rats including control group, model group and diabete rats treated with acarbose group were analyzed, and the data were analyzed by the method of principal component analysis(PCA) and partial least squares-discriminant analysis(PLS-DA). The PCA score plots showed that the three groups were significantly different between the metabolic profile. According to the results of PLS-DA, the MS/MS data of each compound which provide greater contribution to separation of each group was searched from the Human Metabolome Database(HMDB) and Mass Bank. jp databases. Eight kinds of endogenous metabolites were identified as potential biomarkers such as gluconic acid, phenylacetylglycine, creatinine, etc.

Rapid Detection of Active Pharmaceutical Ingredients in Drugs by Microwave Plasma Atmospheric Pressure Desorption Ionization Mass Spectrometry

ZHANG Ti-Qiang, JIN Wei, ZHOU Jian-Guang, ZHANG Ying, ZHU Zhi-Qiang, ZHOU Wei, JIN Qin-Han

2012, 33(09): 1938-1944. doi:10.3969/j.issn.0251-0790.2012.09.011

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A new ionization source, termed microwave plasma atmospheric pressure desorption ionization(MWPAPDI) source, was developed. The stable plasma was generated by microwave plasma torch working at 2450 MHz at atmospheric pressure. Ar was used as working gas. The source was successfully coupled with a Corsair API-TOF time of flight mass spectrometer, and the active pharmaceutical ingredients in drugs were rapidly characterized. The speed was allowed as fast as approximate 360 samples per hour via manual sampling. In the microwave plasma environment, the hydrogen bound moiety of the active ingredients of the drug preparations was directly removed, as a result, the quasi-molecular ions of active component compounds [M+H]⁺ became the main ions and gave simple mass spectra. Without chemical reagents, MWPAPDI has the feature for direct analysis of samples with high throughput, no pollution and in real time. Therefore, the method is believed to be a useful technique for drug discovery and chemical industry.

Electrochemical Detection of Klenow Fragment Exo-(KF^-) Activity Based on Gold Nanoparticles Amplification

LIU Jin-Quan, NI Xiao-Qi, HE Xiao-Xiao, WANG Yong-Hong, WANG Ke-Min, CHEN Zhi-Feng, SU Jing, YAN Gen-Ping

2012, 33(09): 1945-1949. doi:10.3969/j.issn.0251-0790.2012.09.012

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A label-free, simple and fast electrochemical method for Klenow fragment exo-(KF^-) detection was developed based on the properties of gold nanoparticles(AuNPs) such as the large specific surface, small size and the ability of binding much DNA. In this work, thiolated primer DNA was first modified on the surface of electrode. In the presence of template DNA and reporter DNA tethered with AuNPs(AuNPs-DNA), primer DNA and report DNA were hybridized with template DNA to form a sandwich-like hybridization mode, which brings AuNPs-DNA to the electrode surface. When put the modified electrode into the electrolyte containing [Ru(NH₃)₆]³⁺(RuHex), the RuHex quantitatively binds to the DNA via electrostatic interaction. Since AuNPs was loaded with much reporter DNA that can bind a large number of RuHex, this offers the electrochemical signals amplification for the detection. In the presence of dNTPs and KF^-, the extension reaction was triggered, which results in the dissociation of the AuNPs-DNA and release of abundant RuHex molecules. As a result, the electrochemical signal was reduced and the KF^- was detected. Using this method, a detection limit as low as 5 U/mL for KF^- was achieved.

Infrared Spectroscopy Analysis of Structural Changes of Ovornucin as Induced by Temperature

SHAN Yuan-Yuan, MA Mei-Hu, HUANG Xi, GAO Fei

2012, 33(09): 1950-1956. doi:10.3969/j.issn.0251-0790.2012.09.013

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Fourier transform infrared(FTIR) spectroscopy combined with 2D correlation spectroscopy was used to offer some information about the structural stability of ovomucin. Temperature has been chosen as the perturbation to monitor the infrared behavior of ovomucin. The results indicate that the sharp changes in the peak position and the intensity in the infrared spectra of ovomucin occur basically between 55℃ and 65℃. Two-dimensional correlation analysis further showed that the sugar chain in ovomucin is more sensitive to temperature perturbation than the amide area of peptide since it was more likely to change prior to peptide during the heat treatment. The presence of sugar chain in ovomucin molecule was helpful to maintain the stability of protein conformation. The order of secondary structural changes in ovomucin as induced by temperature was α-helix, β-sheet, β-turn and random coil. These results provide preliminary information about the mechanism of ovomucin conformational changes as induced by variable temperature perturbation.

Direct Determination of Lead and Cadmium in Distilled Spirits by Inductively Coupled Plasma Mass Spectrometry Coupled with Chip-based Microflow Injection System

HAO Li, CHENG He-Yong, LIU Jin-Hua, YIN Xue-Feng

2012, 33(09): 1957-1963. doi:10.3969/j.issn.0251-0790.2012.09.014

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A microfluidic chip for introducing variable-volume sample was fabricated. Combined with the 8-way multifunctional valve used in flow injection analysis, the introduction of sub-microlitre sample in inductively coupled plasma mass spectrometry (ICP-MS) was realized. 52% ethanol was used to simulate the distilled spirit. The effects of the volume of the 52% ethanol introduced into ICP-MS on ICP stability and the spectral interference from the spirit matrix were studied. The relationship between the sampling volume and sensitivity was evaluated. The carrier flow rate was optimized. The experimental results showed that neither alteration of plasma stability nor carbon deposition was observed when the sampling volume of 52% ethanol reduced down to 0.8 μL. Further reducing the sampling volume to 0.3 μL, the interference from carbon was eliminated. Based on these observations, a microflow injection method for the determination of lead and cadmium in distilled spirits by ICP-MS via external aqueous calibration was developed. The sample throughput was 45 h^-1 with the detection limits of 12 and 42 ng/L for Pb and Cd, respectively. The contents of Cd and Pb in six distilled spirits were measured. The results agreed well with those determined by ICP-MS with the conventional sampling system after microwave assisted digestion.

