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    24 December 1999, Volume 20 Issue 12
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    Articles
    Syntheses and Crystalline Structures of Clusters Co3(CO)7(μ3-S)(μ,η2-SCNR2)
    LI Song-Bo, LIU Shu-Tang, HU Xiang, WU Bing-Fang, CHANG Fei, XING Yan, JIA Heng-Qing, BAI Shi-Ying, LIN Yong-Hua
    1999, 20(12):  1827-1831. 
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    Through the reaction of Co2(CO)8with four thiuram [R2NC(S)S]2, four new sulfur capped trinuclear cobalt carbonyl clusters Co3(CO)7(μ3-S)(μ,η2-S *C*NR2)(Ⅰ: R=Me; Ⅱ: R=Et; Ⅲ: R= i-Pr; Ⅳ: NR=, were prepared and characterized by elementary analysis, IR, 1HNMR and MS spectroscopy. The crystal structure of the cluster Co3(CO)7(μ3-S)[μ,η2-S*C*N(i-Pr)2] (Ⅲ) was determined by X-ray single crystal diffraction method. The crystal of Ⅲ is monoclinic, belonging to space group P21/n, and the cell parameters are as follows: a =1.1452(2) nm, b =1.5028(3)nm, c =1.2144(2) nm; α=90°, β=92.15(3)°, γ=90°; V=2.0885(7) nm3, Z =4, F(000)=1096, Dc=1.747 mg·m-3, μ=2.588 mm-1, R =0.0407, Rw=0.0624. The structural analysis shows that cluster Ⅲ has a pyrimidal Co3S framework and contains a heterocylic bridging bidentate ligand[μ,η2-S*C*N(i-Pr)2] linked to the Co2 and Co3 atoms of the cluster by a cobalt-carbon and a cobalt-sulfur bond respectively.
    Structural and Luminescent Properties of LnBaB9O16:Eu3+(Ln=La,Y)
    YANG Zhi, LIN Jian-Hua, SU Mian-Zeng, YOU Li-Ping, WANG Wei, TAO Ye
    1999, 20(12):  1832-1837. 
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    Structural properties of LnBaB9O16(Ln=La, Y) were investigated by means of X-ray powder diffraction, electron diffraction and luminescence. These compounds crystallize in the monoclinic crystal system with lattice parameters a =1.3660 nm, b=0.7880 nm, c=1.6253 nm and β=106.15° for LaBaB9O16and a =1.3476 nm, b=0.7776 nm, c =1.6040 nm and β = 106.38° for YBaB9O16. The study of luminescence spectra of Eu3+doped materials reveals that the structures of these two compounds are different. The local symmetry of the rare earth ions is central symmetric in YBaB 9O16and non-central symmetric in LaBaB9O16. The emission intensity of LaBaB9O16:Eu3+is enhanced by partial substitution of La3+with Gd3+. Absorption of LaBaB9O16:Eu3+in the VUV region is relatively weak, which may be related to the small ratio of B:O.
    Synthesis and Structure of Ruthenocene-conjugated Microcyclic Triaza Crown Ether
    YIN Ye-Gao, YI Chang-Hai, CHEUNG Kung-Kai, WONG Wing-Tak
    1999, 20(12):  1838-1841. 
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    Protonated N-(ruthenocenylmethyl)-1,4,7-triazacyclononane(1) and N, N′, N″-tris-(ruthenocenylmethyl)-1, 4, 7-triazacyclononane(2) were prepared and characterized. The structure of 2 was determined by X-ray crystallographic method. The crystal belongs to P21/a space group and cell parameters are a = 1.4285(3) nm, b = 1.9888(3) nm, c = 1.9133(3) nm; β = 109.12(2)°; V =5.1358(1.0) nm3; Z =4. Dc=1.665 g/cm3. 1HNMR spectra of 1 and 2 revealed that the absorptions of the protons on substituted Cp rings in these compounds had a down-field shift from those of the protons on the Cp rings of ruthenocene. The observation suggests that the protonated 1,4,7-triazacyclononane has a deshielding effect on the protons of the ruthenocene units. The CV curve of 2 gave an oxidation wave at 0.84 V.
    Synthesis, Crystal Structure and Properties of H8[P4W14O58Na4(H2O)20]·16H2O
    LIU Zong-Rui, WANG Li, WANG En-Bo, XU Lin, XING Yan, LIN Yong-Hua, JIA Heng-Qing
    1999, 20(12):  1842-1846. 
