Table of Content

10 June 2009, Volume 30 Issue 6

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Articles

Preparation of Nano-sized Mesoporous Silica Dioxide and Al-doped Silica Dioxide at Extremely Low Reactant Concentration

CHENG Hong-Yun, SHI Yan-Tao, NAN Hai-Ming, GENG Yi, CHEN Bao-Hua*, CAI Qiang

2009, 30(6):  1055-1059. 

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Syntheses of nano-sized mesoporous silica dioxide and that with Al doped were preformed at extremely low reactant concentration, and the products were controllable in size(20—70 nm), morphology and pore structure by changing the amount of deionized water or Al source in the reaction. The samples were of high BET surface area(more than 1000 m²/g) and pore volume(1.1—1.8 cm³/g). The pore structure became less ordered, the particle size decreased, the pore volume increased and a certain accumulation of holes appeared when decreasing reactants concentration or introducing Al source in the reaction. The nano-sized mesoporous samples were characterized by transmission electron microscopy(TEM), small-angle X-ray diffraction, and nitrogen adsorption/desorption techniques.

Composite Molecular Sieves Synthesized by Two-stage Crystallization

ZHANG Qiang*, CUI Qiu-Kai, LI Chun-Yi, SHAN Hong-Hong, YANG Chao-He

2009, 30(6):  1060-1065. 

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ZSM-5(core)/SAPO-5(shell) binary structure composite molecular sieves were synthesized by two-stage varying-temperature syntheses, which includes the lower first-stage temperatures and higher second-stage temperatures. The effect of syntheses conditions on the formation and character of core/shell structure zeolite was investigated. These synthesized samples were characterized by XRD, SEM, EDS, FTIR and N₂-adsorption, respectively. In result, compared with the direct high temperature method, the crystallinity of SAPO-5 in composite is lower and that of alone SAPO-5 zeolite is higher by two-stage varying-temperature syntheses at shorter time. So two-stage varying-temperature syntheses can improve the formation core-shell structure zeolies, reduce amounts of self-existent SAPO-5 zeolite.

Preparation and Electric Field Response Behavior of Barium Strontium Titanate with Different Controlled Shapes

WU Xiao-Ni, GAO Ling-Xiang*, LIU Yi, GAO Zi-Wei, PEI Cuo-Ping, GAO Shu-Juan

2009, 30(6):  1066-1070. 

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Barium strontium titanate(Ba_0.85Sr_0.15TiO₃) with star, flower and drum-shapes were prepared under controllable different pH in the chemical co-precipitation systems at a low-temperature. The samples were characterized with XRD, SEM and CA. The results show that the length of Ba_0.85Sr_0.15TiO₃ particle is in the range of 5—15 μm, and its crystal phase is cubic-perovskite structure. Three kinds of Ba_0.85Sr_0.15TiO₃ particles′ electric field response performances were studied when they were in the gelatin aqueous elastomers under DC electric field or without field. It is found that the shape of barium strontium titanate plays an important role on its electric field response capability.

New Chemical Surface Treatment for the Preparation of Biomimetic Calcium Phosphate Coatings on Ti6Al4V

WANG Xiu-Hong, DUAN Ke*, FENG Bo, WENG Jie*, WANG Ri-Zhi

2009, 30(6):  1071-1074. 

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A new non-corrosive surface treatment to prepare biomimetic calcium phosphate coatings on Ti6Al4V was reported. Ti6Al4V samples were repeatedly dipped into a supersaturated solution, withdrawn, and left to dry in air. Calcium phosphate crystallites formed by this dip-dry treatment and their coverage increased stepwise to complete after 10 times of the treatment. The crystallite-covered samples were immersed in the supersaturated solution, and the crystallites grew to uniform calcium phosphate coatings. The mechanism of the treatment was suggested to be an evaporation-driven surface crystallization process. In this method, the calcium phosphate nucleation occurred in a thin wetting film and the drying of the film provided high supersa-turation, therefore it avoids the use of corrosive treatment and high supersaturations.

Synthesis, Characterization and Anti-tumor Activity of a Novel Supramolecular Compound with α-[Mo₈O₂₆]^4- and β-[Mo₈O₂₆]^4-

ZHAO Wen-Xiu, LI Yan, DONG Shun-Fu, PENG Jun*

2009, 30(6):  1075-1079. 

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A novel supramolecular compound with the formula [Ni(C₈N₃H₇)₃]₄[Mo₈O₂₆]₂·7H₂O was synthesized by the hydrothermal reaction of (NH₄)₂[Mo₄O₁₃]·2H₂O, NiCl₂·6H₂O and [2-(1H-pyrazol-3-yl)-pyridine].The inorganic-organic hybrid material was characterized by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The results of X-ray diffraction indicate that the title complex contains both α- and β-octamolybdates. Leading to the connection between the [Ni(C₈N₃H₇)₃]²⁺ complex cation and [Mo₈O₂₆]^4- through hydrogen bonding interactions, and the connection between the complex cation [Ni(C₈N₃H₇)₃]²⁺ groups through π-π stacking interactions between aromatic rings, two kinds of octamolybdate anions as guests were accommodated in a 3D “honeycomb” host supramolecular network. Therefore, in vitro anti-tumor activity of the compound on human ovarian cancer cells SK-OV-3, human lung cancer cells A549, human cervical cancer cells Hela and human breast cancer cells MCF-7 was studied. The results show that the compound has a certain degree of growth inhibition to three different sources of tumor cells. In particular, the IC₅₀ value to the MCF-7 cells is 6.48 μmol /L, it shows that the compound has the value for further study.

Structure and Fluorescence of Two Hetero-Dinuclear Rare Earth Complexes Derived from Schiff-base

ZHOU Yun-Shan, JIANG Fei, ZHANG Li-Juan*

2009, 30(6):  1080-1084. 

