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    24 December 1993, Volume 14 Issue 12
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    Articles
    Different Luminescence Centers and Their Time-Resolved Characteristics in Solid Solution BaFCl1-xBrx:Eu2+
    ZHAO Wei, CHEN Xiao-Bo, SONG Zeng-Fu, SU Mian-Zeng
    1993, 14(12):  1633-1637. 
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    BaFX:Eu2+(X = Cl, Br) and their solid solution BaFCl1-xBrx:Eu2+(x = 0.25, 0.50, 0.75) are excellent X-ray phosphors and photostimulated luminescence materials.We have found that the fluorescence decay curves of the solid solution are composed of a slow and a fast component.Their origins have been discussed on the basis of different luminescence centers.The samples were prepared by solid state reaction.The luminescence of Eu2+ mostly consists of a 5d-4f narrow-band emission.The band emission is centered at 385 nm for BaFCl:Eu2+ and at 389 nm for BaFBr:Eu2+.Their excitation band originating from 4f→5d transition is centered at near 277 nm.BaFX:Eu2+(X = Cl, Br) exhibits a single exponential deccy.For the solid solution BaFCl1-xBrx:Eu2+, only double exponential decays can fit the experimental values well.By a nonlinear least squares method, the lifetime of these samples is given in Table 1.It was found that the fast component τe1 of BaFCl1-xBrx:Eu2+ is a constant and approximately e-qual to that of BaFBr:Eu2+τe.The slow compeonent τsub>τe decreases with the increase of Br content x.The time τe0 taken as the intensity decays to 1/e of the initial intensity is consistent with the values reported in literatures where they were treated as a single exponential decay.In BaFX:Eu2+, the Eu2+ is on the site of Ba2+.Four F- ions and five X- ions are coordinated with it.In the solid solution BaFCl1-xBrx:Eu2+, Cl- and Br- occupy the sites of X- randomly, thus forming different luminescence centers.The ligands Cl and Br around Eu2+ have different configuration with different probabilities as shown in Table 2.The most probable ligand configuration is Cl4Br for x=0.25, Cl3Br2 and Cl2Br3 for x = 0.50, and ClBr4 for x = 0.75, respectively.The Eu2+ with such coordination might be responsible for the slow component in Table 1.The fast component exists in all the solid solution and can be attributed to what resulting from the Eu2+ with Br5 coordination even though the probability of this ligand configuration is small for x-0.25 and 0.50.On the basis of Table 3 and 4, a possible explanation for this result is that the luminescence from the Eu2+ with Br5 configurartion i.e.BaFBr:Eu2+ component in solid solution may be strong in some extent in the band emission and there might exist energy transfer from other centers to this center.
    Studies on the Synthesis and Magnetic Exchange Interaction of Heterobridged Enolic Dicopper Complexes
    CHEN Jing-Tang, LIAO Dai-Zheng, ZHANG Ruo-Hua, ZHAN Ya-Li, LU Jian-Yi
    1993, 14(12):  1638-1641. 
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    Two dicopper complexes containing different exogenous bridges, Cu2(pfhmp)Br ·2H2O(1) and Cu2(pfhmp)C3H3N2 · 2H2O(2), were synthesized, where pfhmp3- denotes dehy-drogen anion of N,N-diisonicotinoyl-hydroxy-4-methylisophthalaldehyde dihydrozone.Based on the elementary analysis, IRand molar conductance, the complexes are proposed to have hetero-bridged structures and enolic configuration.The determination of variable-temperature magnetic susceptibility indicates that the variation of exogenous bridge obviously changes magnetic exchanges interaction between two Cu(Ⅱ) ions.
    Position and Interaction with Framework for Template Molecule Tetramethyl ethyl enediamine Trapped in Cage of Zeolite CF-3 and ZSM-39
    SUN Yao-Jun, WU Tai-Liu, WANG Li-Ping, FEI Lun, LONG Ying-Cai
    1993, 14(12):  1642-1646. 
