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Table of Content

    24 May 1993, Volume 14 Issue 5
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    Articles
    Studies on the Extraction of Gold Using a-Alkyl Substituted Pyridines(Ⅰ)——Determination of the lonization Constant of α-Alkyl Substituted Pyridines and the Extraction Behaviour of Gold
    GAN Wei-Tang, ZHANG Yu-Fan, DONG Li-Jun, WANG Zhong-Guo, NIE Zhi-Qin, LIANG Shu-Sen
    1993, 14(5):  593-597. 
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    The behaviour of nine kinds of a-alkyl substituted pyridines (Ⅰ) in the extraction of gold in hydrochloric acid media has been investigated.The ionization constants of (Ⅰ) were determined.The effect of the.basicity and steric hindrance in (Ⅰ) on the extraction of gold is also discussed.The experimental results indicate that the order of the extractability of (Ⅰ) is HpPY≈i-HPY>HPY> i-PPY>BePY>PPY>BzPY>BpPY>TfPY.The extracted species are found to be 1:2(Au/I) complex in benzene solution.The extraction mechanism and the influences of the diluent, temperature, common metal ions and various anions on the extraction of Au (Ⅲ) are also studied.
    Hydrothermal Synthesis and Characterization of MZr2(AsO4)3,(M=Na, K, Rb, Cs)
    WANG Hai-Zeng, PANG Wen-Qin
    1993, 14(5):  598-601. 
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    MZr2(AsO4)3(M = Na, K, Rb, Cs) compounds were synthesized under hydrothermal conditions:As2O5/ZrO2 = 6.4, M+/As=0.333 (molar ratio), pH≤2.0, 250℃, 5 days.The influence of the concentration and source of reactants on the product phases was investigated.The products were characterized by means of X-ray powder diffraction, Raman and IRspectroscopies.The effect of M+ on the vibrational spectrum of anionic skeleton was preliminarily analyzed.
    Studies on Synthesis and 183W NMR Spectra of a- and β-[SiW9O37M3(H2O)]7-= Al3+, Ga3+, In3+)
    LIU Jing-Fu, MENG Lu, ZHAO Ben-Liang
    1993, 14(5):  602-605. 
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    Salts of the title anions have been prepared from the lacunary tungstates α- and β-SiW9O3410- and characterized by elemental analysis, spectroscopy, polarography.Tungsten-183 NMRspectra of the title complexes consist of two lines (intensity ratio 2:1) as expected for the C3Vstructure of trisubstituted α- and β-Keggin anions.
    Chemical Preparation and Mossbauer Investigation of Iron-Phosphorus-Boron Nanometer Metglass
    HU Zheng, FAN Yi-Ning, CHEN Yi
    1993, 14(5):  606-607. 
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    By changing the initial pHvalue of the mixture solution of FeSO4·7H2Oand NaH2PO2·H2O, Fe-P-Bnanometer metglass with different concentrations of Pand Bwas prepared by chemical reduction method.The content of Pdecreases and Bcontent increases with increasing pHof the mixture solution.Mossbauer experimental results indicate that Pand Bcan influence the magnetic moment of Fe atom to a certain extent, which could be well explained with electron-transfer model.
    Studies on the Extraction of Gold (Ⅲ) Using a-Alkyl Substituted Pyridines (Ⅱ)
    GAN Wei-Tang, ZHANG Yu-Fan, WANG Xin-Sheng
    1993, 14(5):  608-609. 
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    The extraction of gold from aqueous hydrochloric acid solution with α-heptyl pyridine in benzene was investigated.The composition of the extracted species in liquid state is found to be 1:2 (Au/HpPy) from the slope analysis data, but the composition of extracted species in solid state is found to be 1:1 (Au/HpPy) from chemical analysis.The infrared spectral and 1H NMRspectral results indicate that the ion-paired extracted complex may occur in the organic phase.
    Differential Pulse Polarographic Studies on Composite-Coordinated Complexes of Cadmium (Ⅱ) with Oxalate and Succinate
    KANG Jing-Wan, LU Xiao-Quan, GAO Jin-Zhang, BAT Guang-Bi
    1993, 14(5):  610-613. 
