Chemical Research in Chinese Universities

Content of Chemical Research in Chinese Universities Vol.23 No.6(2007)

2007, 23(6): 0-0. doi:

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Syntheses and Structures of Two New Oxalate-bridged Transition-metal Supramolecular Polymers of [M(2-NH₂py)₂(ox)]

ZHANG Xiao, YI Zhi-hui, XUE Ming, XU Yan, YU Jie-hui, YU Xiao-yang , XU Ji-qing

2007, 23(6): 631-634. doi:

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Two new supramolecular polymers [M(2-NH₂py)₂(ox)][M=Co(1), Ni (2); 2-NH₂py=2-aminopyridine; ox=oxalate] were hydrothermally synthesized and characterized by elemental analyses, IR and single-crystal X-ray diffraction analyses. The isomorphic compounds 1 and 2 both possess one-dimensional zigzag chain structures, which are composed of [M(2-NH₂py)₂]²⁺ units bridged by tetradentate oxalate ligands to form three-dimensional supramolecular network via the C—H…O hydrogen bonds and π-π stacking interactions. Compound 1 displays antiferromagnetic interaction.

Crystal Structure, Nano-particle Morphology and Interaction with ATP of [NH₃CH₂CH(NH₂)CH₃]₂ [ M(VI)O²(OC₆H₄O)₂](M=Mo_0.6W₀

LU Xiao-ming , PANG Xiao-li , LI Zhi-qiang , WANG Ting , WANG Zhen , YE Chao-hui

2007, 23(6): 635-640. doi:

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The title complex [NH₃CH₂CH(NH₂)CH₃]₂[ M(VI)O₂(OC₆H₄O)₂](M=Mo_0.6W_0.4) was synthesized via a simple solution-phase chemical route. The determination of single crystal X-ray diffraction revealed that the title compound is crystallized in a monoclinic system with P2(1)/n space group, a=1.0913(10) nm, b=1.0442(10) nm, c=1.8842(19) nm, α=90°, β=96.530(17)°, γ=90°, Z=4, and V=2.133(4) nm³. The mononuclear anionic unit [M(VI)O₂(OC₆H₄O)₂]^2- displays chiral pseudo-octahedral [MO₆] coordination geometry and is linked by chiral cations via hydrogen bond and π…π stacking interaction. The transmission electron microscopy images show that the title complex is comprised of nano-particles with diameters ranging from 20 to 50 nm. The NMR study shows the 1H downfield chemical shifts of [NH₃CH_aH_bCH(NH₂)CH₃]⁺ cations in the title complex when it is mixed with adenosine-triphosphate(ATP), and the chemical shift difference between Ha and Hb is increased greatly, and most of the catecholate ligands dissociate from the central metal atoms. The DNA cleavage activity experiment reveals that DNA cleavage promoted by the title complex is lower than that by Na₂MoO₄ which possesses antitumor pro-perty, but higher than that by Na₂WO₄.

Synthesis of Mg₅(CO₃)₄(OH)₂·4H₂O with Flower-like Micro-structure and Its Catalytic Activity for Transesterification of Dimethyl Carbonate with Phenol

WANG Qiang , WANG Ke-li , WU Xing-long , LUO Sheng-jun , HU Chang-wen

2007, 23(6): 641-645. doi:

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A novel flower-like hydrated magnesium carbonate hydroxide, Mg₅(CO₃)₄(OH)₂·4H₂O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use of template or organic surfactant. Reaction time has an important effect on the final morphology of the product. The micro-structure and morphology of Mg₅(CO₃)₄(OH)₂·4H₂O were characterized by means of X-ray diffractometry(XRD), field-emission scanning electron microscopy(FE-SEM). Brunauer-Emmett-Teller(BET) surface areas of the samples were also measured. The probable formation mechanism of flower-like micro-structure was discussed. It was found that Mg5(CO3)4(OH)2·4H2O with flower-like micro-structure was a novel and efficient catalyst for the synthesis of diphenyl carbonate (DPC) by transesterification of dimethyl carbonate (DMC) with phenol.

