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Table of Content

    24 October 2002, Volume 23 Issue 10
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    Articles
    Preparation and Biodistribution of a Novel Potential Blood Pool Imaging Agent Technetium-99m Labeled COI Complexes
    ZHANG Xian-Zhong, ZHOU Jin-Ming, WANG Xue-Bin
    2002, 23(10):  1829-1832. 
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    The objective of this study is to develop a new potential cardiac blood pool imaging agent. An isonitrile ligand cyclooctylisonitrile(COI) is synthesized and a copper salt[Cu(Ⅰ)(COI) 4BF4] of this ligand is also prepared, the isonitrile and it′s copper salt are characterized by IR and elemental analysis. The complex 99mTcN-COI is prepared by ligand exchange reaction while the complex 99mTc-COI is prepared by a direct labeling method. The results of stability study indicated that both complexes are stable over a period of 6 h at room temperature. The biodistribution of these new complexes in mice indicated that they had significantly different uptake properties in most tissues. But they are all mainly accumulated in blood and maintained in it very good. Especially the T/NT ratios of 99mTc-COI in mice are excellent as a cardiac blood pool imaging agent. Based on its promising properties, the complex 99mTc-COI maybe suitable for cardiac blood pool imaging.
    Synthesis and Crystal Structure of Heterodimetallic Complexes[Cp2V(μ-η2∶η4-PhC4Ph)MCp2′](M=Ti,Zr;Cp′=C5H5,C5H4SiMe3)
    ZHAO Jian-She, GU Ai-Ping, HE Shui-Yang, Choukroun Robert, Valade Lydie, Cassoux Patrick
    2002, 23(10):  1833-1836. 
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    The reaction of [Cp2Ti(C≡CPh)2], [Cp2Zr(C≡CPh)2], [(C5H4SiMe 3)2Zr(C≡CPh)2] and vanadocene in toluene was performed at room temperature and gave heterodimetallic complexes[Cp 2V(μ-η2∶η4-PhC4Ph)·MCp2′] (1, M=Ti, Cp′=C5H5; 2, M=Zr, Cp′=C5H5; 3, M=Zr, Cp′=C5H4SiMe3), respectively. These compounds, which have been characterized by elemental analysis, mass spectrometry, 1H NMR, IR and Raman spectroscopy, exhibit similar magnetic susceptibilities. According to an X-ray diffraction analysis of compound 3, the Cp2V and Cp2′Zr metallocene moieties are bonded to a butadiene(or butadiyne) framework via the two internal carbon atoms for Cp2V, and via both the two internal carbon atoms and the two external carbon atoms for Cp2′Zr. The distances and angles observed around the internal carbon atoms of the butadiene framework indicate that both internal carbon atoms of butadiene skeleton are planar and tetracoordinated.
    Arabinogalactan as a Carrier for Contrast Agent in Magnetic Resonance Imaging
    SUN Guo-Ying, FENG Jiang-Hua, JING Feng-Ying, PEI Feng-Kui
    2002, 23(10):  1837-1841. 
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    Arabinogalactan-Gd-DTPA was synthesized by the reaction of diethylenetriaminepenta-acetic acid(DTPA) bisanhydride with polysaccharide in dry DMSO and characterized by FTIR, elemental analysis and ICP-AES. Its stability was investigated by competition with Ca2+, EDTA, DTPA. The t1-relaxivity is 8.06 mmol-1·L·s-1 in D 2O, 8.48 mmol-1·L·s-1 in 0.725 mmol·L-1 BSA, respectively. t1-weighted MR imaging of rat kidney and liver showed a remarkable enhancement post injection of Arabinogalactan-Gd-DTPA. The results indicate that the arabinogalactan-Gd-DTPA is a potential contrast agent for MRI.
    Syntheses and Crystal Structures of Complexes Zinc and Copper(Ⅱ) Nitrates with 1,10-Dioxa-4,7,13,16-tetraazacyclooctadecane
    GUO Xue-Yan, ZHU Wen-Xiang, YAN Xi, WANG Ru-Ji, LI Yong
    2002, 23(10):  1842-1846. 
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    Two new complexes zinc and copper (Ⅱ) nitrates with 1,10-dioxa-4,7,13,16-tetraazacyclooctadecane (L) were synthesized. Cu(L)(NO3)2 crystalizes in orthorhombic, space group Pbca, a=1.574 4(6) nm, b=1.267 6(4) nm, c=1.898 3(6) nm, Z=8, V=3.789(2) nm3; Zn(L)(NO3)2 crystalizes in orthorhombic system, space group Pnna, a=1.613 56(10) nm, b=1.328 71(11) nm, c=0.862 60(5) nm, Z=4, V=1.849 4(2) nm3. Structure refinement converged to R1=0.043 1, wR2=0.090 4 for Cu(L)(NO3)2 and R1=0.071 8, wR2=0.195 0 for Zn(L)(NO3)2, respectively. Copper(Ⅱ) and zinc ions are coordinated to four nitrogen and two oxygen atoms from the azacrown ether moiety, but not to the nitrate anions. The coordination numbers for both copper(Ⅱ) and zinc ions are six. These complexes have also been characterized by IR, 1H NMR and EPR spectroscopies. The cyclic voltammogram shows that Cu(L)(NO3)2 undergoes a reversible reduction, Cu(Ⅱ)→Cu(Ⅰ) in acetonitrile in the range of -1.0～0 V, E 1/2=-0.56 V and an irreversible reduction, Cu(Ⅰ)→Cu(0) in the range of -1.6～0 V, E1/2=-1.20 V.
    Acidity and Hydrothermal Stability of Mesoporous Materials
    XIAO Feng-Shou, HAN Yu, QIU Shi-Lun
    2002, 23(10):  1847-1853. 