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    Ternary complexes of cadmium (Ⅱ) with succinate(Succ) as primary ligand and oxalate (OX) as secondary ligand were studied by means of differential pulse polarography at 20±0.2℃, 35±0.2℃ and μ= 0.1(NaNO3).On the basis of the values of the stability constant, the thermodynam-ic functions (△G0, △H0, △S0) were calculated.The simple complexes of Cd(Ⅰ) and each kind of ligand were investigated.The positive values of mixing constant (lgKm = 0.83) and stabilization constant(lgKs = 0.52) prove that the ternary complex [Cd(OX)(Succ)] is more stable than the corresponding binary complexes.The stability constants of composite-coordinated complexes are lgβ11 = 4.68, Igβ21 = 5.75 and lgβ12 = 5.68 at 20℃ and lgβ11 = 4.61, lgβ21= 5.74 and lgβ12 = 5.67 at 35℃.
    Oscillographic Precipitating Titration on Uncoupled Platinum Electrode
    ZHU Jun-Jie, YAO Da-Qing, LU Zhong-Gui, GAO Hong
    1993, 14(5):  614-617. 
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    Oscillographic precipitating titration on uncoupled platinum electrode was studied.Anew method of preprocessing Pt electode is given.The theories of oscillographic titration on uncoupled Pt electrode were proposed.This titration is different from classical potentiometric titration.Its titration curve dose not conform to Nernst equation.The potential change is transient, the change of E-t curve on the endpoint is given in the form of peak-shape and can be observed on the oscillograph.The accurate results were obtained.
    The Quantitative Analysis for Cereal s Components by Artificial Neural Networks
    JI Hai-Yan, YAN Yan-Lu
    1993, 14(5):  618-620. 
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    Cereal' s eight components (the concentration between10-1～10-3), that is, protein (Pro), fat(Fat), leucine(Leu), isoleucine(Ile), valine(Val), threonine(Thr), phenylalanine(Phe) and lysine(Lys) were quantitatively analyzed by Artificial Neural Networks.For the eight components the prediction correlation coefficients (R) are 0.969, 0.892, 0.897, 0.884, 0.970, 0,860, 0.854, 0.899, and the coefficients of variability are 2.66%, 5, 39%, 7.62%, 7.06%, 2.97%, 7, 83%, 13.38%, 2.68% respectively.These results are superior to those of SRA, and have no systematical errors with classical chemistry' s methods.
    Research on an Application of Multivariate Discriminant Analysis to Cancer Diagnosis
    ZHU Er-Yi, WANG Xiao-Ru, DENG Zhi-Wei, YANG Peng-Yuan, HUANG Ben-Li
    1993, 14(5):  621-624. 
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    The concentrations of 15 trace elements in human hair samples including both normal people and cancer patient samples are determined by ICP-AESand GFAAS, These concentration data are then treated by use of a technique which involves polynomial expanding, model selection and PLSmethod.The good classification results between two classes of samples are obtained and showed in discrimination plane figure.It is believed that the hair sample can be used as a test sample instead of the blood sample in the diagnosis for the cancer.
    Application Of Marquis Reaction to Fluorescence Analysis of Medicine
    ZHAO Yi-Bing, GUO Xiang-Qun, XU Jin-Gou, CHEN Guo-Zhen
    1993, 14(5):  625-626. 
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    The Marquis reaction has been applied to the fluorescence detection of medicine.In compar ison with the natural fluorescences of 11 medicines investigated, intense fluorescences were obtained after reaction with Marquis reagent.This method is favourable for better selectivity and high sensitivity in the fluorescence analysis of medicine.
    Oscillographic Voltammetric Titration on Anti lgtf-E Curves
    ZHENG Jian-Bin, ZHU Jun-Jie, BI Shu-Ping, GAO Hong
    1993, 14(5):  627-629. 
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    Anew method known as oscillographic voltammetric titration on Anti lgif-Ecurves is presented, and circuit of oscillographic voltammetric titration was improved by this method.In this way, Ga3+, Cd2+, Zn2+, Ni2+, Co2+ were directly titrated with EDTAor EGTA.The experiment results show that the sensibility and accuracy of this method are better than those of oscillographic voltammetric titration on if-Ecurves.
    Syntheses of Crown Ethers (ⅩⅪ)——Syntheses of Polyether of Open Chain Amides and Properties of Its Calcium Ion Selective Electrodes
    GUO Bin, XU Wei, LIU Dong, HUANG Zai-Fu, CHEN Liao-Rong, LUO Bao-Sheng
    1993, 14(5):  630-633. 