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    Anovel heteropoly tungstophosphates, H8[P4W14O58Na4(H2O)20]·16H2O, was synthesized by hydrothermal method and characterized by elemental analysis, IR spectrum and single crystal X-ray structure analysis. The thermal stability of the compound was investigated by using TG-DTA. The crystaLIs triclinic system with space group P1, a = 1.1379(2) nm, b = 1.3632(3) nm, c = 1.6271(3) nm; α=78.20(3)°, β=71.20(3)°, γ=71.62(3)°; V = 2.2525(8) nm3, Z=1, Mr= 4374.38, Dc=3.225mg/cm3, μ=18007 mm-1, F(000)= 1972, R = 0.0742, Rw= 0.2004 . The result of structure analysis shows that the anion of the compound consists of two PW7O29Na2(H2O)10subunits and two linked phosphorous atoms. Akind of microporous with size of 0.6614 nm× 0.3189 nm was formed in the crystal structure.
    Studies of Nanophase LiCoO2Synthesized by Solid State Reaction with Low Heating Temperature(Ⅰ)
    XIA Xi, NULI Yan-Na, GUO Zai-Ping
    1999, 20(12):  1847-1849. 
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    Nanophase LiCoO2was synthesized by solid-state reaction with low heating temperature, i.e. the reactants Co(Ac)2·4H2O and LiOH·H2O in the appropriate molar ratio(1:1) were mixed and ground in agate mortar, then calcined. The samples obtained were characterized by XRD and IR methods. The phenomena during synthesizing are discussed by TG/TDA analysis, and the optimum temperature of heating was chosen. The BET and ICP results suggest that the sample has a large specific surface(54.29m2/g), a low quantity of impurity, thus it may be a good battery material. The nanophase-LiCoO2samples produced have good cyclic performance and a higher working voltage plateau(3.9 V).
    Studies on Stereoselectivity in Tris(phenanthroline) Nickel(Ⅱ) Binding to DNA
    SONG Yu-Min, KANG Jing-Wan, WANG Zhi-Hua, LU Xiao-Quan, GAO Jin-Zhang
    1999, 20(12):  1850-1852. 
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    Binding of Δ-, Λ-[Ni(phen)3]2+to calf thymus DNAwas studied by circular dichroism and electrochemical methods. The selectivity of Δ isomer in binding to a right-handed duplex of DNAwas found. Binding constants and binding site sizes for Δ-and Λ-[Ni(phen)3]2+with DNAwere determined from voltammetric data.
    Theoretical Study on Composite Sampling and Monte Carlo Simulation
    GAO Zhi, HE Xi-Wen, LI Yi-Jun, ZHAO Jie
    1999, 20(12):  1853-1857. 
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    Based on the multinomial distribution theory, an equation for estimating the composite sampling errors was derived in this paper, by which the composite sampling variance is quantitatively related with the concentrations of the sought-for component, the sizes of the subgroups of the population and the number of increments in the sample. Monte Carlo technique was employed to simulate the composite sampling and verify the above equation with satisfactory results. This equation is generally applicable in composite sampling so as to enrich the theory of sampling in analytical chemistry.
    Application of Matrix-assisted Laser Desorption/Ionization-time of Flight-mass Spectrometry in Characterizing a Series of Cationic Porphyrins
    LIU Shu-Qing, SUN Hao-Ran, WANG Ren-Zhang, XU Ji-Qing
    1999, 20(12):  1858-1862. 
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    The matrix-assisted laser desorption/ionization-time of flight-mass spectrometric behavior of a series of cationic porphyrins was studied. The results showed the desorption/ionization ways of cationic porphyrins were different from those of non-ionic porphyrins. The space volume of the side chain groups of the porphyrins apparently affects the desorption/ionization mechanism of the formation of ions. The larger the space volume of the side chain groups and anions is, the larger the portion of the covalence is between the porphyrin cycle cation and the balance anions. As a result, the higher mass ion peaks formed by the porphyrin cycle cation combined with more anions appeared in the MALDI-TOF mass spectra. The desorption/ionization mechanisms of the cationic porphyrins were also discussed in this paper.
    Preliminary Studies on the Background Emission and Emission Properties of Some Elements from OS-Ar-MPT
    LIU Miao, YANG Wen-Jun, ZHOU Jian-Guang, JIN Qin-Han
    1999, 20(12):  1863-1867. 
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    OS-Ar-MPT is an excellent improvement to the Ar-MPT excitation source. The effect of O2flow rate on the background emission and some atomic and ionic lines in the new source is exploited in this paper. The results show that the simplicity of the background emission of the OS-Ar-MPT is beneficial to the atomic emission spectrometry. Moreover, signal to background ratios of most emission lines of all elements studied have been significantly improved. The prospect of the new source is promising.
    Identification of Angiogenesis Inhibitory Factor by HPLC and ESIMS
    YUE Gui-Hua, YANG Peng-Yuan, SHEN Xian-Rong, JI Dong-Mei, REN Da-Ming, LIU Wei-Ping, XU Yun-Min, WANG Hong-Hai
    1999, 20(12):  1868-1870. 