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    XRD, FT-IR, TG-DTAand 13C MAS NMRhave been used to characterize silicon zeolite CF-3 and ZSM-39 hydrothermally crystallized in TMEDA-Na2O-SiO2-H2Osystem.The 13Cchemical shift and the relative intensity of resonance peak in CP (cross polarization) and HPDEC(high power decoupling) NMRspectra for different group of TMEDAreveal the position, the moving and the interaction with framework for the template molecule trapped in different size cages of zeolites.The narrowness, the unusual chemical shift to high field, and the obvious change of the intensity for the 13Cresonance peak of -C2H4- group related to that of -CH3 group in the CPand HPDECspectra, indicate that one molecule of TMEDAis shared by two neighbours of [51264] cage of ZSM-39 and that the -C2H4- group of TMEDAinteracts strongly with oxygen atoms locating at the 6-oxygen-membered ring between the two cages.
    The Synthesis of Some New Type Porphyrins and Their Photosensitivities
    LIU Yu-Wen, WANG Yong-Qiang, WANG Xing-Qiao, WANG Li-Bo, YU Lian-Xiang, CAO Xi-Zhang
    1993, 14(12):  1647-1650. 
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    Four new porphyrins, TIAPP, TNAPP, TMIAPPI, IMNAPPI,and two of their zinc complexes, ZnTMIAPPI, ZnTMNAPPI, are synthesized.Four porphyrins can be dissolved in water.Their structures are characterized by IR, UV-Vis and elementary analysis.Using triethanolamine as donor, porphyrin as photosensitizer and methyl viologen(MV2+) as receptor, the photosensitizing reaction of the four kinds of water-soluable porphyrins is conducted in DMSO-H2Osystem.The results show that all of these new porphyrins possess photo-sensitivity.Among them, zinc porphyins are the best.They have the following order; ZnTMIAPPI> ZnTMN APPI>TMIAPPI>TMN APPI.
    Structural Research of the Cluster Compounds of W2Cl4(OR)4(ROH)2 by EXAFS
    DUAN Yong-Heng, JIN Song-Lin, HONG Bo, MA Li-Dun
    1993, 14(12):  1651-1652. 
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    Five cluster compounds of double tungsten nucleus W2Cl4(OR)4(ROH)2 have been investigated by EXAFSin which R- is Pr-, n-Bu, i-Bu, sec-Bu and n-Oct respcctivily.An in-lab EXAFSspectrometer-FXASwas used to collect the data of W LIedges.The backscattering amplitudes and the phase shifts of W, Cl and Oatoms were obtained from the standard W2Cl4(OCH3)4(CH3OH)2. The structural parameters of the clusters from the curve fitting are listed.The conclusion is that the structures of cluster nucleus of the five compounds do not obviously change with the change of the size and the structure of the group--ORin the compounds.The structural stability results from the double bond and two bridge oxygen bonds between the two tungsten atoms.
    Determinationn of Trace Amount of Metal Ions by Reversed-Phase Ion-Pair Liquid Chromatography with Post-Column Derivatization Chemiluminescence Detection
    ZHANG Xin-Xiang, CHENG Jie-Ke, ZENG Yun-E
    1993, 14(12):  1653-1657. 
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    The separation and determination of Cr(Ⅲ), Fe(Ⅱ), Fe(Ⅲ), Cu(Ⅱ), and Co(Ⅱ) were demonstrated by reversed-phase ion-pair liquid chromatography with chemiluminescence detection.Areversed-phase column (YWQ-C18, 10 μm, 150×4.0 mm i.d.) was used.The ion-pair ion was sodium dodecyl sulfate (SDS) and the eluent was lactic acid.The Chemiluminescence system used was luminol-KOH-H2O2-Brij 35 system.The separation and detection conditions were studied.In the optimization condition the metal ions could be determined in the range from 1.0×10-11 to 1.0×10-5g/mLwith the detection limits of 10 pg Cr(Ⅲ), 0.4 pg Fe (Ⅱ), 20 pg Fe(Ⅲ), 1.0 pg of Cu(Ⅱ), and 0.01 pg Co(Ⅱ), respectively.
