Chem. J. Chinese Universities

Synthesis and Control of the Morphology of YBO₃:Eu Phosphor by Hydrothermal Method

HE Ling, WANG Yu-Hua,

2004, 25(9): 1585-1588.

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YBO₃:Eu³⁺phosphor with different morphologies was successfully prepared by hydrothermal process below 300℃, which is lower about 800℃ than the temperature by solid state method. The reaction conditions, such as starting materials, pH value, reaction temperature, reaction media, catalyst, etc, were investigated. The optimum reaction conditions for preparing spherical vaterite type YBO₃:Eu³⁺ phosphor with uniform size was obtained. Under 254 nm excitation, the main emission peak appeared at 598 nm for spherical shape Y_0.95Eu_0.05BO₃ phosphor synthesized by hydrothermal process and the photoluminescence intensity(⁵D₀→⁷F₁ transition) of it was higher by 50% than that prepared by solid-state reaction. These results indicate that hydrothermal process has a promising application to preparing phosphors for lamps and displays.

Synthesis and Up-conversion Luminescence Properties of Nanocrystal Yb, Ho Co-doped Sodium Yttrium Fluoride

YANG Feng-Zhen, YI Guang-Shun, CHEN De-Pu, CHENG Jing

2004, 25(9): 1589-1592.

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Nanocrystals of up-conversion phosphor, ytterbium and holmium co-doped sodium yttrium fluoride were prepared by a co-precipitation method in the presence of EDTA. Nanocrystals of different sizes with an average diameter of 148, 83 and 41 nm were obtained in defferent molar ratios of EDTA to total Ln³⁺(Y³⁺, Yb³⁺, Er³⁺) of 0, 0.5 and 1, respectively. Up-conversion fluorescent properties of the nanoparticles were also examined.

Synthesis of Cd_1-xMn_xS Quantum Dots via Reverse Micelles and Its Photoluminescence Performance

PANG Qi, GUO Bi-Cheng, WANG Jian-Nong, YANG Shi-He, WANG Yu-Qi, GE Wei-Kun, GONG Meng-Liang,

2004, 25(9): 1593-1596.

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Incorporation of diluted magnetic semiconductors (DMS) in quantum confined systems opens new possibilities for the spin-dependent electronics due to the combination of the exchange interaction and the quantum confinement. In this work, we focus on the synthesis and optical properties of Cd_1-xMn_xS quantum dots (QDs). Cd_1-xMn_xS quantum dots (QDs) were prepared via a reverse micelles. The size of dots was controlled by changing the ratio of w_o (w_o=[H₂O][AOT]). A series of Cd_1-xMn_xS QDs samples with w_o varying from³.5 to 5.5 were prepared. A high-resolution electron transmission microscopy (HRTEM) study of QDs with w_o=3.5 shows that the QDs are nearly mono-dispersed with an average diameter around 4.8 nm and the QDs are defects-free single crystals. The Cd_1-xMn_xS QDs size is varying from 4.8, 5.1, 5.3 to 6.0 nm with w_o varying from³.5, 4.5, 5.0 to 5.5. The molar fraction of Mn²⁺ in the Cd_1-xMn_xS dots is about 1.5% with respect to (Mn²⁺+Cd²⁺) determined by X-ray energy dispersion spectroscopy. Electron spin resonance spectroscopy shows that Mn²⁺ ions are in tetrahedral sites indicating that Mn²⁺ are incorporated into the CdS lattice. The absorption spectra of these samples exhibit a well-defined excitonic peak located from².88 eV to 3.28 eV corresponding to the different values of w_o. The longer wavelength of the absorption peak is exhibited with the larger w_o. Most interestingly, the photoluminescence emission peaks are red-shifted from².26 eV to 1.88 eV with increasing the w_o values from³.5 to 5.5. These emission peaks are believed to originate from the Mn²⁺ ⁴T₁-⁶A₁ transitions in associated states.

Preparation, Characterization and Thermal Stability of the Solid Solution Sn_0.5Ti_0.5O₂ Prepared by Sol-gel Method

LIU Feng-Min, QUAN Bao-Fu, CHEN Li-Hua, LIU Zhi-Qiang, YU Lian-Xiang, LIU Kui-Xue

2004, 25(9): 1597-1600.

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Sn_0.5Ti_0.5O₂ solid solution was prepared by sol-gel method. The structure and thermal stability of the Sn_0.5Ti_0.5O₂ solid solution were investigated by X-ray diffraction(XRD), differential thermal analysis(DTA) and infrared spectra(IR) methods. The thermal-stability of the solid solution Sn_0.5Ti_0.5O₂ depends on the original water bath temperature. In the XRD patterns, the phase separation phenomenon was observed in the gel samples prepared over a 40℃ water bath and sintered at 1 000℃ and the Sn-rich and Ti-rich phases appeared. The solid solution synthesized at 60℃ water bath temperatures had a good thermal-stability after being sintered at 1 000℃ and the phase separation phenomenon appeared after being sintered at 1200℃. But the phase separation phenomenon wasn′t observed in the 80℃ gel samples prepared over a 80℃ water bath and sintered at 1 200℃ and the only existent phase was still ascribed to the solid solution Sn_0.5Ti_0.5O₂. Furthermore, the DTA curves of three samples synthesized at different water bath temperatures show that the sample prepared over a 40℃ water bath has the worst thermal-stability and the sample prepared over a 80℃ water bath has the best thermal-stability.

Synthesis of Cd(OH)₂ Nanorods by Solid-state Chemical Reaction at Room Temperature

CAO Ya-Li, JIA Dian-Zeng, LIU Lang, FAN Zhao-Tian

2004, 25(9): 1601-1603.