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    The studies of SCAIF-I(an unknown protein) by HPLC and ESIMS was reported in this paper. The SCAIF Iis a kind of antiangiogenesis extracted from shark cartilage. The extracted protein was purified by HPLC and then studied by ESIMS. The molecule weight of the SCAIF-I protein was confirmed to be 15601 in the first time. Peptide map of the unknown protein was obtained by HPLC-ESIMS with a trypsin digestion and possible partial sequences were deduced with the online CIDtechnique. With partial sequence information the homologous proteins are searched with protein database. The homology of SCAIF-I summarized in this work is usefuLIn further studies of this unknown protein.
    A New Method for Antibody(Antigen) Immobilization Based on Plasma-Polymerized Film
    WU Zhao-Yang, YAN Yong-Hong, SHEN Guo-Li, YU Ru-Qin
    1999, 20(12):  1871-1873. 
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    Anovel method based on plasma-polymerized films(PPFs) is proposed for immobilization of antibodies(antigens). PPFs are prepared on the surfaces of base sensors by a ratio frequency plasma method with n-butyl amine as a plasma source, and the IR spectrum indicates the existence of amino group in the film. Apolyanion layer is then self-assembled on the film through strong electrostatic attraction. Subsequently, antibodies(antigens) are immobilized on the self-assembled layer through controlling the pHvalue of immobilizing solution. The immobilization of goat-anti-IgG antibody, as an example, on the surfaces of quartz crystal microbalance (QCM) is investigated. After depositing a n-butyl amine PPFon the surface of QCM, a polystyrenesulfonate (PSS) layer is self assembled on the PPFfrom a 2.0 mg/mLof PSSsolution in 0.05 mol/L HCl. The goat anti IgGantibody is then immobilized in antibody immobolizing solution(0.2 mg/mL goat-anti-IgGantibody, pH5.0). This immobilization shows a better frequency response than the covalent immobilization with glutaraldehyde. The QCM immunosensor can quantitatively be used to determine NHIgG in the range of 0.7～126μg·mL-1, and shows a good reproducibility. Moreover, the immunosensor can be easily regenerated by using a pHshift.
    A Novel Low Microwave-Powered Thermospray Nebulizer for Liquid Sample Introdution in Inductively Coupled Plasma Atomic Emission Spectrometry
    DING Lan, JIN Hai-Yan, XU Wei-Qing, LIANG Feng, CAO Yan-Bo, JIN Qin-Han 
    1999, 20(12):  1874-1876. 
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    In this paper, a novel low microwave-powered thermospray system was developed. In this system the focused microwave oven used in traditional microwave-powered thermospray nebulizer was replaced with a TM010microwave resonant cavity, the high pressure pump was replaced with a peristaltic pump. This improvement makes the thermospray system more compact and economical. The influence of several experimental variables(concentration of acid, sample uptake rate, carrier flow rate) on the emission intensity of Mg was evaluated. Compared with the pneumatic nebulization, the detection limits for Mg of this system was improved by a factor of 4.
    StructuraL Identification of Two Diastereoisomeric Saponins from Albizia Julibrissin
    ZOU Kun, ZHAO Yu-Ying, WANG Bin, LI De-Yu, CAI Shao-Qing, ZHANG Ru-Yi
    1999, 20(12):  1877-1882. 
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    Two new diastereoisomeric saponins named as Julibroside J14and Julibroside J15were isolated from the dried stem barks of Albizia julibrissin. On the basis of chemical and spectral methods, their structures were elucidated as 3-O-[β-D-xylopyranosyl-(1→2)-β-Darabinonosyl-(1→6)-β-D-glucopyranosyl]-21-O-｛ (6S)-2-trans-2,6-dimethyl-6-O-[4-O-((6R)-2-trans-2,6-dimethyl-6-O-β-D-quinovopyranosyl-2,7-octadienoyl)-β-D-quinovopyranosyl]-2,7-octadienoyl｝ acacic acid 28-O-β-D-glucopyranosyl-(1→3) [α-L-arabinofuranosyl-(1→4)]-α-Lrhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester (1) and 3-O-[β-Dxylopyranosyl-(1→2)-β-D-arabinopyranosyl-(1→6)-β-D-glucopyranosyl]-21-O-｛(6S)-2-trans-2,6-dimethyl-6-O-[4-O-((6S)-2-trans-2,6-dimethyl-6-O-β-D-quinovopyranosyl-2,7-octadienoyl)-β-D-quinovopyranosyl]-2,7-octadienoyl｝ acacic acid 28-O-β-D-glucopyranosyl-(1→3)-[α-Larabinofuranosyl-(1→4)]-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester(2), respectively.
    Acidity Constants of Herbicidal Sulfonylureas and Sulfonamides from Potentiometric Determinations in Aqueous Dimethyl Sulfoxide
    YANG Guang-Fu, LIU Hua-Yin, YANG Hua-Zheng
    1999, 20(12):  1883-1887. 
