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Table of Content

    24 April 1991, Volume 12 Issue 4
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    Articles
    Synthesis and Magnetism of Binuclear Nickel (Ⅱ) Complexes Using the Dianions of Chloranilic Acids as Bridging Ligands
    Hao Song-qi, Jiang Zong-hui, Liao Dai-zheng, Zhang Zhi-yong, Wang Geng-lin
    1991, 12(4):  427-430. 
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    Four new nicke(Ⅱ) complexes containing the dianions of chloranilic acids(CA) which act as the bridging ligand in these complexes were synthesized, namely [Ni(phen)2CA]3·H2O(1; phen=o-phenanthroline), [Ni2(phen)4CA](ClO4)2·2H2O(2), [Ni(bpy)2CA]·H2O(3; bpy=2,2'-bipyridyl) and [Ni2(bpy)4CA](ClO4)2·2H2O(4). They have been characterized by elemental analyses, IR, electronic spectra, ESR, susceptibility and variable-temperature magnetic susceptibility. Ni (Ⅱ) might display distorted octahedral coordination in the complexes. The variable-temperature magnetic susceptibilities of (2) and (4) were measured (4-300K). Based on the fact that as the temperature is lowered,μell, gradually increases until a maximum is reached and then decreased, considering the combined effects of single-ion zero-field splitting(D) and interdimer interaction(Z'J'), the observed data were fitted to those from a modified Heisenberg model. The obtained parameters: J=100. 34, Z'J'=- 0. 382 for the complex(2); J=69. 66, Z'J'=- 0. 382 for the complex(4). The results indicate that there is a ferromagnetic intracluster interaction (positive J) and antiferromagnetic interdimer interaction (negative Z'J')
    Studies on Coenzyme B12Model Compounds (Ⅲ)--The Synthesis of a Kind of New Alkylcobalt Schiff Base Complexes and Their Stabilities of the Co-C Bond
    Chen Hui-lan, Chen Guan-qing, Miao Bing-wen, Tang Wen-xia
    1991, 12(4):  431-435. 
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    In this paper a series of alkylcobalt complexes RCo(SB)Lin which R=CH3, C2H5, C3H7, n and i-C4H9); L=H2O; SB=bissalicylaldehyde 2,3-dimethyl-2,3-butadiamine, a kind of new coen-zyme B12model compounds, were synthesized and characterized.The complexes are unstable in methanol. Their Co-C bond breaked in the process of thermolysis or photolysis, the products of which were established by using UV-Vis spectrophotometry and spin trapping ESRtechnology. Also the splitting constants were quantitatively determined. It was concluded that both axial alkyl and equatorial ligand influence the stabilities of Co-Cbond.
    A FTIR Spectroscopy Study on Acidic Properties of HZSM-5 Zeolites with Different SiO2/Al2O3Ratios
    Wu En-yuan, Li Quan-zhi
    1991, 12(4):  436-440. 
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    Numbers of acid sites of a series of HZSM-5 zeolites with SiO2/Al2O3from 31. 4 to 137. 1 were determined using IR and NH3-TPD spectra. To calculate respectively the adsorption heats of Bronsted and Lewis acid sites, an equation, ln0/[(1 - 0)P]=Q/RT+C, was established with the help of Langmuir model, and the adsorption heats of Bronsted acid sites were calculated with this equation. It was found that there is a transition of the relationship between Al/u. c. and acidic concentration at Al/u. c.=3. 64. The calculated results show that the adsorption on Bronsted acid sites accords with Langmuir model and the adsorption heats of samples with different SiO2/Al2O3are almost the same, but the strength of Lewis acid sites is heterogeneous and adsorption on Lewis acid sites does not accord with Langmuir model. The extinction coefficients of Bronsted and Lewis sites of HZSM-5 zeolites were also determined, εB=7. 52×10 cm·mol-1and εL=1. 09×10 cm·mol-1.
    Structural Studies on Metal-Serum Albumin (Ⅴ)--Interactions Between Co(Ⅱ),Co(Ⅲ) Ions and HSA or BSA
    Zhou Yong-qia, Liu Hong, Che Yun-xia, Shen Pan-wen
    1991, 12(4):  441-443. 