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Cd(OH)₂ nanorods were synthesized by solid-state chemical reactions of Cd(AC)₂·2H₂O, CdCl₂·2.5H₂O, 3CdSO₄·8H₂O, CdCO₃ and NaOH at room temperature in the presence of a nonionic surfactant, polyethylene glycol 400(PEG-400). The compositions and morphologies of samples were characterized by XRD, TEM and SEM. The results show that surfactant plays a key role in the process of rod-formation and it can act as a soft-template. The method has some advantages, such as simple and facile technique, mild condition and low energy-consumption. It is also expected that the present synthetic method can be extended to prepare other special nanomaterials with desired morphologies by means of choosing suitable surfactant to modify the interface of solid-state chemical reaction.

Synthesis of Metal Porphyrins Bonded with Salicylic Acid and Their Interaction with Bovine Serum Albumin

JIA Tao, WANG Kai, BAO Xiao-Ping, ZHAO Yi-Mei, LI Zao-Ying

2004, 25(9): 1604-1607.

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A synthetic method of porphyrins bonded with salicylic substituents was described. Reaction of bromoalkoxyphenyl porphyrin(1) with salicylic acid gave free porphyrins 2 and 3. Treatment of porphyrins 2 and 3 with Co(OCOCH₃)₂ respectively, afforded metalloporphyrins 4 and 5. These new compounds were confirmed by ¹H NMR, IR, UV-Vis, MS and elemental analysis, and their interaction with bovine serum albumin(BSA) in fluorescence spectrum was observed.

Synthesis of the Nd(Ⅲ) and Hbbimp Complex and Interaction Between the Complex and DNA

ZHOU Chun-Qiong, DENG Xian-He, LIU Gang, YANG Pin

2004, 25(9): 1608-1612.

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A new complex [Nd₂(bbimp)(CH₃COO)(CH₃CH₂O)₂(CH₃CH₂OH)](ClO₄)₂ was synthesized and characterized, in which Hbbimp is 2,6-bis[bis(2-benzimidazolylmethyl)]aminomethyl-4-methylphenoxo. The investigation on the interaction of both complex and CT DNA indicates that the absorbance value and the wave length at the maximum peak of CT DNA are reduced and red-shifted while the intensity of fluorescent spectra of EB-DNA is gradually weaken. UV melting curves prove the existence of the denaturation and degradation together. The only complex is capable of promoting the cleavage of pBR322 DNA at 50℃ and pH 8.0 and can translate most of the supercoiled DNA into nicked DNA. However, the supercoiled DNA can be absolutely translated into the nicked DNA when c(H₂O₂)<1×10^-3 mol/L and n(complex):n(H₂O₂) =1:20.

Preparing Process of SrBi₂Ta₂O₉ Ferroelectric Thin Films by Sol-gel Method Using Soluble Inorganic Salts Source

JI Hui-Ming, GU Yan-Fei, XU Ting-Xian

2004, 25(9): 1613-1616.

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Strontium bismuth tantalate(SBT) and ferroelectric thin films were prepared by a novel sol-gel method on Al₂O₃ and Pt/Ti//SiO₂/Si substrates by using strontium nitrate, bismuth nitrate and fluorine tantalum acid as the sol precursors, and citric acid-ethylene glycol-ethylenediaminetetraacetic acid(EDTA) as the chelating agents. The structure characterization of the sol and as-grown SBT thin films by FTIR, XRD and SEM revealed that the factors such as kind and content of chelating agents and pH value played a key role in the preparing process. The results show that the polycrystalline films with a single orthorhombic-phase are density, homogeneity and crack-free, and average grain size of 150 nm at 750℃ for 40 min in oxygen atmosphere. The ferroelectrics properties of thin films are obtained that remnant polarization(2P_r) and coercive field(2E_c) are 9.6 μC/cm² and 76 kV/cm, respectively.

Synthesis and Characterization of Polycyclic Aromatic Hydrocarbons in GaPO₄-LTA Single Crystals

XI Chun-Yu, LI Guo-Dong, ZHAO Xu, TIAN Ye, ZHANG Yu, CHEN Jie-Sheng

2004, 25(9): 1617-1620.

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Perfect gallophosphate GaPO₄-LTA single crystals, with the LTA framework structure, were synthesized by using 4-methly pyridine(mPy) as the structure-directing template. And the pyrolysis of mPy was studied in the α-supercage of GaPO₄-LTA in vaccum or under a nitrogen flow. Under these conditions, PAHs(polycyclic aromatic hydrocarbons) were produced in the α-cages. The kinds of the species of PAHs formed are closely related to the rate of temperature increase and the terminated temperature. The PAHs formed in the cages of GaPO₄-LTA may act as a precursor for the formation of small fullerene molecules by further rearrangement in the inorganic host.

A Simple Method for Synthesizing WO₃ Nanotubes

CHENG Li-Fang, ZHANG Xing-Tang, CHEN Yan-Hui, LIU Bing, LI Yun-Cai, HUANG Ya-Bin, DU Zu-Liang

2004, 25(9): 1621-1623.

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Highly ordered tungsten trioxide nanotube arrays were synthesized by the combination of (NH₄)₂WO₄ solution and anodic aluminum oxide(AAO) templating method. The morphology and the chemical composition of tungsten trioxide nanotube arrays were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD). The results show that the diameter of the tungsten trioxide nanotube arrays is about 165 nm and just equals to the diameter of pores of AAO template, which reveals that the diameter of the tungsten trioxide nanotube arrays is dependable on the size of the pores in the AAO template. The tungsten trioxide nanotubes are composed by tungsten trioxide nanoparticles formed by reaction(NH₄)₂WO₄^550℃2NH₃↑+WO₃+H₂O↑ in the heating process.