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Two hetero-dinuclear lanthanide(Ⅲ)/Schiff-base complexes {[Ce_1.5Sm_0.5(clapi)]₂}·2CH₃CN(1) and {[La_1.5Sm_0.5(clapi)]₂}·2CH₃CN(2) were synthesized using template method and characterized by elemental analysis and IR spectra. The structure of complex 1 was determined. Unit cell parameter of complex 1: a=1.067056(2) nm, b=1.14700(3) nm, c=1.38734(3) nm, Z=1, D_c=1.650 Mg/m³, F(000)=740. The two complexes exhibit weak red fluorescence of Sm³⁺ ions at room temperature, and the experimental results show that inert fluorescence lanthanide ions can influence the fluorescence of the complexes.

Synthesis and Properties of a Series of Novel Phosphorescent Iridium(Ⅲ) Complexes

HUANG Jia, JIANG Ya-Dong*, TANG Xian-Zhong, DU Xiao-Song, BI Juan

2009, 30(6):  1085-1091. 

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A series of new phosphorescent 2-(phenyl)-benzothiazolate derivatives iridium(Ⅲ) acetylacetonate complexes are synthesized from benzoyl-chloride and substituted benzoyl-chloride, 2-aminothiophenol and iridium trichloride anhydrate via three-step-reaction. All these complexes are characterized by ¹H NMR, FTIR, mass spectrometry and elemental analysis. The solubility, thermogravitometric analysis, UV-Vis absorption, photoluminescence and quantum efficiencies of these complexes are investigated. The results indicate that all these complexes have better solubility in common organic solvents such as dimethyl-sulfoxide and chloroform. The TGA thermograms show that the decomposition temperature of all these complexes are stable up to 338—360 ℃, all the complexes have excellent performance in thermostability, and they can be easily sublimed that makes them suitable for high-vacuum thermal evaporation films. The UV-Vis absorption spectra of these complexes show intense high energy transitions π-π* from 250 to 350 nm, singlet metal to ligand charge-transfer(¹MLCT) from 400 to 450 nm and the triplet metal to ligand charge-transfer(³MLCT) from 450 to 530 nm. A series of strong yellow photoluminescence(in the range of 560 to 600 nm) and high quantum efficiencies of these complexes are also observed at room temperature.

Letters

Studies on ²⁷Al and ²⁹Si NMR Spectroscopies of Sodium Aluminosilicate Solutions

LI Cai-Jin, LI Shou-Gui, XIAO Feng-Shou*

2009, 30(6):  1092-1094. 

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Aluminosilicate zeolites as one of the most important catalytic materials are widely applied in industrial reactions, and understanding of their synthetic mechanism is one of key factors in this field. ²⁷Al and ²⁹Si NMR techniques are one of powerful tools for characterization of zeolite synthesis, but unfortunately the study on ²⁷Al NMR spectra of aluminosilicate solutions is still argumentative, and the assignment of aluminosi-licate species in the solutions are challengeable. In this work, we have carefully compared ²⁷Al NMR spectra of various aluminosilicate solutions, harmonizing the assignments reported previously. Furthermore, we assigned ²⁹Si NMR spectra related to Al species. The peaks at δ: -75.1 and -82.5 in ²⁹Si NMR spectrum are related to Q² Al species, the peaks at δ: -84.5 and -90.8 are related to Q³ and Q⁴ Al species in aluminosilicate solutions, respectively.

Articles

Studies on the Interaction for Bovine Serum Albumin with Phenylbutazone and Ibuprofen by Fluorescence Spectrometry

SUN Yan-Tao, ZHANG Yu-Pu, BI Shu-Yun, SUN Ye, LIU He, ZHAI Yu-Juan, ......

2009, 30(6):  1095-1100. 

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The interaction of bovine serum albumin with phenylbutazone and ibuprofen was studied by fluorescence spectrometry.  The binding and thermodynamic parameters were obtained. The reasonable results were obtained by programmed calculation process based on the calculating equation established. By comparison with the results obtained by the other calculating methods, it is proved that the satisfactory results can be obtained by the proposed method. In addition, the effects of common ions on the binding of the drugs and bovine serum albumin were also examined.

Adaptive Binning Method for NMR Spectroscopic Metabonomics Data Preprocessing

DONG Ji-Yang*, XU Le, XU Jing-Jing, CHEN Zhong*

2009, 30(6):  1101-1108. 

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A novel adaptive binning method was proposed for NMR metabonomic data preprocessing. The statistical discrepancy of each spectral data point is estimated, then the contiguous data points are integrated adaptively based on the statistical discrepancy. Comparing to the fixed width binning, the proposed method can overcome the following negative effects on the subsequently statistical analysis. For example, signals with opposite statistical discrepancies may be superposition in a same region. Both simulated NMR data and experimental spectra from dietary intervention individuals were employed to validate the performance of the adaptive binning. The results show that the proposed method effectively mitigates disturbance from spectral noises and signals without statistical significance. It can increase the interpretability of PCA loading results so that the metabonomics results are more biological significant.

Immunonanogold Catalytic-Cu₂O Particle Resonance Scattering Spectral Determination of Trace α-Fetoprotein

JIANG Zhi-Liang*, ZHANG Yu-Lan, LIANG Ai-Hui, WEI Li-Li, WANG Su-Mei

2009, 30(6):  1109-1115. 

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15 nm-nanogold was used to label monoclone goat antihuman α-fetoprotein antibody(GAFP) to obtain immunonanogold probe(AuGAFP) for α-fetoprotein(AFP). Both nanogold and the probe have catalytic effect on the slow Cu₂O particle reaction between Fehling reagent and glucose that exhibit a resonance scattering peak at 620 nm. Combining AFP-AuGAFP immunoreaction with centrifugation technique, a highly sensitive immunonanogold catalytic-Cu₂O particle resonance scattering spectral assay for AFP was proposed. With addition of AFP, the AFP-AuGAFP immunocomplex increased, the excess probe in the supernatant decreased, and the resonance scattering intensity at 620 nm decreased linearly. The decreased intensity ΔI_RS was linear to AFP concentration[ρ(AFP)] in the range of 0.10—16.0 ng/mL, with a regression equation of ΔI_RS=4.27ρ(AFP)+1.28, and a detection limit of 0.05 ng/mL. This method was applied to the detection of AFP in sera, with high sensitivity and good selectivity, in addition to low-cost reagents and easy controlling reaction.