    Lithium Ion-Selective Electrode
    ZHANG Zeng-Rong, YU Ru-Qin
    1993, 14(12):  1658-1660. 
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    Making use of the extraction chemistry of lithium, a PVCmembrane lithium ion-selective electrode based on 1-phenylazonaphthol-2 (sutan Ⅰ) and tri-n-octylphosphine oxide (TOPO) was prepared.The membrane composition was optimized by orthogonal polynomial regression.Amembrane containing 4.5 mg sutan Ⅰ and 9.0 mg TOPOand 180 mg solvent mediator was obtained.The slope of the electrode was 51.7 mV/decade, with the linear range of 2.0 × 10-5-0.1 mol/Land the detection limit of 4.0× 10-6 mol/L.The electrode showed moderate selectivities for Li+ over Na+ and K+, and was applied to the assary of lithium in Li2CO3 tablets with satisfactory results.
    Rapid Separation of Disaccharides by Capillary Zone Electrophoresis with Interference Refractive Index Detection
    REN Ji-Cun, HE Jin-Lan, DENG Yan-Zhuo, CHENG Jie-Ke
    1993, 14(12):  1661-1664. 
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    Rapid separation of disaccharides by capillary zone electrophoresis in uncoating fused-silica column is presented.Using a pH 9.7, 0.1 mol/Lsodium tetraborate as the runing solution, underivatized disaccharides are transformed into negatively charged borate complexes.Detection is performed with an on-column laser interference refractive index detector (made in home).Four disaccharides are separated by CZEwithin 10 min.The effects of pH, sodium tetr-borete concentration and organic additives on the separation of disaccharides are discussed.
    The Study on Vaporization Mechanisms of Vanadium and Titanium in ICP-AES with Sample Introduction by Graphite Furnace Electrothermal Vaporization
    HU Bin, JIANG Zu-Cheng, ZENG Yun-E
    1993, 14(12):  1665-1667. 
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    In this paper, the vaporization processes of vanadium and titanium in GF-ETV-ICP-AEShave been investigated in detail.By observing and comparing the vaporization behavior of vanadium and titanium in the presence/absence of fluorinating agent, PTFE, together with the results of residues chemical composition analysis after graphite furnace heating cycle, the vaporization mechanisms of vanadium and titanium in graphite furnace have been proposed, and it is verified by the results of thermodynamic calculation.
    Electropolymerization of ο-Aminophenol
    ZHU Yi-Min, ZHAO Feng-Yun
    1993, 14(12):  1668-1670. 
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    Polymerization of ο-aminophenol in acidic aqueous solutions was achieved electrochem-ically on platinum plate electrode.Poly (ο-aminophenol) (PAP) is electroactive in aqueous solutions.The characterization of PAPfilm by infrared spectroscopy suggests that the PAPis a ladder polymer with phenoxazine rings as electroactive sites.The electrochemical reaction of hemoglobin can be promoted at poly (ο-aminophenol) film modified electrode.
    Spectrophotometric Study on the Color Reaction of Silver(Ⅰ) with meso-Tetra (4-sulphophenyl) porphyrin
    PAN Zu-Ting, ZHAO Ye, JIN Zhen-Shu, WANG Ming-Zhi, XU Mian-Yi
    1993, 14(12):  1671-1673. 