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    Mesoporous molecular sieves such as hexagonally ordered MCM-41 have potential applications in catalysis,adsorption and separation,preparation of advanced materials,and molecular devices since they are firstly discovered in1 992 .However,as compared with zeolites,the acidity and hydrothermal stability of these mesostructured materials are relatively low,which strongly affecttheir practical applications in in-dustrial catalytic reactions of petroleum.Here it is systematically summarized that the research work on improvement of acidity and hydrothermal stability forordered mesoporousmaterials,which include(1) the assembly of super acidic components into the mesopores;(2) the addition of inorganic salts,organic am-monium compounds during the synthesis of mesoporous materials or post-synthesis of mesoporous materi-als;(3) the synthesis of mesoporous materials from novel templates such as triblock copolymers;(4) the assembly of mesoporous materials from pre-formed zeolite structure-directing-agent(zeolite seeds solution) with zeolite primary and secondary building structure units.
    Hydrothermal Synthesis and Crystal Structure of [Co(2,2-bipy)3]4[Mo5ⅤMo5ⅥV6ⅣO40(PO4)]2·4H2O Containing Double Tetracapped Pseudo-Keggin Cluster Anions
    ZENG Qing-Xin, LÜ Gao-Meng, LI Ya-Feng, YANG Guo-Yu, XU Ji-Qing
    2002, 23(10):  1854-1856. 
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    The title compound[Co(2,2-bipy)3]4[Mo10V6O40(PO4)]2·4H2O was synthesized by hydrothermal method and its structure was determined with single crystal X-ray analysis. The cluster anion is double tetracapped Pseudo-Keggin cluster anions. The crystal is triclinic, space group P-1 with a=316 5(3)nm, b=1.438 2(3) nm, c=2.764 4(6) nm, α=79.51°, β=89.95°, γ=68.89°, V=4.789 3(17)nm3, Z=1, Dc=2.176 g/cm3, R=0.075 5, wR=0.205 3, S=0.995.
    A New Technology for the Preparation of High-permeance ZSM-5 Zeolite Membrane
    LI Yong-Sheng, WANG Jin-Qu, SHI Jian-Lin, CHEN Lian-Zhang, GUO Shu-Cai, YAN Dong-Sheng
    2002, 23(10):  1857-1859. 
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    High-permeance ZSM-5 zeolite membrane was prepared on porous tubular α-Al2O3 support by varying-temperature hydrothermal synthesis. XRD patterns show that the membrane consists of ZSM-5 zeolite crystals. SEM analysis indicates that few defects exist in the membrane and the thickness of the membrane is about 9 μm. The hydrogen permeance through the membrane is about 2.4×10-6 mol/(m2·s·Pa), and the separation factor for n-C4H10/i-C4H10 mixture (volume ratio 1∶1) is 40, which indicates that it has a high quality with high permeance and selectivity. Repeated nucleation and re-growth of the crystals on the support result in the dense membrane formation.
    Kinetics and Mechanism of Oxidation of Triethanolamine by Diperiodatonickelate(Ⅳ) Ion in Aqueous Medium
    SHAN Jin-Huan, WEI Hai-Ying, WANG Li, SHEN Shi-Gang LIU Bao-Sheng, SUN Han-Wen, WANG An-Zhou
    2002, 23(10):  1860-1863. 
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    The kinetics of oxidation of triethanolamine by dihydroxydiperiodatonickelate(Ⅳ) ion(DPN) was studied by spectrophotometry in aqueous medium. The reaction was found to be pseudo-first order with respect to Ni(Ⅳ) and to be fractional order with respect to triethanolamine. The rate increased with the increase of the concentration of OH- and decreased with the increase of the concentration of IO4-. The observed rate constants: kobs=(k1+k2[OH-])k1k2[OH-][TEA]/{[H2IO63-]+K1[OH-]+k1k2[OH-][TEA]}. Based on these, a mechanism involving the form of activative complex between Ni(Ⅳ) and reduct(TEA) was proposed. In addition, we calculated the equilibrium constants and rate-determining constants at 28 ℃, which were k1=8 008×10-2s-1, k2=0 289 6 mol-1·L·s -1, K1=2 063 and K2=36 471 L·mol -1.
    Studies on the Fluorometric Method for Determining Activity of Catalase and Its Application to Marine Biosamples
    MAO Yu-Xia, ZHENG Hong, GUO Xiang-Qun, CHEN Rong, ZHENG Wei-Yun
    2002, 23(10):  1864-1867. 
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    A new promising method for determining activity of catalase and its application are presented. The measurement of catalase activity is based on the inhibition of catalase on Fenton reaction. Catalase catalyzes the dissociation of H2O2, one of the main reactants of Fenton reaction which yields ·OH stoichiometrically, and restrains the increment of the fluorescence intensity, produced as a result of quinoline hydroxylation. The decrease of fluorescence intensity was linearly related to the activity of catalase and the linear range covered from 1.7×10-3 U/mL to 1.7×10-2 U/mL. A detection limit of 8.5×10-4 U/mL catalase was obtained. This method has been applied to the detection of catalase in marine biosamples and satisfactory results were obtained.
    Studies on the New Liquid Matrix for Laser Desorption/ Ionization Mass Spectrometry
    XIONG Shao-Xiang, CHEN Wen-Zhang, PU Dan, XIN Bin, WANG Guang-Hui
    2002, 23(10):  1868-1872. 
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    Several liquid matrixes with different compositions were formed by using some matrice compounds including nanoparticles, and their applications in matrix assisted laser desorption/ionization time of flight mass spectrometry were systematically investigated with several kinds of compounds such as peptide, protein, macrocycle oligosaccharide, small organic molecules as the testing samples. The similarities and differences between solid and liquid method of sample preparation were explored. It is shown from the experimental results that some liquid matrixes possessed a good versatility and the others are especially efficient to the analysis of particular compounds.
    In situ Rapid Determination of Chromium(Ⅵ) in Water Using Portable Photometer and Diphenylcarbazine Citrate
    CHEN Huan-Wen, XU Shu-Ping, YU Ai-Min, JIN Qin-Han
    2002, 23(10):  1873-1876. 