Application of FT-mid-IR Fiber Optics Technique in the Chemical Reaction

PAN Qing-Hua, XU Yi-Zhuang, LAI Guo-Qiao, LIU Shao-Xuan, CHEN Jing, YANG Li-Min, ZHANG Yuan-Fu, WENG Shi-Fu, WU Jin-Guang

2012, 33(09): 1964-1968. doi:10.3969/j.issn.0251-0790.2012.09.015

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Fourier transform infrared(FTIR) spectroscopy is a sensitive probe of molecular structure which can provide significant information on the structure and composition of unknown substances and confirm the presence of some chemical groups. IR fiber optics possesses high performance which can be applied to transmission of IR light. The coupled technique of FTIR and mid-IR fiber optics can simplify the sample preparation in traditional IR spectroscopy. Formation of new compound is observed in situ and reaction process can be monitored on line using FTIR fiber optics technique. In this study, mid-IR fiber optics technique was applied to liquid phase systems and solid/liquid reaction systems. In the liquid phase system, we investigated the saponification reaction of naphthenic acid-octal alcohol-heptane and the formation mechanism of water in oil (w/o) microemulsion during saponification. The interaction between naphthenic acid and octal alcohol was observed. With adding ammonium hydroxide, the peak around 1708 cm^-1 disappeared and the peak at 1548 cm^-1 enhanced and the peak position of water emerged and shifted to 1637 cm^-1 from 1642 cm^-1, which is the position of water molecule in IR spectroscopy. It showed that water is constrained in aqueous droplet of naphthenic acid-octal alcohol-heptane and microemulsion is formed through the saponification. In the solid/liquid reaction system, complexation reaction between o-phthalic acid and europium chloride was investigated. The interaction between o-phthalic acid and EuCl₃ in neural medium was ignored in previous study, but this weak interaction was observed using FTIR fiber optics technique in our present investigation. The results showed that the component and structure of the final complex were effect by the difference of adding sequence. Therefore, FTIR fiber optics technique may become a new method of monitoring chemical reaction in real time.

Odorless and Efficient Thioacetalization Reaction of Oximes

YU Hai-Feng, LIAO Pei-Qiu

2012, 33(09): 1969-1972. doi:10.3969/j.issn.0251-0790.2012.09.016

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Thioacetals are important compounds because they can be considered as both useful protecting groups of carbonyl compounds in the synthesis of multi-functional complex molecules and acyl carbanion equi-valents in C—C bond forming reactions. Since many reactions have been developed to prepare oximes from non carbonyl compounds, to lead to a novel and efficient method for thioacetal preparation, transthioacetalization of oximes has received more and more attention. Unfortunately, the transformation usually suffers from the use of harmful, odorous thiols which can lead to serious safety and environment problems. From the green chemistry point of view, an efficient and odorless transthioacetalization of oximes involving an environment friendly reagent is of great importance and necessity. In this work, using odorless and stable α-oxo ketene dithioacetals 1 as thiol equivalents, the thioacetalization reaction of oximes 2 were studied. In the reaction system of MeCOCl-EtOH(95%) or 4-dodecylbenzenesulfonic acid(DBSA)-H₂O, the thioacetalization reaction were carried out in reflux temperature. It is noteworthy that the odor of thiols can not be perceived during either the reaction or workup.

Self-assemblied Binding Mode of Cucurbit[6]uril with 2,2'-(Octane-1,8-diyl)dibenzimidazolium Dichloride

YI Jun-Ming, XUE Sai-Feng, TAO Zhu

2012, 33(09): 1973-1977. doi:10.3969/j.issn.0251-0790.2012.09.017

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The self-assemblied binding modes of cucurbit[6]uril(Q[6]) with 2,2'-(octane-1,8-diyl)dibenzimidazolium dichloride(SBO) was investigated by means of ¹H NMR, fluorescence emission and UV-Vis spectra. The experiment results revealed that the host Q[6] prefered to including the aromatic benzoimidazolyl moieties of the protonated SBO at a lower molar ratio of Q[6] to guest less than 1 in water medium, at higher molar ratios of Q[6] to guest or in water medium, a chain shape guest could be borne two Q[6] molecules and form a dumbbell shape inclusion complex. The study may provide information in drug delivery, designment of molecular knots, machines and switches.

Total Syntheses of 5,7-Dihydroxy-3-isopentenylflavone and 5-Hydroxy-3-isopentenylflavone Natural Compounds

HUANG Chu-Sheng, LIU Hong-Xing, SHI Jian-Cheng, LIN Sen, DUAN Hong-Xia

2012, 33(09): 1978-1983. doi:10.3969/j.issn.0251-0790.2012.09.018

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The total syntheses for 5,7-dihydroxy-3-isopentenylflavone(1a, yield 80.6%) and 5-hydroxy-3-isopentenylflavone(1b, yield 84.9%) were performed through selective protection of phenolic hydroxyl groups, acylation, Bake-Venkataraman rearrangement, prenylation, cyclization and demethylation, which started from 2,4,6-trihydroxyacetophenone and 2,6-dihydroxyacetophenone, respectively. The structures of all the compounds were characterized by ¹H NMR and ¹³C NMR, and the biological activities of the target compounds(1a and 1b)were predicted by the density functional theory(DFT) calculations. The results showed that the isopentenyl substituent at C3 could remarkably improve the biological activities of the flavonoids, and it was requirement for various biological activities of the flavonoids. In addition, the biological activities were 5,7-dihydroxy-3-isopentenylflavone(1a)>5-hydroxy-3-isopentenylflavone(1b). The reason might lie in the fact that the 7-OH of the flavonoids could enhance the biological activities. The synthetic routes in the present work might reveal potential applicability in the total syntheses of other 3-alkylfavones natural compounds and the biological activities of the target compounds could lay a good foundation on studying the structure-activity relationship of 3-alkylfavones.