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    Ahighly sensitive spectrophotometric method has been developed for the determination of trace silver, based on the color reaction of silver(Ⅰ) with meso-tetra(4-sulphophenyl) porphyrin (TPPS4) in the presence of cetyltrimethylammonium bromide (CTMAB) and β-cy-clodextrin(β-CD).The silver(Ⅰ) complex formed is sensitive, stable, and remained unchanged in strong acid medium.The apparent molar absorptivity of the complex is 5.21 × 105 L/mol · cm at 424 nm.The composition ratio of the complex was determined to be 1:1:2(Ag:TPPS4:CTMAB) by both the continuous variation method and the molar ratio method.Beer's Law is obeyed for silver in the range of 0-8 μg/25 mL.The interference of foreign ions was also examined.The method can be used for the determination of silver in the fixer waste water, photographic paper and ores, and the results are the same as those of AAS.
    Studies on Kinetics of Reaction Between Metal Ion and Phthalocyaninesulfonates
    WU Xing, YAO Rong, ZHANG Guo-Lin, XU Wen-Qin
    1993, 14(12):  1674-1676. 
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    The kinetics of reaction between metal ion and phthalocyaninesulfonates has been studied by electronic absorption spectroscopy and the kinetics of reaction between Cu(Ⅱ) and trisulfophthalocyanine (S3Pc) was studied in this way.It shows that the rate of reaction between Cu(Ⅱ) and S3Pc and can be expressed as follows:v =k1k2[Cu][L]2.
    Studies on Synthesis and Characteristics of High Performance Liquid Chromatography Bonded Pase Containing Diaza Crown Ether
    DA Shi-Lu, HE Guo-Liang, WANG Zhong-Hua
    1993, 14(12):  1677-1681. 
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    Anew silica gel bonded phase, propyloxy methyl-diaza-1-8-crown-6 silane bonded phase (DN18-C-6), was synthesized via solid-liquid phase three-step-reaction on the surface of prorous silica:the prorous silica gel grafting with γ-gllycidoxypropyltrimethoxysilane; the epoxy-substituted silica reacting by ethylenediamine; the reaction with polyethylene glycol ditosylate in the presence of sodium hydride as catalyst.It possessed good thermal and chemical stabilities and highly separation selectivity for aromatic amine and phenols and the components of nucleic acid.The complexation capacities of DN18-C-6 for sodium and postassium picrate, CuSO4, AgNO3, Ni(NO3)2 were determined.It showed a good ability to complex with them.
    Studies on Chiral Thiophosphoric Acids and Their Derivatives (Ⅹ) ——Stereochemistry of Methanolysis of O-Ethyl-O-Phenyl Thiophosphoramidates
    TANG Chu-Chi, ZHANG Mian-Ji
    1993, 14(12):  1682-1686. 
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    Optically active (+)-or(--)-(R)-0-ethyl-O-phenyl thiophosphoramidates 2 were obtained with the inversion of configuration at phosphorus atom by the reaction of optically active (--)-(R)-O-ethyl-O-phenyl thiophosphorochloridate 1 with various primary or secondary amines, or ammonia in the presence of base.The acid methanolysis of 2 was carried out in 4.7 mol/L HCl-MeOHsolution, and resulted in cleavage of P-Nbond to give the products with the inversion of configuration.The alkaline methanolysis of 2 occurred in MeONa-MeOHsolution, and gave the products with the inversion of configuration with PhOas a leaving group.These results can be satisfactorily interpreted in the light of trigonal bipyramidal(TBP) intermediates concepts.
    Syntheses, Structure and Second Harmonic Generation of Some Arylphosphonic(arsenic) Acids and Their Salts
    WANG Hai-Ping, DAI Chao-Yang, QIN Jin-Gui, LIU Dao-Yu, CHEN Shu-Kang, WANG Cheng-Rui, WU Bai-Chang, CHEN Chuang-Tian
    1993, 14(12):  1687-1691. 
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    By combining the distorted inorganic anion groups and organic conjugated systems, a series of arylphosphonic(arsenic) acids and their salts were designed and synthesized.Their electronic spectra indicated the presence) to some extent, of intramolecular charge transfer (ICT).The crystal structure of para-methylphenylphosphonic acid showed that the molecules were packed as dimers in crystals due to the hydrogen bonding.Their second harmonic generation (SHG) effects were measured by the Kurtz powder method.Six compounds exhibited nonlinear optical property.