Effect of Single-walled Carbon Nanotubes on Cellulose Phenylcarbamate Chiral Stationary Phases

CHANG Yin-xia , REN Chao-xing , RUAN Qiong , YUAN Li-ming

2007, 23(6): 646-649. doi:

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Single-walled carbon nanotubes(SWNTs) have a high adsorption ability and nanoscale interactions. Cellulose trisphenylcarbamates possess high enantioseparation ability in high-performance liquid chromatography(HPLC). Single-walled carbon nanotubes mixed with cellulose trisphenylcarbamate are coated on the silica gel as chiral stationary phases and higher enantioseparation factors are obtained. After a single-walled carbon nanotube is linked to the 6-position of cellulose 2,3-bisphenylcarbamate, its enantioseparation resolution increases compared to that of the cellulose trisphenylcarbamate. It is the first time that SWNTs have been applied to enantioseparation. The results indicate that the single-walled carbon nanotubes are good promoters of chiral recognition. This method can be used to improve the enantioseparation efficiency of the polysaccharide chiral stationary phases.

Detection of Serine Octamer by Desorption Electrospray Ionization Mass Spectrometry in Resultant Mixture of Aspartic Acid Exposed to Sunshine Under Natural Conditions

CHEN Huan-wen , LI Ming , JIN Wei, , JIN Qin-han, , ZHENG Jian

2007, 23(6): 650-653. doi:

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Serine, one of the nonessential amino acids, is of principal interest because of its capability to form magic-number ionic clusters, which provide a remarkable preference for homochirality. With L-aspartic acid as the precursor, this study provides experimental evidence for serine formation in weak acidified aqueous solutions in the presence of iron, with exposure to sunlight, which simulates the natural conditions of the prebiotic aqueous environment. The resultant mixture is directly analyzed via desorption electrospray ionization mass spectrometry(DESI-MS), without any sample preseparation. The serine monomer is successfully detected as protonated molecules, giving a peak at m/z 106, which is confirmed by the MS/MS fragments. Protonated serine octamer(m/z 841) is also observed with significant abundance in the MS spectra and is confirmed by the MS/MS data, which shows the formation of the serine octamer by a synthesized serine in the resultant mixture. It is also found that the serine octamer yielded equivalent abundance in the DESI mass spectra in a wide pH range(pH=1—5), and that existence of ferrous salt and sunshine are essential for the conversion of aspartic acid to serine in the acidic water solution.

Stability and Determination of Metamizole Sodium by Capillary Electrophoresis Analysis Combined with Infra-red Spectroscopy

XIANG Qian , NIU Gang , WU Xian-hua , CHEN Gang

2007, 23(6): 654-658. doi:

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Metamizole sodium was chosen as a representative of unstable analytes for investigation by discussing the effects of oxygen and solvent on its degradation reaction using the capillary electrophoresis technique. A possible degradation mechanism was deduced from the observed behavior and was confirmed by infra-red spectroscopic study. The degradation reaction could be inhibited obviously by methanol instead of water as the solvent of analyte. Under the optimized conditions: separation voltage of 20 kV, and 5 mmol/L disodium hydrogen phosphate and 5 mmol/L borax with 10% methanol(pH 9.12) as the running buffer, the standard curve of metamizole sodium was linear in a range of 3.77—74.07 mg/L. A satisfactory result was achieved when the technique was used to detect metamizole sodium in tablet.

Lead and Cadmium Adsorption onto Iron Oxides and Manganese Oxides in the Natural Surface Coatings Collected on Natural Substances in the Songhua River of China

DONG De-ming , ZHAO Xing-min , HUA Xiu-yi , ZHANG Jing-jing , WU Shi-ming

2007, 23(6): 659-664. doi:

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Natural surface coatings collected from natural substances(NSCsNS) were employed to study the roles of the main chemical components(iron oxides, manganese oxides, and other components) in controlling the adsorption of lead(Pb) and cadmium(Cd) in aquatic environments. The selective chemical extraction followed by the adsorption of Pb and Cd experiments and statistical analysis, were used to investigate the adsorption property of each component. Hydroxylamine hydrochloride was used to remove manganese oxides selectively, and sodium dithionite was used to extract iron oxides and manganese oxides. The result indicated that iron oxides and manganese oxides played an important role in the adsorption of Pb and Cd on NSCsNS, and the relative contribution was about two-thirds. The contribution of manganese oxides was the greatest, with a lesser role indicated for other components. The adsorption ability of manganese oxides for Pb and Cd was greater than that of iron oxides or other components for Pb and Cd. The Pb adsorption observed in each component was greater than Cd adsorption.