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    The acidity constants of herbicidal sulfonylureas and sulfonamides have been potentiometrically determined at 25 ℃ in DMSO/H2O mixed solvent. The linear relationships between the experimental pKavalues and the energy level of frontier orbital and substituent parameters have been found, which suggested that pKavalues obtained from this mixed solvent were suitable for the structure activity relationships analyses.
    The Synthesis of the Precursor of the Bicyclic--Enediyne 6-Sulfony-13-oxo-bicyclo[9.3.0]-tetradec-3,8-diyne(Ⅱ)
    ZHI Yong-Gang, TENG You-Wei, ZHANG Liang-Fu, Just-George
    1999, 20(12):  1888-1891. 
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    6-Sulfony-13-oxybicyclo[9.3.0]tetradec-3,8-diyne is the precursor of the bicyclic enediyne which has been synthesized from cis-1,2,3,6-tetrahydropathalican hydride by 8-step reactions. We got the goal compound by reduction of anhydride, ozonolysis of 8-oxabicyclo[4.3.0]non-3-ene, Witting reaction with PPh3/CBr4, formation of alkyne and esterification, reduction of the ester, formation of the mesylate, cyclization with sodium sulfide nonhydrate. The structures of new compounds 4_9 have been identified by elementary analysis, NMR, IRand MS spectra.
    Asymmetric Synthesis of 5-Hydroxytryptamine Receptor Agonist(1R,2S)-(-)-2-(2-hydroxyphenyl)-N,N-dipropylcyclopropamine
    WU Xin-Yan, SHU Fu-Chang, ZHOU Qi-Lin
    1999, 20(12):  1892-1896. 
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    The synthesis of the potent 5-HT receptor agonist(1R,2S)-(-)-2-(2-hydroxyphenyl)-N,N-propylcyclopropamine was described in this paper. Asymmetric cyclopropanation of 2-methoxystyrene with(dicyclohexyl)methyl diazoacetate in the presence of 1%(molar fraction) copper(Ⅰ) triflate and bis(oxazoline) ligand gave chiral cyclopropane-1-carboxylate. After selecting alkaline hydrolysis, trans cyclopropane-1-carboxylic acid was obtained. The subsequent Curtius rearrangement and hydrolysis in dilute hydrochloric acid were accomplished to yield the(1R,2S)-(-)-2-(2-methoxyphenyl)cyclopropylamine. N,N-Dialkylation with n-propyliodide and demethylation by 48% aq. HBr provided the desired optically pure(1R,2S)-(-)-2-(2 hydroxyphenyl)-N,Nd-ipropylcyclopropylamine.
    New Synthetic Method for Dithiocarbamates
    LI Run-Tao, GE Ze-Mei, CHENG Tie-Ming, CAI Meng-Shen
    1999, 20(12):  1897-1902. 
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    In the presence of anhydrous potassium phosphate, different kinds of dithiocarbamates were prepared from the reaction of primary amines, secondary amines and piperazine with carbon disulfate and a variety of alkyl halides at room temperature in high yields. It is not affected for the presence of -CONR 2, -OH, -CO2H,-NO2, -CO2R, -CH(OR)2, -C=C-, -CH2OR, furan ring and saccharide ring in amine or alkyl halide.
    Studies on Schiff Bases Possessing Hormone Activity (Ⅲ)--Synthesis and Activity on Schiff Bases of Thiadiazole
    WANG Yan-Gang, CAO Lei, YANG Jun, YE Wen-Fa, ZHOU Qing-Chun, LU Bing-Xi
    1999, 20(12):  1903-1905. 
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    Twelve new Schiff bases of thiadiazole have been synthesized for the first time. Their physical constants, UV, IR, 1HNMR and elementary analysis were originally characterized, biological activity were originally studied. It is found from the results of biological activity tests that some compounds have a remarkable activity on plant growth hormone. Compounds Ⅲa and Ⅲk have a good activity on cytokinin, compounds Ⅲe and Ⅲj and Ⅲl have an excellent activity on auxin.
    The Theoretical Studies of Interaction of Transition metals with Silylene Ligands(Ⅰ) -- Ab Initio Study of MSiH2+
    LI Ji-Hai, FENG Sheng-Yu, GAO Jian-Jun, LIU Shao-Jie
    1999, 20(12):  1906-1909. 
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    The HF/6-311+G*basis set was used to study the complexes of silylene, 1SiH2, with first row-transition-metaLIons. The MSiH2can be regarded as the result of coordination of 1SiH2with metaLIons, and are of coplanar structure. Their M=Si bonds are obviously of double bond characteristic. M=Si bond dissociation energies appear in periodic trends from Sc to Cu, and have an approximate linear relationship with metaLIon promotion energies.
    Ab Initio Calculations of the Potential Energy Curves and Vibrational Levels of SO
    ZHU Hua, XIE Dai-Qian, YAN Guo-Sen
    1999, 20(12):  1910-1915. 