Synthesis and Characterization of Novel Layered Crystalline Organic Polymer-inorganic Hybrid Materials Zinc Poly(styrene-phenylvinyl phosphonate)-phosphate Ammonium

MIAO Qiang, FU Xiang-Kai, HUANG Jing, LI Chao, CHEN Guo-Dong, WANG Guo-Ming

2012, 33(09): 1984-1990. doi:10.3969/j.issn.0251-0790.2012.09.019

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A series of organic polymer-inorganic hybrid materials, zinc poly(styrene-phenylvinyl phosphonate)-phosphate ammonium(ZnPS-PVPPA), was prepared with mild and facile conditions from the copolymer of styrene-phenylvinyl phosphonic acid with zinc acetate dihydrate and ammonium dihydrogen phosphate treated with different ratios of inorganic phosphate to organic phosphonate. The structures of ZnPS-PVPPA were characterized by FTIR, TG, XRD, SEM and TEM and their catalytic abilities were also tested. It could be deduced that the compounds were novel types of layered crystalline organic polymer-inorganic hybrid materials and possessed high thermal stability and porous structure. The heterogeneous catalysts were synthesized to catalyze the asymmetric epoxidation of unfunctional olefins via ZnPS-PVPPA as supports, aryldiamines as linkers and axial coordinating with Salen Mn(Ⅲ). The catalytic results indicated that the superior catalytic abilities were obtained in the asymmetric epoxidation of α-methylstyrene and indene with m-CPBA/NMO as oxidant, such as up to 99% e.e. according to indene. Meanwhile, the supported catalysts could be reused and still display fine catalytic abilities after recycled 8 times and have potential applications for industry.

Effects of Cu²⁺ on Fluorescent Properties of Biphenyl-4-carbaldehyde Modified Polyamidoamine Dendrimers

HAN Qiao-Rong, LU Tian-Hong, JIANG Yu-Liang, WANG Bing-Xiang

2012, 33(09): 1991-1994. doi:10.3969/j.issn.0251-0790.2012.09.020

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Two PAMAM-BPA dendrimers(G₁-BPA₄ and G₂-BPA₈) of generation one and two modified with biphenyl-4-carbaldehyde, were synthesized respectively. These PAMAM-BPA dendrimers were characterized by IR,¹H NMR and MALDI-TOF MS. The effects of Cu²⁺ on the fluorescent properties of these dendrimers was studied. The results indicated that Cu²⁺which usually as the fluorescent quenching agent, in proper concentration ranges, could enhance the fluorescence intensity of dendrimer G₁-BPA₄ and dendrimer G₂-BPA₈, perhaps due to the presence of the dendrimer effect. It provides a new research content for this kind of dendrimers as the dendrimer-copper hybrid fluorescent materials or as a fluorescence probe of Cu²⁺.

Monobromination of Aromatic Compounds Catalyzed by Iodine or Ammonium Iodide

ZHU Min, LI Li, ZHANG Hui, LIU Cai-Qin

2012, 33(09): 1995-1999. doi:10.3969/j.issn.0251-0790.2012.09.021

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Brominated aromatic compounds have considerable importance in the bulk and fine chemical industries, and they are also found widespread used as intermediates in organic chemistry, for example, in cross-coupling reactions. The preparation of brominated aromatic compounds with molecular bromine is a well-known reaction in organic chemistry. The method requires transition metal-based catalysts and the side product gene-rated in the course is corrosive and toxic hydrogen bromide. To improve the bromination process, considerable efforts especially in recently have been devoted and several bromination reagents have been successfully used in place of molecular bromine, and now the research in exploring the scope of it is still a much-sought process. We have developed an efficient monobromination of electron-rich aromatic compounds catalyzed by iodine or ammonium iodide. In our method, a catalytic amount of molecular iodine or ammonium iodide reacted with benzene and m-chloroperbenzoic acid in the presence of p-toluenesulfonic acid to form the recyclable hypervalent iodine intermediate, with which the bromination of electron-rich aromatic compounds and potassium bromide was fast in THF at room temperature, providing regioselective monobrominated products in good yields. The method has some advantages such as mild reaction conditions, simple procedure and good yields.

Chemical Composition and Bioactivity of Polypeptide from Velvet Antlers of Cervus nippon Temminck

ZHANG Zheng-Yao, DUAN Leng-Xin, ZHOU Qiu-Li, XIN Ji-Le, LIN Yong, ZHANG Yang

2012, 33(09): 2000-2004. doi:10.3969/j.issn.0251-0790.2012.09.022

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In order to study the isolation and purification of an active peptide component from velvet antler of sika deer(Cervus nippon Temminck), confirm the primary structure of the novel peptide and compare the sequence and the activity with those of velvet antler of red deer(Cervus elaphus Linaeus), the velvet antler polypeptide was isolated and purified by ion exchange chromatography, gel filtration and RP-HPLC, which showed a single peak in HPLC chromatography and a single band in SDS-PAGE. The molecular weight was measured by MALDI-TOF MS. This polypeptide consists of a single linear chain of 32 amino acid residues VLSATDKTNVLAAWGKVGGNAPAFGAEALERM. The experiment results of bioactivity showed that the polypeptide had stimulant effects on the growth of rat epithelial cells, rabbit costal chondrocytes and rat NIH3T3 cell line, respectively in vitro. The straight chain of 32 amino acid residues of the velvet antler polypeptides of Cervus nippon Temminck was consisted with that of Cervus elaphus Linaeus, but they make a difference of 5, 8, 11 and 30 amino acid. There was no effect on stimulating proliferation of cells.