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    Eight ligands(Ⅰ -Ⅷ), seven of which were new compounds, were synthesized in this paper.Compounds Ⅰ - Ⅶ are open chain amides and Ⅷ, a macrocyclic lactam.Their structures were determined by IR, 1H NMR, MSand elemental analysis.Calcium ion selective electrodes based on these new neutral carriers were studied, among which a superior carrier was found.Satisfactory results were obtained by using this electrode to determine the calcium ion in human serum.The limit of detection is lower than intracellular free calcium ion activity (1.4×10-7 mol/L) in microelectrode, and were better than electrodes on other crown ethers including ETH1001 and ETH129.
    Applying Molecular Mechanics, Molecular Graphics and Quantum Chemical Method to Study of Structure and Mechanism of Organic Reagent (Ⅱ)——GP Theory for Reaction Between Pyridyl Azo Organic Reagent and Metallic Ion
    LAI Cheng-Ming, NIU Shu-Qiang, ZHANG Dong-Rui, LIN Shao-Fan
    1993, 14(5):  634-637. 
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    In this paper, we have studied the mechanism of reaction between pyridyl azo organic reagents and metallic ions by means of GP Theory.It has been found that the reaction may be the charge control or orbital control, so there are two different coordinate positions.
    Studies on Reactions of Sulfur-containing Carbanions and Their Applications (Ⅶ) ——Synthesis of 4,4-disubstituted1,7-Difunctional Compounds
    LIU Guang-Jian, ZHANG Zheng, WANG Yu-Liang, ZHOU Wei-Qing, ZHANG Li-Kang, BAI Ya-Luo
    1993, 14(5):  638-641. 
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    1,7-Difunctional compounds and some of their derivatives are of considerable importance in both of synthetic chemistry and fine chemical industry.This paper reports a facile and efficient one-pot synthesis of substituted 1,7-dif unctional compounds via the double conjugate addition of α-arylsul-fonylacetates (1-4) to the α, β-unsaturated esters (5,8-10), nitrile (6) and ketone (7) under very mild conditions.Eight new substituted 1,7-difunctional compounds (14-21) including 1,7-heptanedioic acid esters (14, 17, 21), 1,7-heptanedinitrile (15), 2,8-nonanone (18), 7-oxo-oc-tanoate (19) were synthesized and fully characterized, the yields are excellent.The effects of Michael acceptors, phase-transfer catalyst and solvents on the double conjugate addition were also discussed briefly.
    Isomerization/Chlorination of S-Alkyl(Aryl)O,O-dialkyl Dithiophosphate ——A New Method for Synthesis of S-Alkyl S-Alkyl(Aryl) Dithiophosphoric Acid Derivatives
    TANG Chu-Chi, WU Gui-Ping
    1993, 14(5):  642-645. 
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    Eleven compounds, among which nine are new compounds, of S-alkyl S-alkyl (aryl) dithiophosphpric acid derivatives have been synthesized by using a new convenient method which is based on the isomerization/chlorination of S-alkyl (aryl) O,O-dialkyl dithiophosphate with phosphorus oxychloride to give S-alkyl S-alkyl (aryl) phosphorochloridodithiolate.Then, this phosphorochlo-ridodithiolate reacts with various nuclosphiles, such as alcohol, phenol, mercaptan, thiophenol, ammonia in the presence of acid-binding agent to obtain S-alkyl S-alkyl (aryl) dithiophosphoric acid derivatives, such as S-alkyl S-alkyl (aryl) O-alkyl(aryl) phosphorodithiolate, S-alkyl S,S-dialkyl (aryl) phosphorotrithiolate, S-alkyl S-alkyl (aryl) phosphoramidodithiolate.The results of the tests in biological activity show that these compounds prepared possess a certain insecticidal or fungicidal activ-itiy.
    The Syntheses and Characterization of Zirconium (Ⅳ),Tin(Ⅳ) Titanium (Ⅳ) Complexes with Aeylhydrazones and Thioacylhydrazones
    WANG Ji-Tao, GAO Sheng-Hua, LIAO Xiang-Min, LIU Feng-Quan
    1993, 14(5):  646-650. 
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    Acyl- and thioacvlhvdrazones formed by condensation of salicylaidehyde or 2-hydroxy- 1 -naphthaldehyde with acylhydrazines or methanediacylhydrazines can react with Cp2ZrCl2, Ph2SnCl2, TiCl4, and SnCl4 to give 9 novel complexes.The products were characterized by elementary analysis, IRand 1H NMR.The complex of Ph2SnCl2 with methanediacyl hydrazone was structurally characterized by X-ray diffraction.
    Ent-kaurene Diterpenoids from Euphorbia Wangii
    JIA Zhong-Jian, SHI Jian-Gong, YANG Li
    1993, 14(5):  651-652. 