    Studies on the Electrochemical Oxidation of Substituted Benzaldehyde and Acetophenone Oximes
    ZHU Shi-Mtn, XIA Qiu-Wen, HU Hong-Wen
    1993, 14(12):  1692-1696. 
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    The electrochemical oxidation of 10 substituted benzaldoximes and 5 substituted ace-tophenone oximes has been studied.The results indicate that the benzaldoximes are first oxidized to iminoxy radicals and then transformed via chemical coupling of the radicals to the dehy-drodimers adsorping on the electrode, it appears to be an irreversible reaction and absorptive process.The acetophenone oximes are also oxidized to iminoxy radicals, but the dehydrodimers formed by radical coupling rapidly decompose to the ketone and other products, diffusing easily to the medium, it appears to be a reversible electrode reaction and an irreveribly adsorptive process.The products of electrochemical oxidation of benzaldehyde and acetophenone oximes have been confirmed by controlled potential electrolysis and UV-spectrophotometry.For both the monosubstituted benzaldehyde and acetophonone oximes there exists a linear relationship between the oxidative potentials and the Hammett constants of the substituents.The oxidative potential increases with increasing electrowithdrawing power of the substituent.The electrochemical oxidation can be used for generating iminoxy radicals from oximes.
    The Research on the Relation of the Activity and Incubation Time of β-GIucuronidase
    ZHANG Yi-Zhong, LIU Xin, YE Li, ZHANG Chang-Jiu, ZHANG You-Jie
    1993, 14(12):  1697-1699. 
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    To analyze the urinary steroids with GC-MS, conjugated fraction as usual is first hy- drolyzed with β-Glucuronidase at 55℃ for 3 h or 37℃ for 12 h.This is a time consuming step for performing the routine doping control analysis.In this paper the relation between the hy-drolyzing activity and the incubation time of β-Glucuronidase from E.Coli was studies.It was found that the hydrolyzed was completed within 1 h.
    A Theoretical Study of Proton Transfer Reaction and Spectroscopic Properties of 2-(2'-Hydroxyphenyl)benzoimidazoIe
    XU Wen-Guo, FENG Ji-Kang, SUN Jia-Zhong
    1993, 14(12):  1700-1704. 
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    The AMIand INDO/S-CIsemiempirical MOmethods were used to investigate ground and excited state proton transfer reactions of 2-(2'-hydroxyphenyl)benzoimidazole.The potential energy curve, barrier, transition state in the ground and excited states were obtained.The relative stabilities of some isomers and anions, hydrogen bond energy and the theoretical assignment for the spectra of the related isomers were studied.The results are in satisfactory agreement with the experiment values.The mechanism of the photochemical reaction and spectroscop-ic properties were discussed.
    The Relationship Between the Centroids of the Localized Molecular Orbitals and Molecular Structure
    LIANG Guo-Ming, TIAN An-Min, YAN Guo-Sen
    1993, 14(12):  1705-1709. 
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    The relationship between the centroids of the localized molecular orbitals (LMO) and the chemical bonds in molecules has been discussed.Amethod through LMO's centroids to determine the bonding behavior and various bond types is given.
    Studies on Catalytic Electro-oxidation of Hydrazine on Modified Graphite Electrode by Coordination Compounds of d-Transition Metals with TP(ο-NO2)TBP
    ZHU Zhen-Ping, REN Jian-Guo, QIN Zi-Bin
    1993, 14(12):  1710-1714. 
