Table of Content

24 March 2002, Volume 23 Issue 3

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Articles

Shape-controlled Synthesis of Alumina Nanoparticles by Carboxy-containing Organic Molecules

NING Gui-Ling, CHANG Yu-Fen, LIU Yan-Lai, TENG Fei, LIN Yuan

2002, 23(3):  345-348. 

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Shape-control has been much more difficult to be achieved in the synthesis of nanoparticles. For the aim to establish whether a favorable combination of functional organic molecules and inorganic precursors might produce predictable particle morphology, several carboxy-containing organic compounds, such as acetic acid(AcOH), acetoacetic ester(EAA), poly(amidoamine)dendrimer(PAMAM) and the like, have been investigated in both organic solvent and aqueous solution in the synthesis of Al₂O₃ nanoparticles from aluminium alkoxide and aluminium nitrate precursors, respectively. The spherical particles with different sizeranges(<10 nm, 20-40 nm, 50-100 nm), and the fibrous with changed aspect ratios(from 100 nm/4 nm to 10 nm/4 nm) were observed and characterized, whose distribution was dependent on the property of organic compounds and its concentration used. Apossible shapecontrol mechanism was proposed and discussed.

Gd³⁺→Eu²⁺ Energy Transfer in BaLiF₃:Eu,Gd

JIA Zhi-Hong, LI Hong, YE Ze-Ren, SHI Chun-Shan

2002, 23(3):  349-352. 

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Photoluminescence characteristics and the energy transfer between Gd³⁺ and Eu²⁺ in BaLiF₃ matrix have been investigated. Aseries of concentrations of Gd³⁺ ion with a fixed Eu²⁺concentration doped in BaLiF₃:Gd³⁺, Eu²⁺ has been studied. When the doping concentration for Gd³⁺ was 0.3%, the system reached the highest energy transfer efficiency. Due to the competitive absorption for the Gd³⁺ and the Eu²⁺ ions in BaLiF₃:Gd³⁺:Eu²⁺, when the doping concentration for Gd³⁺ ion exceeded 0.3%, the continuously increasing concentration of Gd³⁺ ions caused the competitive absorption ratio for Gd³⁺ increasing and the emission intensity of Eu²⁺ decreasing. The energy transfer processes were discussed, while the transfer probability was calculated to be 1.35×10⁵s-1.

Influence of the Synthesis Condition on the Crystallization of Fe-β Zeolite Molecular Sieves in the Absence of Aluminum

HE Hong-Yun, PANG Wen-Qin, LIU Wu-Yang, DENG Feng

2002, 23(3):  353-357. 

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Crystalline Fe-β zeolite molecular sieves have been hydrothermally synthesized. Crystallization rate and average crystal size of Fe-β zeolites have been investigated as a function of n (SiO₂)/ n (Fe₂O₃),n(Na₂O)/ n (SiO₂) and n [(TEA)₂O]/ n (SiO₂) ratios in the initial gel by using two silica sources. The iron content and structural characteristics of products have been determined by means of X-ray diffraction, IRspectra, DTA/TGA, SEM, NMR and ICP. The results show that the crystal sizes of Fe-β zeolites are uniform. The DTA curve of Fe-β, IRspectra and unit cell parameters of the resulting Fe-β zeolites were obviously changed due to the incorporation of iron atoms into the framework.

Synthesis of a Novel Cubic Highly Ordered Mesoporous Silica Templated with Tri-headgroup Quaternary Ammonium Surfactant

SHEN Shao-Dian, LI Yu-Qi, WU Fang-Hui, FAN Jie, TU Bo, TAO Feng-Gang, ZHAO Dong-Yuan

2002, 23(3):  358-360. 

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A new highly ordered mesostructured silica(possible space group Fm3m) was synthesized by using triheadgroup quaternary ammonium surfactant CH₃(CH₂)₁₇N⁺(CH₃)₂CH₂CH₂N⁺(CH₃)₂CH₂CH₂CH₂N⁺(CH₃)₃·3Br^-(CM_18-2-3-1) under a basic condition. The cubic mesoporous silica product has an average pore size of 2.9 nm, a large BET specific surface area of 991 m²/g and a large pore volume of 0.98 cm³/g.

Research for the Thermochemical Properties of the Formation Reaction of -N-Phenyl-N′-(1,2,3-thiadiazol-5-yl)urea

SUN Xiao-Hong, LIU Yuan-Fa, GAO Sheng-Li, ZHANG Xiao-Yu

2002, 23(3):  361-363. 

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The enthalpy change of formation reaction of the N-phenyl-N′-(1,2,3-thiadiazol-5-yl)urea has been determined by a microcalorimeter, using 5-amino-1,2,3-thiadiazole and phenylisocyanate as starting materials in the solvent of THF. The reaction temperature was kept at 25 ℃. On the basis of experimental and calculated results, the enthalpy change is Δ_rH_m^o=(-142.304±0.390) kJ·mol^-1; the reaction order is n=1/2; the rate constant k=1.3579×10^-4 s^-1 and the activation free-energy is ΔG_m^o=95.098 kJ·mol^-1. The result indicates that the title reaction takes place easily at room temperature.

Studies on Nitrogenization Reaction in Liquid-phase Sintering of SiC Ceramic

YE Yu-Han, HE Bang-Shun, WANG Cun-Kuan

2002, 23(3):  364-366. 

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SiC ceramic was sintered through liquid phase by using SiO₂ as the sintering additive. Mixed NO₂ and CO gas was used as the sintering atmosphere. The microstructure of the densified SiC ceramic was observed by using transmission electron microscopy(TEM), Bar-like ting crystal was found to distribute in the intergranular phase. The crystal was identified by spatially-resolved electron energy-loss spectroscopy(EELS) to be SiO₂NO₂O. It is suggested that nitrogen, coming from the sintering atmosphere, attends the chemical reaction in SiC ceramic at sintering temperature and is responsible for the appearance of the SiO₂NO₂O crystalline.