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    From the acetone extract of the whole plant of Euphorbia tcanyu(Euphorbiaceae), four new ent-kaurene diterpenoids, named as euphorangin A, B, Cand D, were obtained.Their structures were elucidated as ent-llα-acetoxykaur-16-en-3β-ol, ent-kaur-16-en-3β, 15β-diol, ent-11α, 16α-epoxykauran-3β-ol and ent-11α, 16α-epoxykauran-3-one, respectively, on the basis of spectral methods (EIMS, IR, 1H NMR, 13CNMR, DEPT) including 2D NMRtechniques (1H-1H COSY, 1H-13C COSY, 1H-1H NOESY) and chemical methods.
    Synthesis of Insect Sex Pheromone of Asian Corn Borer with Various Link Polymeric Wittig Reagents
    CHEN Jia-Wei, HUANG Jin-Xia, XU Jing
    1993, 14(5):  653-655. 
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    Insect sex pheromone of Asian Corn Borer was synthesized by the reaction between various link polymeric Wittig Reagents and self made 12-bromo-dodecanol.Adiscussion on the capacity of functional group and the effect on the reaction was included.
    Gas Chromatographic-Mass Spectrometric Detection of Methylphenidate's Metabolite in Urine
    CUI Kai-Rong, ZHANG Chang-Jiu, WANG Shan, CHEN Shi-Zhi
    1993, 14(5):  656-657. 
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    Arapid sensitive method has been developed for the detection of the metabolite (ritalinic acid) of methylphenidate in urine by using GC-MSD.The derivatization agents are MSTFAand MBT-FA.The recovery and detection limit are 77.2%±2.l%(n= 4) and 3 ng, respectively.This method is fit to detect the methylphenidate in doping control.
    Infrared Studies of SO42-/ZrO2 Superacid System
    GAO Zi, CHEN Jian-Min, TANG Yi
    1993, 14(5):  658-662. 
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    Structural changes in the SO42-,/ZrO2 superacid system caused by desorption of preadsorbed water and pyridine were studied with IRspectroscopy.The experimental observations show that SObonds in the surface sulfur species of the hydrated samples exist in two forms, i, e., the ionic SObond (Ⅰ) and the covalent SOdouble bond(Ⅱ).Ⅰ transforms into Ⅱ with the removal of water from the sample.The presence of two types of SObonds and the transformation from Ⅰ to Ⅱ were also observed in samples preadsorbed with pyridine.In addition, the asymmetric stretching frequency of SObond Ⅱ shifts to a higher frequency during desorption of preadsorbed water or pyridine, suggesting that the bond order and the double-bond character of the SObond are increased.It is found that only Lacid sites are present on the surface of the carefully dried SO42-/ZrO2 sample.After adsorbing water, some Lacid sites may transform into Bacid sites in the ratio of 1:1.However, the number of Lacid sites in the sample is always higer than that of Bacid sites.The structure of the Bacid sites formed after hydration has been discussed by using the results of changes in bond order, bond length and partial charge on oxygen.
    Effect of Ce3+ Ion in Bath on the Structure Defect and Weldability of Electrodeposited Tin
    YAO Shi-Bing, LIU Zan-Jin, CHEN Bing-Yi, ZHOU Shao-Min
    1993, 14(5):  663-666. 
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    The relationship between the structure defect and weldability of Sn coating, electrodeposited from the acidic bright bath containing Ce3+ ion as the additive, has been investigated by means of flu-orometry, X-ray photoelectron spectroscopy (XPS) and positron annihilation lifetime spectroscopy (PALS), It was shown that the co-deposition of Ce and Sn did not occur during the electrodeposition process.The.effect of Ce3+ in the bath was to inhibit the hydrolysis and oxidation of Sn2+ resulting in the stabilization of the electrolyte as shown in Table 2 and Fig.1, which in turn decreased the oxygen content in the Sn coating surface(Fig.2).This is one of the reasons for that Ce3+ ion in bath is favorable to improving the weldability of the coating.But the experimental results of PALSshowed that only those Sn coating obtained from the bath containing～3.5 g/Lof Ce3+ possessed a lower structrue defect as indicating by the positron average lifetime τ, which was responsible for the higher weldability as shown in Fig.3.
    Application of Modified Iron Oxy chloride (FeOCl) to the Lithium Battery
    CHEN Zhen
    1993, 14(5):  667-671. 