New Detection Method of Gastric Endoscope Samples Using Fourier Transform Mid-spectroscopy

LI Qing-Bo, SUN Xue-Jun, ZHANG Yuan-Fu, XU Yi-Zhuang, YANG Li-Min, SHI Jing-Sen, WU Jin-Guang

2004, 25(9): 1624-1627.

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A new detection method of gastric endoscope samples with promising perspective in clinical application was first proposed in this paper. The identification of stomach cancer, chronic atrophic gastritis and superficial gastritis for a total of 184 gastric endoscope samples was first investigated by using Fourier transform mid-infrared spectroscopy. The spectral characteristics for different classifications of gastric tissues were summarized and correlated with the corresponding pathological results. The experimental results indicated that the changes of molecular composition and structure with various diseases of stomach tissues occur, so the distinct differences were observed among the FTIR spectra of the normal, atrophic gastritis, superficial gastritis and malignant gastric tissues, which were used to classify the diseases and determine the degree of diseases of the gastric endoscope samples. The results demonstrate that FTIR method possesses promising perspective to be developed as a new non-invasive, rapid, accurate and in vivo gastric endoscope detection technique in clinical application.

A Flow Analysis System Based on Microfluidic Chip with Continuous Sample Introduction and Gravity-driven Flows

HUANG Yan-Zhen, FANG Qun, LI Dan-Ni

2004, 25(9): 1628-1631.

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An integrated microchip analytical system with gravity-driven flow was developed, equipped a novel continuous sample introduction interface with cannula configuration, featuring high sampling throughput(80-100 samples/h), low sample and reagent consumption and long continuous working time. Stable and fast flow rate for the streams of sample and reagents in microchannel of the chip were achieved by the use of horizontally oriented reservoirs and stretched outlet tubing, respectively.The performance of the system was tested by using H₂O₂ as a model sample with chemiluminescence detection by the luminol-K₃[Fe(CN)₆]-H₂O₂ reaction, achieving a good precision of 0.3%(RSD, n=5), a carryover of 1.1% for sample changing and a detection limit of 2.0×10^-7 mol/L.

Method for Chemical Changes in Compatibility of Traditional Chinese Medicine Radices Paeoniae Rubra and Litusticam Wallichii

LI Xiu-Ling, XIAO Hong-Bin, XU Qing, WANG Long-Xing, LIANG Xin-Miao

2004, 25(9): 1632-1636.

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The theory of herb compatibility is essential part of traditional Chinese medicines(TCM) prescription. No work has been reported on changes of multiple components in TCM compatibility. It is the first time that basic idea about studying changes of multiple components in TCM compatility was put forward. High-performance liquid chromatography-photodiode array detector-mass spectrometry(HPLC-PAD-MS) was used in this study. Information of retention time, ultraviolet(UV) spectra and molecular weights was compared to confirm the origin of peaks in TCM co-decoction. Then, changes of multiple components in TCM compatibility were carried out. Uniform chromatographic method was the foundation of basic idea. Meanwhile, the origins of peaks in TCM co-decoction were breakthrough. To explore the chemical changes of compatibility of Radices paeoniae rubra and Litusticam wallichii, a reproducible and stable chromatographic method was established. Then, chromatographic data were processed with the uniform chromatographic method. Information of retention time, UV spectra and molecular weight was obtained in HPLC-PAD-MS run. By comparing retention time, UV spectra and molecular weight of each peak in co-decoction with those of Radices paeoniae rubra and Litusticam wallichii, the origin of each peak in co-decoction was confirmed. Finally, the chemical changes of compatibility of Radices paeoniae rubra and Litusticam wallichii in co-decoction were compared with those of combined-decoction. The results indicate that two peaks change in content and one peak regenerate after compatibility.

Electrocatalytic Oxidation of Hydrogen Peroxide at a Glassy Carbon Electrode Modified with Platinum-decorated Carbon Nanotubes

ZHU Yu-Nu, PENG Tu-Zhi, LI Jian-Ping

2004, 25(9): 1637-1641.

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A chemical vapour deposit(CVD) method was used for decoration nano-platinum particles onto carbon nanotube surface. A glassy carbon electrode modified with platinum-decorated carbon nanotube(CNT-Pt/GCE) was prepared. The electrochemical oxidation of hydrogen peroxide(H₂O₂) was studied on this modified electrode. The rate constant k s of the electro-oxidation reaction was obtained from kinetic equations. The k s at CNT-Pt /GCE was 2.65 times of that at Pt electrode, which shows good catalytic activities for electro-oxidation of H₂O₂ in phosphate buffer medium. The mechanism of the electro-oxidation reactions was proposed. This modified electrode can be used to fabricate biosensors based on oxidase.

apillary Electrophoresis Immunoassay Chemiluminescence Detection of zmol Bone Morphogenic Protein-2 in Rat Vascular Smooth Muscle Cells

WANG Jun-Hua, HUANG Wei-Hua, LIU Yan-Ming, CHENG Jie-Ke

2004, 25(9): 1642-1644.

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In this study, a capillary electrophoresis immunoassay(CEIA) method based on the enhanced chemiluminescence(CL) detection was developed. A horseradish peroxidase(HRP) label catalyzing the luminol/H₂O₂/p-iodophenol(PIP) reaction was performed, and the HRP was detected with detection limit(S/N=3) of 4.4 pmol/L(53 zmol), which is one of the highest sensitivity of HRP reported yet. The HRP was linked to bone morphogenic protein-2(BMP-2) in rat vascular smooth muscle(VSM) cells in noncompetitive format and first detected by CL. HRP-Ab₆-mAb-BMP-2 complexes were baseline separated from free HRP label in 3 min. The detection limit(S/N=3) of BMP-2 is 6.2 pmol/L(75 zmol). This technique has been applied to arteriosclerosis pathology research. The change of BMP-2 contentin VSM cells which were stimulated by angiotensin Ⅱ(AgⅡ) for different hours was investigated in the concentration range of 1.0-10.0 pmol/L. The results are in accord with that obtained by common used Pathology image analysis system.