A Miniaturized Surface Plasmon Resonance Sensor Based on Resonant Angle Shift Measurment

CHEN Huan-Wen, SONG Qing-Yu, YANG Rui, JIN Qin-Han, LIN Quan, YANG Bai, YU Xue-Feng

2002, 23(3):  367-370. 

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A new kind of miniaturized surface plasmon resonace(SPR) sensor was developed by using an optical resin synthesized in our lab as the transducer prism and a linear charge coupled device(CCD) as the detector. The sensitivity, resolution and linear dynamic range of the sensor were discussed. The sensor has been used to determine alcohol and KH₂PO₄ in water, and the results were satisfactory.

Determination of Effective Components in Riyebaifuning Tablet by Nonaqueous Capillary Electrophoresis with Electrochemical Detection

ZHENG Yi-Ning, XIE Tian-Yao, MO Jin-Yuan, WEI Shou-Lian

2002, 23(3):  371-375. 

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In formamide(FA) medium, the separation and determination of the effective components in Riyebaifuning tablet by nonaqueous capillary electrophoresis with electrochemical detection in the presence of TrisH₃BO₃ as the background electrolyte were reported. The effect of potential of working electrode, different concentrations of FA, pH, the concentrations of background electrolyte, operation voltage and injection time on capillary electrophoresis were discussed. At the detection potential of 0.9 V(vs. SCE), acetaminophen(AP), pseudoephedrine hydrochloride(PH), dextromethorphan hydrobromide(DM), chlorphenamine maleate(CM) were separated within 12 min by using 25mmol Tris-25 mmol H₃BO₃(pH=8.5) as a carrier electrolyte at a positive voltage of 27 kV. There are an excellent linearity between peak current and concentration of analytes in the concentration range of AP 0.5—200 mg/L; PH0.8—300 mg/L; DM 2.5-350 mg/L; CM 0.5-330 mg/L. The detection limits(S/N=3) are AP 0.1 mg/L; PH 0.55mg/L; DM 1 mg/L; CM 0.2 mg/L.

Isolation and Identification of Etofesalamide-2-glucuronide

CHU Da-Feng, GU Jing-Kai, ZHONG Da-Fang, SI Duan-Yun, ZHOU Hui

2002, 23(3):  376-378. 

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Preparation of glucuronide conjugates of etofesalamide[N-(4-ethoxyphenyl)-2-hydroxyl-benzamide], a novel drug for acne therapy, in rabbit was discribed. Urine samples from 0 to 12 h were collected after single oral administration of 400 mg etofesalamide to two rabbits. The samples were lyophilized and extracted with methanol, and then etofesalamide-2-glucuronide in them was prepared with semipreparative HPLC. The molecular structure of this compound was confirmed by electrospray ion trap mass spectrometry and ¹H NMR.

The Investigation of Oscillographic Chronopotentiometry at Silver Disk Electrode and Its Mechanism

YU Ke-Qi, DONG She-Ying, TANG Hong-Sheng, GAO Hong

2002, 23(3):  379-381. 

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A new method of oscillographic chronopotentiometry at silver disk electrode for the determination was initially investigated and established. By using it, we determined a series of ions. The detection limits were decreased two or three orders of magnitude of that for the oscillographic chronopotentiometry at mercury electrode. This method was characterized by fine sensitivity, stable oscillogram and was not used for mercury. The research on mechanism of this method showed that these achievements were caused by the characteristics of silver electrooxidation and electroreduction and the A.C. oscillographic chronopotentiometry(ACOC).

Kinetic Analysis of TNF Immune Complex by Using Surface Plasmon Resonance

YANG Fan, CUI Xiao-Qiang, YANG Xiu-Rong, CHEN Ting, LU Jun

2002, 23(3):  382-384. 

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The kinetic analysis of the interaction between tumor necrosis factor(TNF) and its monoclonal antibody was performed by surface plasmon resonance(SPR) technique. The monoclonal antibody was immobilized to the surface of CM5 sensor chip by amine coupling. TNFat different concentrations was injected across the mAb immobilized surface. The interaction was recorded in real time and could be seen on the sensorgram. One cycle, including association, dissociation and regeneration, lasted no more than 15min . The interaction results was evaluated using 1:1 Langmuir binding model. The kinetic rate constants were calculated to be: k_a=1.68×10³ L·mol^-1 ·s^-1 , k_d=1.73×10^-4 s^-1 , and the affinity constants K_A=9.7×10⁶ L·mol^-1 , K_D=1.03×10^-7 mol·L^-1 . The χ² was 3.47, which showed that the interaction is consistent with the 1:1 model. We can see from the results that although there are two binding sites in one mAb molecule, TNFreacts with each site in an independent and noncooperative manner.

Solid Phase Derivatization of Amino Acids and Peptides on Alkaline Silica Gel Support

SHANGGUAN Di-Hua, ZHAO Ying-Xin, HAN Hui-Wan, ZHAO Rui, LIU Guo-Quan

2002, 23(3):  385-387. 

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A solid phase derivatization method of amino acids and peptides was described. Samples were added on alkaline silica gel cartridge and dried. The derivatization was carried out by passing the derivatization regent dissolved in anhydrous solvent through the cartridge slowly, then the cartridge was washed with a selected solvent, finally, the derivatives were eluted. The eluates were separated and detected by means of HPLCwith fluorescence detector. Three derivatization reagents, 9-fluorenylmethyl chloroformate(FMOC-Cl), 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole(NBD-Cl) and fluorescein isothiocyanate(FITC) were investigated with this method. The results showed that the method was suitable for derivatization of amino acids and some of peptides with FMOC-Cl because of its highly reacting activity and low polarity, the sideproducts of the FMOC-Cl with water were greatly decreased, the excess FMOC-Cl was eliminated completely, and the silica gel support did not significantly affect the reaction rate and yield for amino acids. NBD-Cl was not suitable for this method because of the low yield of derivatization. FITCwas also not suitable for this method because of its strong polarity.