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    Modified FeOCI, which was chemically prepared by Cl ion exchanging in aqueous aniline solution, shows a good discharge and charge 'characteristics.In the present study, the differences between FeOCIand modified FeOCIare reported in the bahaviour of XRD, EPMAand IRspectra.The comparision of spectra for the oligomer of polyaniline and the modified FeOCIconfirms very similar structure.XRDresults show that the modified FeOCIdisplays a reversible structure changes in charge and discharge.The charge-discharge curves gave a higher discharge voltage.
    Studies on Structure and Properties of Tetraphenylporphyrin and Its Derivatives (Ⅳ)——Linear Relationship Between Spectra or pKa and Substituent Constants of Two-protonic Tetraphenylporphyrin and Its Derivatives
    LUO Ming-Dao, LI Liang-Chao, YAN Xiao-Ci, QU Song-Sheng
    1993, 14(5):  672-674. 
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    The visible and UVspectra of the two-protonic tetraphenylporphyrin (H2TPP2+) and its derivatives were dissected with HMOmethod and group theory.Then the relationship between the sub-stituent constants σand λmax or pKa of tetraphenylporphyrin (TPP), H2TPP2+ and their derivatives were determined.That isi Y=P - A1σ1- -A2σR(or OR(+))+A3ES, where, Yis λmax or pKa of TPP, H2TPP2+ and their derivatives, respectively.Pis λmax or pKa of TPP, H2TPP2+, respectively, σ1, σR (or σR(+)) and Es are the induction effect, the resonance effect and the steric effect of the substituent constants of these compounds, respectively.A1, A2 and A3 are the empirical constants.The calculated values are in good agreement with the experimental values.
    Studies on the Mechanism of Electrodeposition and Electrocrystallization of Te, CdTe and HgCdTe
    YE De-Liang, ZHANG Ying-Zhou, SU Wen-Duan, ZHOU Shao-Min
    1993, 14(5):  675-680. 
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    The electrodeposition and nucleation mechanism of Te, CdTe and HgCdTe at glassy-carbon or titanium electrode were investigated.The results show that; (1)The cathodic reduction of HTeOjf in acidic solution obeys the four-electron reduction mechanism.The electrocrystallization of Te at Ti electrode is followed by three-dimensional instantaneous nucleation mechanism controlled by diffusion of HTeO2+ ions.(2)CdTe is electrodeposited according to the reduction of tellurous acid followed by the electroreduction of Cd2+ and Te.Howerer, the electrocrystallization of CdTe is relatively complicated.According to the variation of step potential, temperature and pHof the solution, the electro-crystallization of CdTe at Ti electrode is transformed from three-dimensional instantaneous nucleation controlled by diffusion to two-dimensional instantaneous nucleation mechanism.(3)The mechanism electrodeposition of HgCdTe can be considered as following:(这里有图片19930524-675-1.gif)And its electrocrystallization growth depends on the nucleation of CdTe, and it seems to follow the two-dimensional instantaneous nucleation mechanism under our experimental conditions.
    The Electronic Spectra and Structure of Iron Complex Cations with a Series of Valences (Ⅰ-Ⅵ)
    LI Zhi-Ru, ZHENG Zhi-Ren, LI Qian-Shu, FENG Ji-Kang
    1993, 14(5):  681-684. 
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    The iron complex cations with valences (Ⅰ- Ⅵ), Fe(OH)4n-(n=3,2,1),FeO(HO)3-1,FeO4n-(n=3,2) are studied by INDO/CImethod.The calculated values of wave numbers and oscillator strength of the bands correspond with the experimental results.We have assigned the bands and their nature of charge transfer.Regular change of the transitions with the valences of iron as well as the lables of the bands are observed.In addition, it is found that the characters of Fe-Obonds are non-covalent for Fe(Ⅰ) and Fe(Ⅱ), single bonds for Fe(Ⅲ) and Fe(Ⅳ), and double bonds for Fe (Ⅴ) and Fe(Ⅵ), respectively.
    Studies on Localized Molecular Orbitals of Organic Chain Molecules
    MA Li, YANG Zhong-Zhi, SHEN Er-Zhong
    1993, 14(5):  685-690. 
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    By using Foster-Boys Localization procedure and ab initio STO-3Gmethod, more than one hundred of organic chain molecules which contain C, H, Oand Natoms were investigated and the LMOenergies and their interaction parameters were obtained.For numerous organic chain molecules containing C, H, O, Natoms, these parameters and LMOmodel can be employed to get the energies of corresponding canonical molecular orbitals and their relation to LMO's and to predict their ionization energies which are in good agreement with experimental results.