Metabonomic Studies on Intact Livers and Liver Extracts from Rats Treated with Neodymium Nitrate

LIAO Pei-Qiu, WEI Lai, LIU Wei, WU Yi-Jie, LI Xiao-Jing*, NI Jia-Zuan, ......

2009, 30(6):  1116-1120. 

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The biochemical effects of neodymium nitrate were studied by NMR spectroscopic-based metabonomic approach. Male Wistar rats were treated intraperitoneally with different doses(2, 10 and 50 mg/kg body weight) of Nd(NO₃)₃. Liver samples from Nd³⁺-treated rats were analyzed either by 600 MHz ¹H MAS NMR techniques for intact liver or using high resolution(liquid state) ¹H NMR for liver chloroform/water/methanol extracts. All NMR spectra data were analyzed by pattern recognition using principal components analysis. Liver lesions induced by Nd(NO₃)₃ were represented by increased triglyceride, leucine(isoleucine), lactate, alanine, pyruvate, phosphocholine and glucose concentration, and reduced trimethylamine N-oxide(TMAO) concentration in liver. Histopathology examination showed cell necrosis and inflammation in the liver of 50 mg/kg body weight dosed rats. It was demonstrated that neodymium nitrate could cause damages to rats liver by disturbing the energy metabolism(glucose and lipid metabolism) and amino acid metabolism in the liver.

Simultaneous Multi-response Optimization and Capillary Electrophoresis with Laser Induced Fluorescence Detector for Rapid Detection of Foodborne Pathogenic Bacteria

QU Ling-Li, LI Yuan-Qian*, ZHENG Bo, HE Cheng-Yan, HE Ling, LI Yong-Xin

2009, 30(6):  1121-1127. 

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A rapid, sensitive and reliable method for monitoring foodborne pathogenic bacteria by multiplex PCR-capillary electrophoresis with laser induced fluorescence detector was developed. Four sets of primers were designed to simultaneously amplify the gene segments of invA gene in salmonella, rfbO157 gene in E.coli.O157∶H7, ipaH gene in Shigella and Vpara(16S—23S rDNA IGS) gene in Vibrio parahemolyticus and the multiplex PCR system was optimized. The separation conditions of capillary electrophoresis were optimized by central composite design(CCD) and simultaneous multiresponse optimization. The method was applied to the rapid detection of above PCR products by a capillary coated with linear polyacrylamide and 1.0％MC-4000 sieving buffer with SYBR Green Ⅰ as DNA fluorescent dyes under a separation voltage of 5.2 kV. The proposed method was able to simultaneously detect the PCR products of the above four genes under the optimization conditions of PCR reaction and capillary electrophoresis within 25 min. The within-day precisions of migration time were 0.92%—1.58%. Compared with agarose gels electrophresis, the proposed method is rapid, sensitive and accurate.

Letters

Immobilization of DNA Hydrogel Plugs in Glass Microfluidic Channels and Its Applications

ZHANG Yu, YU Hao, DONG Xiu-Ling, QIN Jian-Hua*, LIN Bin-Cheng*

2009, 30(6):  1128-1130. 

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A method of DNA probes immobilization and specific target sequences capture in a microfluidic chip was presented. Acrydite-modified DNA probes are immobilized in silanized glass microfluidic channels via photopolymerization in a polyacrylamide matrix. The resulting polymeric, hydrogel plugs are porous under electrophoretic conditions, and the immobilized DNA probes can be hybridized with fluorescence labeled complementary DNA. The total analysis process can be completed within 5 min, and the limit of detection is 0.1 μmol/L. This method is simple, rapid and feasible. The double-stranded DNA can be chemically denatured, and the chip is reusable. The conditions for photopolymerization, hybridization, and denaturation were discussed as well.

Articles

Designment of a New Self-assembling Peptide D-EAK16 with D Amino Acid into 3D Nanofiber Scaffold

YU Zu-Xiao, CHEN Jia, LUO Zhong-Li*

2009, 30(6):  1131-1134. 

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A new generation self-assembling peptide as a research model was synthesized with D amino acid. Circular dichroism, AFM and cell 3D culture were used to study the objective model, D-EAK16. The result reveal that a stable secondary structure of D-EAK16 is β-sheet at 30 ℃. D-EAK16 can form transparent hydrogel with 99% water content, which can self-assemble to nanofibers and to the scaffold in physiological solution such as PBS and DMEM. Toxicity of the ECM(extracellular matrices) was not found when cultured the cell stains HO-8910 and SPC-A-1 in the solution of D-EAK16. Moreover, there is no significant difference to toxicity between the nano-scaffolds made of D or L amino acid. We hope these synthetic peptides can be as a 3D microenvironment of the cells(just similar to the bodies), widely use in the biomedical engineering.

Synthesis, Structure and Properties of a Novel Photochromic Dyad Based on Spirooxazine and Ferrocene

YANG Su-Hua, PANG Mei-Li*, GUO Xin-Fu, HUO Xiao-Lian, HAN Jie, MENG Ji-Ben*

2009, 30(6):  1135-1139. 

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A novel photochromic compound 2 based on spirooxazine and ferrocene residue was synthesized by esterification reaction of 9′-hydroxy spirooxazine and ferrocene carboxylic acid in the presence of DCC. Its structure was characterized by ¹H NMR, ¹³C NMR, IR, HRMS, and X-ray single crystal diffraction. The UV measurement show that compound 2 has good photochromic properties in several organic solvents and good fatigue resistance property. The special property in dichloromethane was proved to be caused by acidichromism when irradiated with high pressure Hg lamp without ice bath. The photochromic property of compound 2 in solid PMMA thin film was also studied. In the acidic condition, or under irradiation with high pressure Hg lamp without ice bath, the dichloromethane solution of compound 2 exhibit a good fluorescence. Additionally, compound 2 show a good reversibility of the redox, which is determined by CV. Ferrocene derivatives have the property of absorbing light, and this property may be helpful to extend the fatigue life of photochromic compounds. Besides, the new compound may posses photo-electromagnetic property owing to the existence of metal ion.

Synthesis, Electroluminescent Properties of 2-[2-(9-Aryl-9H-carbazol-3-yl)vinyl]-8-hydroxyquinoline and Their Each Zinc(Ⅱ) Complexes

WANG Guang-Rong, ZENG He-Ping*

2009, 30(6):  1140-1145. 