Two-dimensional Convolution and Its Application in Peak Purity Assessment

SHEN Wei-Yang, HU Yu-Zhu

2002, 23(3):  388-390. 

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A simplified method has been proposed for finding two-dimensional convolute integers, including central and non-ecentral point evaluation and multi-convolution integers. The results are equal to the corresponding reports, but the calculation is much simple. The performance of 2D-convolution for the detection of a minor compound in the presence of a main one is also discussed.

Electrocatalysis of Hemoglobin at Rhein Modified Glassy Carbon Electrodes

ZHANG Yu-Zhong, ZHAO Hong, YUAN Zhuo-Bin

2002, 23(3):  391-393. 

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The electrochemical behavior of rhein modified glassy carbon electrodes were studied. Three peaks in CVappeared in the potential rang of +0.4— -0.8 V(vs. Ag/AgCl) in 0.06 mol/L H₂SO₄. p¹ and p³ are a couples of oxidationreduction peak, the electrode process contains two electrons and two protons. The formal potential(E^o')is -0.202 V(vs. Ag/AgCl) at the scanning rate of 50 mV/s. The cathodic peak potential shifts linearly in the negative direction with increasing solution pH with a slope of 67 mV per pH unit. The rhein modified electrode shows an electrocatalytic activity for reduction of hemoglobin in 0.06 mol/L H₂SO₄ solution. The peak currents are proportional to the concentrations of the hemoglobin in the range of 6.0×10^-8—1.3×10^-6 mol/L, the relative standard deviation is 3.5% for 6 successive determination of 1.0×10^-7 mol/Lhemoglobin solution. The catalytic mechanism has been discussed.

Synthesis and Clone of Ribosome Inactivating Protein-Gelonin Gene by the Combination of Chemical and Enzymatic Method

LI Zhuo-Yu, SHI Ya-Wei, YUAN Jing-Ming, Wise J. G, Trommer W. E

2002, 23(3):  394-398. 

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An ambiguous DNA sequence for gelonin was inversely deduced from the amino acid residues of gelonin, a ribosome inactivating protein. Based on the favorable code of protein synthesis in E.coli and the requirement of gene cloning in the subsequent work, a modified base sequence, but no any change for amino acid residues, of gelonin was designed by inserting several restriction endonuclease sites and silent mutation. In order to make the chemical synthesis of the gene convenient, the total DNA sequence of gelonin was divided into four fragments about the length of 175 bp to 220 bp and two complementary strands in each fragment with a length of 100 to 120 nucleotides were chemically synthesized from the beginning of 5′-terminus with a 20 bp overlapping in both 3′-teminus. In such case, the two single polynucleotides for each fragment could anneal to form a double-strand DNA fragment. Then each ds DNA fragment was separately cloned into the vector pUC 118 to construct the recombinants: pYW1, pYW2, pYW3 and pYW4 respectively by T₄DNA polymerase in the presence of dNTP and pyrophosphatase. With the relevant endonuclease sites of each fragment, a recombinant, pUC-gel was formed by cloning technology. Finally, an expression vector, pETgel which was ligated with pET-28a and gelonin gene was constructed and then expressed in host E.coli. The result showed that a 28000 band in expression products, equal to the apparent molecular weight of gelonin, significantly occurred on the 12% SDS-PAGE after incubation in soluble form.

Studies on the Biological Activities and Synthesis of Tri(2-methyl-2-phenylpropyl)tinoxide Derivatives

ZHANG Zhao-Gui, HUANG Yan-Qin, ZOU Yang, ZHANG Shu-Kui, XIE Qing-Lan

2002, 23(3):  399-402. 

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Seventeen tri(2-methyl-2-phenylpropyl)tinoxide derivatives were synthesized and characterized by IR, ¹H NMR and elemental analysis. Compound 7 crystallizes in the triclinic space group P1 with a=1.3944(6) nm, b=1.4846(6) nm, c=1.8028(7) nm, α=77.777(7)°, β=82.425(8)°, γ=73.581(8)°, V=3.488(2) nm³, Z=4, F(000)=1612, D_c=1.509 g/cm^-3. The ω/2θ scan technique was employed to collect data in the range of 1.16°<θ<25.03°. The refinement of structure for 14452 reflections was converged to final R=0.0378, wR=0.1025. The molecular structure consists of fourcoordinated tin atom in a slightly distorted tetrahedral configuration. The bioassay tests showed a high acaricidal activity of some compounds.

Synthesis of the Thiosemicarbazides of 1-Aryl-1,4-dihydro-3-carboxy-6- methyl-4-pyridazinone and Their Antiviral Activity Against TMV

ZOU Xia-Juan, JIN Gui-Yu, YANG Zhao

2002, 23(3):  403-406. 

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Several new thiosemicarbazides of 1-aryl-1,4-dihydro-3-carboxy-6-methyl-4-pyridazinone were synthesized by reaction of hydrazide of 1-aryl-1,4-dihydro-6-methylpyridazin-3-carboxy-4-one with arylisothiocyanates. The structures of compounds were confirmed by IR, ¹H NMR spectral data and elemental analyses. The preliminary biological test shows that some compounds (2d, 2l, 2t) possess a high antiviral activity against TMV.

Synthesis of Solid Supramolecular Complex of Cyclohexyl Amino Modified β-Cyclodextrin with Oxazine and Its Luminescent Property

KANG Shi-Zhao, ZHAO Yan-LIU Yu, WANG Ji-You

2002, 23(3):  407-409. 