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    Ab initio MRD CIcalculations have been carried out for six low lying states of SO. The potential curves for the X3Σ-ground and a1Δ, b1Σ+, A3Π, c1Π, d1Σ-excited states were determined with the use of ECP. The bond lengths of the lowest four states were found to be in good agreement with the experimental results. In addition, vibrational levels and rotational constants have been calculated and were found to compare well with the measured data. The vibrational levels and rotational constants for the isotopomers 34S16O and {32S18O} were also studied and discussed.
    Differential Diffusion Quantum Monte Carlo Method
    HUANG Hong-Xin, YAN Chao, ZHANG Xiao-Ju, CAO Ze-Xing
    1999, 20(12):  1916-1920. 
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    Adifferential approach for self-optimizing diffusion quantum Monte Carlo calculation was proposed in this paper, which is a new algorithm combining with three techniques such as optimizing, diffusion and correlation sampling. This method can directly be used to calculate the energy differential between two systems in the diffusion process, make the statistical error of calculation reduce to the order of 10-5hartree, and recover about more than 80% of the correlation energy. We employed this approach to set up a potential energy surface of a molecule, used a "rigid move" model, and utilized Jacobi transformation to make energy calculation for two configurations of a molecule have a good positive correlation. So, an accurate energy differential could be obtained, and the potential energy surface with a good quality can be depicted. In the calculation, a technique called "post-equilibrium remaining sample" was set up firstly, which can save about 50% of computation expense. This novel algorithm can also be applied to studying other related fields such as molecular spectroscopy and the energy variation in chemical reactions.
    Theoretical Studies of P-Doped Fullerenne C58P2
    CHEN Zhong-Fang, MA Ke-Qin, PAN Yin-Ming, ZHAO Xue-Zhuang, TANG Ao-Qing 
    1999, 20(12):  1921-1925. 
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    Asystematic study on the molecular structures and relative stabilities of all the possible C58P2isomers has been performed by using the semiempirical MNDOmethod. The most stable isomer of C58P2was obtained, and the static properties such as the heats of formation, HOMO-LUMO gap energies, heats of atomization, ionization potentials, affinity energies, absolute electronegativities and global hardness have been predicted theoretically. The calculation results show that the P-doped fullerene C58P2has a considerable stability and is the potential synthesis target, though it is less stable than its carbon analogue. The isomer-7 corresponding to 1,4-substitution to the cyclohexatriene unit is the most stable isomer for C58P2The stabilities decrease with increasing the distance between the heteroatoms. The redox characteristics of C60can be enhanced by doping phosphorus atoms. Based on the absolute electronegativities, the electron transfer directions in dimmer formed by C60and its doped fullerenes are predicted.
    Studies on Micelle Ionization for Sodium Dodecyl Sulfate in Aqueous Solution Using Weak Electrolytes Theory
    NI Liang, JIANG Wen-Hua, HAN Shi-Jun
    1999, 20(12):  1926-1930. 
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    Above the critical micelle concentration, sodium dodecyl sulfate (SDS) can aggregate and form micelle in aqueous solution. It will display its own conductance behavior different from that of general strong electrolyte solution. Therefore, we proposed a new model, named as micelle ionization model, where the micelle is treated as one kind of weak electrolyte and the molar conductivity is expressed by conductance equation of weak electrolyte. The formula for calculating the micelle ionization degree for SDS is deduced. According to the observed conductance data of SDS aqueous solutions in this work, the ionization degree of SDS micelle is determined. The calculated values of the ionization degree are in good agreement with those from literatures, which indicates that the new model can be used satisfactorily to describe the conductance behavior of ion-type surfactant SDS solution.
    Geometry and Stability of Cobalt-Sulfide Clusters ConS+n-i(n=2,3)
    WANG Su-Fan, FENG JI Kang, CUI Meng, SUN Chai-Chung, GAO Zhen, KONG Fan-Ao
    1999, 20(12):  1931-1935. 
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    The possible geometrical structures of Co2S+, Co3S2+clusters were optimized using the methods of ab initio Molecular Orbital Unrestricted or Restricted Hartree-Fock (UHF, RHF) and Density Function Theory (DFT). The corresponding most stable geometrical structure for Co2S+and Co3S2+are found to be Cs symmetry respectively. The electronic structures and vibrational spectrum of the most stable geometrical structures of Co2S+, Co3S2+are analyzed by the same method. As the result, the calculation can be used for explaining the mechanism of bond forming for the Cobalt-Sulfur cluster.
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    DING Jie, XIE Su-Yuan, YU La-Jia, HUANG Rong-Bin, ZHENG Lan-Sun
    1999, 20(12):  1936-1939. 