Effect of Polyacrylic Acid on the Adsorption of Cd onto Natural Biofilms

HUA Xiu-Yi, DONG De-Ming, JIANG Xu, HU Jin-Rui, GUO Zhi-Yong, LIANG Da-Peng

2012, 33(09): 2005-2012. doi:10.3969/j.issn.0251-0790.2012.09.023

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Dissolved natural organic matters(DNOM) usually have significant effects on the behavior of trace metals in aquatic environment. As an important solid material existing wildly in natural waters, natural biofilm also affect the behavior of trace metals remarkably, by the action of adsorption. In this study, polyacrylic acid(PAA) was selected as a surrogate for macromolecular DNOM to investigate the effect of DNOM on the adsorption of Cd by natural biofilms. Cd adsorption to natural biofilms without PAA and with different concentrations of PAA was carried out. The influences of solution pH value and component addition sequence on the effect of PAA were also measured. The presence of PAA generally decreased the adsorption of Cd, and the effect was influenced by the concentration of PAA, the solution pH value, the adsorption sequence and the thickness of the biofilms. Higher concentration ratio of PAA to Cd or higher pH value usually resulted in more significant decreasing effect on adsorption. The influence of adsorption sequence on the effect of PAA was insignificant in lower pH range, while in higher pH range, the decreasing effect of PAA on adsorption was more considerable for simultaneous adsorption and PAA first adsorption, than for Cd first adsorption. As to the thickness of biofilms, the effect of PAA was usually significant for thinner biofilms. The role of PAA on adsorption could be attributed to the competition between PAA and the biofilms for available Cd, and to the formation and adsorption of ternary surface complexes. Higher pH value facilitated the complexation between PAA and Cd, and impeded the adsorption of negatively charged complexes on the biofilms.

Molecular Dynamics Simulation of Hydrophobin Proteins on the Surface of Single-walled Carbon Nanotubes

LIU Ying-Zhe, CAI Wen-Sheng, SHAO Xue-Guang

2012, 33(09): 2013-2018. doi:10.3969/j.issn.0251-0790.2012.09.024

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Carbon nanotubes (CNTs) coated by hydrophobin proteins through noncovalent interactions were shown to be soluble and dispersed in water. However, the detail of the microscopic structure and underlying interaction mechanism is fragmentary. In the present work, atomistic molecular dynamics (MD) simulations have been conducted to elucidate the adsorption mechanism of hydrophobin HFBI on the surface of single-walled carbon nanotubes (SWNTs) in an aqueous environment. Three initial orientations of HFBI towards SWNTs were taken into account, and the relative binding free energies were calculated. Different adsorption conformations were obtained from MD simulation trajectories with an aggregate time of 240 ns. The present results reveal that the adsorption mode, where the adsorption sites fully come from the hydrophobic patch of the protein, is the most energetically favored. Furthermore, the main secondary structures of protein are preserved in the entire course of adsorption due to four disulfide bonds.

Preparation,Characterization of Hydrophobic Spherical CaCO₃ Particles and Influence on Properties of Polypropylene

ZHAO Li-Na, WANG Ji-Ku, KONG Zhi-Guo, WANG Zi-Chen

2012, 33(09): 2019-2024. doi:10.3969/j.issn.0251-0790.2012.09.025

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Monodisperse hydrophobic spherical CaCO₃ particles were prepared by carbonation in the presence of dodecyl dihydrogen phosphate(DDP). The surface property of CaCO₃ particles was transformed from hydrophilic to hydrophobic when the mass ratio of DDP to CaCO₃ changed from 0 to 2%. X-Ray diffraction(XRD) patterns showed that the crystal form of CaCO₃ particles was turned from calcite to aragonite with increasing the dosage of DDP in the reaction. FTIR spectra indicated the existence of the alkyl groups from the DDP in the products. When the mass ratio of DDP to CaCO₃ was 2%, the active ratio reached 99% and the contact angle of modified CaCO₃ particles was 120.43°. Simultaneously, the effects of the reaction temperature and the dosage of DDP on the morphology and behaviors of aragonite crystals were discussed. When the schematic illustration on the formation process of hydrophobic spherical CaCO₃ particles was discussed in the work. When the obtained modified CaCO₃ was added into polypropylene(PP), the mechanical properties and processabilities of PP improved greatly.

Preparation of Carbon Supported PdPb Catalysts and Its Electrocatalytic Performance in Oxidation of Formic Acid

GENG Xiao-Wei, WU Bing, GAO Ying

2012, 33(09): 2025-2029. doi:10.3969/j.issn.0251-0790.2012.09.026

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The carbon supported PdPb catalysts with different Pd and Pb mass ratios were prepared in the aqueous solution by a chemical reduction method. The studies show that the PdPb/C catalysts can promote the activity for formic acid electrooxidation and change the reaction mechanism. As the catalysts with small ratio of Pb, it can enhance the dispersion of active component and largely enhance the electrocatalytic activity of the catalysts toward the electrooxidation of formic acid. When the mass ratio of Pd and Pb is 8: 1, the catalyst shows the highest catalytic activity for formic acid oxidation, and the peak current density increases 180% compared to that on Pd/C. When the mass ratio of Pd to Pb is 2: 1, the catalyst shows the best behavior of stability.

Effects of Stoichiometry and Dehydrogenation Back-pressure on the Dehydrogenation Behavior of LiBH₄+xMg₂NiH₄ Composites

DENG Shuai-Shuai, XIAO Xue-Zhang, CHEN Li-Xin, HAN Le-Yuan, LI Shou-Quan, GE Hong-Wei, WANG Qi-Dong

2012, 33(09): 2030-2034. doi:10.3969/j.issn.0251-0790.2012.09.027

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The effects of stoichiometry (x=0.25, 0.5, 0.75, 1.0, 1.25) and hydrogen back pressure on the dehydrogenation behavior of LiBH₄+xMg₂NiH₄ composites were investigated systematically by methods of X-ray diffraction(XRD) and temperature programmed desorption(TPD) analysis. The results show that the stoichiometry x has a great effect on the dehydriding kinetics of LiBH₄+xMg₂NiH₄ composites. With the increase of x value for the LiBH₄+xMg₂NiH₄ composites, the decrease of the dehydrogenation temperature and the improvement of the dehydriding kinetics are observed but with a loss of dehydrogenation capacity. Thereinto, LiBH₄+0.75Mg₂NiH₄ composite has the best dehydriding kinetics and a relatively high hydrogen storage capacity under initial hydrogen back pressure of 1×10^-4 or 0.4 MPa. The analysis shows that both the stoichiometry x of the LiBH₄+xMg₂NiH₄ mixtures and hydrogen back pressure can influence the wetting between liquid LiBH₄ and solid Mg₂NiH₄, and have a great effect on the dehydrogenation path and kinetics furthermore.