Amperomertric Glucose Biosensor Based on Sol-gel Chitosan/Silica Hybrid Material

TAN Xue-Cai, ZHAI Hai-Yun, LI Yin, ZOU Xiao-Yong, CAI Pei-Xiang

2004, 25(9): 1645-1647.

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A new type of sol-gel/organic hybrid composite film based on chitosan(CS) with methytrimethoxysilane(MTOS) was developed for the fabrication of an amperometric glucose biosensor. The hybrid composite film was used to immobilize glucose oxidase(GOD) on the surface of Prussian Blue(PB)-modified glass carbon electrode. Effects of some experimental conditions such as pH, temperature and applied potential etc. on the current response of the biosensor were investigated. The biosensor has a fast response less than 10 s and linear calibration range from 5.0×10^-6 to 2.4×10^-3 mol/L with detection limit of 1.0×10^-6 mol/L. The apparent Michaelis-Menten constant K_m is found to be 3.2×10^-3 mol/L. The activation energy for enzymatic reaction is calculated to be 21.9 kJ/mol. The biosensor has a high sensitivity(420 μA·mol^-1·L), long-term stability and good selectivity. This method has been used to determine the content of glucose in the real blood samples.

Synthesis of 24-Methylenecholest-5-en-3β,19-diol

LU Wei-Gang, SU Jing-Yu, ZENG Long-Mei

2004, 25(9): 1648-1651.

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With stigmasterol as the starting material, 24-methylenecholest-5-en-3%β%,19-diol(1), a cytotoxic hydroxylated sterol, was synthesized in 10 steps in 16% overall yield. The side chain of stigmasterol was converted to a keto-containing structure 4 %via% ozonization, the Wittig reaction and hydrogenation. The key intermediate cholest-5-en-24-oxo-3%β%,19-diol(8) from compound 4 was prepared according to the following procedures: HOBr addition, lead tetraacetate/I₂-irradiation reaction, zinc dust reduction and KOH/CH₃OH hydrolyzation. Finally, the synthesis of the target product 1 was completed by the Wittig reaction with methenetriphenylphosphorane. The physical constants and NMR data of compound 1 were identical with those of the natural product. This is the first report for the synthesis of 24-methylenecholest-5-en-3%β%,19-diol(1). Compound 1 exhibits a significant cytotoxic activity against human CN2 and Mgc803 cell lines with IC₅₀ values of 3.5 and 4.0 μg/mL respectively.

Synthesis, Relaxivity of Gd(Ⅲ), Fe(Ⅲ) and Mn(Ⅱ) Complexes with Dihydropyridine Derivatives of Diethylenetriaminepentaacetic Acid

ZHENG Shu-Zhan, JIAN Ya-Jun, BAI Yin-Juan, XIE Zhan-Feng, CHANG Jian-Hua

2004, 25(9): 1652-1656.

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Four novel ligands of DTPA-dihydropyridine derivatives which were designed for magnetic resonance imaging contrast agents were synthesized by the reaction between DTPA-dianhydride and 4-aniline-1,4-dihydropyridines. Their complexes of gadolinium, manganese and iron were prepared. Spin-lattice relaxivities(t₁) of the complexes was investigated. The results showed that all the complexes have relaxation effects on the protons in surrounding water molecules. The Gd(Ⅲ) complexes have higher relaxivities than those of Fe(Ⅲ) and Mn(Ⅱ) complexes. The NMR t₁ relaxivities(R₁) of Gd(Ⅲ)DTPA-dihydropyridines complexes are 5.50, 5.58, 5.20 and 5.49 L·mmol^-1·s^-1, which are higher than that of their parent complex, GdDTPA^2-. That indicating that the Gd(Ⅲ) complex possesses the precondition to be the contrast agents for magnetic resonance imaging.

Design, Synthesis and Biological Activity of EBF Analogues

YANG Xin-Ling, HUANG Wen-Yao, LING Yun, KAN Wei, FANG Yu-Ling, ZHANG Zhong-Ning

2004, 25(9): 1657-1661.

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Based on the features of active structures of (E)-β-farnesene(EBF) analogues summarized by Nishino and Bowers, 13 compounds(Ⅰ₁-Ⅰ₁₃) with a novel framework were designed by the method of linking active sub-structures which had the active framework of EBF analogues and the active structure of Neonicotinoid insecticide analogues. Thus, the target compounds were prepared in 24%-59% yield through 2-3 step reactions from the starting material geraniol. Their structures were confirmed by IR, ¹H NMR, and MS. The results of bioassay demonstrated that most of the compounds show an obvious activity against adult Lipaphis erysimi at the test concentration. Especially at a lower concentration, some of them had a better activity than imidacloprid. For example, Ⅰ₁₀ and Ⅰ₁₃ exhibited respectively 93.1% and 87.1%, but imidacloprid showed 66.7% inhibiting rate at 25 mg/L.

Catalysis of 1,1,3,3-Tetrafluorohexylethyldistannoxane in the Ring-opening Reaction of Epoxides

XIANG Jian-Nan, YIN Xia, CHEN Chao-Yue, FAN Hong-Li, HE Chun-Lian

2004, 25(9): 1662-1665.