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The solid supramolcular complex of a novel β-cyclodextrin derivative(2) with oxazine was synthesized and characterized by means of elemental analysis, FTIR, ¹H NMR and TG. The results obtained show that supramolecular complex formed by compound 2 with oxazine is 1:1 stoichiometry. We also studied the luminescent property of the supramolecular complex. As compared with oxazine, the emission wavelength of supramolecular complex produces a blue shift of 155 nm. Meanwhile, its luminescence intensity is 4.9 times more than that of oxazine and the width of the fluorescence peak is narrowed to 51 nm.

Synthesis and Characterization of Cp^tRh(PMe₃)(Se₂C₂B₁₀H in 16-and 18-Electron Half-sandwich Rhodium Complexes with 1,2-Dichalcogenolate Carborane

KONG Qing-An, JIN Guo-Xin, LIN Yong-Hua

2002, 23(3):  410-412. 

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The reaction of [Cp^tRhCl₂]₂(1) (Cp^t=η⁵-^tBu₂C₅H₃) with 1,2-dilithium dichalcogenolate carborane Li₂E₂C₂B₁₀H₁₀(E=S, Se) afforded the 16-electron rhodium(Ⅲ) half-sandwich complexes Cp^tRh(E₂C₂B₁₀H₁₀)[E=S(3a), Se(3b)]. 18-Electron trimethyl phosphine rhodium(Ⅲ) half-sandwich complexes Cp^tRh(PMe₃)(E₂C₂B₁₀H₁₀)[E=S(4a), Se(4b), Te(4c)] can be synthesized both by addition of PMe₃ into 16-electron complexes 3a, 3b and by the reaction Cp^tRh(PMe₃)Cl₂(2) with Li₂E₂C₂B₁₀H₁₀(E=S, Se, Te). The molecular geometry of 4b was determined by X-ray diffraction structural analysis.

Structure Amendment of a Natural Epoxycembranoid Isolated from the China South Sea Soft Coral

LIU Zuo-Sheng, LI Wei-Dong, LI Yu-Lin

2002, 23(3):  413-415. 

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The structure of a new natural epoxycembrene-C isolated from soft coral Sarcophyton molle in of china the south sea , was amended as(11S, 12S)-epoxycembrene-C via the first asymmetric synthesis of (-)-7,8-epoxycembreneCand(+)-11,12-epoxycembrene-C.

Syntheses and Structural Studies of Zirconocenes via Amino-substituted Fulvene

BAI Sheng-Di, DU Chen-Xia, YUAN Xin-Liang, LIU Dian-Sheng 

2002, 23(3):  416-418. 

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As a discovery of C—C coupling and amine elimination reaction by treatment of 6-dimethylamino-6-methylfulvene with zirconium tetrachloride, experiments using amino-substituted benzofulvene 1a or aminopentafulvene 2a, instead of 6-dimethylamino-6-methylfulvene, gave bis[1-(dimethylamino)ethenyl-indenyl]zirconium dichloride 1c which was characterized by X-ray diffraction as monoclinic, space group C2/c, a=2.0288(4) nm, b=0.9817(2) nm, c=1.4589(3) nm, β=115.73(3)°, V=2.6175(9) nm³, Z=4, R=0.0723, and bis[(1-methyl-4,5-dihydro-2-pyrrolnyl)cyclopentadienyl]zirconium dichloride 2c as triclinic, space group P1, a=0.80749(16) nm, b=0.94340(19) nm, c=1.4238(3) nm, α=91.04(3), β=97.41(3), γ=106.68(3)°, V=1.0286(4) nm³, Z=2, R=0.0800.

Studies on the Synthesis and Bioactivity of Pinacolone(or Arylethanone) Containing 1H-1,2,4-Triazole Group and Their Derivatives

XU Liang-Zhong, LU Xiao-Lan, ZHANG Shu-Sheng, JIAO Kui

2002, 23(3):  419-421. 

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Sixteen new compounds containing 1H-1,2,4-triazole group were synthesized through C-alkylation of α-(1H-1,2,4-triazol-1-yl) pinacolone (or 1-arylethanone) with arylthioalkyl bromide and their structures were confirmed by ¹H NMR spectra, IR, MS and elemental analysis. Preliminary biological test shows that the synthesized compounds exhibited some fungicidal activity.

Studies on the Structure and Stability of (ClAlNH)_n Cluster Series

WU Hai-Shun, XU Xiao-Hong, ZHANG Cong-Jie, JIN Zhi-Hao

2002, 23(3):  422-427. 

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The optimized geometries, electric states and infrared spectra of (ClAlNH)_n(n=1—10) clusters were investigated using ab initio method with HF/6-31G^* level and density function theory (DFT) with B3LYP/6-31G^* level. The polyreaction processes of oligomerization (ClAlNH)_m(m/n)(ClAlNH)_n were discussed. It is shown that the ground state geometric structures of (ClAlNH)_n(n=1—10) clusters are C_s(n=1), D_2h(n=2), D_3h(n=3), T_d(n=4), C_s(n=5), D_3d(n=6), C_s(n=7), S₄(n=8), D_3h(n=9) and C_2h(n=10) symmetry at all levels of theory, respectively. The stability of (ClAlNH)_n clusters with n of even mumber(n=2, 4, 6, 8, 10) is higher than that with n of odd number(n=1, 3, 5, 7, 9).

Mass Spectrometric Study of Ag/Se Cluster Ions and Reaction of Ag and Se Clusters

XING Xiao-Peng, ZHAO Xiang, ZHANG Xia, GAO Zhen 

2002, 23(3):  428-431. 