Influence of Magnesium Content on Structure and Performance of A₂B₇-type RE-Mg-Ni Hydrogen Storage Alloys

GAO Zhi-Jie, KANG Long, LUO Yong-Chun

2012, 33(09): 2035-2042. doi:10.3969/j.issn.0251-0790.2012.09.028

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La_0.8-xGd_0.2Mg_xNi_3.1Co_0.3Al_0.1(x=0, 0.1, 0.15, 0.2, 0.25, 0.3, 0.4) alloys were prepared by induction melting followed by annealing treatment at 1173 K for 8 h in Ar atmosphere. Phase structure analyses show that main phase is the Ce₂Ni₇-type phase and the phase abundance of Ce₂Ni₇- and Gd₂Co₇-type is 98.8% at the lower Mg content. When x≥0.25, the alloys are mainly composed of A₂B₇-type, CaCu₅-type and PuNi₃-type structure. The phase abundance of the PuNi₃- and CaCu₅-type phase increase with the high content of Mg. The unit cell parameters of main phases decrease and hydrogen absorption plateau rises with the increasing content of Mg. Electrochemical measurements show that as the Mg content increases, the discharge capacity and cyclic stability of alloy electrodes both first increase and then decrease. La_0.65Gd_0.2Mg_0.15·Ni_3.1Co_0.3Al_0.1 alloy electrode exhibits the maximum electrochemical discharge capacity(393 mA·h/g) and the best cyclic stability(S₁₀₀=92.82%). The high rate dischargeability first decreases then increases and final decreases. The appropriate Mg content improves electrochemical kinetics property of alloy electrodes.

Theoretical Studies on the Basicity of the Boron-substituted Zeolite Interacted by NH₃

LIU Nan-Nan, DING Yi-Hong

2012, 33(09): 2043-2046. doi:10.3969/j.issn.0251-0790.2012.09.029

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The basicity of boron-substituted zeolite interacted by NH₃ was studied by theoretical calculations via density functional theory(DFT) method at the B3LYP/6-311++G(d,p) level. We found that the B-NH₂ group itself didn’t have high basicity. However, when the proton or Lewis acid was adsorbed to it, the coexisting Si-OH group contributed to the basicity by forming a hydrogen bond with B-NH₂. Besides, the Si-NH₂ group and the coexisting B-OH group cooperatively had rather high basicity. Thus, the boron-substituted zeolite interacted by NH₃, which contains the B-NH₂ together with B-OH groups and the Si-NH₂ together with B-OH groups, could be a kind of promising basic material.

Electrodeposition of Cu Nanoparticles Layers in Ionic Liquid and Surface Enhanced Raman Spectroscopic Properties

YANG Feng-Zhu, XU Min-Min, YUAN Ya-Xian, MEI Jin-Hua, YAO Jian-Lin, GU Ren-Ao

2012, 33(09): 2047-2050. doi:10.3969/j.issn.0251-0790.2012.09.030

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The electrodeposition of Cu layers were investigated in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF₄) ionic liquid on ITO electrodes by constant potential method. The results indicate that Cu²⁺ undergoes two one-electron reduction processes, involving the transformation to Cu⁺ and the deposition of Cu. The XRD and SEM were employed to characterize the composition and surface morphology of the deposition layers, indicating that they were strongly depended on the applied potentials. The mixture nanoparticles of Cu and Cu₂O was obtained at relative positive potentials, while pure Cu layer was formed at extremely negative potentials. With negative movement of applied potentials, the surface layer became more compact and the morphology underwent a process from flower-like, rod-like to spherical particles. SERS detection of pyridine on the Cu layer was performed, suggesting its high activity and uniformity as a SERS substrate.

Mechanisms of Electron Transfer and Dynamic Process at the Multiphase Interface in Dye Sensitized Solar Cell

LIU Wei-Qing, KOU Dong-Xing, HU Lin-Hua, DAI Song-Yuan

2012, 33(09): 2051-2055. doi:10.3969/j.issn.0251-0790.2012.09.031

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The multiphase complex interface made up of the transparent conductive oxide substrate(TCO), nano-porous TiO₂ film and electrolyte was formed at the substrate of the anode in dye sensitized solar cell(DSC). The mechanisms of electron transfer and dynamic process at this multiphase complex interface were investigated by electrochemical impedance spectroscopy(EIS). The multiphase interface structure was simplified by an insulating layer which electropolymerized on the exposed TCO. According to changes of the contact interface structure and electron transfer pathway, the corresponding equivalent circuits were constructed. The interface electron transfer mechanism was analyzed and the electron transfer kinetic constants for the electron transfer across the main contact interfacial were obtained at different bias. The results show that different mechanism of interfacial electron transfer and kinetics process can be distinguished by adjusting the bias and simplifying the multiphase interface structure.