Novel Brфnsted Acidic Ionic Liquid Based on a Cyclic Guanidinium Cation: a Green, Efficient, and Recyclable Dual Slovent-catalyst System for Fisher Esterification

GUO Xu, DUAN Hai-feng, SUN Hai, CAO Jun-gang , LIN Ying-jie

2007, 23(6): 665-668. doi:

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A novel Brфnsted acidic ionic liquid(IL) based on the cyclic guanidinium cation has been synthesized. This IL, as a strong Brфnsted acid catalyst or solvent, shows high catalytic activity and biphsaic behavor in the esterifications of carboxylic acids and alcohols. The produced esters as a separate phase can be conveniently decanted out from the IL and the IL is recyclable without any loss of catalytic activity.

Esterification and Selective Esterification in the Presence of TiCl₄

SHANG Yan-mei , LI Jing , ZHANG Ping , SONG Zhi-guang , LI Ye-zhi, , HUANG Hua-min

2007, 23(6): 669-673. doi:

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A series of carboxylic acids was esterified to the corresponding esters with TiCl₄ as catalyst at room temperature, in high yields. This catalyst was highly effective for the selective esterification of primary alcohols with carboxylic acids, in the presence of secondary alcohols, and for the selective esterification of saturated acid with alcohol in the presence of conjugated acid or aromatic acid. On account of the high yield, high chemoselectivity, mild condition, and being free of other dehydrants, this is an efficient method.

Synthesis and Herbicidal Activity of Novel 5-Substituted Benzenesulfonylureas

WANG Mei-yi, MU Xiao-li, GUO Wan-cheng, LI Yong-hong , LI Zheng-ming

2007, 23(6): 674-678. doi:

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Sulfonylurea herbicides have been widely used because of their low application rates, good crop selectivities and low mammalian toxicities. However, some sulfonylureas might persist unfavourably in the environment with residual problems. In order to look for ecologically safer and environmentally benign sulfonylureas, and on keeping the pyrimidine ring being monosubstituted, 15 novel C5-monosubstituted benzenesulfonylurea compounds were synthesized. The structures of all the compounds synthesized were confirmed by elemental analysis and ¹H NMR. Preliminary herbicidal activities of these new sulfonylurea compounds were determined by ALS screening (in vitro) and pot bioassay experiments(in vivo). The herbicidal results show that some novel sulfonylureas are comparable to commercial Foramsulfuron and Monosulfuron.

Synthesis and Spectroscopic Properties of Cyclotriphosphazenes Containing 6-(4-Hydroxyphenyl)-2,2'-bipyridine Side Groups

ZHANG Jun-feng , GAN Xin , OU Xue-mei , FU Wen-fu

2007, 23(6): 679-682. doi:

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Two novel cyclotriphosphazene derivatives containing 6-(4-hydroxyphenyl)-2,2'-bipyridine(hopbp) side groups, N₃P₃(dobp)₂(hopbp)₂(1) and N₃P₃(dobp)(hopbp)₄(2)(dobp=2,2'-dioxybiphenyl), were synthesized and characterized. These compounds display strong fluorescent emission both in solution and in solid state. Their absorption and emission spectra are sensitive to proton: the addition of HBF₄ to the methanol and dichloromethane solution(9∶1, volume ratio) of compound 1 led to a red-shift from 350 to 460 nm for the emission spectrum, and the process was also characterized by isosbestic points of absorption spectra at 267, 287 and 313 nm.