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The time-of-flight mass spectrometry was used to study Ag/Se cluster ions produced by laser ablation of solid samples, and a Laser Double Ablation Reactor was used to study the reaction of Ag and Se clusters. In Ag/Se binary cluster ions produced by laser ablation, [(Ag₂Se)_nAg⁺], [(Ag₂Se)_nAg₃⁺] are main compositions of positive cluster ions, while [(Ag₂Se)_nAgSe^-], [(Ag₂Se)_nAgSe₂^-], [(Ag₂Se)_nSe^-] are main compositions of negative cluster ions. The photolysis rates of positive cluster ions is higher than those of Ag/Sclusters. During the laser double ablation experiment, the AgSe_n⁺(n=4—9), AgSe_n^-(n=4—7) were detected. In the series AgSe_n⁺, the ions AgSe₄⁺, AgSe₆⁺ are comparatively abundant. It seems that the clustering mechanisms in the two processes are different.

Internal Photoemission in Polyaniline

HUANG Huai-Guo, LUO Jin, ZHANG Hong-Ping, WU Ling-Ling, LIN Zhong-Hua

2002, 23(3):  432-436. 

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After self-assembling a p-aminothiophenol(PATP) monolayer on bare Au electrode, polyaniline(PANI) films were prepared by electropolymerization on the modified Au electrode and three forms of PANI(reduced PANI, partially-oxidized PANI and oxidized PANI) were obtained by electrochemical method. The SEM pattern shows that there are some hills of PANIon a compact layer of PANI. The cyclic votammograms of the probe[K₃Fe(CN)₆/K₄Fe(CN)₆] for the three forms of PANI film show that partially-oxidized PANI has a good electron transport performance. The potential dependence of magnitude and spectra of the photocurrent of PANIfilms were observed. The bandgap energy of 1.45 eV for oxidized PANI, which is the threshold energy of its photocurrent spectra, was obtained. The spectra of photocurrent for partiallyoxidized PANI film shows that it has the characteristics of sub-band gap photocurrent spectra and follows Fowler rule(IPCE^1/2～hν). The bandgap energy of insulating matrix in partially-oxidized PANIis determined as 3.33 eVby the Flowler plots, and the insulating matrix in partially-oxidized PANIis verified to be reduced PANI. The flatband potential, in the order of 0.63 V vs. SCE, is obtained from Mott-Schottky plots. Aphotoelectrochemical process based on internal photoemission in partially-oxidized PANI, which agrees with the model of granular metal island that assumes metallic polymer particles are embedded in the insulating matrix, is proposed.

Studies on Dynamic Evaporation of Gasoline Under Magnetization

ZHANG Qiang, WANG Xiao-Dong, JIN Ri-Guang

2002, 23(3):  437-439. 

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The dynamic evaporation of gasoline was studied with the methods of TGand dynamic evaporativity experiment, it was found that the dynamic evaporativity of gasoline was improved after treatment of gasoline or air under a magnetic field.

Theoretical Study on the Intermolecular Interaction of N-methyl Nitroamine Dimers

JU Xue-Hai, XIAO He-Ming, GONG Xue-Dong

2002, 23(3):  440-443. 

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Three optimized geometries of N-methyl nitroamine dimers were obtained with %ab initio% calculation at HF/6-31G^* level. All the binding energies of the dimers, evaluated as the sum of the HFinteraction energy and MPcorrelation interaction energy, are corrected for the basis set superposition errors(BSSE) and for zero point energies(E_ZP). The corrected combining energy of the most stable dimer is -18.81 kJ·mol^-1. The internal rotation of methyl has an influence on the intermolecular interaction. The change of the Gibbs free energy proceeding from monomer to the most stable dimer is 10.02 kJ·mol^-1 at 298.2 K. The effect of temperature on the process has also been discussed.

Studies on Electronic Spectra and Second-order Nonlinear Optical Property of Substituted fulleropyrrolidine Derivatives

KAN Yu-He, SU Zhong-Min, SUN Shi-Ling, YANG Yan-Jie, ZHU Yu-Lan, REN Ai-Min, FENG Ji-Kang

2002, 23(3):  444-447. 

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The electronic spectra of fulleropyrrolidine derivatives were studied by using INDO/CImethods on the basis of the optimized geometrics with AM1 method. It was shown that the exception of the absorption was beyond 400 nm. The results are in good accordance with the experiment results. The nonlinear second-order optical susceptibilities β_μ of the molecule were calculated according to the sum-over states(SOS) formalism. The conclusions show that these fulleropyrrolidines are good candidates with large β_μ values, between -30.14×10^-30 and -65.49×10^-30 esu.

Synergetic Enhancement of Photoconductive Property in TiOPc/VOTPP Composite

WANG Mang, SUN Jing-Zhi, ZHOU Cheng

2002, 23(3):  448-452. 

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Nonlinear enhancement of photosensitivity were observed in organic photoreceptors based on TiOPc/VOTPP composite. Absorption spectra revealed no evidences of interactions between the electronic states of TiOPc and VOTPPunder ground state, X-ray diffraction analyses didn't show the changes in their condensed states in composite photoreceptors. Photoinduced discharge experiment indicated that the nonlinear effect was ascribed to the contribution of photogenerated carriers resulted from the excitation of gap states, which were intensified by the composing of heteromolecules. The data obtained from XPSmeasurement on composite materials suggested that there existed a fractional charge transition from TiOPc to VOTPP molecules, such photoinduced charge transfer between the two components was another factor related to the nonlinear effect. This synergetic enhancement effect provide a strategy for designation of novel photoconductive materials and devices driven in a low field based on weak electron donor/weak electron acceptor composites.

Geometry Structures and Bonding Rule for Nanoclusters Ni_nZr_n(n=3-5)

WANG Yi-Ping, DONG Kun-Ming, TAN Kai, WANG Xian, LIN Meng-Hai, LIN Lian-Tang, ZHANG Qian-Er

2002, 23(3):  453-456. 

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According to the chemical bond theory and topological principle, 26 clusters Ni_nZr_n(n=3—5) have been optimized with quantum chemistry method Gamess. The results indicate that zirconium atoms play an active role in the forming of metallic bonds and the cluster tends to form a planar net structure. We have also found that the electronic structure of Ni_nZr_n(n=3—5) planar clusters is a isolobal analogy to alkenes, which show that the strong bonds and the weak bonds are interlaced.