Synthesis and Photo-electricity Properties of Hydroxyphenyl-pyrimidine Beryllium(Ⅱ) Complex

LI Peng, ZHANG Heng-Jun, ZHU Dong-Xia, SHAN Guo-Gang, LIAO Yi, SU Zhong-Min

2012, 33(09): 2056-2060. doi:10.3969/j.issn.0251-0790.2012.09.032

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A novel chelating ligand 2-hydroxyphenyl-pyrimidine (HPP) was designed and synthesized through Suzuki coupling reaction. Its beryllium complex bisberyllium was also prepared in high yields and characterized by IR and ¹H NMR. Upon photoexcitation, the complex displayed intense blue emission (λ_max=460 nm) in methanol solvent at room temperature. In addition, a white organic electroluminescent device was fabricated by vacuum thermal evaporation with a double-layer structure of indium tin oxides(ITO)/N,N'-bis(naphthalene-2-yl)-N,N'-diphenyl--4,4'-diamine (NPB)(45 nm)/Be(PP)₂(60 nm)/Al(300 nm) using the Be(PP)₂ as emitting and electro-transporting material. The non-doping device showed a lower turn-on voltage of 4 V, a maximum brightness of 103 cd/m², a commission internationale de I'Eclairage (CIE) color coordinates of (0.37, 0.39) and luminous efficiency of 0.13 lm/W.

Preparation of Pt-S₂O₈^2-/ZrO₂-Al₂O₃ Catalyst by Microemulsion Method and Its Performance for Isomerization

SONG Hua, SHI Yang, SONG Hua-Lin

2012, 33(09): 2061-2066. doi:10.3969/j.issn.0251-0790.2012.09.033

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Pt-S₂O₈^2-/ZrO₂-Al₂O₃(Pt-SZA-M) solid superacid catalyst was prepared by microemulsion method. The isomerization performance of catalysts prepared with the microemulsion method and dipping method was compared with n-pentane isomerization as a probe reaction. The catalysts were characterized by XRD, FTIR, BET, TG, TPR and TEM. The results showed that compared with the Pt-SZA catalyst, the Pt particles on Pt-SZA-M were smaller(4.5 nm) and more uniform; the specific surface area of Pt-SZA-M was 109.6 m²/g, which was 15.4% higher than that of Pt-SZA(95.0 m²/g). The initial reduction temperature of Pt-SZA-M was decreased by 10-20℃ compared with that of Pt-SZA, which indicated that loading Pt by microemulsion method could improve the oxidative activity of catalyst and enhance the dissociation adsorption ability of H₂ on the surface of catalyst. The activity test of isomerization performance indicated that compared to the Pt-SZA, the activity of isomerization of the Pt-SZA-M under low temperature was significant improved, at reaction temperature of 230℃, pressure of 2.0 MPa, hydrogen/hydrocarbon molar ratio of 4: 1 and weight hourly space velocity(WHSV) of 1.0 h^-1, the isopentane yield was 60.8%. The isopentane yield was stabilized in ca. 58.0% and the selectivity was higher than 95.0% within 100 h.

Influence of Mo Content on Microstructure and Catalytic Performance of Ni-Mo-B Amorphous Alloy Catalyst for Dinitrotoluene Hydrogenation

YAN Shao-Wei, FAN Hui, LIANG Chuan, LI Zhong

2012, 33(09): 2067-2073. doi:10.3969/j.issn.0251-0790.2012.09.034

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A series of amorphous Ni-Mo-B catalyst was prepared by KBH₄ reduction for liquid phase dinitrotoluene(DNT) hydrogenation. The results showed that Ni-B catalyst exhibited high activity and selectivity in liquid phase hydrogenation of DNT to diaminotoluene(TDA), the activity of Ni-B catalyst has been enhanced obviously by introduction of Mo, and the selectivity of TDA was 100% when the molar fraction of Mo was smaller and equal to 6%. The characterizations of XRD, DSC, TEM, XPS, ICP and H₂-TPD showed that the addition of Mo could enhance the extent of long-range disorder, reduce the particle diameter from 60 nm to 15 nm, weaken the strength of Ni-H bond, improve the thermal stability and antioxidation, which resulted in the increasing activity of Ni-B. when the molar fraction of Mo was 6%, the conversion of DNT and the selectivity of TDA reached 99.8% and 100%, respectively.

Synthesis, Structure Characterization and Thermochemistry of Pyridine-2,6-dicarboxylic Acid Potassium Hydrogen

ZHONG Wen-Wen, DI Ming-Zhe, DI You-Ying

2012, 33(09): 2074-2079. doi:10.3969/j.issn.0251-0790.2012.09.035

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Pyridine-2,6-dicarboxylic acid potassium hydrogen(KHDPC) was synthesized and its crystal structure was determined by single crystal X-ray diffraction. Low-temperature heat capacities of the compound were measured with an automated adiabatic calorimeter over the temperature range from 78 K to 360 K. Experimental heat capacities were fitted by least-squares method and a polynomial equation of heat capacities vs. reduced temperature was obtained. The smoothed molar heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated based on the fitted polynomial equation. A reasonable thermochemical cycle was designed on the basis of a designed reaction of the substance, and standard molar enthalpies of dissolution for the reactants and products of the supposed reaction in the selected solvents were measured by an isoperibol solution-reaction calorimeter, respectively. Eventually, standard molar enthalpy of formation of the compound was derived to be -(1052.69±1.52) kJ/mol by Hess thermochemical cycle.

Fabrication of the Eosin Y-MWNTs-NiO Photocatalytic System and Its Photocatalytic Activity for H₂ Evolution from Water

MU Jin, CHEN Li-Li, KANG Shi-Zhao, LI Xiang-Qing

2012, 33(09): 2080-2084. doi:10.3969/j.issn.0251-0790.2012.09.036

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A photocatalytic system containing Eosin Y, multiwalled carbon nanotubes(MWNTs) and NiO (Eosin Y-MWNTs-NiO) was fabricated and activated by hydrogen reduction treatment. The photocatalytic hydrogen evolution over this photocatalytic system was investigated using triethanolamine as a sacrificial reagent. The results displayed that the Eosin Y-MWNTs-NiO was an efficient photocatalyst with the highest rate of H₂ evolution of 344 μmol·g^-1·h^-1 under visible light irradiation. Therein, the hydrogen reduction treatment played an important role in the improvement of photocatalytic activity. The activity of the photocatalytic system Eosin Y-MWNTs-6%NiO unactivated by hydrogen was only one-tenth of that of the activated one. Moreover, the photocatalytic hydrogen evolution was studied as functions of pH of the solution and dosage of the catalyst, respectively. Based on the results obtained, the mechanism was discussed preliminarily.