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    The trace Cr(Ⅵ) is usually determined by colorimetry using diphenylcarbazine, which is not able to be dissolved in water. In this paper, the diphenylcarbazine citrate was synthesized and the solubility of the diphenylcarbazine citrate was improved notably. Therefore, a new rapid spectrometry for Cr(Ⅵ) determination in situ was established using the reagent newly synthesized and the portable photometer made in our lab. In the weak acid medium, diphenylcarbazine citrate is colored by Cr(Ⅵ) to form a magenta-colored complex as the diphenylcarbazine usually does. The molar absorptivity for Cr(Ⅵ) is 3.32×104 L·mol-1·cm-1 at 540 nm, and the Beer's law is obeyed in the range of 0.03-2.00 mg/L. All the analysis can be completed within 3 minutes. Contents of Cr(Ⅵ) in electroplating waste water and industrial waste water were determined in situ, and all the results were satisfactory.
    Catalytical Rearrangement of 1,6-Dihydro-S-tetrazine with Isocyanate
    HU Wei-Xiao, SUN Ya-Quan, YUAN Qing, YANG Zhong-Yu
    2002, 23(10):  1877-1881. 
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    3,6-Dimethyl-1,6-dihydro-S-tetrazine reacts with phenyl isocyanate over different catalysts to afford different products. When using N,N-dimethylaniline as the catalyst, N-phenyl-1,6-dihydro-3,6-dimethyl-S-tetrazine-1-cabonamide was obtained; when using 4-dimethylaminopyridine (DMAP) as the catalyst, the new kind of compound was obtained. Using 14 different substituted phenyl isocyanates, 14 new compounds were prepared with a low or medial yield. The structure of compound 3i was determined by X-ray crystal analysis as N,N′-di(o-methylphenyl)-3,6-dimethyl-1,4-dicarbonamide. It shows that the catalytical rearrangement occurred. The mechanism was discussed briefly with aid of 1H NMR results. The anticancer activity of these new compounds were tested in vitro. And the results show that some of them have good bioactivity.
    Synthesis and Biological Activities of Imidazolo[2,1-b]-1,3,4-thiadiazole,S-Triazole[3,4-b]-1,3,4-thiadiazole Derivatives Bearing 1H-1,2,4-triazole
    ZHANG Yan, LIU Dong, DAI Chao-Feng, ZHANG Zi-Yi, XU Peng-Fei, HUI Xin-Ping, WANG Qin
    2002, 23(10):  1882-1886. 
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    Eighteen novel imidazolo-1,3,4-thiadiazoles and S-triazole-1,3,4-thiadiazoles containing 1H-1,2,4-triazole were synthesized and their structures were confirmed by elemental analyses and spectral analysis. And the characteristic data of 1H NMR and MS were explained reasonably. Furthermore, we also proposed the synthetic mechanism of 2,5,6-substituted-imidazolo-1,3,4-thiadiazole. Primary antibacterial test against E.coli, P.aeruginosa, B.subtilis and S.aureus showed that most of them had good antibacterial activities.
    Studies on New Immunoadsorbent for Myasthenia Gravis
    YAN Wei-Rong, YU Yao-Ting, YANG Li, ZHANG Wei-Hua, MIAO Peng-Chong
    2002, 23(10):  1887-1890. 
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    Myasthenia Gravis(MG) is an serious nerval specific autoimmune disease. The pathogenic factor of the disease is the anti-AChR antibodies in the blood of patients which react against the acetylcholine receptor(AChR). Literature reported that the AChR ab could be adsorbed by adsorbent linked with special amino acids or proteins. In order to remove AChr ab from blood, we studied the selectivity and adsorption capacity of various ligands and matrixes. Experimental results showed that immunoadsorbent prepared by coupling L-tryptophan to epichlorohydrin-activated cellulose bead(6%) gave the best result. Adsorbent of 1.0 g in 3.0 mL of serum could remove 25% of antibody from the serum, which will have a high potential application in the future.
    Ansa-metallocene Complexes(Ⅵ)—— Synthesis,Structure and Application in Ethylene Polymerization of Tetramethyldisiloxane-bridged Mixed Metallocene Complexes
    XU Shan-Sheng, WU Tao, CUI Hui-Ling, DAI Xu-Liang, WANG Bai-Quan, ZHOU Xiu-Zhong, ZOU Feng-Lou, LI Yang
    2002, 23(10):  1891-1895. 
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    Tetramethyldisiloxane-bridged asymmetric cyclopentadienyl ligands react with n-butyl lithium and MCl4·2THF to give tetramethyldisiloxane-bridged substituted asymmetric metallocenes(Me2SiSiMe2)(C5H4)(Cp′)MCl2[Cp′=C5H 3Bu-t, M=Ti(1), Zr(2); Cp′=C9H6, M=Ti(3), Zr(4)]. Complexes 1-4 were characterized by means of 1H NMR, mass spectra and elemental analyses. The crystal structure of complex 1 was determined by X-ray diffraction analysis. Complexes 1-4 were used for the catalytic polymerization of ethylene after the activation with methyl aluminoxane(MAO).
    Mechanism Studies on Reactions of ·OH,·H和ea-q with 2-Chlorophenol in Aqueous Solutions
    DONG Wen-Bo, WANG Shu-Hui, YAO Si-De, HOU Hui-Qi
    2002, 23(10):  1896-1900. 
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    Pulse radiolysis of aqueous 2-chlorophenol in dilute solutions under different conditions was studied. The main characteristic peaks in these transient absorption spectra were attributed and the build-up/decay trends of several transient species were investigated. Under alkaline conditions, the reaction of ·OH radical and 2-chlorophenol produces o-chlorinated phenoxyl radical with a rate constant of 1.0×109 L·mol -1·s-1; while under acid conditions, the initial product is mainly OH-adduct. The reaction between ·H and 2-chlorophenol produces H-adduct. In alkaline and nearly neutral solutions, ea-q can capture Cl directly from 2-chlorophenol with a rate constant 1.25×109 L·mol-1·s-1and 6.3×108 L·mol-1·s-1, respectively.
    Preparation and Reaction of α-Bromoketene Dithioacetals
    ZHAO Yu-Long, LIU Qun, SUN Ran, XU Xian-Xiu, PAN Ling
    2002, 23(10):  1901-1902. 
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    Bromo ketene dithioacetals (5) were prepared in high yields by reaction of α,α-diacetyl ketene dithioacetals (4) with bromine catalyzed by FeBr3 at room temperature. This new reaction is proposed involving an ipso electrophilic addition-deacetylation mechanism.