Methanation of Carbon Dioxide by Hydrogenating over Ni Supported on Al₂O₃ Catalysts

FEI Jin-Hua, HOU Zhao-Yin, QI Gong-Xin, ZHENG Xiao-Ming

2002, 23(3):  457-460. 

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Methanation of carbon dioxide by hydrogenating over Ni/Al₂O₃ and Ni-CeO₂/Al₂O₃ catalysts was investigated by methods of reaction and in-situ diffuse reflectance FTIR(in-situ DRFTIR). The results showed that carbon monooxide was not the product over those catalysts whether CeO₂ was added or not, but the yield of methane was increased with CeO₂ addition. At 300 ℃, the yield of methane over Ni-CeO₂/Al₂O₃ catalysts was two times higher than that over Ni/Al₂O₃ catalysts. The DRFTIR results showed that methane came from two processes, which were hydrogenation of CO₂^- species and formate species over the catalysts. The more effective species was formate on the surface of catalyst. The reason why the activity of Ni/Al₂O₃ catalyst was promoted by addition CeO₂ was that a large amount of formate forms over Ni-CeO₂/Al₂O₃ catalyst.

Pulse Radiolysis Kinetic Studies of the Self Decay of α-Hydroxyl Ethyl Peroxyl Radicals and Their Reactions with Quercetin and Pyrocatechol

ZHANG Fu-Gen, WU Ji-Lan, LI Feng-Mei, LIU An-Dong

2002, 23(3):  461-465. 

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Lipid Peroxidation(LPO) plays an important role in many pathological processes, while quercetin is an effective LPO inhibitor. α-Hydroxyl ethyl peroxyl radical was chosen to act as a model of lipid peroxyl radical in the kinetic studies of its reaction with quercetin and pyrocatechol. The 1st and 2nd order decay rates of αhydroxyl ethyl peroxyl radical in ethanol solution were obtained for the first time to be (40.4±2.6) s^-1 and (6.9±0.9)×10⁸ mol^-1·L·s^-1, respectively. The rate constant of the reaction between αhydroxyl ethyl peroxyl radical and quercetin was determined to be (2.1±0.3)×10⁷ mol^-1·L·s^-1 through pulse radiolysis studies. Pyrocatechol was chosen to act as a model compound of polyphenols and its reaction with αhydroxyl ethyl peroxyl radical was studied. The rate constant of the reaction between α-hydroxyl ethyl peroxyl radical and pyrocatechol was determined to be (3.1±0.1)×10⁵ mol^-1·L·s^-1.

Preparation of Azobenzene Substituted Pyrazoline Derivatives and Studies on their Electronic Spectroscopy

JIN Ming, LU Ran, CHUAI Xiao-Hong, ZHANG Yi-Hua, ZHAO Ying-Ying

2002, 23(3):  466-468. 

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Bifunctional pyrazoline derivatives 5 and 6 containing azobenzene group were prepared. The difference between them was the length of the flexible chain connecting the two chromophores. Compound 6 had four more methylenes than compound 5. UV-Vis spectra of compounds 5 and 6 were the simple superposition of the absorbance of the azobenzene and pyrazoling and showed that pyrazoline had no effect on the isomerization of azobenzene. When there were two methylenes between azobenzene and pyrazoline, the fluorescent intensity of compound 5 decreased greatly compared with that of compound 6. It means that the intramolecular Electronic Energy Transfer has taken place in compound 5. In compound 6, this process could not occur because of the longer flexible chain between the two chromophores.

Studies on the Dissociation Behavior of Carboxylic Groups at the Open End of Single-Walled Carbon Nanotubes by Tip Chemistry

YANG Yan-Lian, ZHANG Jin, NAN Xiao-Lin, LIU Zhong-Fan

2002, 23(3):  469-471. 

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We have demonstrated here the dissociation behavior of carboxylic groups at the open end of Single-Walled Carbon Nanotubes(SWNTs) by tip chemistry. SWNTs were cut into short pipes by acid oxidation and thus carboxylic groups were produced at the end of the tubes. The SWNTs can be immobilized onto AFMtips by surface condensation between aminoterminated self-assembled monolayers(SAMs) on AFM tips and carboxylic groups at the end of SWNTs. The pK_1/2 value of the SWNTs was then obtained from the force titration measurements of the SWNTs tips vs. hydroxylterminated SAMs. The results showed a different force titration behaviour and variable pK_1/2 values among different SWNTs tips, indicating the variations in the chemistry from tube to tube.

Synthesis of Tetra-iron Substituted Sandwich-type Pentadecatungstodiarsenate and Its Multilayers on Glassy Carbon Electrode by Self-assembly with Electrocatalytic Properties

BI Li-Hua, LIU Jian-Yun, SHEN Yan, JIANG Jun-Guang, WANG Er-Kang, DONG Shao-Jun

2002, 23(3):  472-474. 

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A novel sandwichtype compound, Na₁₂[Fe₄(H₂O)₂(As₂W₁₅O₅₆)₂]·38H₂O(denoted as Fe₄As₄W₃₀) was synthesized. The compound was well characterized by means of IR, UV-Vis, ¹⁸³W NMR and elemental analyses. Redox electrochemistry of the compound has been studied in acid buffer solutions using cyclic voltammetry(CV). The compound containing multilayer films has been fabricated on the 4-aminobenzoic acid(4-ABA) modified glassy carbon electrode(GCE) surface by alternate deposition with a quaternized poly(4-vinylpyridine) partially completed with [Os(bpy)₂Cl]^2+/-(denoted as QPVPOs). CV, X-ray photoelectron spectroscopy(XPS) and UV-Vis spectroscopy were used to characterize the asprepared multilayer films. It is proved that the multilayer films are uniform and stable. The electrocatalytic activities of the multilayer films were investigated on the reduction of two substrates of important analytical interest, NO₂^- and H₂O₂.