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    By using an atmospheric pressure chemicaLIonization(APCI) source, negative ion mass spectra of eight perchlorinated polycyclic aromatic hydrocarbons(PAH), hexachlorobenzene, perchloronaphthalene, perchloroacenaphthylene, perchloroanthracene, perchlorophenanthrene, perchlorofluoranthene, perchloropyrene and perchlorocorannulene, have been recorded for the first time. In the ion source, the negative ions, whose masses are 19 less than the molecular weights of their pristine compounds, can be produced by losing a chloride atom and capturing an oxygen anion. Molecular ions of the samples can be produced from the perchlorinated PAHs containing a five membered ring. The results show that APCIis the right ion source for mass analysis of the organic compounds with low polarity such as the perchlorinated PAHs.
    Reaction Mechanism of NO2Determination by the TEA Method
    LI Mi, ZHANG Xin-Xiang, YING Li-Ming, ZHAO Xin-Sheng
    1999, 20(12):  1940-1944. 
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    The reaction of triethanolamine(TEA) with NO2was investigated at room temperature. The reaction products were characterized by FABMS, NMR, FTIR, HPLC and UV spectra. It was found that triethanolamine nitrate and triethanolamine nitrite are the main products of the reaction. (HOC2H4)3NH+was identified based on FABMS, 1HNMR, and 13CNMR spectra. Meanwhile, NO3-and NO2-were also determined by FTIR, HPLC and UVspectra. The quantitative relationship between TEA and NO2that infolved in the reaction was determined by experiments. It was found that when TEAwas reacted with NO2in CHCl3with the exclusion of water, a white precipitate formed immediately on addition of NO2, this precipitate could solve easily in strong polarized solvents such as water. Triethanolamine nitrate was obtained through TEA reacted with HNO3in CHCl3at room temperature, moreover the comparison of its spectra and the ones of the products was made. Apossible reaction mechanism was proposed to explain the experimental results. Because N2O4molecule is electron deficient while TEA contains atoms which have one or more lone pairs of electrons available in s or p orbitals, a molecular addition compound might be the reactive intermediate, which can easily be hydrolyzed to give the final products. This reaction mechanism requires a stoichiometric factor of 0.5 for the conversion of gaseous NO2to nitrite ion, which is in agreement with literature values.
    Studies of Surface Photovoltage Spectroscopy on Quantum-Sized ZnO Nanoparticles
    ZHANG Xin-Tong, ZHUANG Jia-Qi, XU Jin-Jie, XIE Teng-Feng, WANG De-Jun, BAI Yu-Bai, LI Tie-Jin, YAO Jian-Nian
    1999, 20(12):  1945-1947. 
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    In the present work, we prepared two kinds of quantum-sized ZnO particles whose size were 3nm(P1) and 5nm(P2), respectively, and studied their surface properties with surface photovoltage spectroscopy(SPS) and electric field induced surface photovoltage spectroscopy(EFISPS). The photovoltaic response of the two samples showed opposite dependence on external electric field. And when electric field was applied, the thresholds of photovoltaic response of the two samples were all red-shifted. The results showed that the surface properties of P1 were different from those of P2, because of their different preparation process. We assigned that basic zinc acetate structure exist on the surface of P1 sample. While for P2 sample prepared by aging P1, that kind of surface structure disappeared, but the particles might be doped with lithium ions in the aging process.
    Shear Thickening in Colloidal Dispersion Gel of Partially Hydrolyzed Polyacrylamide/Aluminum Citrate
    HOU Wan-Guo, ZHU Wei-Qun, LIU Shang-Ying, SUN De-Jun, SHENG Yong-Gang
    1999, 20(12):  1948-1950. 
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    Shear thickening implies that the viscosity of a fluid increases with increasing rates of shear. In the past work reported, all shear thickening phenomena were observed in concentrated solid/liquid colloidal suspension. In this paper, the shear thickening was observed in colloidal dispersion gel, with very lower volume fraction, of partially hydrolyzed polyacrylamide(PHPA)/aluminum citrate. Colloidal dispersion gels are made of low concentrations of polymer and crosslinker. Polymer mass fractions normally range from 0.01% to 0.12%. In this concentration regime, there is not enough polymer to form a continuous network, so a conventional bulk type gel cannot form. Instead of a solution of separate gel bundles forms, and it is a mixture of predominantly intramolecular and minimaLIntermolecular crosslinks. In the work reported here, the colloidal dispersion gels are made of PHPA of 0.03%, KCl of 0.5%, thiourea of 0.1% and Al3+with a mass fractions range of 0-0.003%, the Al3+:PHPA mass ratio changes from 0 to 0.1. The critical shear rates(CSR) for the onset of shear thickening are about 200 s-1for all CDGsystems studied, i.e ., the Al3+:PHPA mass ratio don't affect the CSR. In the lower shear regime than CSR shear thinning was observed and in the higher shear regime than CSR the shear thickening was observed. The shear thickening may be explained with cluster-formation mechanism.