Synthesis, Self-assembly and Colloidal Stability in Physiological Milieu of Worm-like PICmicelles of Poly(ethylene glycol)-b-poly(ethylenimine)/plasmid DNA

ZHANG Xin-Miao, ZHANG Jia-Wei, WEI Guang-Yao, LIU Dong-Xu, YU Da-Hui, YAO Wei-Guo, DONG Wen-Fei

2012, 33(09): 2085-2091. doi:10.3969/j.issn.0251-0790.2012.09.037

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The block copolymers of poly(ethylene glycol)-b-poly(ethylenimine)(PEG-b-PEI) with different molecular ratios between PEG and PEI were synthesized by classical ring-opening polymerization. By simply mixing PEG-b-PEI with plasmid DNA(pDNA), worm-like polyion complex micelles (PICmicelles) were spontaneously formed in solution. Their structures and morphologies in physiological milieu were investigated and characterized by ¹H NMR, gel permeation chromatography(GPC), dynamic light scattering(DLS), atomic force microscope(AFM) and gel electrophoresis, etc. The influence of numerous parameters, including NaCl dissociation, protein absorption, anionic species substitution and enzymatic digestion, on the colloidal stabilities of such worm-like PICmicelles were evaluated and demonstrated. The results indicated that the longer cationic segment could be helpful to efficiently condense pDNA and improve the colloidal stability against salt dissociation and anionic species substitution. However, it could also result in insufficient PEG shielding effect against protein absorption and enzymatic digestion.

Synthesis of Tri-arm PLLA-PDLA Block Copolymers and Its Stereocomplex Crystallization Behavior

SHI Wen-Peng, ZHAO Chen-Yang, LI Su-Ming, FAN Zhong-Yong

2012, 33(09): 2092-2098. doi:10.3969/j.issn.0251-0790.2012.09.038

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The tri-arm poly(L-lactide) was prepared by ring-opening polymerization(ROP) of L-lactide(LzLA) with 1,1,1-tris(hydroxymethyl)ethane(TME) as an initiator. The terminal hydroxyls of the pre-polymer were activated by stannous octanoate. Then a series of novel tri-arm poly(L-lactide)-poly(D-lactide)(PLLA-PDLA) block copolymers were synthesized by ROP of D-lactide(DLA) with functioned PLLA-SnOct pre-polymer as a macroinitiator. Nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography(GPC) results confirmed the configuration of the tri-arm PLLA-PDLA block copolymers with high isotacticity and high molecular weight. The block structure of copolymer could be readily adjusted in terms of the feed ratio of monomer with the PLLA pre-polymer. Differential scanning calorimetry(DSC) and wide-angle X-ray diffraction(WAXD) demonstrated that the stereocomplex PLA(Sc-PLA) were formed between intramolecular and intermolecular PLLA and PDLA blocks. The melting temperature(T_m) of Sc-PLA crystals was above 200℃, which was much higher than that of pure PLLA. These results show that a novel tri-arm PLLA-PDLA block copolymer would be promising as a heat-resistant PLA engineering material.

Enzymatic Degradation of Biocompatible Block Polyelectrolyte Micelles in Aqueous Solutions

MAO Jun, BO Shu-Qin, JI Xiang-Ling

2012, 33(09): 2099-2105. doi:10.3969/j.issn.0251-0790.2012.09.039

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Enzymatic degradation behavior of biocompatible block polyelectrolyte poly(L-lactide)-b-poly[2-(dimethylamino)ethyl methacrylate](PLLA-b-PDMAEMA) micelles in aqueous solutions at two different temperatures (25.0℃, 36.8℃) and two different pH values (pH=4.9, 7.4) was investigated by laser light scattering (LLS) and atomic force microscopy (AFM). It is found that there is an enzyme inactivation time during the degradation process. Before this time, the degradation mechanism of PLLA-b-PDMAEMA micelles follows a one-by-one process. After this time, the degraded micelles with cracks or tunnels in their cores aggregate into large micelles to minimize their surface area exposed to the solvent, therefore minimize the free energy of the micelles. After increasing temperature, the activity of the enzyme increases, and the degradation rate of micelles is much faster. At pH=4.9, the coronas of the micelles are stretched due to the electrostatic repulsion, because of which the degradation rate of micelles is faster at pH=4.9 than that at pH=7.4.

Synthesis and Characterization of Electromagnetic Functionalized Polyoyrrole/γ-Fe₂O₃ Nanospheres by Chemical One-step Method

ZHANG Zhi-Ming, LI Qiong, WANG Yue, CUI Zhi-Jie, YU Liang-Min

2012, 33(09): 2106-2110. doi:10.3969/j.issn.0251-0790.2012.09.040

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A "Chemical one-step method" (COSM) was used to prepare the electromagnetic functionalized polypyrrole/γ-Fe₂O₃(PPy/γ-Fe₂O₃) nanospheres without any dopant. In this method, FeCl₃ acted as an oxidant for the polymerization of pyrrole and as a source of γ-Fe₂O₃, which also required the initial presence of Fe(Ⅱ), provided by the addition of FeCl₂. In this paper, the amount of FeCl₂ had little effect on the morphology; however, the conductive and magnetic properties of PPy/γ-Fe₂O₃ nanospheres were greatly affected by the amount of FeCl₂. The conductive and magnetic properties of PPy/γ-Fe₂O₃ nanospheres increased and reached maximum values simultaneously with increasing amounts of FeCl₂. The resulting electromagnetic PPy/γ-Fe₂O₃ nanospheres show maximum conductivity of 72.1 S/cm and saturation magnetization of 10.07 A·m²/kg.