The Synthesis of Zinc(Ⅱ)-L-Cysteine and Its Structural Characterization with X-ray Powder Diffraction

KANG Li-Tao, SHI Guo-Shun, SHEN Xiao-Liang, MA Li-Dun, XU Xiang-Fa

2002, 23(3):  475-477. 

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The X-ray powder diffraction data of L-Zn(C₆H₁₀O₄N₂S₂)·0.5H₂O was collected by conventional X-ray powder diffractometer. It was indexed successfully. The cell parameters were attained, a =2.0172(4) nm, b =0^9607(2) nm, c =0.5033(1)nm, M₂₀ =33, F₃₀ =27(0.0114, 100), V = 0.9754 nm³, the density D_X=1.81 g/cm³, so Z =4, and the possible space group is ascribed to P2₁22.

Synthesis and Oxidative Catalysis of Microporous Heteropolyoxometalates Cs_xH_5-xPW₁₀V₂O₄₀SiO₂

PENG Ge, HU Chang-Wen, WANG Yong-Hui, CHEN Li-Dong, WANG En-Bo, FENG Shou-Hua, LIU Yan-Yong

2002, 23(3):  478-480. 

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Microporous heteropolyoxometalates Cs_xH_5-xPW₁₀V₂O₄₀SiO₂ were synthesized by a solgel technique and characterized by IR, UV-Vis, BETadsorption/desorption isotherm. The structural frameworks of Cs_xH_5-xPW₁₀V₂O₄₀ are preserved within the silica networks. Cs_xH_5-xPW₁₀V₂O₄₀SiO₂ are a kind of polyoxometalatesilica gel hybrids with uniform micropores of ca. 0.65 nm. They show a high catalytic activity for oxidation reaction of benzyl alcohol by H₂O₂(30) in liquid-solid systems and product selectivity for benzaldehyde(>96). The highest activity is observed at x=2.5 in Cs_xH_5-xPW₁₀V₂O₄₀SiO₂ and little formation of benzoic acid and a more deeply oxidized product is observed.

Emulsion Polymerization of Styrene and Butyl Acrylate in the Presence of Inorganic SiO₂ Nanoparticles

ZHANG Jing, YANG Yu-Kun 

2002, 23(3):  481-485. 

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Emulsion co-polymerization of St/BAin the presence of inorganic SiO₂ nanoparticles was studied. Firstly, the most effective emulsifiers for this emulsion copolymerization were chosen. Then, the influence of temperature and SiO₂ content on conversion were studied and the results convicted that SiO₂ could reduce the conversion of monomer. By SEMit was proved that SiO₂ had been encapsulated into emulsoid of St/BAand SiO₂ could influence the fracture structure of emulsion polymer. Residues appeared during the polymerization, this phenomenon was researched by elemental analysis. The mechanical and thermal properties of composites were measured to find that SiO₂ content had great influence on these properties. In the end an improved emulsion polymerization process by beforehand emulsifying SiO₂ nanoparticles was presented and a better result was obtained.

Synthesis and Properties of Optically Active Polyquinolines Containing 1,1'-Binaphthyl Unit

HOU Shi-Fa, JIANG Jin-Yue, DING Meng-Xian, GAO Lian-Xun

2002, 23(3):  486-489. 

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Optically active 2,2'-dimethoxy-6,6'-diacetyl-1,1'-binaphthyl(DMDABN) was prepared from 2,2'-dimethoxy-1,1'-binaphthyl, and its structure was comfirmed by elemental analysis, NRM, IR and MS. Optically active polyquinolines were synthesized with DMDABN and 4,4'-diamino-3,3'-dibenzoyldiphenyl ether by Friedlander reaction. These polyquinolines showed high glass transition temperatures(474—578 K), high decomposition temperatures(703—770 K), insolubility in many common organic solvents and strong chiral activity.

Chemical Reactivity Characteristics of β-Chitin from Squid Pen and Its Comparison with α-Chitin

DONG Yan-Ming, RUAN Yong-Hong, WU Yu-Song, WANG Mian, QIU Wei-Bi, XU Cong-Yi

2002, 23(3):  490-495. 

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Being different from the literature results, the chemical reactivity of β-chitin was found to be poorer than that of α-chitin for O-propionylation reaction(basically a heterogeneous reaction). But the chemical reactivity of β-chitin was almost the same as that of α-chitin for N-acetylation reaction(a homogeneous reaction). The poor reactivity of β-chitin is explained by the higher crystallinity shown by the results of X-ray diffraction, the closer fibrillar structure shown by microscopy, and the higher stability of crystals shown by higher decomposition temperature in the thermogravimetric curves. After β-chitin was fibrillated by wet grinding, the O-propionylation reactivity increases evidently, but was still lower than that of α-chitin. Four levels of fibril structure can be distinguished in fibrillated β-chitin by polarized optical microscopy and scanning electron microscopy, i.e. fibrillar bundle, fibril, microfibril and elementary fibril with diameter in the order of 10¹, 10⁰, 10^-1 and 10^-2 μm respectively. Amodel for four levels of fibril structure of β-chitin is first suggested. Because more free hydroxyl groups are exposed on all levels of fibrils, the chemical reactivity of fibrillated β-chitin enhances.

Synthesis of Phenyl/Amino-capped Tetraaniline by Chemical and Electrochemical Methods

SUN Zai-Cheng, KUANG Li, JING Xia-Bin, WANG Xian-Hong, LI Ji, WANG Fo-Song

2002, 23(3):  496-499. 