    Effect of Substituents on Photovoltaic Properties of Azo Pigment
    XIE Teng-Feng, WANG De-Jun, ZHU Lian-Jie, LI Tie-Jin, FEI Hao-Sheng, ZHOU Xue-Qin, WANG Mang
    1999, 20(12):  1951-1953. 
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    The surface photovoltaic properties of four azo pigments(A, B, C, D) were studied by surface photovoltage spectra (SPS) and field induced surface photovoltage spectra (FISPS). The SPV responses of samples A and D were all enhanced when a negative electric field was applied and were all weaken when a positive voltage was applied. It shows that samples A and D indicate n-type characteristics. On the contrary, samples B and C indicate p-type characteristics. Combining with phase technique and molecular structure of azo pigments, the effect of group on Fermi energy level and conduction type of azo pigments was discussed.
    Studies on the Phase Transformation and Stability of the Sintered Compacts FeSi2Doped with Mn and Co
    CUI Xiang-Hao, ZON Won-Ik, WEI Chang-Ping
    1999, 20(12):  1954-1956. 
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    In this paper, p-type Fe1-xMnxSi2(x=0-0.12) and n type Fe1-yCoySi2(y=0-0.12) were synthesized by means of ceramic technology. The influence of additive amounts of Mn and Co, and heat treatment on the amounts of β-phase formed were studied. Experimental results indicate that addition of Mn and Co could inhibit the amounts and velocity of phase formation. High relative density(Dr) of p-type Fe1-xMnxSi2and n-type Fe1-yCoySi2causes excellent corrosion resistance and heat resistance which are beneficial for manufacture of thermoelectric components.
    STM Tip Induced Local Etching and Deposition on Cu Surfaces
    XIE Zhao-Xiong, MAO Bing-Wei, TANG Jing
    1999, 20(12):  1957-1959. 
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    At cathodic potential of bulk copper deposition in dilute Cu2+solution, tip was found to be able to induce local dissolution of copper by applying a rather positive tip potential, although meanwhile the copper was still deposited on the surface far from the tip area. The more positive the tip potential or the electrode potentiaLIs, the faster induced dissolution rate is. At a rather negative tip potential, deposition of Cu was enhanced by the tip while in the case Cu was dissolved locally with a more positive tip potential. Amechanism based on overlap of double layers between tip and substrate was proposed.
    Synthesis of Monodisperse Pheyl-capped Oligoaniline Pentamer and Hexamer in the Leucoemeraldine Oxidation State and EB State and Its UV Studies
    GAO Jun-Bo, LI Ke, SUN Hui, YU You-Hai, WANG Ce, WU Zhong-Wen, ZHANG Wan-Jin, JI Yi-Ping
    1999, 20(12):  1960-1964. 
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    Aniline pentamer and hexamer in the leucoemeraldine oxidation state were synthesized through a novel method. The method was accomplished by the reaction of parent aniline tetramer in the pernigraniline oxidation state with diphenylamine and N-phenyl-1,4-phenylenediamine in the leucoemeraldine oxidation state respectively. The oligomers in the leucoemeraldine oxidation state were characterized by IR, NMR, elemental analysis and MALDI-MS. Aniline pentamer and hexamer in the emeraldine oxidation state were synthesized by the oxidation of Ag2O in DMF. It was found that some fragmentation occurred when the pentamer and hexamer were oxidized by (NH4)2S2O8and FeCl3·6H2O. The pentamer and hexamer in the emeraldine oxidation state was studied by UV/V is spectra. The relative intensity of exciton peak for pentaaniline showed a little increase compared with that of hexaaniline.
    Effect of Methyl Substitution on Polyhydroxyamine-linked Thioxanthones Photoinitiator
    YANG Jian-Wen, YANG Xiao-Mao, CHEN Yong-Lie
    1999, 20(12):  1965-1968. 
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    The effect of methyl substitution on the molecular conformation and photochemical properties of 2-(2-hydroxy-3-[bis(2-hydroxyethyl)amino]propoxy)thioxanthone(HAPTX) was investigated by 1HNMR, 13CNMR, UV absorption and fluorescence spectra. The two methyl groups at 1,3-position of thioxanthones may interact with 2-alkoxyl group through steric repulsion and lead to the photochemical properties of HAPTX with 1,3-dimethyl substitution different from others.
    Emulsion Polymerization of MMA/BA in the Presence of Ionic Surface Active Monomers(Ⅰ)--Syntheses and Polymerization Reactivities of the Surfmers
    ZHANG Mao-Gen, WENG Zhi-Xue, HUANG Zhi-Ming, MAO Xin, PAN Zu-Ren
    1999, 20(12):  1969-1973. 