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The (E)-2-[2-(9-p-tolyl-9H-carbazol-3-yl)vinyl]-8-hydroxyquinoline(8), (E)-2-{2-[9-(4-methoxyphenyl)-9H-carbazol-3-yl]vinyl}-8-hydroxyquinoline(9) and their zinc(Ⅱ) complexes (10 and 11) were synthesized and confirmed by UV-Vis, FTIR, ESI-MS, FAB-MS, ¹H NMR and elemental analysis. The thermal analysis results indicate that complexes 10 and 11 have good thermal stability, which is very essential for fabricating stable organic electroluminescent devices. The single-layer OLEDs with structure of ITO/Organ layer(50 nm)/Al(100 nm) were prepared based on them all emit yellow, in which the peak emission of electroluminescent were 592, 583 nm individually. The OLED based on complex 10 exhibited better device performance with a maximum luminance of 489 cd/m² and luminance efficiency of 0.41 cd/A than those of the device fabricated by complex 11, which were 402 cd/m², and 1.81 cd/A. The electroluminescent studies carried out on the two newly synthesized Zn(Ⅱ) complexes clearly demonstrate that fine control of the electroluminescent properties is possible through the modification of substitute in position 2 of the 8-hydroxyquinoline rings.

Preparation of Folate Targeted Pullulan Acetate Nanoparticles and Cell Uptake in vitro

ZHANG Hui-Zhu*, ZHANG Qi-Qing

2009, 30(6):  1146-1151. 

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Pullulan acetate(PA) was synthesized via the reaction of pullulan with acetic anhydride. Folate was coupled to PA by N,N′-dicyclohexylcarbodiimide(DCC) and 4-dimethylamino-pyridine(DMAP) mediated ester formation. The products were characterized with ¹H NMR spectroscopy and X-ray diffraction(XRD). The solvent diffusion method was used to prepare epirubicin(EPI) loaded nanoparticles. The morphology of nanoparticles was sphere measured by transmission electron microscopy(TEM), and the size of nanoparticles was 200—500 nm determined by dynamic light scattering(DLS). The results revealed that drug loading efficiencies and diameters of nanoparticles increased as the drug/materials ratio increasing. The EPI release rate in vitro was measured using a dialysis tube. Cellular uptake extents of PA and FPA were evaluated with confocal microscopy. The result show more fluorescently labeled cells can be clearly visualized in the absence of folate in the medium than presence of 1 mmol/L folate when KB cell incubated with FPA/EPI nanoparticles, suggesting FPA/EPI nanoparticles are endocytosed in a folate receptor-mediated manner.

Photosynthesis and Differentially Expressed Proteins in Two Morphologic Filaments of Spirulina platensis

LIN Chong-Yang, SHEN Xiao-Wen, ZHAO Zhen-Kun, WU Han-Zhi, XU Hong*

2009, 30(6):  1152-1157. 

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The two kinds of different morphological filaments(spiral and linear ) of Spirulina platensis were separated and grown as axenic cultures. The photosynthetic characteristics show that compared with linear filaments, spiral filaments have higher light-saturated photosynthetic rate and light saturation point, and appeare to be more acclimated to high light intensity. Whereas linear filaments might be more acclimated to low light intensity for their lower light compensation point. To explore the morphologensis determination mechanism of Spirulina, the proteins that were differentially expressed in the spiral and the linear forms were studied. Two dimensional gel electrophoresis was performed to separate differentially expressed proteins that were subsequently identified by MALDI-TOF mass spectrometry. The 2-DE and PMF analysis revealed that at least nine proteins or subunits might relate to the morphogenesis of Spirulina platensis. The identified proteins include three proteins related to peptidoglycan metabolism, two photosynthetic proteins, one transmembrane channel protein, one protein related to cell division, as well as two unknown proteins.

Investigation on the Fluorescent Labeling Between CdTe/CdS Core/Shell Quantum Dots and Protein

ZENG Qing-Hui, ZHANG You-Lin, DU Chuang, SONG Kai, SUN Ya-Juan, ......

2009, 30(6):  1158-1161. 

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Aqueous CdTe/CdS core/shell quantum dots(QDs) were synthesized via successive ion layer adsorption and reaction. The quantum yield was increased from 15%(CdTe) to 38%(CdTe/CdS) after the passivation of the CdS shell. Compared with the bare core, the core/shell QDs were more photostable and suitable for bio-labeling. Both covalent conjugation and electrostatic adsorption were adopted to couple the QDs with the protein, which could be proved well by the agarose gel electrophoresis method. The photoluminescence(PL) of the CdTe/CdS core/shell QDs were also studied after the bio-conjugation. The PL intensity of the QDs was enhanced after coupled with proteins by the two methods. Due to the dipole-dipole interactions, the covalent coupling will lead to the red-shift of the PL peak of the core/shell QDs. On the contrary, because of the decrease of the surface charge, electrostatic adsorption will cause the blue-shift of the PL peak.

Dehydrogenation of Propane to Propene over Ga₂O₃/HZSM-5 Catalysts

REN Ying-Jie, HUA Wei-Ming, YUE Ying-Hong*, GAO Zi

2009, 30(6):  1162-1167. 

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Dehydrogenation of propane to propene in the presence of CO₂ was carried out over Ga₂O₃ catalysts supported on HZSM-5 with different Si/Al molar ratios. The structural and acidic properties were characterized by XRD, XRF, N₂ adsorption, ²⁷Al MAS NMR, NH₃-TPD and model acid-catalyzed reaction. It is found that the stability of supported Ga₂O₃ catalysts for the reaction improves with increasing Si/Al molar ratio of HZSM-5 support, which is thought to be caused by the decrease of the acidity of the catalysts, resulting in the suppression of the side reactions. The stability can also be enhanced by the mesopores generated by steaming, due to the promotion of the diffusion and desorption of the propene.

Theoretical Investigation on the Configuration and Photochemical Properties for Zinc-indigo Complex

WANG Feng-Yun, WANG Su-Fan*, HUANG Yu-Cheng, YE Shi-Yong, ZHOU Tao

2009, 30(6):  1168-1172. 