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    The catalytic properties of coordination compounds of Co(Ⅱ), Fe(Ⅲ), Ni(Ⅱ), andZn(Ⅱ) with meso-tetrakis (ο-nitrophenyl) tetrabenzoporphyrin [MTP(ο-NO2)TBPor MTBP] on modified graphite electrode for the electro-oxidation of hydrazine have been examined.The results indicate that the oxidation peak potentials shift to more cathodic direction360 mVfor Co (Ⅱ)TBPand 250 mVfor ClFe(Ⅲ)TBPcomparing with graphite electrode, respectively, but shift very little for Ni(Ⅱ)TBPand Zn(Ⅱ)TBP.The catalytic activity was found to decrease in the order:Co(Ⅱ)TBP>ClFe(Ⅲ)TBP>Ni(Ⅱ)TBP>Zn(Ⅱ)TBP.The catalytic kinetics with Co(Ⅱ)TBPand ClFe(Ⅲ)TBPwas studied.The reaction order in OH- is 1 for Co(Ⅱ)TBPand 2 for ClFe(Ⅲ)TBP, respectively.The order in N2H4 is 1 for both complexes.Tafel slopes of 118 mVfor Co(Ⅱ)TBPand 86 mVfor ClFe(Ⅲ)TBPwere obtained.
    Ammoxidation of Propane over V/Sb Catalysts
    LI Jing, CHENG Tie-Xin, JIANG Chun, DOU Bo-Sheng, YU Zuo-Long
    1993, 14(12):  1715-1718. 
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    The ammoxidation of propane was studied over the V/Sb oxide catalysts.The effects of the catalyst composition, structure, reactivity of labile oxygen and surface base-acidity on the catalytic acitivty have been examined by using XRD, TPD-O2, TPRand TPD-NH3. The experiment found that the catalyst with V/Sb=1/5 gave higher activity and selectivity.The results show that the active phase is VSbO4 in the catalyst, the synergistic effects between VSbO4 and Sb2O4 phases have an important influence on the activity of the catalyst.
    Determination of Three-Dimensional Structures of Amethystonal in Solution by< 2D-NMR and Molecular Mechanics Calculation
    YANG Yan-Wu, JI Ang, HE Bing-Lin, XU Xiao-Long, WANG De-Hua, QIAN Bao-Gong, ZHAO Qing-Zhi
    1993, 14(12):  1719-1724. 
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    Amethystonal was an effectively antineoplastic, antiphlogistic and antibacterial component first isolated from the leaves of Rbdosia amethystoides(Beath) C.Y.WUet Hsuen., a Chinese herbal medicine collected in Henan province of China.The 13Cand 1H NMRspectra were comepletely assigned by decoupled 13Cspectrum, DEPT, hetero- and homo-nuclear correlation spectra.The proton coupling constants were measured by resolution-enhanced ID-1Hspectrum and 2D-J-resolved spectrum.The interproton distances between proton i and j were calculated according to 1/rij6∝, where Aij was the integration value of the cross peak in phase sensitive NOESYspectrum.The initial spatial structure of amethystonal in solution was computed by WUPHmethod with the structural parameters measured by NMRexperiments as input data, and the minimized three dimensional structure was obtained through the molecular mechanics calculation on the basis of WUPHcalculation.The interproton distances of each proton pairs obtained from the cross peaks in phase sensitive NOESYspectrum were calculated from the atomic coordinates, and the coupling constants of protons were predicted from the dihedral angles given by MM2 method with Karplus equation.The maximum deviation between interproton distances calculated with energy minimizing calculation and that obtained from NOESYexperimental data of amethystonal was 0.045 nm, and the root-mean-square deviation was 0.023 nm.The analysis of interproton distances together with the analysis of coupling constants indicated that the com-binization of WUPHmethod based upon the NMRexperimental data with the molecular mechanics (MM2) calculation could provide the three-dimensional structure of amethystonal in solution.
    Anisotropies of Highly Oriented Undoped and Iodine-doped cis-Polyacetylene
    WANG Rong-Shun, CHEN Er-Yue, HUANG Zong-Hao
    1993, 14(12):  1725-1728. 