Synthesis, Structural Characterization of Ferrocenyl Iminophosphines and Amidophosphines as Well as Their Application in the Suzuki Reaction

GONG Jun-fang, ZHANG Yan-hui, FAN Xin-heng, WANG Da-wei, SONG Mao-ping , WU Yang-jie

2007, 23(6): 683-687. doi:

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Ferrocenyliminophosphine 1 and 1,1'-bisferrocenyliminophosphine 2 were easily prepared from the condensation of formylferrocene or 1,1'-diformylferrocene with 2-(diphenylphosphino)aniline. The following reduction of imine group by LiAlH₄ led to the formation of the corresponding ferrocenyl amidophosphines 3 and 4. The new ligands 2—4 were well characterized by IR, ¹H NMR, ³¹P NMR spectra, elemental analysis, and ESI-MS. The catalytic activity of all the ligands with palladium compounds in the Suzuki reaction was evaluated. Ligand 1, in combination with Pd(OAc)₂, was found to be the most effective for the Suzuki reaction of aryl bromides with phenylboronic acid. Typically, the use of 0.1%(molar fraction) of Pd(OAc)₂/ligand 1 in the presence of two equivalents of K₂CO₃ as base in toluene at 110 ℃ provided good to excellent yields of the coupled products.

Prokaryotic Expression, Purification, Antibody Production of a NH₂-Terminal Fragment of mCLCA3 Protein and Analysis of mClCA3 Protein Expression in Asthmatic Mouse Lung

HOU Xia , WU Qing-tian , ZHANG Yu-ping , ZHU Na , LIU Yan-li , FENG Xue-chao , MA Tong-hui

2007, 23(6): 688-692. doi:

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mCLCA3 is a member of calcium activated chloride channel(CACC) family that may play an important role in mucin packaging and secretion in asthmatic and cystic fibrosis lung. To study the protein structure and expression of mCLCA3 in asthmatic mouse lung, an N-terminal 269 amino acid peptide of mCLCA3 was expressed in E. coli, purified to homogeneity and rabbit polyclonal antibodies against this peptide were generated. Immunohistochemistry of asthmatic mouse lung using the antibody indicated exclusive mCLCA3 expression in mucin granules of goblet cells in airway surface and lumen. Immunoblot analysis of lavage fluid from asthmatic mouse lung revealed a single 90 kDa protein form of mClCA3. The results demonstrate that the 90 kDa N-terminal peptide, neither the full-length protein nor the reported N-terminal 35 kDa cleaved form of mClCA3 is the major functional form involved in the packaging and exocytosis of mucin granules in asthmatic goblet cells.

Protease-catalyzed Synthesis of Bz-Arg-Gly-Asp-OMein Full Aqueous Medium

HOU Rui-zhen , LI Hong-mei , LIU Yun-jia , ZHANG Long , XU Li , ZHANG Xue-zhong

2007, 23(6): 693-696. doi:

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Synthesis of N-benzoyl-argininylglycylasparagine methyl ester(Bz-Arg-Gly-Asp-OMe), a precursor tripeptide of Arg-Gly-Asp) was catalyzed by papain under kinetic control, at alkaline pH, in a full aqueous medium. The substrates were N-benzoyl-argininylglycine ethyl ester and asparagine dimethyl ester. An aqueous solution of 0.1 mol/L KCl/NaOH containing 8 mmol/L EDTA and 2 mmol/L DTT was selected as the reaction medium. The synthesized hydrophilic tripeptide was soluble in the reaction medium during the reaction process, however, the secondary hydro-lysis of the tripeptide product was not considerable. The effects of different factors, including water content, temperature, reaction time, and molar ratio of the substrates, on the yield of Bz-Arg-Gly-Asp-OMe were examined. The optimal reaction conditions were 0.05 mol/L Bz-Arg-Gly-OEt and 0.15 mol/L Asp(-OMe)₂·HCl in 0.1 mol/L KCl/NaOH solution(pH 8.5), at 40 ℃, and a reaction time of 60 min, with a maximum conversion yield of 62.4%.

Prokaryotic Expression and Polyclonal Antibody Preparation of PRL3

SHEN Xing-gui, LI Wan-nan, WANG Jing, JIANG Yi-qun, LI Qing-shan , FU Xue-qi

2007, 23(6): 697-700. doi:

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Phosphatase of regenerating liver 3(PRL3), which belongs to the superfamily of protein tyrosine phosphatases(PTPs), represents a group of low molecular weight PTPs that participate in tumorigenesis and metastasis processes. Presented here are the results of cloning, prokaryotic expression, purification, and polyclonal antibody preparation of PRL3. To obtain a specific polyclonal antibody against PRL3, the authors have prepared GST-PRL3 to immunize rabbits and purify an anti-PRL3 polyclonal antibody by negative selection affinity columns. Western blot analysis shows that the anti-PRL3 polyclonal antibody has a specific binding ability with PRL3 protein. The anti-PRL3 polyclonal antibody provides a good tool to further study the function of PRL3.