    Reaction Mechanism Between ClONO2 and Cl(2P3/2)
    SUN Ren-An, TAO Zhan-Liang, SUN Yan-Bo, JIN Fei, HAN Ke-Li
    2002, 23(10):  1903-1906. 
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    The reaction mechanism of reaction ClONO2+Cl(2P3/2) Cl2+NO3(a) and the reaction ClONO2+Cl(2P3/2)ClO+ClONO(cis)(b) and the reaction ClONO2+Cl(2P3/2)ClOCl+NO2 has been studied with Gaussian 98, B3LYP/6-31G* method. The transition states of various possible reaction pathways are obtained and are verified by internal reaction coordinate (IRC) analysis. The results show that the activation energy of reactions (a), (b) and (c) are 4.5, 57.6 and 37.3 kJ·mol-1, respectively. In comparison with the reactions (b) and (c) , reaction (a) is the main reaction because of this activation energy.
    Quantum Chemical and Thermodynamic Studies on the Graphite Intercalation Compounds of Metals
    ZHANG Gui-Ling, DAI Bai-Qing, WEI Yong-De
    2002, 23(10):  1907-1901. 
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    The B3LYP calculation of DFT method was employed to calculate graphite intercalation compounds of alkali metals, alkaline earth metals and transition metals (A-GIC, AE-GIC and T-GIC). According to the atomic net charges, Mulliken overlap populations and electron numbers of valence obitals, the electronic structures and bonding characters were discussed to clarify the relations between structure and function of A-GIC and AE-GIC. From the B3LYP and the thermodynamic calculated results, the synthesis possibilities of T-GIC (unknown in experiments) were also analysed.
    Critical Aggregation Number of Pseudo-micelle in Binary Systems of Anionic Surfactants and Water-soluble Nonionic Macromolecules
    XIA Yong-Mei, FANG Yun, LIU Xue-Feng, CAI Kun
    2002, 23(10):  1911-1914. 
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    Interaction in binary systems of anionic surfactants and water-soluble nonionic macromolecules was studied by means of steady-state fluorescence quenching. The above binary systems were composed of sodium dodecyl sulfate(SDS) or sodium dodecane sulfonate(AS) with polyethyleneglycol(PEG) or polyvinylpyrrolidone(PVP). The occurrence of aggregates in the above systems was deduced from the detected pseudo-micelle aggregation number Np. It was discovered that Np is simply increased linear with increasing surfactant concentration c. [Np]1 is defind as the first critical aggregation number of the pseudo-micelle corresponding to c1 in γ-lgc curves. The experimental results show that [Np]1 for a certain type of macromolecule is eventually not changed with the change of molecular weight and concentration of macromolecule. Thus [Np]1 seems to be an invariant or a structural eigenvalue which depends solely on the molecular structure of both surfactant and macromolecule.
    Adsorption Equilibrium and Kinetics of Alkyl Polyglucoside on the Air/Water Interface
    CHAI Jin-Ling, XU Jun, LI Gan-Zuo, ZHANG Gao-Yong, LI Ying, CHEN Wen-Jun
    2002, 23(10):  1915-1920. 
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    The air-solution equilibrium(γe) and dynamic surface tensions were measured by Wilhelmy method and maximum bubble pressure method(MBPM), respectively, of alkyl polyglucoside(APG) aqueous solution C9.6G1.3. The adsorption equilibrium and kinetics of APG on the air-solution interface were studied. The CMC of APG was determined to be 0.032 g/L. The above results show that at the start, the adsorption process is controlled by a diffusion step; Then it changes to a barrier control mechanism with a adsorption barrier between 4 and 7 kJ/mol. The effects of temperature, inorganic salts and alcohols on the adsorption equilibrium and kinetics were also discussed.
    Synthesis and Characterization of Double-tailed Phosphate Surfactant and Extraction of Protein with Its Reversed Micelles
    YAN Yun, CHU Ying, LIN Yi, XING Shuang-Xi, LIU Ying-Ying, LIU Jing-Lin, WU Zi-Sheng
    2002, 23(10):  1921-1925. 
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    A new phosphate surfactant that has never been reported before, sodium di-ethyloleyl phosphate acid(DEOPA), which fits for the extraction of proteins with reversed micellar system, has been synthesized. Its structure has been characterized with 1H NMR and FTIR spectrum. Its surfacial physico-chemical properties, such as cmc(Critical Micellar Concentration), HLB(Hydrophilic-Lipophilic Balance), and its solubilization effect to water was detected. Extraction of proteins using reverse micelles composed of DEOPA and isooctane was carried out. The results show that DEOPA is of relatively high surfactant activity, which means it fits for composing reversed micellar systems, and is of superiority when extracting large molecular weight proteins.
    The Theoretical Studies on the Structures and Relative Stability of Isomers of C36O
    YANG Zuo-Yin, LI Rui-Fang, YANG Xia, WANG Gui-Chang, SHANG Zhen-Feng PAN Yin-Ming, WU Ben-Xiang, ZHAO Xue-Zhuang
    2002, 23(10):  1926-1929. 
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    All of the isomers, C36O, have been optimized under the conditions of unrestrictive symmetries with the ab initio calculations and the HF/STO-3G base sets. The results of the total energies (HF/6-31G) suggest that there are iso-energy and most stable isomers formed on C6v or D2d symmetrical cages of C36. The strain analyses show that the relative stability of these isomers are not corresponding with the strains released in their cages. In comparison with C36(OH)2, the carbon atoms around the addition sites in C36O have greater strains because of the three-membered ring which is composed of C-O-C. At last in this paper, the IR absorption spectroscopies of the iso-energy of the isomers have been predicted theoretically.
    Distribution of Silicon and Aluminium Atoms as Well as Surface Acid Properties of Aluminated β Zeolite
    BAO Jia-Qing, XIE Zai-Ku, LU Xian, CHEN Qing-Ling
    2002, 23(10):  1930-1935. 