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    The two-dimensional energy-band structures of highly oriented undoped and iodine-doped cis-polyacetylene are calculated by EHMO/COmethod in this paper, and their electronic anisotropies are discussed.The ratio between the conductivity in the direction parallel to the molecular chain and that in the direction perpendicular to the molecular chain (σ∥/σ⊥) depends on the ratio between the valence band widths and the conduction band widths in the two directions.The σ∥/σ⊥ decreases after iodine-doping as a result of the increase in interchain coupling.The results are in good agreement with experimental ones.
    Studies on the Stability for the Carbon Tube Cage-Alkene
    TANG Au-Chin, LI Qian-Shu, HUANG Xiao-Zhong
    1993, 14(12):  1729-1730. 
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    Eigenvalue of Huckel Hamiltonian for carbon tube cage-alkene C2p(k+2)(p= 3,4.5, …; k=1,2,3,…) has been discussed with the help of group theory and graph theory.Then the eigenvalues of some sets with 4≤p≤12, 1≤k≤12 have been calculated by the derived formulas in text and certain general rules on the stability were obtained from the calculated results.
    Studies on Preparation and Properties of Nanocrystalline CoxFe3-xO4
    KANG Hong-Ye, YANG Hua, LI Xiu-Min, ZHAO Hai-Yan, ZHAO Mu-Yu
    1993, 14(12):  1731-1733. 
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    The nanocrystalline CoxFe3-xO4 was prepared by the improving coprecipitation method and the dependence of size distribution, magnetization and superparamagnetism properties on the composition of nanocrystalline CoxFe3-xO4 is investigated.The cation distribution and saturation magnetization were derived.
    Theoretical Studies on Conduction Mechanism of Iodine-doped 1,4-cw-polyisoprene
    WANG Rong-Shun, ZHANG Jing-Ping, SU Zhong-Min
    1993, 14(12):  1734-1736. 
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    Two-dimentional electronic energy bands of iodine doped 1, 4-cis-polyisoprene(PI) are calculated by semiempirical EHMO/COmethod.The results show that the conductivity of iodine doped PIresults from the conduction of both directions parallel and perpendicular to the polymer chain; the conductivity of interchain is higher than that of intrachain.I3n-(n<1) anions are the dominant contributors to the conductivity in parallel to the chain direction, while both I3n- anions and double bonds of interchains play an important role in conductivity in the direction perpendicular to the chain.
    Separation of σ-π Bonds in Localized Molecular Orbitals
    LIANG Guo-Ming, GU Jian-De, TIAN An-Min
    1993, 14(12):  1737-1739. 
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    Aprocedure for separating σ and π bonds in the localized molecular orbitals was presented.Combined with ab initio and Boys localization method, the procedure was applied to the investigation of 19 compounds containing multiple bonds.The results of separation of σ and π bonds show that the procedure presented here is a successful and useful one.
    NMR and Quantum Chemical Studies of Tri(2 methyl 1-aziridinyl) Phosphine Oxide Isomers
    HUA Shi-Ying, GUO Chun-Xiao, LUO Kui-De GAO, Xin-Feng
    1993, 14(12):  1740-1742. 
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    1H, 13C, 15N, 31Pand 17O NMRspectra of tri(2-methyl-1-aziridinyl) phosphine oxide were studied and simulated.The quantum chemical calculations on this compound were also carried out by AMIprogram.The optimized results show that there exist four kinds of isomers for the compound, two of them are enantiomer, and their geometrical configurations were obtained.
    Syntheses of New Poly phosphates as Drug Release Materials
    MAO Hai-Quan, ZHUO Ren-Xi, FAN Chang-Lie, FAN Li-Hong, FU Ya-Ping
    1993, 14(12):  1743-1747. 
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    New polyphosphates with amphiphilic structures were synthesized by solution poly-condensation using tyrosine alkyl esters and alkyl phosphodichloridates as monomers.Their structures were confirmed by NMR, FTIRand elemental analysis.The average molecular weight, intrinsic viscosity and thermostability of these polyphosphates were investigated.The in vitro degradation and protein (BSA) release profile were also studied.