Effects of Micronutrients on Oxidative Stress and Islet Function in Type 1 Diabetes Mellitus Rats: Relationships to Th2 Type Cytokines, Interleukin-4, and Interluekin-10

ZHANG Gui-zhen , LI Mei-hua , SONG Yang , LIU Ting , GAO Shen , SUN Ying

2007, 23(6): 701-704. doi:

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To observe the effects of the micronutrients on oxidative and autoimmune destruction of islets so as to prevent a person from the onset and development of type 1 Diabetes Mellitus(T1DM), the interleukin-4 and interleukin-10 expressions of lymphocytes in peripheral blood and spleen of T1DM rats were determined by flow cytometry. GSH-Px activity and MDA level in the rats' pancreas were measured using biochemical methods. The insulin contents in serum and β cell insulin secret storage were tested by RIA and IHC, respectively. There was an increase in the percentages of IL-4 and IL-10 positive lymphocytes in the peripheral blood and spleen of the groups of rats supplemented with various combinations of micronutrients(p<0.01 and p<0.05, respectively); the blood glucose concentration decreased(p<0.05); both the functional β cell in islets and the insulin content in pancreatic tissue increased(p<0.05 and p<0.01); the GSH-Px activity and MDA level of pancreas in the rats enhanced and decreased respectively(p<0.01 and p<0.05). The results suggest that micronutrients may alleviate the islet lesions by upregulating the expressions of IL-4 and IL-10 and lowering oxidative stress in diabetic rats.

Chemical Constituents from Bletilla ochracea Schltr.

CAI Jin-yan , ZHAO Lin , ZHANG De-zhi

2007, 23(6): 705-707. doi:

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To study the chemical constituents in Bletilla ochracea Schltr., repeated column chromatographies and preparative TLC were used for the isolation of compounds, and spectroscopic techniques(NMR, IR, UV and MS) were used for their structural identification. Seven compounds, 2,7-bis(allyloxy)-5-methoxy-3-methyl-9,10-dihydrophenanthrene(1), gastrodin(2), gastrodigenin(3), β-sitosterol(4), stigmasterol(5), 4-hydroxybenzaldehyde(6), and daucosterol(7) were obtained from the roots of B. ochracea Schltr. Compound 1 is structurally illustrated as a novel compound, and the others are isolated from the title plant for the first time.

Electrochemical Activation of CO₂ for the Synthesis of Ethyl Carbanilate under Mild Condition

NIU Dong-fang, XU Cheng-tian, LUO Yi-wen, ZHANG Li , LU Jia-xing

2007, 23(6): 708-711. doi:

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A novel electrochemical procedure for the synthesis of ethyl carbanilate from aniline and carbon dioxide was developed via the selective cathodic reduction of carbon dioxide in CO₂-saturated DMF solution containing 0.1 mol/L TEABr at room temperature, followed by the addition of EtI as an alkylating agent. The synthesis was carried out under mild[p(CO₂)=1.0×10⁵ Pa, t=20 ℃] and safe conditions. Influences of the nature of the electrodes, the current densities, the passed charges during electrolysis, temperatures, and supporting electrolytes on the yield of ethyl carbanilate were studied to optimize the electrolytic conditions. The selectivity of ethyl carbanilate is 100%.

Facile Fabrication of Large Area Polystyrene Colloidal Crystal Monolayer via Surfactant-free Langmuir-Blodgett Technique

RUAN Wei-dong, LÜ Zhi-cheng, JI Nan, WANG Chun-xu, ZHAO Bing , ZHANG Jun-hu

2007, 23(6): 712-714. doi:

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A facile and novel method for the production of a large area of well-ordered polystyrene(PS) colloidal crystal monolayer was established using the surfactant-free Langmuir-Blodgett(LB) technique. The hydrophobic property(film-forming ability) of PS spheres was improved by a thermo-rheology treatment before LB assembly, and a large film was obtained. In contrast to the traditional LB technique, no surfactant was needed in this method, which could eliminate the additional contamination of surfactants in the preparation process and provided the products with versatile applications in nanosphere lithography(NSL) for biosensor, surface plasmon resonance, and surface enhanced Raman spectroscopy.