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Based on the structures of the cis- and trans-indigo isomers, the possible geometries and photochemical properties of zinc-indigo complex were symmetrical investigated and analyzed by density function theory. It is predicted that there are different mechanisms for the excitation of the frontier orbitals between cis- and trans-forms, which result in the different absorption spectra for the isomers. From the configuration analyses of the Zinc-indigo isomers, it is assumed that there are three isomers for the cis- form indigo molecules working as ligand to Zinc ion, and one for trans-form. Because Zn-O₄ is the most stable isomer, a conclusion can be drawn that the isomeration of indigo may exist during complex formation. From the characteristic absorption spectra of the compounds, the possible mechanism for indigo decoloration can be predicted when it works as the indicator to detect the metallic content.

Promote Action of Phosphotungstic Acid for Electrooxidation of Fomic Acid at Carbon Supported Pd Catalyst

YANG Gai-Xiu, DENG Ling-Juan, TANG Ya-Wen, LU Tian-Hong*

2009, 30(6):  1173-1176. 

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The promote action of phosphotungstic acid(PWA) in the electrolyte for the electrooxidation of formic acid at the carbon supported Pd(Pd/C) catalyst in the direct formic acid fuel cell(DFAFC) was investigated using the energy dispersive spectromettry(EDS), X-ray diffraction(XRD) and electrochemical techniques. It was found that the adsorbed PWA could promote dehydrogen of formic acid, leading to the acceleration of the oxidation of formic acid at the Pd/C catalyst. Furthermore, the promote action is related to the PWA concentration. When the concentration of PWA is lower than 0.15 mg/mL the promote action increases with increasing the concentration of PWA. However, when the concentration of PWA is higher than 0.15 mg/mL overfull adsorbed PWA would cover too more active points of the Pd/C catalyst, leading to that the promote action of PWA decreases with increasing the concentration of PWA. Therefore, when the Concentration of PWA is 0.15 mg/mL the electrocatalytic performance of the Pd/C catalyst is best for the oxidation of formic acid.

In situ X-ray Diffraction Investigation on Reduction Process of Ammonia-synthesis Fused-iron Catalysts and the Formation Mechanism of Its Active Phase

ZHENG Yi-Fan*, LIU Hua-Zhang*, LI Xiao-Nian

2009, 30(6):  1177-1182. 

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Two types of ammonia-synthesis fused-iron catalysts, A110 and ZA-5, which based on Fe₃O₄ and Fe_1-xO precursors respectively, were investigated by simulating actual reduction conditions of their preparation with in situ X-ray diffraction. During in situ X-ray diffraction, the transformation of crystal phase, the structures of their precursors and active phase based on X-ray diffraction data were analysed. The results show that the reduction temperature ranges of ZA-5 and A110 are 300—362 ℃ and 343—450 ℃, respectively; the reduction temperature of Fe_1-xO-based catalyst ZA-5 is lower than that of Fe₃O₄-based catalyst A110; the reduction rate of Fe_1-xO-based catalyst ZA-5 is faster than that of Fe₃O₄-based catalyst A110; crystallite size ratios of D₍₂₁₁₎/D₍₁₁₀₎ estimated from (211) and (110) crystal planes of catalysts ZA-5 and A110 are 0.7014 and 0.8631 respectively; catalyst ZA-5 owns more developed high active (211) crystal plane, the value of the microstrain of its active phase is stronger than that of catalyst A110, and the value decreases gradually as the temperature increasing. The morphology simulation of active phase based on Popa technology by Rietveld ana-lysis show that the morphology of the active phase of catalyst A110 is cupped cubic, and that of catalyst ZA-5 is a mixture of cube and globe; high active crystal planes (111) and (211) of catalyst ZA-5 develop better than that of catalyst A110; the morphology of active phase crystal of catalyst ZA-5 is well developed octahedron at 335 ℃, and compared with at other temperatures, its crystal plane (111) is the most developed at this temperature; the morphology of active phase of catalyst ZA-5 transforms from octahedron to globe as the temperature increasing gradually; the match of octahedral structure catalyst ZA-5 is better than that of its precursors, and catalyst ZA-5 can be reduced more easily compared with catalyst A110.

Interaction of Gold Nanoparticles with R-phycoerythrin

JIN Ming-Shan, YUAN Hui-Qing, JING Ji-Rong, SUO Zhang-Huai*, SUN Li

2009, 30(6):  1183-1188. 

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Gold precursor solutions with pH values of 1, 5, 7, and 9 were prepared and the solutions were reduced to obtain colloid gold nanoparticles using NaBH₄ solution as reducing agent in presence of stabilizer. It is found that PVP, PVA, and Tween80 other than sodium dodecylbenzenesulfonate, PEG-1000, and OP emulsion are good stabilizers. When the colloid gold without any stabilizer has the maximum absorption at 525 nm, the absorption PVP-stabilized gold nanoparticles is shifted to 510 nm and the size of gold particles is about 5—8 nm. The interaction of gold nanoparticles with R-phycoerythrin was first investigated by UV-Vis absorption spectroscopy, X-ray fluorescence spectroscopy and transmission electron microscopy. It is found that the triple peak type of R-phycoerythrin at 498, 538 and 566 nm was observed. The average diameter of gold nanoparticles was about 10 nm and highly dispersed and stable in R-phycoerythrin solution. The intensity and position of the absorption spectrum at 538 nm was changed at the presence of gold nanoparticles and its intensive fluorescence emissions at 578 nm were decreased. It is suggested that the interaction between R-phycoerythrin and gold nanoparticles has an effect on the strcuture of R-phycoerythrin and can change the micro-environment of red-colored phycoerythrobilin chromophores in R-phycoerythrin. The results from gel-column chromatography and spectrophotometer analysis of R-phycoerythrin-gold colloid solution indicate that the interaction is also present, probably being resulted from amino groups included in R-phycoerythrin molecule.

Temperature Characteristics and Splitting of PL Spectra of Er³⁺∶Yb³⁺∶Tm³⁺ Co-Doped Borosilicate Glasses

ZHANG Li, LI Cheng-Ren*, MING Cheng-Guo, WANG Bao-Cheng, XU Wei

2009, 30(6):  1189-1193. 