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Tetrafluorohexylethyldistannoxane compound(1) was synthesized conveniently from diphenyltin dichloride(6) by a new synthetic route, in which compound 6 reacted with R fMgI to afford Ph 2Sn(R_f)₂(7) that was subjected to anhydrous hydrochloride to give (R_f)₂SnCl₂(8), then compound 8 was hydrolyzed with sodium hydroxide to form the fluorous tin oxide(5), the mixture(molar ratio 1:1^05) of 5 and 8 in acetone was refluxed to synthesize compound 1, the total yield was 52%. The catalysis of compound 1 was studied in the ring-opening reaction of epoxide in fluorous biphasic system. The results showed that 95% yield of the ring-opening reaction between styrene epoxide and methanol was obtained by the catalysis of compound(1) in the fluorous biphasic system. Regioselective ring-opening reaction of 100% occurred, which was confirmed by ¹³C NMR. 2-Methoxy-2-phenylethyl 3-phenylpropante was prepared conveniently in one pot and fluorous biphasic system at a high yield. The catalyst can be recovered qualitatively and reused without any lost almost. In summary, compound 1 was prepared in a higher yield by a new synthetic route and its catalysis was developed in the ring open reaction between epoxides and alcohol.

Synthesis and Properties of a New Donor Model Compound for PSⅡ

SHI Feng, LI Hong-Yang, PENG Xiao-Jun, CHEN Xiao-Qiang, ZHANG Rong, WANG Dong-Ping, FAN Jiang-Li, SUN Li-Cheng

2004, 25(9): 1666-1672.

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As a model compound for redox components on the donor side of photosystem Ⅱ(PSⅡ) in green plants, a supramolecular complex 2 was synthesized and characterized. In this complex, two {[(2-hydroxy-3-(morpholin-4-ylmethyl)-5-tert-butyl-benzyl)(pyridyl-2-methyl)amino]methyl} arms are linked to the ortho-positions of a phenol which is expected covalently to be linked to Ru(Ⅱ) tris-bipyridine through an amide bond. The arms on the substituted-phenol can coordinate two Mn(Ⅲ) ions. The structure of complex 2 was confirmed by electrospray ionization mass spectrometry(ESI-MS) and 2D-NMR(gCOSY, HSQC and HMBC). Its photochemical and electrochemical properties were studied. The results showed that the MLCT band of the compound was red-shifted compared to that of [Ru(bpy)₃]²⁺ and the luminescence quantum yield was enhanced. In addition, the oxidation potential of ruthenium was higher than the phenol+/phenol and Mn(Ⅲ, Ⅳ)/Mn(Ⅲ), which was consisted with the electron transfer sequence of the donor side of PSⅡ in nature. All these showed that this compound was a good model to mimic the donor side of PSⅡ.

Synthesis of S-Triazolo-1,3,4-thiadiazine, Imidazolo- 1,3,4-thiadiazole and Imidazolo-1,3,4-oxadiazole Derivatives Containing Isoxazole

LIU Fang-Ming, ABLAJAN Keyume, WANG Hou-Yong, SHAO Ling

2004, 25(9): 1673-1675.

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Isoxazole derivatives were characterized by broad spectrum of biological activities, but the condensed heterocyclic compounds containing isoxazole were scarcely reported. In this paper, we studied the 1,3-dipolar cycloaddition of p-methoxybenzohydroxamoyl chloride with ethyl sodioacetoacetate to obtain a key intermediate 2. Through compound 2, fifteen novel S-triazolo-1,3,4-thiadiazines(5a-5e), imidazolo-1,3,4-thiadiazoles(9a-9e) and imidazolo-1,3,4-oxadiazoles(10a-10e) containing isoxazole, which have potentially useful biological activities, were synthesized. The structures of the products were confirmed by elemental analyses and spectral analysis. And the characteristic data of IR, ¹H NMR and MS were explained reasonably.

Improvement of Oxidizing Agent for DNA Microarray in situ Synthesis

NIE Li-Bo, XIAO Peng-Feng, TANG Jian-Xin, TAN Mei-Jun, CHEN Hong, HE Nong-Yue

2004, 25(9): 1676-1678.

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The phosphorous amide approach is of the highest coupling efficiency among the DNA in situ synthesis approaches at present. The strict anhydrous condition is required in the process of DNA in situ synthesis, and the DNA synthesis in the molecular stamp method must be performed in the anhydrous glove box. Because various volatile reagents remain in the glove box, the reagent gases invade into the coupling reaction system so that the coupling efficiency is decreased. This decrease is caused by the pyridine contained in the oxidizing agent. An improved oxidizing agent system of I₂/Ac₂O/AcOH/THF for the synthesis of oligodeoxy-nucleotides was reported. Using this oxidizing agent, 16-mer oligodeoxynucleotide probes were successfully synthesized on the CPG(controlled pore size glass) or the modified glass slide and a single step coupling efficiency of 98.2% was achieved. The synthesized DNA probes were hybridized with fluorescence and gold-labeled target oligodeoxynucleotides respectively. The fluorescence intensity and gray level for the synthesized probes in the I₂/Ac₂O/AcOH/THF oxidizing agent were similar to those in the traditional phosphorous amide approach possessing a water- and pyridine-containing oxidizing agent I₂/H₂O/Pyridine/THF. The reported oxidizing agent will make the contact printing approach to in situ synthesized DNA microarrays more feasible by eliminating the decrease of coupling efficiency which is because the cross reagent interfering arises from pyridine and water.