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    The interactions between Co(Ⅱ) ion and HSAor BSAwere studied by means of charge transfer spectra. Both Co(Ⅱ) and Co(Ⅲ) have been found at the binding sites of albumin. The coordination environment of Co(Ⅱ) and Co(Ⅲ) are likely to be identical, which are octahedral type involving α-amino and carboxyl. So these ions are likely to locate at the N-terminal of albumin.
    Synthesis and Characterization of 5,12-Diphenyl-7,14-Dimethyl-1,4,8,11-Tetraazamacrocyclotetradecane-N,N"-Diacetic Acid and Its Lanthanide Complexes
    Chen Li-qin, Xu Ji-de, Ni Shi-sheng
    1991, 12(4):  444-446. 
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    Asimple stereospecific synthesis of c-meso-meso-5, 12-diphenyl-7,14-dimethyl- 1,4,8,11-tetraazamacrocycloteradecane-N,N"-4iacetic acid(H2L3) is reported. The 14 lanthanide (La through Lu, Pm excluded) complexes with this ligand have been prepared in methanol solutions by the interaction of H2L3with the rare earth chlorides. All these complexes in microcrystalline powder have constant stoichiometry, Ln(H2L3)CIs·nH2O, irrespective of the metal to ligand ratio used in the preparation. These compounds are characterized by elemental analysis, thermoanalysis, conductivity measurements and IRspectra.
    Oscillopolarogram Based on if～Curve
    Qi Hong, Gao Hong
    1991, 12(4):  447-449. 
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    This paper presents a method in which charging current is taken off from ACoscillopolaro-graphy. Some Instrumental devices controlled by micro computer were designed. With these devices we determined the i1～E and ip～C curves of T1+, In3+, Cd2+, Pb2+, Zn2+ions. Where ifis the faradic current, ipis the peak current and Cis the concentration of depolarizer. The determining sensitivity of ACoscillopolarography was improved.
    Studies on the Complex States of Heavy Metal Ions in Seawater (Ⅰ)--2nd Order Derivative Convolution Stripping Voltammetry at HMDE
    Mo Jin-yuan, Cai Pei-xiang, Zheng Jia-long, Zheng Pei-sheng, Liang Hao-bo
    1991, 12(4):  450-453. 
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    The relationship between the complex stability constants and peak potential of 2nd order derivative convolution anodic stripping voltammetry at HMDE has been established. The expression is as follows: The shift of peak potential varies with the concentration of the ligand, the differences between the peak potential of free metal ions and that of the complex ions are measured at constant ionic strength and various concentrations of the ligand.
    Studies on the Photochemical-Fluorimetric Method (Ⅱ)--Detarmination of Trace Chromium (Ⅵ) in Water by Using Catalytic-Kinetic Photochemical Fluorimetry
    Guo Xiang-qun, Xu Jin-gou, Shen Kun
    1991, 12(4):  454-457. 
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    Anew catalytic-kinetic photochemical fluorimetry for the determination of Cr(Ⅵ) in water is discrtibed. The method is based on the catalytic effect of Cr(Ⅵ) on the photo-oxidation reaction of Rivanol. Abetter linear relationship curve was obtained over the range of 1-200 ng/mL Cr(Ⅵ) and the relative standard deviation of the determination was 2. 3. This method has been applied to the direct determination of trace amounts of Cr(Ⅵ) in water with a good result. The mechanism for the photo-oxidation reaction of Rivanol catalyzed by Cr(Ⅵ) was discussed and a kinetic equation was given.
    The Equation for Chronoamperometric Current at Finite Disk Electrodes
    Zhang Zu-xun
    1991, 12(4):  458-461. 
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    Asimple analytical expression for the chronoamperometric current at finite disk electrodes, which is accurate at any time, is given by:it=4nFDRT0θ/(1+θ ) f(Υ)=0.7852+0.8862τ-1/2+0.2148τ1/2/(1.128+τ1/2) Where n is the number of electrons involved in the oxidation of substance R, Fthe faraday. DRis the diffusion coefficient of R, τ0 the radius of the disk electrode, CR*is the bulk concentration of substance R, t is the time and τ=4DRt/r02r0, 0=expnF(E-E0)/RT].
    Catalytic Spectrometric Determination of Trace Silver Via Using Oxidation of Azophloxine with Potassium Persulfate
    Zheng Zhao-sheng, Ling Lin
    1991, 12(4):  462-463. 