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    The changes of surface properties of Hβ including distribution of silicon and aluminium atoms as well as surface acid properties after treatment by NaAlO2 were studied. The samples were characterized by XRD, NH3-TPD, Pyridine-IR, 29Si MAS NMR and 27Al MAS NMR. The surface properties of Hβ zeolite changed after NaAlO2 aqueous solution treatment as follows: the total acid amount increased, Bronsted acid sites and Lewis acid sites increased. NaAlO2 aqueous solution treatment of zeolite beta may has function of realumination at a Si(0Al)A site by an isomorphous substitution Al(OH)4- anions. The results of activity for disproportionation and trans-alkylation of toluene and C9 aromatics over samples with and without NaAlO2 solution treatment were also compared. The comparison results show that the sample with NaAlO2 solution treatment has a higher aromatics conversion and a higher (B+X) selectivy, which indicates that the catalytic activity of zeolite beta increase as a result of NaAlO2 solution treatment due to a change in the surface acid properties.
    Asymmetric Hydrogenation Catalyzed by RuCl3 and a Non-chelate Chiral Diphosphine
    LI Qing-Shan, ZHANG Yu-Hua, YIN Yuan-Qi
    2002, 23(10):  1936-1938. 
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    The asymmetric hydrogenation of α-acetaminocinnamic acid and itaconic acid catalyzed by RuCl3 and a non-chelate chiral diphosphine, (2S,5S)-2,5-bis(diphenylphosphine)-1,4∶3,6-dianhydro-2,5-dideoxy-L-iditol(BDPI), was studied. The conversion of both reaction was 100% and the enantiomer excess was strongly affected by the ratio of [BDPI] to [RuCl3]. The maximum of e.e. value was 68% and 92% for the asymmetric hydrogenation of α-acetaminocinnamic acid and itaconic acid, respectively.
    Hydroformylation of Higher Olefins Catalyzed by Thermoregulated Phase-separation
    WU Xiao-Wei, WANG Yan-Hua, CHENG Fang, JIN Zi-Lin
    2002, 23(10):  1939-1943. 
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    The solubility of nonionic tension-active phosphine ligand P[p-C6H4O(CH2CH2O)nH]3(PETPP, n=6-12, N=3n) in different solvents was investigated. It was found that PETPP(N=18-36) possesses a distinct critical solution temperature(CST) in toluene. A novel concept(Thermoregulated Phase-separable Catalysis, TPSC) based on CST of PETPP for separating a catalyst from the reaction mixture is presented. TPSC system involves only the organic phase, while no water was added. At room temperature(tCST, the catalyst is soluble in organic solvent. At the reaction temperature(t>CST), the reaction proceeds homogeneously. After the completion of the reaction, on cooling to room temperature(t2)/V(CO)=1/1], the conversion of 1-decene and yield of aldehyde reached up to 98 6% and 96 0%, respectively. After recycling use of the catalyst for 10 times, the conversion of 1-decene was still more than 94.9%.
    Quantum Chemistry Study of Nitrogen Cages N12
    ZHAO Jun-Fang, LI Nan, ZHANG Zhi-Pei, ZHANG Xing-Chen, GAO Feng-Xin
    2002, 23(10):  1944-1947. 
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    Nitrogen clusters have drawn considerable attention in recent years, because of not only their theoretical interest, but also their possible use as environmentally friendly high-energy-density materials(HEDMs). In this work, quantum chemical ab initio method has been applied to the study of seven cage-like N12 isomers , including two previously studied nitrogen cages N12. Full geometry optimization, harmonic vibrational frequency, and thermodynamics calculations for seven different N12 molecules have been performed at the RHF/6-31G * level of theory. The calculation results show that all of the seven structures were found to be local minima on the potential energy hypersurface at the RHF/6-31G*, and the cage-like N12 with D3d symmetry is the most stable in seven N12 isomers. From the results presented here, it seems that there is not a direct relationship between the stability of the isomers and their symmetry. We also found that the five-membered ring is a fundamental stable structural unit for large even number nitrogen clusters. The more the five-membered rings, the more stable the isomer would be. In addition, the energy differences relative to six N2 molecules are also calculated and it appears that these seven cage-like N12 isomers would be very energetic materials. The present study would provide some theoretical data for synthesizing more stable nitrogen clusters in the future.
    Raman and DRIFT Spectra of Kaolinite/Formamide Intercalation Compound
    WANG Lin-Jiang, WU Da-Qing, YUAN Peng, LIN Zhong-Yu, DIAO Gui-Yi, PENG Jin-Lian
    2002, 23(10):  1948-1951. 
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    Raman spectroscopy and diffuse reflectance infrared spectroscopy(DRIFT) techniques have been used to study kaolinite and its intercalation compound with formamide. In the hydroxyl stretching vibration region of Raman spectrum, the formamide intercalation resulted in the decrease of the intensities of kaolinite inner surface hydroxyl bands at 3 699, 3 682, 3 665 and 3 642 cm-1, and the appearance of additional bands at 3 610, 3 628 cm-1. The two additional bands are attributed to the inner surface hydroxyls which formed hydrogen bond with the formamide C=O group. In the low frequency region of Raman spectrum, the ν1(A1g) mode of kaolinite Al(O,OH)6 octahedra consists of two bands at 180 and 193 cm-1, which shift to a high frequency and become a single band centred at 201 cm-1 after intercalation. It shows that the intercalation process decreases structural difference among the inner surface hydroxyls and makes them have a same orentation. The fact that the Raman active bands at 3 628 and 3 610 cm-1 were not observed in the DRIFT spectrum shows that the C=O group is linearly linked with the inner surface hydroxyls and that the vibration group is highly symmetric. In the NH stretching region of DRIFT spectrum, there were two bands at 3 336 and 3 466 cm-1 corresponding to the two types of the hydrogen bonds between formamide NH group and kaolinite. In the carboxyl stretching region, an additional band at 1 667 cm-1 is assigned to C=O group that bonded to the inner surface hydroxyl of kaolinite. The formamide intercalation induces that the inner hydroxyl Al-OH vibration band 930 cm-1 shift to high frequency 933 cm-1, which is due to that the formamide NH group was keyed into the ditrigonal hole of kaolinite. The formamide intercalation not only resulted in the breaking of the hydrogen bonds between the Al(O,OH)6 octahedral hydroxyl groups and the SiO4 tetrahedral oxygens, but also the formation of new different type hydrogen bonds between formamide molecule and kaolinite inner surface hydroxyl and the SiO4 tetrahedral oxygen.