Structural Characterization and Catalytic Properties of Three-way Catalyst La_1-xCe_xFe_1-y-nCo_yRu_nO₃

LI Li, YUAN Fu-Long, FU Hong-Gang, GUANG Huan-Zhu, ZHANG Guo, JIANG An-Xi

2004, 25(9): 1679-1683.

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The La_1-xCe_xFe_1-y-nCo_yRu_nO₃(x,y=0.1-0.5, n=0.01-0.1) were synthesized by sol-gel method. The phase structures of the compounds do not change with Ru being doped, but 2θ decreases and crystal cell parameters increase determined by employing XRD technique. IR analysis show that the position and shape of adsorption peaks are almost the same in all compounds, except for the 600 cm^-1 peaks stretching to a high frequency and are changed in disorder with Ru content increasing. Comparing to unsubstituted samples, the band of sample with n=0.01 stretching to a higher region was observed with Ru being introduced into the compound, and the max adsorption peaks emerged in ν 1 when n=0.05, but the strength of peaks in ν 2 was very weak. The enhanced bond strength of Fe-O and Co-O could be attributed to the coordinative effect of Fe-O-Ru and Fe-O-Co, and also the deformation of Fe-O-Co structures. XPS testifies that Fe elements have many valences as the charge densities arise in the out layer. Ce combines with multihydroxy but not oxygen in the surface layer, meanwhile, the content of other oxygen species increased and catalytic activities improved. O₂-TPD results show that the temperature of adsorption oxygen and lattice oxygen decreased and the content of vacancy of oxygen increased. The catalytic activities are improved which is related to the A ion vacancies when x(Ce)≤0.2. H₂-TPR is in accordance with TPD in the result. The catalytic activities are improved which is related to the A ion vacancies and the enhancing lattice oxygen activities, and La_0.8Ce_0.2Fe_0.7Co_0.2Ru_0.1O₃ is the best one among all catalysts mentioned above.

Lipase-catalyzed Synthesis of Isoamyl Isobutyrate in Reversed Micelle System

WANG Yuan-Hong, CHU Ying, LIU Jing-Lin, Lv Zhong-Xian, LIU Ying-Ying, WU Zi-Sheng

2004, 25(9): 1684-1688.

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A new method of lipase-catalyzed esterification of isoamyl isobutyrate by CCL in the reversed micelle of CTAB/n-hexane and AOT/n-hexane has been reported. The effects of such factors as water content(w₀), ratio of substrate to enzyme, pH of buffer and temperature on the synthesis of esterification were investigated. Experimental results show that the reaction rate of esterification in the system of CTAB/n-hexane is faster than that in the system of AOT/n-hexane, and that the conversion of esterification reaches a climax of 99% in the two systems in 80 h. Both the two kinds of reversed micelle provide a suitable micro-environment for the selected lipase(CCL), which shows superactivity 6 and 4 times as much as that in organic solvent, respectively.

Interaction Between Daunorubicin and DNA at Co Ion Implanted Modified Glass Carbon Electrode

WANG Jing, HU Jin-Bo, SHANG Jun, LI Qi-Long

2004, 25(9): 1689-1692.

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With Co/GCE as the working electrode, an interaction between daunorubicin and DNA was studied. The peak current of daunorubicin decreased with increasing the concentration of DNA and then disappeared, which indicated that an unelectroactive complex of DNR with DNA was formed. The UV-Vis spectrum showed that the daunorubicin intercalated into DNA. In the presence of DNA, the electrochemical behavior of DNR was unchanged. The binding constant and binding-site size of DNR-DNA interaction were obtained by nonlinear regression analysis, to be 1.09×10⁸cm³/mol and 4, respectively. One helix in the DNA structure combined two DNR.

Electrochemical Effect Induced by Fluctuations-dissipation of Time-dependent Electrode Processes —— The Stochastic Model of Potentiostatic DME Systems

ZHANG Wen-Hua, WEI Guo-Ying, LUO Jiu-Li

2004, 25(9): 1693-1697.

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A stochastic theory of non-equilibrium thermodynamics of time-dependent potentiostatic D.M.E. processes was established in this paper. Based on a simplified stochastic model of non-steady state irreversible electrode processes the quantitative analysis of both the fluctuations and dissipation in this kind of important physico-chemical systems becomes possible. By means of it, we introduce successfully the basic stochastic formula of non-equilibrium thermodynamics of the potentiostatic DME(dropping mercury electrode) processes as well as a stochastic algorithm useful for theoretical deduction of the polarogram curve. Furthermore, in a limit case of the slow growth of the drop for the DME process with very hesitative diffusion steps(Ψ_EC→0) the polarogram equation induced by the fluctuations is derived under the quasi-steady state approximation. The result corroborates the polarogram equation from Nernst formula in the near equilibrium region. As a typical illustration, an example is given to calculate the deviation of polarogram curve induced by the fluctuations. Under the condition that the asymptotic form of probability distribution is established on the basis of the central limit theorem, the deviation of the current becomes the largest with the potential close to the half-wave potential. This means the fluctuations have great influence on the half-wave potential with very hesitative diffusion steps.

Effect of CF₃COOH on Decay Mechanism of the Excited State of a Free-base-Porphyrin-Perylene-Diimide Array

SUN Jing-Zhi, YANG Xin-Guo, LI Han-Ying, HUANG Ji, WANG Mang

2004, 25(9): 1698-1701.