Selecting Reorganization of Bisphenol A by Molecularly Imprinted β-Cyclodextrin Polymer in Aqueous Solution

HU Pin, XIONG Zhen-Hu, LIU Jian-Ming

2012, 33(09): 2111-2116. doi:10.3969/j.issn.0251-0790.2012.09.041

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Molecularly imprinted polymers (MIP) were synthesized by mixing bisphenol A(BPA) as the template, β-cyclodextrin as the monomer and hexamethylene diisocyanate (HDI) as the cross-linker in anhydrous dimethyl sulfoxide (DMSO). The obtained polymer particles were characterized by infrared spectrophotometer (IR) and scanning electron microscopy (SEM). The results of equal and unequal opportunity competition adsorption between bisphenol A(BPA) and bisphenol C(BPC) confirmed that β-CD-MIPs exhibited much better recognition and selectivity for BPA than BPC. The parameters of thermodynamics for the adsorption process verified the adsorption reaction was spontaneous and exothermic process and low temperature was favorable for adsorption.

Phenylethynyl-terminated Imide Oligomer of Having Pendent Phenylethynyl Group with Good Thermal Stability

YANG Ming, PAEK Cholhyok, ZHOU Hong-Wei, CHEN Chun-Hai, DANG Guo-Dong

2012, 33(09): 2117-2120. doi:10.3969/j.issn.0251-0790.2012.09.042

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A diamine monomer 3,5-diamino-4'-phenylethynylbenzophenone (DPEB) was synthesized and phenylethynyl-terminated imide oligomers having pendent phenylethynyl group (n=4) was prepared by the reaction of 3,3',4,4'-biphenylenetetracarboxylic dianhydride (s-BPDA), DPEB and 2,5-bis(4-aminophenoxy)-biphenyl(p-TPEQ), and end-capped with 4-phenylethynylphthalic anhydride (PEPA). The imide oligomer had low T_g and provided wide processing window. The cured films were prepared by molding the oligomer powder at 370℃ for 1 h under pressure. DMA results show the introduction of pendent phenylethynyl group increases T_g of the cured film and the retention of storage modulus beyond T_g is promoted.

Synthesis of Bis(β-hydroxyimino)titanium Complexes and Their Catalysis for Ethylene Polymerization

ZHANG Dan-Feng, SUN Yue, DENG Xiao-Juan, CHEN Qian, DONG Bao-Jun

2012, 33(09): 2121-2128. doi:10.3969/j.issn.0251-0790.2012.09.043

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Three β-hydroxyimino ligands: (2,6-^emPr₂C₆H₃)N＝C(Ph)CH₂CH(Ph)OH(1a), (2,6-^emPr₂C₆H₃)N＝C(Ph)CH₂C(Ph)₂OH(1b), (2,6-^emPr₂C₆H₃)N＝C(Ph)CH₂C(C₁₂H₈)OH(1c) and their bis-ligated complexes: [(2,6-^emPr₂C₆H₃)N＝C(Ph)CH₂CH(Ph)O]₂TiCl₂(2a), [(2,6-^emPr₂C₆H₃)N＝C·(Ph)CH₂C(Ph)₂O]₂TiCl₂(2b) and [(2,6-^emPr₂C₆H₃)N＝C(Ph)CH₂C(C₁₂H₈)O]₂TiCl₂(2c) were synthesized. The structures of the ligands and complexex were characterized by ¹H NMR, MS and IR. In the presence of methylaluminoxane (MAO) as cocatalyst, the effects of experimental conditions in which Al/Ti molar ratio, time, temperature and pressure were varied on ethylene polymerization by catalyst 2b were investigated. These catalysts can produce polyethylene(PE) with very high molecular weight under the broad reaction conditions. The melt points of all PE samples are around 140℃. The results of ethylene polymerization by 2a-2c show that the bulky of substituents on the β-carbon influents on the catalytic activities very much. The catalyst 2b with two phenyl groups on the β-carbon gives the best catalytic activity among the three complexes.

Preparation and Properties of New Antibacterial Polysulfone Ultrafiltration Membranes

WANG Xue, XU Jia, JIANG Yu-Ye, GAO Xue-Li, GAO Cong-Jie

2012, 33(09): 2129-2134. doi:10.3969/j.issn.0251-0790.2012.09.044

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A novel antibacterial polysulfone (PSF) ultrafiltration (UF) membrane with capsaicin derivatives function structure was prepared. First, copolymer P(H-co-M) through the radical cause was polymerized with N-(4-hydroxyl-3-methoxyl phenmethyl)acrylamide(HMBA) and methyl methacrylate (MMA) as unconverted monomer. P(H-co-M) was confirmed by the infrared absorption spectrum(FTIR) and thermo gravimetric analysis. Then, the copolymer P(H-co-M) was introduced to PSF casting solution by the blending method, and the antibacterial UF membrane was prepared through the immersion precipitation phase-inversion method. The effects of copolymer content in the casting solution on the separation performance and antibacterial property of the UF membrane were investigated. When P(H-co-M) content was 0.5%(mass fraction), the modified UF membrane exhibited the best separation performance with flux of 122.2 L/(m²·h) and rejection of 84.4% for a 5 mg/L humic acid solution, which increased by 13.5% and 9.2% compared to the PSF UF membrane, respectively. In addition, the antibacterial performance was improved significantly. When P(H-co-M) content was 0.5%, the antibacterial rate was as high as 58.8%; When P(H-co-M) content was 1.0%, the largest antibacterial rate was obtained (80.7%). The excellent performance of the modified UF membrane indicates that the novel antibacterial UF membranes with capsaicin derivatives function structure open a new field in the high-efficient membrane materials.

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