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Er³⁺∶Yb³⁺∶Tm³⁺ co-doped borosilicate glasses were prepared by high-temperature scorching under solid phase. The temperature characteristics of the photoluminescence spectra were measured in the range of 300—573 K under pumping by a 978 nm semiconductor laser, and spectra splitting of green and red up-conversion emissions at room temperature were discussed. The mechanisms of the energy transfer among Er³⁺, Yb³⁺ and Tm³⁺ ions were analyzed. The results show that photoluminescence intensities of the samples at 480, 517, 534 and 657 nm descend monotonously with the increasing temperature, almost disappear at 490 K. However, the photoluminescence intensity of the near infrared at about 900 nm stronger and stronger when sample temperature increases, and peak wavelength shift to the short-wavelength direction. The photoluminescence spectra take on marked splitting at room temperature, but the splitting become weaker at high temperature.

In situ IR Study of COS Hydrolysis over Lanthanum Oxysulfide: Effect of O₂, H₂S and SO₂

JIN Xing-Mei*, MA Jian-Xin, ZHOU Wei

2009, 30(6):  1194-1198. 

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The effect of the presence of O₂, H₂S and SO₂ in the feed on the COS hydrolysis was studied comparatively over La₂O₂S and γ-Al₂O₃. Compared to the traditional γ-Al₂O₃ catalyst, La₂O₂S was observed to be obviously superiosity in resistance to the poisoning of oxygen and sulfide at higher temperature. A certain amount of O₂ or H₂S+O₂ has no effect on the activity of La₂O₂S, while decrease the activity of γ-Al₂O₃ signi-ficantly. The presence of SO₂ would decrease the activity of both catalysts,but the impact on La₂O₂S weakens as the temperature rises. The analysis of TPD and in situ IR reveals that O₂, H₂S and SO₂ shows different adsorption characteristics over La₂O₂S and γ-Al₂O₃. Hence, COS proceed the two catalysts via different reaction mechanisms. Spectroscopies of H₂S, O₂ in situ IR reveal that La₂O₂S hydrolyze via Eley-Rideal mechanism. The rare-La₂O₂S catalyst displays an excellent poisoing performance,because SO₂ can transfer the lattice S^2- inside the La₂O₂S.

Optimizing the Surface Modification of Poly(tetrafluoroethylene) in a Flowing Afterglow Ar Plasma

LIU Hong-Xia, CHEN Jie-Rong*

2009, 30(6):  1199-1204. 

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In the ideal tube-reactor, double Langmuir electron probe and electron spin resonance(ESR) were used to measure the distribution of electrons, ions and free radicals in Ar plasma. Surface modification of poly(tetrafluoroethylene)(PTFE) in Ar plasma active discharge zone and afterglow zone were studied respectively. The surface properties were characterized via the contact angle measurement, scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). The results show that the concentration of electrons and ions decreases rapidly with increasing the distance from the center of induction coil, which approximated to 0 at 30 cm, whereas the concentration of free radicals reduces slowly, which is 96% of initial one. The surface wettability of PTFE strongly depends on the plasma radio frequcency(RF) power, the treatment time and the argon flux. But regardless of conditions, Ar afterglow plasma is more effective than the conventional Ar plasma in PTFE surface modification because the enhanced reaction of radicals and the inhibited etching action of discharged particles. After a short treatment time(30 s) by Ar afterglow plasma, the surface composition of PTFE is modified and the F/C atomic ratio decreases from 3.27 to 2.30, O/C atomic ratio increases from 0.02 to 0.09. Both the defluorination from PTFE and introducing oxygen functionalities(e.g. CO) into PTFE surface are the primary reasons of surface wettability improvement.

In situ Surface-Enhanced Raman Spectroscopic Investigation of Formaldehyde Oxidation on Au_core@Pt_shell Nanoparticles Coated Platinum Electrode in Different Media

RAO Gui-Shi, ZHANG Lei, KE Hui-Xian, ZHONG Qi-Ling*, REN Bin*, TIAN Zhong-Qun

2009, 30(6):  1205-1209. 

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Au_core@Pt_shell nanoparticles were synthesized by chemical reduction method. The samples were cha-racterized by scanning electron microscope(SEM) and energy dispersive spectroscopy(EDS). In situ surface-enhanced Raman spectroscopy(SERS) was utilized to investigate the electro-oxidation behavior of formaldehyde in different media adsorbed on Au_core@Pt_shell nanoparticles coated platinum electrode. Surface-enhanced Raman scattering spectra with high quality were acquired. The results show that formaldehyde can dissociate spontaneously to produce strongly adsorbed intermediate, CO, in acidic, neutral, and alkaline media on a Au_core@Pt_shell nanoparticles coated platinum electrode. However, the bridge adsorbed CO were increased more significantly in alkaline media. In addition, the bridge adsorbed CO could be oxidized more easily than the linear adsorbed CO. The Raman signal of CO disappeared at -0.4 V in alkaline media, it shifted negatively about 950 mV than in acidic or neutral media.The study demonstrates that Au_core@Pt_shell nanoparticles coated on platinum substrate as electrode exhibited better electrocatalytic properties for the oxidation of formaldehyde in alkaline media than in acidic or neutral media.

Studies on the Thermo-Chemical Properties of Ionic Liquid Based on Alanine[C₄mim][Ala]

TONG Jing, SUN Ying-Chun, FANG Da-Wei, YANG Jia-Zhen*

2009, 30(6):  1210-1213. 

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The enthalpies of solution of the ionic liquid(IL) based on alanine 1-butyl-3-methylimidazoliam alanine([C₄mim][Ala]), with various amount of water, Δ_solH_m(wc) was measured over a molality range of about 0.01—0.06 mol/kg by the solution-reaction isoperibol calorimeter at 298.15 K. According to Archer′s method, the standard molar enthalpies of solution of [C₄mim][Ala] with a known amounts of water, Δ_solH_m⁰(wc) were obtained. Plotting Δ_solH_m⁰(wc) against water content(w₂), was carried out, a good straight line was obtained and the intercept was the standard molar enthalpy of solution of [C₄mim][Ala] without water, Δ_sH_m⁰(pure IL)=Δ_sH_m⁰(pure IL)=-60.74 kJ/mol. Using an oxygen-bomb combustion calorimeter, the molar combustion enthalpy of [C₄mim][Ala] was determined at 298.15 K and the standard molar formation enthalpy of [C₄mim][Ala], Δ_fH_m⁰=(-675±11) kJ/mol, was obtained.