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The effects of CF₃COOH concentration on the decay mechanism of a photo-excited free-base-porphyrin-perylene-diimide molecular array(TrPP-MDPTCDI) were investigated with UV-visible absorption spectroscopy and fluorescence spectroscopy. The data revealed that, the molecular array gave off a characteristic emission from the protonated free-base porphyrin upon the photo-excitation of both porpyrin and perylene-diimide subuntits. Based on the electronic structure, the protonation allowed the [H₂²⁺TrPP^*-MDPTCDI] to be relatively stable in all the photo-excited species. As a result, the electron transfer from free-base-porpyrin to perylene-diimide, a predominate decay channel in the absence of CF₃COOH was effectively inhibited, and the [H₂²⁺TrPP^*-MDPTCDI] formed upon the excitation of protonated free-base porphyrin(λ=438 nm) relaxed directly to the ground state with fluorescence; while the [H₂²⁺TrPP^*-MDPTCDI] formed upon the excitation of perylene-diimide subunit (λ=491 nm) relaxed via a charge-separation mediate species to [H₂²⁺TrPP-MDPTCDI^*], which decayed with radiation of protonated free-base porpyrin; the latter course was accompanied with a low efficiency energy transfer from perylene-diimide to the protonated free-base porphyrin subunit.

Theoretical Study on the Scattering Resonance States for I⁺HI (v=0)→IH(v′=0)+I System

SUN Xiao-Min, WANG Hua-Yang, CAI Zheng-Ting, FENG Da-Cheng, BIAN Wen-Sheng

2004, 25(9): 1702-1705.

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The ab initio partial potential energy surface is calculated on QCISD(T)//MP2 level for heavy-light-heavy I⁺HI(ν=0)→IH(ν′=0)+I system. For H and I atom, 6-311++GG^** basis set and SDD basis set including the relativistic effect are used separately. The scattering resonance states are found for the title system and the six scattering resonance states are identified as the Feshbach type in the collision energy range from 0 to 0.58 eV which are compared with the theoretical results of quantum scattering and the experimental ones of threshold photodetachment spectroscopy. The partial potential energy surface can reveal effectively the mechanism of the scattering resonance states formation.

Quantum Chemical Description for Molecular Lipophilicity and Hydrophilicity(Ⅰ) ——Molecular Lipophilic and Hydrophilic Surface

DU Qi-Shi, WEI Dong-Qing, LI Ai-Xiu

2004, 25(9): 1706-1710.

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In this research the structure-based method, heuristic molecular lipophilicity-hydrophilicity potential (HMLP), describing of molecular lipophilicity and hydrophilicity potential on molecular surfaces was introduced. The ESP (electrostatic potential) V(r) on molecular van der Waals surface is calculated, then molecular lipophilicity potential L(r) is constructed by comparing the polarity with the ESP on the surrounding atoms through a screening function. HMLP can be used to describe the molecular interactions with polar and non-polar solvent molecules taking the advantage of the polarity of HMLP. Therefore, HMLP is a unified lipophilicity and hydrophilicity potential, its positive values represent lipophilicity and negative values represent hydrophilicity. Several examples given in this paper show that HMLP gives a better descriptions for ligand-receptor interaction than other methods, such as atomic partial charges and empirical lipophilicity potential. After parameterization and indexing, hopefully, HMLP may be applied to the studies of function and structure of proteins and the genomic decoding of DNA and RNA.

Effect of Eu ³⁺ Doping on the Photocatalytic Activity of Nanoparticles TiO₂

YANG Qiu-Jing, XU Zi-Li, XIE Chao, XUE Bao-Yong, DU Yao-Guo, ZHANG Jia-Hua

2004, 25(9): 1711-1714.

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The photocatalytic activities of Eu³⁺-doped TiO₂ nanoparticles prepared by sol-gel method and characterized with XRD and TG-DTA were stidied via photocatalytic oxidation of n-heptane. The enhanced photocatalytic activity of Eu³⁺-doped TiO₂ can be attributed to the fact that Eu³⁺ ions enter into the lattice of TiO₂ to lead to the lattice expansion, enhancing the distortion of lattice, and inhibiting the crystal phase transformation and the increase of grain size. It is found that the x(Eu³⁺)= 0.3% was optimal, and the photocatalytic activity of Eu³⁺-doped TiO₂ decreased with increasing the calcination temperature, and the higher the pH, the greater the photocatalytic activity.

Indirect Electrooxidation of Hydroxypivalaldehyde

WANG Hai-Tao, ZHANG Heng-Bin, XU Yu-Ling, CAO Xue-Jing, LIN Ying-Jie

2004, 25(9): 1715-1718.

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In an electrolytic cell with an ion exchange membrane, Br^- was oxidized to Br₂, which was used as an oxidant to oxidize hydroxypivalaldehyde to hydroxypivalic acid. The effects of temperature, pH, anode potential and concentration of reactants on current efficiency and selectivity was explored. The results indicate that the current efficiency and the selectivity of the reaction for forming hydroxypivalic acid are very high, the highest current efficiency is 91.4%, the selectivity was generally greater than 90%.

Effect of Alkanethiol Self-assembled Monolayers on the Electrochemical Polymerization of Pyrrole on the Gold Electrodes

GONG Shao-Yun, SHEN Yan-Fei, ZHOU Wei-Hong, LI Jing-Hong

2004, 25(9): 1719-1722.

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Pyrrole was polymerized on alkanethiol self-assembled SAMs monolayers modified gold electrodes through electrochemical method. The effects of alkyl chain length and the end functional groups of the SAMs on the polymerization of pyrrole were studied by chronoamperometry, cyclic voltammograms and electrochemical impedance spectroscopy. In the case of SAMs with a high integrity, the polypyrrole grewon the top of SAMs. However, in the case of a large number of pinhole defects, the formation of polymer nuclei on pinhole sites scattered in the SAMs, and then the polymer grewon the entire surface of the SAMs. These results showed that the electrochemical polymerization was easier with shorter alkyl chains, and high hydrophobility of the SAMs could promote the polymer film growth.