    Rotationally Inelastic Scattering of the Ar+TlF System
    LIU Wen-Jian, DENG Cong-Hao
    1993, 14(5):  691-695. 
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    In this paper, we propose a new method to deal with the rotationally inelastic scattering of the A+B Ccollison system.We neglect the off-diagonal elements in the coupled potential terms and fit the Morse potential to the Lennard-Jones potential by making them being equal to each' other at the zero and deepest points.Then we can obtain the two analytical solutions of the decoupled equations.Asymptotic analysis shows that they correspond to the incident and outgoing waves, respectively.The overall wavefunction is expanded by the two solutions.The S-matrix can be obtained by solving the linear equations.The results obtained from this method prove to be better than those from IOScompared with the exact CCresults.
    Theoretical Studies on the Reaction Mechanism of Cycloaddition Reaction Between Ketene or Substituted Ketenes and Cyclopentadiene
    JIANG Jian, FANG De-Cai, FU Xiao-Yuan
    1993, 14(5):  696-701. 
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    The cycloaddition reactions between ketene or substituted ketenes and cyclopentadiene have been studied by means of semiempirical AMImethod.The geometries of transition states and intermediates of each reaction path have been optimized by Berny technique, and the transition states were ascertained by frequency analysis.The results can be sumed up as follows:The reactions between ketene or methylketene and cyclopentadiene are concerted but nonsynchronous, taking place through twisted transitions states, with small charge transfer from cyclopentadiene to the ketenes.An analysis based on frontier molecular orbitals shows that the reaction mechanisms correspond to "2×[l + l]" description.Two types of orbital interactions are available in the vicinity of TS.One of them is the interaction of ketene LUMOwith cyclopentadiene HOMO, the other is that of ketene HOMOwith cyclopentadiene LUMO.Of these two interactions, the former is stronger than the latter, so that in TS, one ofthe C-Cbond is almost formed, while the distance of the other C-Cbond is rather large.The reac-ttions between chloromethyl-substituted ketene and cyclopentadiene proceed via a stepwise pathway.The stereoselectivity of the reactions observed through experiments are correctly predicted by the calculations and are analyzed in terms of electronic and steric effects of the substituents on the reacting ketene.
    Prediction for Partial Molar Volumes in Mixed Electrolyte Aqueous Solutions by Pitzer Theory
    SHENTU Yan-Ming, LI Yi-Gui
    1993, 14(5):  702-705. 
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    The partial molar volumes of mixed electrolyte aqueous solutions are calculated by using Pitzer theory, and the predicting equations were established.The partial molar volumes for HNOs-UO2(NO3)2-H2O, KCl-Na2SO4-H2O, NaCl-Na2SO4-H2O, NaCl-CaCl2-H2O, KCl-CaCl2-H2O, KC1-MgCl2-H2O, KCl-NaBr-H2Osystems are estimated by using new Pitzer single and mixed parameters of apparent molar volumes, and compared with the partial molar volumes calculated from experimental densities.This paper establishes a new method for predicting the partial molar volumes of mixed electrolyte aqueous solutions.
    Study of Copper Electrodeposition on HOPG by in Situ Electrochemical Scanning Tunneling Microscope with Atomic Resolution
    LI Chun-Zeng, XIE Zhao-Xiong, MAO Bing-Wei, ZHUO Xiang-Dong, MU Ji-Qian, YE Jian-Hui, FENG Zu-De, TIAN Zhao-Wu
    1993, 14(5):  706-707. 
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    Ahome-built in situ electrochemical scanning tunneling microscope (ECSTM) was applied to investigation of the electrodeposition of Cu on HOPGin CuSO4 solution under potential control.During potential cycling, the deposition and dissolution processes of Cu were clearly observed.At about-250 mV(vs.Cu2+/Cu) it was found that the STMimages changed with time.Aregular hexagonal lattice was observed first, with a next-neighbour atomic distance of 0.40±0.02 nm, which is considered to be HOPG(0001)-(√3×√3)R30° Cu adlattice.Following that, Cu(111) and Cu(110) faces appeared, both showing long range-corrugation patterns.
    The Properties of the Surface Oxygen on Manganese-Cerium Composite Oxide
    LUO Meng-Fei, CHEN Min, ZHOU Lie-Hua, YUAN Xian-Xin
    1993, 14(5):  708-710. 
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    In the paper, the manganese-cerium composite oxide catalysts were prepared by copreeipita-tion.The crystal structure of the catalysts and the desorptlon properties of surface oxygen on the catalysts were investigated by using the methods of TPD-MSand XRD.There are three peaks in the TPD-MSoxygen spectra of Mn2Oa and Mn2O3-CeO2 catalysts.