Dye-sensitized Solar Cell Based on Tetradodecylammonium Chloride-type Low Molecular Mass Gelator Based Gel Electrolyte

HUO Zhi-Peng, DAI Song-Yuan*, ZHANG Chang-Neng, LIU Wei-Qing, FANG Xia-Qin, ....

2009, 30(6):  1214-1218. 

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Quasi-solid-state dye-sensitized solar cell(DSC) was fabricated using tetradodecylammonium chloride as a low molecular mass gelator to form gel electrolyte. The differential scanning calorimetry measurement shows the solution-to-gel transition temperature(T_SG) of the gel is 74 ℃. It is also found that the gelation decreased the apparent diffusion coefficient(D_app) values of triiodide and iodide ions in electrolyte. The influence of gelation on the charge recombination at the dyed TiO2 mesoscopic electrode/electrolyte interface was investigated by adopting electrochemical impedance spectroscopy(EIS) technology. The result showed that the gelation increased the dark reaction at the dyed TiO₂ mesoscopic electrode/electrolyte interface. The result of the accelerated aging test showed that the gel electrolyte based DSC exhibited much better stability than the device based on the liquid electrolyte.

Theoretical Studies on Molecular Behavior of C₅₀(D_5h) Derivative: Heterofullerene C₄₈P₂

XU Xiu-Fang*, SHANG Zhen-Feng, LI Rui-Fang, ZHAO Xue-Zhuang

2009, 30(6):  1219-1226. 

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A systematic investigation on all possible P-doped C₅₀(D_5h) isomers C₄₈P₂ was performed using the semiempirical methods AM1 and MNDO and density functional theory method B3LYP/3-21G. The equilibrium geometrical structures, heats of formation, HOMO-LUMO energy gaps, aromaticity, infrared vibrational spectrum and electronic absorption spectrum were studied. Further, the molecular behavior was compared with those of C₄₈X₂(X=B, N). The results indicate that: (1) the isomer C₄₈P₂-78, which corresponds to 1,4-substitution in the six-membered ring located on the equator, is the most stable isomer for C₄₈P₂. (2) The driving force governing the stabilities of the present studied C₄₈P₂ isomers is the strain being inherent in the C₅₀ cage, while the stability doesn′t correlate with the aromaticity. (3) The more stable C₄₈P₂ isomers have larger HOMO-LUMO energy gap compared with C₅₀. (4) The vibrational spectra and electronic absorption spectra of these substituted fullerenes have been calculated, which could serve as a framework to interpret future experimental results. The computed nucleus independent chemical shifts(NICS) values also provide a basis for the possible characterization of these C₄₈P₂ isomers. (5) C₄₈P₂ and C₄₈X₂(X=B, N) have the same rule of doping and governing force of stability, and larger HOMO-LUMO energy gap compared with C₅₀.

Letters

Patterning Adsorption of Polyethylene Oligomer on the Side-wall Carbon Nanotubes

LIU Jia, ZHAO Li, Lü Zhong-Yuan, LI Ze-Sheng*

2009, 30(6):  1227-1229. 

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The patterning adsorption of the polyethylene oligomer(PE) on the side-wall of carbon nanotubes(CNTs) composed of CNT(5,5), CNT(10,0) and heterojunction was researched using the classical molecular dynamic simulation. The configuration of the PE chains on the side-wall of the CNTs depended on the dimensional matching of PE and CNT mostly. The patterning adsorption was presented when the length of the PE chains and the pure CNT part matched.

Articles

Rheological Study on the Crosslinking of NEPE Propellant

ZHANG Wei*, FAN Xue-Zhong, CHEN Yong-Duo, XIE Wu-Xi, LIU Zi-Ru, WEI Hong-Jian

2009, 30(6):  1230-1234. 

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The curing process of the NEPE(nitrate ester plasticized polyether) propellant was studied by means of the dynamic rheology method. The results indicated that the viscoelastic properties of the propellant slurry changes obviously in different curing stages, in the initial curing stage(viscous fluid state), where G′(storage modulus) and G″(loss modulus) increases slowly, G′ is less than G″; in the medium of the curing process, the propellant slurry is gelated, G′ and G″ increase significantly in the mean time, G′ is equivalent to G″ and higher than that; in the finial curing stage(viscoelastic state), where G′ and G″ increase to the maximum and level off, G′(~106 Pa) is obviously higher than G″(~105 Pa). It was experimentally show that tgel(gel time) of the propellant decreases as the curing temperature increases, while G′_gel(storage modulus at gel point) and G′_∞(storage modulus at the end of curing) change slightly, which are in the range of 622 Pa to 781 Pa and 831.1×10³ Pa to 868.3×10³ Pa, respectively. It was found that the crosslinking kinetic of the propellant in the initial curing stage is reaction controlled, and follows the first-order model. The curing of the propellant is in agreement with the Hsich kinetic model. k_c(reaction rate constant), t_gel and τ(characteristic relaxation time in the Hsich model) are used to calculate the apparent activation energy(ΔE_c, ΔE_g and ΔE_τ) of the curing of the propellant, which are 129.6, 122.1 and 120.6 kJ/mol, respectively.

Preparation of Modified Electrode and Chiral Recognition Properties of PAEK Macrocyclic Oligomer Bearing 1,1′-Bi-2-naphthyl Moiety

YANG Li-Guo, JIN Hai-Yan, WANG Yong-Guo, CUI Yan, CAO Hui, BEN Teng*, ......

2009, 30(6):  1235-1239. 