    NMR and FTIR Characterization of Surface Acidity of Fluorinated γ-Asl2O3
    LIU Chang-Kun, YIE Zhao-Hui
    2002, 23(10):  1952-1955. 
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    The effect of fluorination on the surface acidity of γ-Al2O3 and the influence of the amount of fluorine on the types strength and number of acid sites have been studied. IR spectra of pyridine(PY) and 2,6-dimethylpyridine(DMPY) adsorbed-desorbed on fluorinated γ-Al2O3(F/γ-Al2O3) and 31P MAS NMR of trimethylphosphine(TMP) adsorbed on F/γ-Al2O3 have been used to measure the acidities of F/γ-Al2O3 . It has been found that F/γ-Al2O3 presents both Brnsted and Lewis sites. IR spectra of pyridine adsorbed on F/γ-Al2O3 pretreated in vacuum at 300 K show four bands at 1 451, 1 491, 1 580 and 1 617 cm-1, the bands are assigned to PY adsorbed on Lewis acid sites, and two bands at 1 544 and 1 640 cm-1 are assigned to PY adsorbed on Bronsted acid sites. IR spectra of 2,6-dimethylpyridine adsorbed on F/γ-Al2O3 pretreated in vacuum at 300 K shows a major band at 1 637 cm-1 due to DMPY adsorbed on Bronsted acid sites. 31P MAS NMR spectra of trimethylphosphine adsorbed on F/γ-Al2O3 pretreated in vacuum at 353 K show three peaks at δ -56 5, -28 2 and -21 9 are assigned to TMP chemisorption to different types of Lewis sites, and a peak at δ -2 8 is assigned to TMP chemisorption to Bronsted acid site. When the fluorine content increases, the total number of Lewis acid sites decreases, whereas their strength increases, a few of new types of Lewis acid sites are created simultaneously. The number and strength of Brnsted acid site presents a maximum for samples with 2%-3% of fluorine content. TMP as a sensitive NMR probe molecule is introduced for acidity measurements on F/γ-Al2O3 surfaces in the present study. 31P MAS NMR results agree with that of IR.
    A Study of Influence on TiO2 Sol with UV Irradiation
    GUAN Zi-Sheng, YAO Jian-Nian, MA Ying, SONG Yan-Lin, JIANG Lei
    2002, 23(10):  1956-1959. 
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    Influence on TiO2 sol irradiated with UV was studied by UV-Vis absorption spectra, dynamic laser light scattering(DLS) and TEM. The results show that absorbance of TiO2 sol decreased in the visible region and increased in the near ultraviolet region, and the bandgap of TiO2 sol increased during the process of UV irradiation. Comparison of TiO2 sol without UV irradiation, average size of TiO2 sol particles irradiated with UV decreased and its size distribution was more homogenous, and its crystallite was improved and anatase TiO2 was formed at room temperature.
    Investigations on the Adsorption Behavior of Water on Ag Electrode/Acetonitrile Interface by Using Surface-enhanced Raman Spectroscopy
    GU Ren-Ao, SUN Yu-Hua, CAO Pei-Gen, YAO Jian-Lin, REN Bin, TIAN Zhong-Qun
    2002, 23(10):  1960-1964. 
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    The surface-enhanced Raman scattering(SERS) spectrum of the trace amount of water on the silver/acetonitrile interface was investigated as a function of the applied potential and the concentration of water. The results show that several adsorption modes of water exist in the electrochemical double layer of silver. At relatively positive potentials, the water molecule was co-adsorbed with acetonitrile through weak hydrogen bond, which was hardly affected by the increase of the concentration of water. The frequency of ν(O-H) appears at 3 487 cm-1. When the scanning potentials were negative values, the water molecule turned to interact with the surface complex [Ag(CN)n](n-1)- produced by the dissociation reaction of the solvent acetonitrile. The frequency of ν(O-H) centered at ca. 3 583 cm-1 which red-shifted with the increase of the concentration of water. At more negative potentials, the hydrogen evolution reaction of water occurs seriously, and the quantity of OH- produced led to the formation of the crystallite LiOH which had the vibration of ν(O-H) locating at 3 665 cm-1. The formation of LiOH·H2O, in which the frequency of ν(O-H) was at 3 563 cm-1, becomes possible when increasing the quantity of water to 1.0 mol/L in the bulk solution.
    Relationship Between the Molecular Structure of 2,2′-Spirobiindan-1,1′,3,3′-tetraone and It′s Derivatives and Their Nonlinear Second-order Optical Properties
    ZHANG Suo-Qin, FENG Ji-Kang, REN Ai-Min, LI Yao-Xian
    2002, 23(10):  1965-1968. 
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    The geometry structure, electronic spectra and nonlinear second-order optical properties of 2,2′-spirobiindan-1,1′,3,3′-tetraone and it′s derivatives were investigated by using AM1 and ZINDO series method. The calculated UV-Vis spectra is in good agreement with the observed value; All studied molecule has no absorption above 400 nm, that is to say, these molecule has a good transparence. The relationship between the nonlinear second-order optical properties and the studied molecular structures of the compound and its derivatives was studied. The calculated results show that the electronic donating substituents attached on 5 position and the electronic withdrawing substitutents attached on the 5′ position have the highest nonlinear second-order ooptical susceptibilities these molecules are potential NLO materials due to the good transparence as well as large nonlinear second-order optical susceptibilities.
    A Novel Reaction System to Degradation of Organic Toxicants in Water
    WANG Yu-Ling, CAI Nai-Cai, ZHANG Huai-Song, LONG Fei
    2002, 23(10):  1969-1973. 