    Singly and Strongly Bound Multiply Excited States of B2
    CAO Ze-Xing, YAN Guo-Sen, TIAN An-Min
    1993, 14(5):  711-713. 
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    The optimized geometries of several low-lying electronic states of B2 are obtained by using an energy gradient technique and SCFor SOCIenergy minimization methods with a standard 6-31G* basis set.In the upper states of B2, an increase in bond strength can occur in case of one and two-excitations from the σn antibonding MOinto either a bonding σq orπn MO, and the bonding effect of πn, is superior to that of σa,.The transition energies(ET) are given at an accurate second order configuration interaction (SOCI) level of theory, and based on the close agreement between the calculated and observed ET, the Douglas-Herzberg transition is assigned by transition from C3∑M- to the ground state X3∑M-.In addition, we have obtained the vibrational frequencies(ωe) for the ground and excited states with the model potential function method.
    Preparation of Monodispersed Colloids of CdS by Nonionic Microemulsion
    HAO Ce, WANG Ze-Xin, HAN En-Shan, MA Yong-Xu, CHEN Zong-Qi
    1993, 14(5):  714-716. 
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    The present paper reports the method that the monodispersed particles of cadmium sulfide are formed by precipitation in the nonionic microemulsion.The microemulsion consisting of Cd2+ ions was mixed with that consisting of S2- ions at 25 ℃- Various sizes and shapes of monodispersed particles of CdShave been obtained by adjusting the constitution of the microemulsion consisting of Tx10-cyclohexane-octanol, ions concentration and different cadmium salts.Furthermore, the conditions affecting the particle size and shape, the relationship between the reactants and the precipitation regions are studied and the effects of ions on the mierocircumstance in the microemulsion are discussed.
    Studies on the Activation Energies and the Mechanism of Electric Conductivity of W/O Type Microemulsions
    SHEN Xing-Hai, WANG Wen-Qing, GU Guo-Xing
    1993, 14(5):  717-719. 
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    Variations of activation energies (△E) with water content for microemulsions composed of SDS-alcohol (1-butanol-l-octanol)-heptane-water were determined.It is found that ASbutanol system decreases slightly with the increase of water content, while that of pentanol system presents a maximum at its percolation threshold.For hexanol, heptanol and octanol systems, the activation energies exhibit rising trends before the limitations of added water.It is also found that the activation energy increases with the increase of the length of alcohol chain, which means that the longer the length of alcohol chain, the bigger the strength of the interfacial membranes of particles.Based on the above results, the mechanism of electric conductivity of W/Omicroemulsions is suggested, i.e., cations' hopping through the membranes of particles among the inner water cores results in producing the electric conductivity.
    Studies on the Micromorphoiogy of Polysiloxane-Polyurea Segmented Copolymer Using TEM and SAXS
    CHEN Lei, HE Xian-Dong, YU Xue-Hai, ZU Yu-Ping, YANG Chang-Zheng
    1993, 14(5):  720-724. 
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    The micromorphology of segmented polysiloxane-polyureas based on polydimethylsiloxane or polycyanopropyimethylsiloxane soft segments and semicrystalline methylene diphenylene diiso-cyanate and diethyleneamine hard segments was examined using transition electron microscopy(TEM) and small angle X-ray scattering (SAXS).Specimens for eletron microscopy studies were prepared by thin film casting.The spherical morphology was observed in all of the samples.The size of the hard domain of polycyanopropylsiloxane polyurea is smaller and more regular than that of polydimethylsiloxane polyurea.The micrcdomain spacings and the size of the poiyurea hard segment measured by TEMwere compared to the results calculated from SAXSdata.It is also found that there are two steps In the accumulation of the hard domains.At the first step, a few polyurea aggregate by hydrogen bond to form the ''fundamental particles".In the second step, these "fundamental particles" gathered up together further to form the hard mierodomains.The slower evaporation rates of the solvents caused the larger polyurea mierodomains.
    Preparation and Crosslinking of Acrylate Copolymer Latex Containing Carboxyls/Epoxy Resin (Ⅳ) ——Preparation and Crosslinking of the Mixed Latex Under Moderate Temperature
    YU Ding-Sheng, LIU Shu-Xia, JIAO Shu-Ke
    1993, 14(5):  725-728. 