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Modified electrode of poly(aryl ether ketone) macrocyclic oligomer containing 1,1′-bi-2-naphthyl moiety was successfully prepared, which was used to recognize chiral supramolecules that were derived from tryptophan and tungstophosphoric acid(D, L, DL-H₃Trp₂-[PW₁₂O₄₀]/GC in 1.0 mol/L H₂SO₄) by the cyclic voltammogram method. By means of vibrational circular dichroism spectroscopy, we found that different solvents treatment could alter the plane angle of the two naphthyl groups(i.e., dihedral angle) of S-PENEKC. Therefore, the selectivity of chiral recognition based on S-PENEKC could be achieved by different solvents treatment, which was approved by the results from electrochemical experiments.

Gas Permeation Property of 6FDA-mPDA and Its Asymmetric Hollow Fiber Membranes

DING Xiao-Li, CAO Yi-Ming*, WANG Li-Na, ZHAO Hong-Yong, JIE Xing-Ming, ......

2009, 30(6):  1240-1244. 

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2,2′-Bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride(6FDA)-1, 3-phenylenediamine(mPDA) polyimide was synthesized by chemical imidization in a two-step procedure. The density of the polymer dense membrane, the fractional free volume and the glass transition temperature were measured. The ultra-thin hollow fiber membranes with a dense skin were fabricated with different air gap. The hollow fiber membranes have an O₂ permeance of 19.10 GPU and a CO₂ permeance of 106.34 GPU with the O₂/N₂ selectivity of 5.99 and the CO₂/CH₄ selectivity of 82.00 at 25 ℃, 0.5 MPa. The calculated thickness of the dense skin based on O₂ permeance is 96 nm. The temperature effect on the gas separation performance was investigated. The permeances of the O₂, N₂, CH₄ and CO₂ increase with an increase in temperature, while the selectivities of O₂/N₂ and CO₂/CH₄ decrease. The physical aging phenomenon of the asymmetric hollow fiber membranes spun with different air gap distances was investigated. The results show the permeance of the ultra-thin membranes sharply decreases and the selectivity increases. And the thickness of the dense skin affected the aging behavior.

Synthesis, Characterization, in Vitro Degradation and Cytotoxicity of Poly{[2-(2-oxy-1-pyrrolidiny) ethoxy]_1.0(methoxyethoxyethoxy)_1.0] phosphazene}

YIN Yue-Fan, LI Yan-Mei, ZI Yan-Nan, Zhou Yi-Ping, BI Yun-Mei*

2009, 30(6):  1245-1252. 

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Polydichlophosphazene(PDCP) was prepared by the ring-opening polymerization of hexachlorocyclotriphosphazene in the presence of 2%AlCl₃. A new mixed substituent poly(organophosphazene) bearing 2-(2-oxy-1-pyrrolidiny) ethoxy and methoxyethoxyethoxy side groups was synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the sodium salt of 1-(2-hydroxyethyl)-2-pyrrolidone and sodium methoxyethoxyethoxide. Its structure was verified by ³¹P NMR, ¹H NMR, ¹³C NMR, IR and DSC. Its molecular weight was determined by vapor pressure osmometry(VPO). 18-Crown-6 was used in the synthesis of poly[di(2-oxy-1-pyrrolidiny)ethoxyphophazene](PYRP) as phase transfer catalysis in order to improve its synthetic method. The new polymer and PYRP were water-soluble and their in vitro degradation behavior was studied at varied pH conditions. The results indicate that the degradation of poly(organophosphazenes) with (2-oxy-1-pyrrolidiny)ethoxy side groups is dependent on pH of the buffer solution. The rate of hydrolysis was more rapid at pH=5.0 than at pH=7.4 and pH=8.0. It was shown that addition of methoxyethoxyethoxy side group to PYRP structure resulted in a decrease in the rate of hydrolysis. The hydrolysis products of the poly(organophosphazenes) were analyzed by ³¹P NMR, thin layer chromatography(TLC) and titration methods. A hydrolysis pathway of the new polymer in buffer solutions with pH=5.0, 7.4 and 8.0 was proposed. The degradation of the polymers at pH=5.0 involved a hydrolytic cleavage of (2-oxy-1-pyrrolidiny)ethoxy from the chain followed by the degradation of the phosphorus-nitrogen backbone to form phosphate and ammonium. However, the degradation of the polymers at pH=7.4 and pH=8.0 was only cleavage of the side group. The MTT test for the new polymer and its hydrolysis products at pH=5.0 in HepG2 cell revealed that an increase in polymer concentration from 1.3 to 800 μg/mL was not harmful for the cell survival. The hydrolysis products of the new polymer at 800 μg/mL were able to promote cell proliferation.

Letters

Study on Liquid-crystalline Copolymers as a New β-Nucleator to Induce Crystallization Structure of Isotactic Polypropylene

HU Jian-She*, KONG Bo, CHAO Chun-Ying, SUN Jing

2009, 30(6):  1253-1255. 

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The effect of a new liquid crystalline copolymer(LCP-H₂) on the crystallization structure of isotactic polypropylene(iPP) was investigated using wide-angle X-ray diffraction. The experimental results show that LCP-H₂ of low mass fraction can induce β-form in iPP. The nucleating activity of LCP-H₂ mainly depended on its content and crystallization temperature. The content of β-form(Kβ) increased with increasing the nucleator content and crystallization temperature, Kβ value reached a maximum value(35%) when the nucleator mass fraction was 0.8% and the crystallization temperature was 125 ℃.

Natural Anticoagulant and Endothelial Cell-Compatible Multilayer for Endovascular Stents Surface Modification

LIN Quan-Kui, YAN Jia-Jie, JI Jian*, SHEN Jia-Cong

2009, 30(6):  1256-1258. 

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Thrombosis and in-stent restenosis constitute major clinical failures of endovascular stent implantation. In this research, a polyelectrolyte multilayered film of heparin/collagen was constructed onto the endovascular stent via layer-by-layer deposition. The in vitro human platelet adhesion test and blood clotting time assessments demonstrated that the fabricated multilayer took on excellent hemocompatibility. The in vitro human umbilical vein endothelial cell culture results show that the endothelial cell adhesion and proliferation are greatly promoted after the multilayer modification. Such multilayered endovascular stents with excellent hemocompatibilty and human endothelial cytocompatibility may have great potential in clinical applications.