Dehydrogenation of 2-Butanol over Supported Copper Catalysts

WANG Zhen-Lü, WU Tong-Hao, YANG Piao-Ping, YU Jian-Feng, ZHU Wan-Chun, JING Shu-Bo, LIU Guo-Zong, WANG Guo-Jia

2004, 25(9): 1723-1726.

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The Cu/SiO₂ and Cu-ZnO/SiO₂ catalysts were prepared by impregnation method. The effect of contents of copper and zinc oxide on the structure and property of catalysts and the activity of these catalysts on the dehydrogenation of 2-butanol and the selectivity for MEK were studied. These catalysts were characterized by means of XRD and TPR. The results indicated that the high dispersing metallic copper was the main active sites in this reaction, ZnO could disperse and stable copper species. Some interaction between copper and zinc oxide would lead to the increasing of condensation product.

Stochastic Resonance of Internal Signal with Two Parameters in Intercellular Calcium Ion System Oscillations

GAO Feng-Xin, LI Ya-Ping, LI Qian-Shu

2004, 25(9): 1727-1729.

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In a model of intercellular calcium ion system oscillations, internal stochastic resonance(ISR) is investigated under the modulation of two parameters, viz., degree of extracellular stimulation β and leak rate k_f. When either β or k_f is subjected to a noise, ISR can occur. When noise is added to the two parameters simultaneously, internal stochastic bi-resonance(ISBR) occurs. The distance to the bifurcation point is found to be able to enhance or suppress the ISBR, and to affect the number of peaks of ISR.

Refinement of Oxygen Dioxide Through Removing Nitrogen Oxides by Means of Reduced Method of Urea Water Solution

WANG Shu-Jiang, YANG Ji

2004, 25(9): 1730-1732.

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A new process was proposed for removing the nitrogen oxides(NO_x) from the CO₂ waste gases from the lime torrefied ratary furnace in Shanghai Baoshan Steel and Iron Company by means of absorption method of aqueous urea solution in order to recover highly pure CO₂ for producing high quality beverage. The result obtained shows that the concentration of nitrogen oxides can be decreased from 6.5×10^-4 mol/L to below 2.0×10^-6 mol/L, the removing rate was over 99%. In the experiment, we made NO coming from the reaction NO₂ +H₂O be all oxidized to NO₂ by using a special oxidized method, which was the key step for removing nitrogen oxides.

Studies on Electrochemical Stability of Room Temperature Ionic Liquids

YANG Jia-Zhen, JIN Yi, CAO Ying-Hua, SUN Li-Xian, TAN Zhi-Cheng

2004, 25(9): 1733-1735.

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In this paper three air and water-stable room temperature ionic liquids(RTILs): N-butylpyridinium tetrafluoroborate(BPBF₄), 1-butyl-3-methylimidazolium tetrafluoroborate(BMIBF₄), and 1-ethyl-3-methylimidazolium ethyl sulfate(EMISE) were synthesized. Their electrochemical windows were measured by cyclic voltammetry at 303.15-343.15 K. The cyclic voltammograms show the order of windows which represent the electrochemical stability of RTIL is: BPBF₄<BMIBF₄<EMISE. When temperature increases the windows reduce, that is, the stability of RTIL reduces with the increase of temperature. The difference among the windows of the three RTILs is mainly dependent on the order of the reductive limits of the cations: EMI⁺|-1.40 V|>BMI⁺|-0.95 V|>BP⁺|0.02 V|. It is very interesting that while the oxidative limit of anion BF₄^- and the reductive limit of all the cations reduce with the increase of temperature, but the oxidative limit of anion SE^- increases.

Synthesis of Fluorinated Poly(ether sulfone) with High Thermal Stability and Its Application for Arrayed Waveguide Grating Multiplexer

WANG Fei, LI Ai-Ze, SUN Wei, ZHAO Yu, ZHANG Da-Ming, JIANG Zhen-Hua, LIU Shi-Yong

2004, 25(9): 1736-1739.

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A new arrayed waveguide grating(AWG) multiplexer was fabricated by using synthesized 3F-PES as the waveguide core. The DSC and TGA exhibit T g and the temperature at which 5% mass loss occurred in air of 3F-PES are 170 and 542℃, respectively. The infrared absorption spectrum indicates that 3F-PES has a high optical transparency in the infrared communication region. The AFM exhibits the roughness of the 3F-PES film is 0.35 nm. The arrayed waveguide grating(AWG) multiplexer was fabricated by using the 3F-PES as the waveguide core. The AWG multiplexer exhibits a wavelength channel spacing of 1.603 nm and a center wavelength of 1 550.15 nm.

Synthesis and Photochromism Property of Three Naphthacenequinone Phenolic Resins

LIAN Hui-Qin, WU Xue

2004, 25(9): 1740-1742.

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Three naphthacenequinone photochromic phenolic resins, naphthacenequinone phenolic resin(2), methyl-naphthacenequinone phenolic resin(3) and chloro-naphthacenequinone phenolic resin(4) were synthesized by an one-step method, i.e. the reaction between 6-chloro-5,12-naphthacenequinone(1) and phenolic resins. The polymers have similar photochromic properties in THF solution with photochromic compound 6-phenoxy-5,12-naphthacenequinone. It was found that the substituents attaching to the main chain backbone of the polymer have a slight effect on the reaction and rate of photoisomerization of polymers. The rate constants were influenced by the molecular weight.

Preparation of PES-SiO₂ Hybrids Through Sol-gel Method

FENG Cai-Hong, JIAO Qing-Ze, LI Qian-Shu, MING En-Ze

2004, 25(9): 1743-1746.

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