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    In this paper the mixting process and crossh'nking reactions of the acrylate copolymer latex containing carboxyls and the latex containing epoxy resin have been investigated.The experimental results showed that the mixed latex has a good mechanical stability, whose storage life can reach 5 months under ambient temperature.It is demonstrated that benzyl dimethyl amine is a preferable accelerator for the cTosslinking reaction and the crosslinking mechanism is mainly a mono-esterification process in presence of benzyl dimethyl amine by the analysis of mass spectra and IR.The mixed latex could be cured under moderate temperature (<100℃).The coated film of mixed latex exhibits good physical properties than those of initiate latexes.
    Investigation of the Synthesis and Stability of Poly (γ-chloropyridine)
    PING Xue-Zhen, QIU Xing-Yu
    1993, 14(5):  729-732. 
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    The synthesis of poly(γ-chioropyridine) and its hydrolytic and thermal stability were studied.The results showed that the polyd'-chloropyridine) was insoluble in normal organic solvents.It was soluble in water and its chains could be broken by hydrolysis.The viscosity of solution decreased with the prolonged time.The reaction order of the thermal decomposition of poly (γ-chloropyridine) was 1.7, and the activation energy of the thermal decomposition was 97 kJ/mol.
    Structure Elucidation and Spectral Assignments of Ponicidin by Two Dimensional Nuclear Magnetic Resonance Techniques
    YANG Yan-Wu, JI Ang, HE Bing-Lin, XU Xiao-Long, QIU Jian-Qing, WANG De-Hua, QIAN Bao-Gong, ZHAO Qing-Zhi, ZHANG Yan-Bing, XUE Hua-Zhen
    1993, 14(5):  733-737. 
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    The 13Cand 1Hchemical shifts of ponicidin, which is one of antineoplastic and antiseptic effective components isolated from Rabdosia rvbescens (Hemsl.) Hara, were completely assigned by het-eronuclear chemical shift correlation spectroscopy, long-range heteronuclear chemical shift correlation spectroscopy (COLOC-S) and homonuclear chemical shift correlation spectroscopy.Since the BIRDand TANGOpulse sandwich in COLOC-Spulse sequence were used to suppress effectively the one-bond cross peaks and decouple the modulation of long-range cross peak intensities due to the one bond couplings, the most three-bond 13C-1Hinteraction in ponicidin were dectected simultaneously in one COLOC-Sspectrum, and some four-bond cross peaks were also observed in the same spectrum.After carefully analyzing the 13Cand 1Hchemical shift data, the XHCRcross peaks at 3.790/72.06, 4.196/72.98 and 5.010/69.79 ppm were deduced as the cross peaks of methylene carbon atoms directly bonded to oxygen, the long-range 13C--1Hcross peaks in COLOC-Sspectrum confirmed that the 13Cresonance signals at 72.06, 72.98 and 69.79 ppm were assigned to Cl, C6 and C14 methylene group, and the corresponding1Hchemical shifts were 3.790, 4.196 and 5.010 ppm, respectively.The chemical shift assignments of other 13C Hresonance signals were completed by combining the COLOC-Sspectrum with hetero- and homo-nuclear correlation spectra.The 1Hresonance signals of two methyl group geminated at C4 carbon atom were identified unequivocally with the cross peaks in NOESYspectrum.The results show that the 2D NMRmethods are very useful for the structure elucidation and spectral assignments of natural organic compounds, and the reliable structure parameters could be provided for calculating the three dimensional structures of ponicidin in solution.
    Syntheses and Properties of High Performance Poly(Aryl Ether Ether Ketone) Copolymers——Copolycondensatlon of Hydroquinone, 4,4'-DiphenoI and 4,4'-Difluorobenzophenone
    ZHANG Wan-Jin, JI Xiang-Ling, YUAN Jing, NA Hui, WANG Jun-Zuo, WU Zhong-Wen
    1993, 14(5):  738-740. 
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    Poly (ether ether ketone) (PEEK), a high-temperature resistant thermoplastic resin, has been used in a lot of fields because of its excellent properites.With the development of high technology, the resins having higher service temperature are required.Aseries of terpolymers(DPEEKs) have been prepared by copolycondensation of hydroquinone, 4,4'-diphenol and 4,4'difluorobenzophenone with alkali metal carbonate at 320-350℃ using diphenylsulphone as solvent for the reaction.The Ts of a DPEEKby the nucleophilic substitution route is higher than that of a PEEK.The relationships between Ts, Tm and the molar ratio of 4,4'-diphenol are studied by a differential scanning calorimeter.The DPEEKs possess higher service temperatures than PEEK, and their mechanical properties are as good as those of PEEK.
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