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Phenyl/amino-capped tetraaniline was prepared by chemical oxidation coupling and electrochemical cyclic voltammetry methods. The MacDiarmids method of oxidation coupling was improved. The aqueous HCl was replaced with a mixture solution of HCl and acetone and (NH₄)₂S₂O₈ was used as oxidant instead of FeCl₃. The reaction displays a higher yield and the product tetraaniline has a higher purity owing to the improvement. In the mixture solution system, tetraaniline can be synthesized by electrochemical cyclic voltammetry method. The mechanism by which tetraaniline was prepared from p-amino dipheny-lamine was proposed. The product was characterized by MALDI-TOF MSand FTIR.

Preparation and Simulation of Gradient Refractive Index Polymer Rod by Interfacial-gel Polymerization

CHU Jiu-Rong, XU Chuan-Xiang, WEN Xu-Ming, WANG Shou-Tai

2002, 23(3):  500-503. 

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A gradedient refractive index(GI) polymer rod was prepared by interfacialgel polymerization, in which the polymerization was performed in a PMMA tube and bromobenzene(BB) was used as a higher refractive index molecule. By decreasing the reaction temperature to 60—70 ℃, and in the early stage of the reaction, gas in the reaction mixture under vacuum could be easily overflowing from it, in the later stage, the reaction mixture under a high pressure was compressed and the defects of voids or bubbles of the GIpolymer rod were decreased. By using the new technology, a GIpolymer rod, without any defect of void or bubble, was made. Adetailed mechanism of gradedient refractive index formation was given and simulated according to the Vrentas-Duda free volume theory.

Structure and Property Characterization of Dibutyltin Maleate-Styrene-Butyl Acrylate Copolymer

QIAN Qing-Rong, CHEN Qing-Hua, YAN Zhi-Sen, ZHANG Wen-Gong

2002, 23(3):  504-507. 

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Benzoic peroxide(BPO) was used as an initiator in bulk terpolymerization of dibutyltin maleate, styrene and butyl acrylate(DBTM-St-BA). The structure and properties of the copolymer were characterized by GPC, IR, ¹H NMR, TGanalysis, Congo red test and dynamic thermoreheological test. The results showed the occurrence of copolymerization. The number-average molecular weight of terpolymer was above 10⁴. The thermal stability and flowability in PVCprocess of copolymer was superior to that of DBTM. It may be used as polyfunctional PVC stabilizer.

Synthesis and Thermal Behavior of Phosphorus-containing Thermotropic Wholly Aromatic Copolyesters

CHEN Xiao-Ting, TANG Xu-Dong, WANG Yu-Zhong 

2002, 23(3):  508-510. 

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A series of flame retardant thermotropic wholly aromatic copolyesters were derived from acetylated 2-(6-oxido-6H-dibenz<c,e><1,2>oxa phosphorin-6-yl)-1,4-dihydroxy phenylene(DOPO-HQ), p-acetoxybenzoic acid(p-AHB), terephthalic acid(TPA) and isophthalic acid(IPA) by melting polycondensation. The structure and basic properties of polymers, such as glass transition temperature(T_g), melting temperature(T_m), thermal stability, and liquid crystallinity were investigated by FTIR, elemental analysis, differential scanning calorimetry(DSC), thermogravimetry analysis(TGA), and thermal polarized optical microscope. The copolyesters have relative high T_g values which range from 456 to 465 K. The T_m obtained from DSCcurves(P-20 and P-25) and initial flow temperatures(T_f) observed on hotstage polarizing microscope are from 544 to 568 K. The decomposing temperatures(T_d50%) in nitrogen range from 704 to 735 K, and char yields at 923 Kare 41～52. All the copolyesters, except P-40, are thermotopic and nematic.

A Study of Molecular Orientation of Polymethylene Chains

ZHANG Lin-Xi, HUANG You-Xing, ZHAO De-Lu

2002, 23(3):  511-513. 

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In this paper, molecular orientation behavior of polymethylene chains was investigated on the basis of considering long-distance interactions by using the enumeration calculation method and the rotational isomeric state(RIS) model. The chain lengths are from N=12 to N=24, and the Lennord-Jennes potential was adopted in the nonlocal interaction calculations. The molecular orientation function(Legen-dre polynomial) may be well expressed as <P₂(ζ)>/(λ²-λ^-1)=a(λ²-λ^-1)+b here a and b only depend on the chain length, and decrease with the increase of chain length, especially for b. In the meantime, we also calculate the Helmholtz free energy change in the process of tensile deformation. Comparisons with Gaussian chains are made, and our results are close to those obtained from the Roe and Krigbaum theory.

Emulsion Polymerization of m-Chloroaniline and Characterization of Macromolecular Chain Structure

DAI Li-Zong, XU Yi-Ting, ZOU You-Si, WU Hui-Huang

2002, 23(3):  514-516. 

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In this work poly-m-chloroaniline(PmClAn) was synthesized by emulsion polymerization. By discussing the influences of reaction temperature and concentrations of initiator on the polymerization reaction, it was found that PmClAn with mean molecular weight of 1.85×10³(corresponding to 15 chain elements) could be obtained under the following conditions: 80 ℃, [M]=0.187 mol/L, [SDS]=4.8×10^-2mol/L, [KPS]=5.6×10^-2 mol/L(where M, SDS and KPS stand for monomer, emulsifier and initiator K₂S₂O₈, respectively), reaction period 2.5 h. From ¹H NMR, FTIR, TEM and SEM measurements the structure of PmClAn was determined. It was found that in the macromolecular chain the ratio of benzoid to quinoid units was 3:2, and that PmClAn was characterized by its typical molecular crystalline being monoclinic with crystall-cell parameters of a=0.679 nm, b=2.304 nm, c=0.5734 nm, α=90°, β=100.9° and γ=90°. By using MM+ molecular mechanics methode in Hyper Chem program, X-ray diffraction data were analyzed, thereby the configuration of PmClAn chain was determined and optimized.