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    The carbon-PTFE O2(air)-Fed cathode with a high current efficiency was prepared on which H2O2 was electro-generated by using O2 in air. It was used to degrade the organic toxic contaminants in the new type reaction system-electrochemical oxidation system, photo-excitation oxidant system and the photoelectro-Fenton system. The decomposition rate of H2O2 was measured in different systems under different conditions and was compared with the traditional system. The reaction rate of aniline to mineral was measured in the new type systems, and the results indicated the decomposition rate of H2O2 has an excellent parallel relation with the degradation rate of aniline, when the carbon-PTFE O2 (air)-Fed worked in suit successively. Besides, the best system to degrade the organic molecule was the photoelectro-Fenton system, in which H2O2 was decomposed fastest. By comparing with photoelectro-Fenton system and photo-Fenton system, it reveals the important role of interface between the carbon-PTFE O2(air)-Fed cathode and solution in photoelectro-Fenton system. In this paper, we also discuss the mechanism of aniline to mineral in photoelectro-Fenton system.
    Electrochemical Characteristic of Alizarin Red S Existing in Polypyrrole Film as a Dopant
    DING Jie, SHUI Kwok-Keung
    2002, 23(10):  1974-1978. 
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    The cyclic voltammetry was employed to study the influence of the polymerization potential and charge on the property of the polypyrrole(PPy) film electrode containing Alizarin Red S(ARS), and of the scan potential range on the redox behavior of ARS. It has been demonstrated that the interaction of ARS molecules with PPy chains exists in the redox process of ARS between -0.60 V and 0.40 V. Based on the experimental finding, a possible reaction mechanism was suggested.
    Preparation and Photochromic Properties of Tungstosilicate Acid/Organoamino-modified Silica Nanocomposite Films
    ZHANG Tie-Rui, JIN Ming, FENG Wei, LU Ran, BAO Chun-Yan, ZHAO Ying-Ying, LI Tie-Jin
    2002, 23(10):  1979-1981. 
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    A novel inorganic-organic nanocomposite film was prepared and characterized by IR, UV-Vis, XRD and DTA-TG. IR and UV-Vis spectra show that the Keggin structure of SiW 12O404- polyanion is preserved in the composite film and there is an interaction between H4SiW12O40 and the organic substrate. The composite film showed a reversible photochromism. Under UV irradiation, the composite film turns blue and charge transfer occurs by oxidation of R-NH3+ and reduction of SiW 12O404-. When the irradiated samples are placed in air and sheltered from the light, they change back to their original color, and recover again when being exposed to UV light.
    Characterization and Chain Structure of PEG/PBT Copolymer with the Constant Mass Ratio of Soft to Hard Segment
    ZHANG Yong, YE Ling, FENG Zeng-Guo, ZHANG Ai-Ying, TIAN Xiao-Juan, XU Rui-Xing
    2002, 23(10):  1982-1987. 
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    A series of polyether ester thermoplastic elastomers based on polyethylene glycol(PEG) and poly(butylene terephthalate)(PBT) are synthesized and characterized by means of NMR, FTIR and DSC and mechanical testing. The influence of the constant mass ratio(70/30) of soft to hard segment on the copolymer's thermal and mechanical properties is investigated. It is found that, firstly, the length of hard segments is increased with increasing PEG molecular weight from 400 to 4 000(Mn); secondly, four domains corresponding to the amorphous and the crystal phase of soft and hard segments coexist in some compositions; thirdly, the glass transition temperature(Tg) of the soft segment is decreased, meanwhile its molten point(Tm) and the degree of crystal(wc) are increased with the increase of its molecular weight; finally, the inherent viscosity changes from 1.23 to 1.64 dL/g with ascending PEG molecular weight and shows a slight depression after the molten moulding which can be ascribed to a thermooxidative degradation. All copolymers are distinguished by the high elastic deformation in the stress-strain curves. With the increase of PEG molecular weight, the elongation at break εb, the tensile strength σb and the yield stress σy are all improved, while the elastic modulus E changes slightly around 9 MPa.
    Structure Characterization of Poly(vinyl chloride)-g-butyl Acrylate Copolymer
    BAO Yong-Zhong, WU Jian-Zhong, WENG Zhi-Xue, HUANG Zhi-Ming, PAN Zu-Ren
    2002, 23(10):  1988-1991. 
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    Poly(vinyl chloride)-g-butyl acrylate(PVC-g-BA) copolymers were synthesized by suspension-swelling graft copolymerization by using commercial and dehydrochlorinated PVC. The structure of dehydrochlorinated PVC and PVC-g-BA copolymers were characterized. PVC was slightly dehydrochlorinated and conjugated double bonds were formed as PVC was heated in alkali solution, and the molecular weight of PVC was slightly decreased. By using dehydrochlorinated PVC in the graft copolymerization, the grafting degree and grafting efficiency of BA were increased. The intrinsic viscosity, weight average molecular weight and index of molecular weight distribution of PVC-g-BA copolymer increased with increasing grafting degree.
    Preparation of Periodic Sub-micrometer Structure by Visible Laser on Poly(urethane-imide) Surface
    LI Mei, LU Qing-Hua, SUI Yu, LI Gang, QIAN Yu, WANG Zong-Guang
    2002, 23(10):  1992-1995. 
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    Poly(urethane-imide) (PUI) greatly absorbs the visible light of 532 nm because it contains azobenzene side groups. For the first time, laser-induced periodic surface structures (LIPSS) were generated on PUI films with a linearly polarized laser of 532 nm, the second harmonic generation of an Nd∶YAG laser. The absorption of the molecular chain was necessary to form LIPSS and the increase of the content of the azobenzene side groups accelerated the appearance of LIPSS. The direction of LIPSS was parallel to the polarization direction of the laser beam and the periodicity was near the wavelength used. The influence of the laser parameters, including the incidence angle, the number of laser pulse and the length of laser pulse on the configuration and the periodicity of LIPSS was studied. The obtained surface pattern was observed by atomic force microscope.
    Condensed State of Pauci or Multi-chain Crystals of Ultra High Molar Mass Polyethylene by Freeze-drying
    FAN Zhong-Yong, WANG Yi-Ren, BU Hai-Shan
    2002, 23(10):  1996-1999. 