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    Two surface active ionic monomers(surfmers)[sodium sulfonated lauryl(allyl glyceryl) succinate(ZC-L) and sodium sulfonated lauryl(methacryloyl glyceryl) succinate(ZD-L)] were synthesized and used in the emulsion copolymerization of methyl methacrylate(MMA) and butyl acrylate(BA). The investigation was emphasized particularly on ZC-L for its molecular structure, surface tension behavior and the reactivity for homo and copolymerization. The surface tensions of MMA/BA/Surfmer, MMA/Surfmer and BA/Surfmer copolymer latexes were remarkably higher than that of MMA/BA/sodium dodecyl benzene sulfonate copolymer latex, while similar to or higher than that of MMA/BAemulsifier-free copolymer latex, indicating that the surfmers were covalently bonded on polymer latex particles, and there is only a little remained in the aqueous solution. The ZC-Lcopolymerization reactivity with MMA/BA is better than that of ZD-L.
    Resitivity-temperature Characteristics of CB/HDPE Gel Composites Formed Under Electron Beam Irradiation
    ZHANG Jian-Feng, ZHENG Qiang, CAO Su-Hua, YI Xiao-Su
    1999, 20(12):  1974-1977. 
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    Resistivity-temperature characteristics of CB/HDPE composites crosslinked by irradiation of electron beam were studied. The results showed that CB/HDPE gel composites, which were generated through extraction by xylene for crosslinked samples, exhibited much higher PTCintensity and distinctive NTCeffect during the first heating-cooling cycle. But much better stability of resistivity as well as diminished NTC effect were observed when the composites was exposed to heating-cooling cycles subsequently. The phenomena observed above were related to the structure stability of the gel, suggesting that crosslinking of the polymeric matrix is an effective method to stabilize conductivity and alleviate NTCeffect for polymer composites filled with conductive particles.
    Kinetic Analysis for Polycondensation of ABgType Monomers
    ZHOU Zhi-Ping, YAN De-Yue
    1999, 20(12):  1978-1981. 
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    This article studied the kinetics of the polycondensation of ABgmonomers(where Aand Bdenote different sorts of functional groups which can react with each other, and g is the number of Bfunctional groups in a monomer). The molecular weight distribution function and the number-and weight-average molecular weights had been derived, which are in agreement with those given by Flory using statistical approach. Numerical results show that the more the Bfunctional groups in a monomer, the wider the molecular weight distribution of the resulting hyperbranched polymer. The polydispersity increases with increasing the conversion of Agroups, and increases very fast when the polycondensation approaches completion. This conclusion is qualitatively in agreement with experimental data reported by Turner and coworkers.
    Polymerization of Ethylene with Calix[8]arene Neodymium-Al(i-Bu)3System
    SHEN Zhi-Quan, CHEN Yao-Feng, ZHANG Yi-Feng, KOU Rui-Qiang, CHEN Lin-Shen 
    1999, 20(12):  1982-1984. 
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    Calix[8]arene neodymium was prepared by reacting calix[8]arene with metallic sodium in a mixture of benzene and isopropanol, then with anhydrous neodymium chloride. Calix[8]arene neodymium in combination with Al(i-Bu)3as a cocatalyst was active in the polymerization of ethylene. Effects of Al/Nd molar ratio, concentration of catalyst and temperature on the ethylene polymerization were studied in detail. Polyethylene having Mv of 97×104was obtained under the following conditions: [Nd]=8×10-4mol/L, the molar ratio of Al to Nd=15, 80 ℃, 0.5 h; ethylene pressure=1.2 MPa, and the catalytic activity is 24 kg PE/(mol Nd·h) .
    The Thermotropic Liquid Crystalline Behavior of a Novel Poly(aryl ether ketone)
    SUN Hui, ZHENG Yu-Bin, ZHANG Wan-Jin, WU Zhong-Wen
    1999, 20(12):  1985-1986. 
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    Novel thermotropic liquid crystalline poly(aryl ether ketone) was synthesized via the random copolycondensation of 4,4′-difluorobenzophenone, 4,4′-biphenol and tert-butylhydroquinone. The results of differential scanning calorimetry, polarizing light microscope and X-ray diffraction confirmed the liquid crystalline property of the polymer. The polymer may be of great use in blending with normal poly(aryl ether ketone)s.
    A Shear-induced Ordered Structure in PS/Montmorillonite Nanocomposite(Ⅰ)--Wide Angle X-ray Diffraction and Transmission Electron Microscopy Studies
    CHEN Guang-Ming, QI Zong-Neng
    1999, 20(12):  1987-1989. 
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    A shear-induced ordered structure in PS/montmorillonite nanocomposite was observed for the first time by wide angle X-ray diffraction technique. Atransmission electron microscopy result showed that the randomly placed primary particles of montmorillonite were oriented parallel to the pellet surface, and the interior of the primary particles became more ordered as well. These results suggested that the orientation of the primary particles as well as the interior ordered structure induced by the shear flow were perhaps the origin of the ordered structure in the PS/montmorillonite nanocomposite.
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