Studies on the Cloud Points of Nonionic Surfactants with QSPR

CHEN Mei-ling , WANG Zheng-wu , ZHANG Ge-xin , GU Jin , CUN Zhe , TAO Fu-ming

2007, 23(6): 715-719. doi:

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With quantum chemical parameters, topological indexes, and physical chemistry parameters as descriptors, a quantitative structure-property relationship(QSPR) has been found for the cloud points of four series of nonionic surfactants(a total of 65 surfactants). The best-regressed model includes six descriptors, and the correlation coefficient of multiple determination is as high as 0.962.

Poly(meta-phenylene) Derivative with Rigid Twisted Biphenyl Units in Backbone: Synthesis, Structural Characterization, Photophysical Properties and Electroluminescence

ZHENG Yan, YANG Bing, ZHANG Hai-quan, LU Ping, SHEN Fang-zhong, LIU Lin-lin, XU Hai, YANG Guang-di , MA Yu-guang

2007, 23(6): 720-725. doi:

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A soluble poly(meta-phenylene) derivative with rigid twisted biphenyl unit was synthesized by the Yamamoto coupling reaction. The polymer is soluble in common organic solvents, and the number-average molecular weight is about 6500. The UV-Vis and quantum chemical calculation indicate that the different conformation segments named “conformers” exist in the polymer backbones; it was also further confirmed by the single crystal X-ray diffraction study of the dimeric model compound. The π-π* transition of biphenyl segments of twisted and planar conformations made the polymer exhibit a strong absorption around 256 nm and a weak absorption at about 300 nm. Furthermore, the polymer exhibits a strong UV photoluminescence at 372 nm when the excitation wavelengths are longer than 300 nm. The ultraviolet-emitting electroluminescence(EL) device with the single layer structure shows EL λmax of the derivative at 370 nm.

Morphology and Mechanical Properties of Nylon 6/PBT Blends Compatibilized with Styrene/Maleic Anhydride Copolymer

QIN Shu-hao , YU Jie , ZHENG Qiang , HE Min , ZHU Hong

2007, 23(6): 726-732. doi:

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The mechanical properties and dynamic mechanical properties of blends composed of Nylon 6 and poly(butylenes terephthalate)(PBT), with styrene/maleic anhydride(SMA) as compatibilizer, were studied. The observation on the morphologies of the etched surfaces of the cryogenically fractured specimens via scanning electron microscopy(SEM) demonstrated that in the compatibilized Nylon 6/PBT blends, there exists a finer and more uniform dispersion induced by the in-situ interfacial chemical reactions during the preparation than that in the corresponding uncompatibilized blends. On the other hand, the overall mechanical properties of the compatibilized blends could be remarkably improved compared with those of the uncompatibilized ones. Moreover, increasing the amount of the compatibilizer SMA leads to a more efficient dispersion of the PBT phase in Nylon 6/PBT blends. Furthermore, there exists an optimum level of SMA added to achieve the maximum mechanical properties. As far as the mechanism of this reactive compatibilization is concerned, the enhanced interfacial adhesion is necessary to obtain improved dispersion, stable phase morphology, and better mechanical properties.

Microwave-assisted Solvothermal Synthesis of YF₃∶Yb³⁺, Tm³⁺ Nanobundles

ZHANG Ji-shuang , QIN Wei-ping, , ZHANG Ji-sen , WAN Yan , CAO Chun-yan , JIN Ye , WEI Guo-dong , WANG Guo-feng , WANG Li-li

2007, 23(6): 733-735. doi:

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The microwave-assisted solvothermal strategy was used to synthesize single crystalline YF₃:Yb³⁺, Tm³⁺ nanobundles for the first time. The nanobundles consisting of nanoribbons can be obtained in seconds. The nanobundles present bright blue upconversion luminescence under 980 nm excitation from a laser diode, which provides a promising upconversion material for optoelectronic or biological applications.