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    Aggregates of single-, a few- and multi-chain crystals with folded-chain structure were prepared by a freeze-drying procedure from dilute solution of ultra-high molar mass polyethylene in para-xylene with mass concentration ranged from 10-3 to 10-5 g/mL. The chains in UHPE are very long (104 nm); they can form several lamellae themselves or enter many lamellae to crystallize together with other chains. By means of DSC, the thermal analysis of the freeze-dried samples indicated that their melting temperature and crystallinity decreased as the solution concentration decreased. Average crystal volume and the number of chain per crystal were estimated according to the melting point of samples, and also they decreased with the decrease of the solution mass concentration. Because of lower entanglement concentration in the freeze-dried samples, the resulted crystals would have a higher perfection. Crystal dimensions normal to (110) and (200) were measured by using WAXD, and the average crystal volume was estimated on the basis of the measured dimensions and it is in agreement with the data from the DSC measurement.
    Synthesis of Liquid Crystalline Aromatic Aldehyde Compounds
    HE Ke-Ke, ZHANG Xiao-Jing, LI Zi-Fa, ZHANG Shu-Yuan, ZHENG Shi-Jun, YANG Zhen-Hua, GUO Kai, ZHOU Qi-Feng
    2002, 23(10):  2000-2004. 
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    A series of novel 4-(4'-alkoxybiphenyl-4-carboxy)benzaldehyde was synthesized via Einhorn raction by using 4-hydroxybenzaldehyde and p-alkoxybiphenylyl carbonyl chloride as the raw materials. The compounds were identified by using elemental analysis, infrared spectrum, nuclear magnetic resonance, and mass spectrometry. The liquid-crystalline behavior of the compounds was characterized by differential scanning calorimetery(DSC), polarizing optical microscopy(POM), and polarimetric analysis. It was found that all the compounds went into liquid crystal phase over the Tm. The typical chiral smectic Cphase or smectic phase or cholesteric phase, and nemetic phase texture can be observed. In this study, we found that the rotation was maintained during the synthesis process and all the chiral compounds were optically highly active. Both melting point(Tm) and isotropization temperature(Ti) except those of compounds 2a and 4a change regularly with the carbon numbers of the end alkoxy increased. There is a gradual increase in smectic phase length and in the smectic-nemetic transition temperature. At the same time there is a gradual decrease in nemetic phase length until in the dodecyl, purely smectic properties are encountered.
    Synthesis and Properties of Highly Soluble Polyimide Containing Perylene Units
    HUANG Wei, YAN De-Yue, LU Qing-Hua
    2002, 23(10):  2005-2007. 
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    A series of high molecular weight copolyimides containing various amounts of perylene units in the main-chain were synthesized. The products were characterized by FTIR, NMR, UV-Vis, fluorescence spectroscopy, GPC, DSC and TGA measurements. They are highly soluble in conventional solvents such as chloroform, THF, cyclohexanone etc. and form optically transparent films by solution casting or spin-coating. The copolyimide containing 0.5%(molar fraction) perylene units exhibits the highest solid-state fluorescence. The polyimides are thermally stable up to 400 ℃ and exhibit glass transition temperatures in the range of 340～360 ℃. The number-average molecule weight ranges from 1.72×104 to 1.25×105 and the molecule weight distribution mediated between 1.9 to 2.4.
    Synthesis of Grafted Polymer Particles with Unusual Form
    CHEN Ming-Qing, LIU Xiao-Ya, YANG Cheng, Akashi Mitsuru
    2002, 23(10):  2008-2010. 
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    PEG macromonomer having one methacryloyl end group for per polymer chain was selected as reaction stabilizer. The distribution of molecular weight of the macromonomer was less than 1.1 based on the GPC analysis. Poly(acrylonitrile/styrene) particles with sub-micron sizes were prepared by dispersion copolymerization of acrylonitrile with styrene by using 2,2'-azobisisobutyronitrile(AIBN) as a free radical initiator in the presence of PEG macromonomer in V(ethanol)∶V(water)=7∶3 mixed solvents at 60 ℃ for 24 h. The particles having narrow size-distribution were obtained and studied by transmission electron microscopy(TEM) and laser light scattering(LLS). The surfaces of the particles have unusual structures(strawberry form or wheel form shows) which can be control by changing molecular weight of PEG macromonomer and other reaction conditions. The structure of the freeze-dried particles was investigated by X-ray diffraction(XRD) system and showed a distinct diffraction peak at 2θ=22.6°, indicating that the particles are crystallized.
    Reinforcement Property in Silicon Sealant by Nano CaCO3 Particles
    WANG Yue-Lin, WU Qing, DU Rong-Ni, WANG Yong, GAO Xiao-Ling, FU Qiang
    2002, 23(10):  2011-2013. 
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    Reinforcement property of structural silicon sealant as a function of the size and loading of nano CaCO3 particles has been investigated by mechanical measurement and DMA experiments. The tensile strength and elongation at break of silicone sealant were found greatly enhanced by nano CaCO3 particles. The smaller the particle size, the higher the tensile strength and the elongation will be. The storage modulus is also remarkably increased with the increasing of CaCO3 loading and decreasing of CaCO3 particle sizes, as revealed by DAM. Two relaxation peaks are seen for silicon sealant. One is around 153 K, corresponding to the glass transition temperature(Tg), and the other is around 233 K, corresponding to the melting temperature(Tm). Both Tg and Tm increase with the increasing of CaCO3 loading and decreasing of CaCO3 particle sizes. DMA results suggest that the interaction between nano CaCO3 particles and silicon sealant is quite strong. The molecular motion of silicon sealant is highly limited by the dispersed nano CaCO3 particles.
    Studies on Monodisperse Core/Shell Conductive Polymer Composite Materials(Ⅰ)——Characterization of Monodisperse Core/Shell Polystyrene/Polypyrrole Structure
    YANG Zheng-Long, HOU Wen-Bo, LIU Zheng-Ping, HUANG Li-Yan, PENG Xiao-Gang
    2002, 23(10):  2014-2016. 
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    Monodisperse core/shell latex particles composed of a polystyrene(PS) core and a thin conductive polypyrrole (PPy) shell were synthesized by means of two-stage emulsion polymerization. Proofs for the success of core/shell synthesis were obtained by using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy(XPS). Pressed pellet conductivity measurements on the dried composites indicated a low percolation threshold of 13.8%. The conductivity for the composites was higher than that of a heterogeneous admixture of dried PS latex and PPy bulk powder. The highest conductivity of the core/shell composite was 0.14 S/cm.
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