    Studies on the Infrared Spectral Behavior of Ultra-high Molecular Weight Polyethylene
    LIAO Kai-Rong
    1993, 14(12):  1748-1751. 
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    The change of infrared spectral behavior of ultra-high molecular weight polyethylene (Mw>10×105) with temperature was studied.It was found that the absorption strengthes of three bands (1368, 1352.and 1304 cm-1) arised from amorphous regions were increased with increasing temperature, but the increasements were less than those of the conventional molecular weight polyethylene (Mw= 10×104), especially in the case of temperature range higher than 140℃.The change of short-range conformation distributions of methylenes in molecules with temperature was independent of molecular weight while the gauche conformation distribution of methylenes was increased with the increase of temperature.Both the spectral results obtained in heating and cooling processes showed that the bands of 1352 and 1304 cm-1 were more sensitive to the change of the state of the crystalline phase than the band of 1368 cm-1.
    Sorption Rate Equation of Carboxyl-Containing Starch Graft Polymer for Some Heavy Metal Ions
    HU Zhong-Ai, WANG Xue-Feng, ZHANG Fu-Long
    1993, 14(12):  1752-1755. 
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    Water-insoluble carboxyl-containing starch graft polymer(carboxyl-containing starch) was prepared by grafting acrylonitrile onto highly cross-linked starch, followed by base saponifi-cation to convert nitrile group into a mixture of carboxamide and carboxylate groups.Ceric ammonium nitrate was used as initiator for the graft polymerization.The sorption kinetic properties of carboxyl-containing starch for several heavy metal ions have also been studied systematically.It is shown that the sorption rate of carboxyl-containing starch is very rapid and the time of reaching its equilibrium is short.The relationship between the sorption amount and time completely complies with following equationQ/Q∞=at/(1+at).
    Synthesis and Structural Studies on Side Chain Liquid Crystalline Polyacrylates Containing Para-Nitro Azobenzene (Ⅲ) --Crystalline Behaviour of the Polymers
    LIN Min, ZHOU En-Le, XU Ji-Ping
    1993, 14(12):  1756-1759. 
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    The crystalline behaviour of the side chain liquid crystalline polyacrylates containing para-nitro azobenzene was studied by DSC, WAXDand polarized microscopy.It was found that increasing the length of the spacer and decreasing the MAcontent in the copolymers can improve the crystallinity of the copolymers.The different crystalline ability of the copolymers on different substrates also reflected the effect of the non-crystalline component MAon the crystallinity of the copolymers.
    Structure, Morphology and Ionic Conductivity of Graft Polymer Networks Containing LiClO4
    LI Dan, HU Chun-Pu, YING Sheng-Kang
    1993, 14(12):  1760-1762. 
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    Two kinds of poly(ethylene oxide) (PEO800 and PEO2000) macromer, which have different functionalities, were synthesized and polymerized in the presence of LiClO4 to form so-called “graft polymer network”.The PEO800 networks were completely amorphous and showed quite good ambient ionic conductivity (σ298K = 4.8×10-5 S · cm-1).However, the PEO2000 networks were crystalline and the conductivities for these polymer networks were lower than that of PEO800 systems.The relationship between the structure and morphology as well as the conductivity for those graft polymer networks has been discussed.
    Semi-Continuous Emulsion Copolymerization of Vinyl Acetate and Butyl Acrylate
    KONG Xiang-Zheng, YUAN Qing
    1993, 14(12):  1763-1765. 
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    Copolymerization of vinyl acetate and butyl acrylate was carried out by using semi-continuous emulsion process.Monomer conversion, particle size, particle number of latexes and micromolecular structure and thermodynamical properties of the copolymers were measured and compared with corresponding copolymers prepared through batch process.Results show that homogeneous copolymers and latex particles could be obtained by semi-continuous process and the properties of copolymers are very significantly different from those of batch copolymers.
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