Quantification of Erdosteine in the Low-volume of Dog Plasma by Liquid Chromatography Tandem Mass Spectrometry

LIU Dan , WANG Yan , TANG Yun-biao , CHEN Xiao-yan, , ZHONG Da-fang,

2007, 23(6): 736-741. doi:

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The combination of erdosteine and ambroxol hydrochloride showed better mucolytic effect in much lower dosage. A sensitive and selective liquid chromatographic-tandem mass spectrometric (LC/MS/MS) method for the determination of erdosteine in dog plasma was developed and validated. In this determination, quantification was completed with only 25 ml plasma. Plasma proteins were precipitated by acetonitrile, followed by vortex mixing and centrifugation. Chromatographic separation was performed on a C₈ column with a mobile phase consisting of 0.5% ammonia, 0.01% formic acid and methanol at a flow-rate of 0.5 ml/min. MS detection using negative electrospray ionization (-ESI) as an interface was used in selected reaction monitoring (SRM) to monitor transition m/z 248→m/z 110 (erdosteine) and m/z 404→m/z 114 (lisinopril, internal standard). The limit of detection was 0.2 ng/ml for erdosteine in plasma and the linear range was 0.2-2000 ng/ml with a correlation coefficient (r₂) of 0.9904. The intra- and inter-day relative standard deviation across three validation runs over the entire concentration range was less than 10.0%. The accuracy determined at three concentrations (0.5, 25.0 and 1800 ng/ml for erdosteine) was within ±3.0% in terms of relative error. The method recoveries were greater than 80.4%. The method herein described was simple, reproducible and feasible and was successfully applied for the evaluation of pharmacokinetic profiles of erdosteine in 8 Beagle dogs.

A New Furospirostanol Saponin, Ophiofurospiside B from Ophiopogon japonicus(Thunb.) Ker-Gawl

XU Tun-hai , XU Ya-juan , CHEN Ping , HAN Dong , ZHAO Hong-feng , SI Yun-shan , XU Dong-ming , LI Yu , NIU Jian-Zhao

2007, 23(6): 742-744. doi:

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A new furospirostanol saponin, namely as Ophiofurospiside B (1) was isolated together with three known steroidal glycosides from the tubers of Ophiopogon japonicus (Thunb.) Ker-Gawl. Their structures elucidated by spectroscopic analyses including 2D-NMR and ESI-MS.

Template-directed Synthesis of Carboxylic Acid-functionalized Tetracationic Cyclophane

XI Hai-tao , SUN Xiao-qiang , CHEN Juan , MENG Qi , PAN Yi , HU Hong-wen

2007, 23(6): 745-748. doi:

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We have synthesized cyclo(ethyl 3,5-(paraquat-p-phenylene-paraquat) benzoate) tetrakis(hexafluorophosphate) starting from the paraquat dication and ethyl 3,5-bis(bromomethyl)benzoate in the presence of the template molecule 1,5-bis(2- (hydroxyethoxy)ethoxy)naphthalene. In 14 days, the reaction mixture changed from light yellow to light red. Successive precipitations with CH₂Cl₂ and Et₂O yield carboxylic acid-functionalized cyclophane as a white solid in a 23.7% yield.

Activity and Enantioselectivity of Lipase Immobilized in CTAB Microemulsion-based Gels

SONG Shao-fang , LUAN Yu-xia , LU Fu-sui

2007, 23(6): 749-752. doi:

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Microemulsion-based gels (MBGs) were developed using CTAB with n-butyl alcohol as co-surfactant and their physical properties were investigated. The optimum composition of lipase-containing MBGs was determined by catalyzing the esterification of n-hexanoic acid and n-hexanol in n-heptane. The enantioselectivity, storage and reusage of immobilized lipase were studied using the esterification reaction between racemic ibuprofen and n-octanol as the indicator reaction. The results showed that lipase in CTAB MBGs had high activity and good enantioselectivity and could be stored for a long time under a freezing condition and reused many times without obvious decline of activity and enantioselectivity. This provided important information for the application of lipase-containing MBGs in organic reaction.

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