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    Based on the catalytic effect of Ag(Ⅰ) on the oxidation of azophloxine with potassium per-sulfate in the presence of α,α' -bipyridyl as an activator, a new catalytic spectrophotometric method for determining trace amounts of Ag(Ⅰ) is studied. The limit of detection for Ag is 1. 0×10-4μg/ mL. The linear range of determination of silver is 2. 0×10-4-4. 0×102μg/mL. The method has been used to determine trace Ag in ores with satisfactory results.
    Fluorescence Method for Screening Anticancer Drugs
    Zhang Kai-cheng, Chen Jiang-hua, Li Zhi-liang
    1991, 12(4):  464-465. 
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    Anew method for screening anticancer drugs is proposed. Ethidium bromide(EthBr),a fluorescent dye, can insert into the double helix chains of DNA and increase the intensity of fluorescence. So do some drugs. When this drug is added to the EthBr-DNA fluorescent system, the fluorescence intensity will be decreased. We find that the drug which van decrease 50% in fluorescent intensity of EthBr-DNA system can act with tumour. The fluorescence method is in accordance with the test of S-180 in mice and has more reliability than the methylene blue test.
    Effects of CTMAB on the Fluorescence Spectrum of HPTS and the Inclusion Complexation of β-CD
    Li Long-di, Tan Yu-qing
    1991, 12(4):  466-468. 
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    The fluorescence spectrum of 8-hydroxy-1, 3, 6-pyrenetrisulfonate(HPTS or HOPSA) in the presence of CTMAB or/and β-CD were studied. The results show that the fluorescence spectrum of HPTSis largely changed as the cetyl trimethyl ammonium bromide (CTMAB) gradually is increased. When β-CD is gradually added into the system of HPTS-CTMAB, however, the changes described above were inverted. These changes were discussed based on the comparisons of fluorescence spectra for HPTSin various medium solutions, 1H NMR spectra of HPTSor/and CTMAB solutions and the inclusion complexation between CTMAB and β-CD. We consider that the main reason for above effects is relative to the electric interaction between the anion HPTS and cations of CTMAB and the properties of the micro-environment round HOPSAmolecule.
    The Determination of Luminescence-Labelled Agent ABEI by Electrogenerated Chemiluminescence
    Yao Qing, An Jing-ru
    1991, 12(4):  469-470. 
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    The electrogenerated chemiluminescence of ABEI and ABEI-HCG in H3BO3-KCl-Na2CO3buffer solution at pH 11. 06 was studied. Co(Ⅱ)(200～600 μg/L) is capable of catalyzing the ABEIluminescence when a pulse potential is applied to the electrodes. Antibody of HCGis combined with ABEIto obtain ABEI-IgG. The detection limit of ABEIand ABEI-IgGare 2. 0×10-11mol/Land 2. 1×10-10mol/L, respectively. The concentration of ABEI, from 1.0×10-10to 5.0×10-7mol/ Lis in a linear relationship with the intensity of light.
    Molecular and Crystal Structures of (μ-σ,π-Trans-C8H5CH=CH)(μ-C2H5S)Fe2(CO)6
    Song Li-cheng, Hu Qing-mei, Zhou Zhong-yuan, Hu Guo-zhi
    1991, 12(4):  471-474. 
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    (μ-CO)(μ-C2H5S)Fe2(CO)6was prepared from [(μ-CO)(μ-C2H5S)Fe2(CO)6] Et3NH and transor trans-β-C6H5CH=CHBr.Its crystal belong to minoclinic space group Cc.The parameters are:a=1.8053nm,b=1.0436nm,c=1.9045nm;β=93.68°;Dc=1.66g/cm3;Z=8;R=0.0413.Bond Length of Fe-Fe is 0.2542nm.The length of C=C double bond of C=Cdouble bond of C6H5CH=CH ligand is 0. 1358 nm. Ethyl group is attached to bridging sulfur atom by an e-type of bond.
    A Investigation of Cyclic Tri-hydrogen Group
    Liu Jing-jiang, Huang Chang-hua, Lu Liang-de, Wang Yan-zhong
    1991, 12(4):  475-478. 
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    In this paper the compounds containing cyclic tri-hydrogen group are investigated by FTIR, PMR, GCand ab initiu calculation. Triformol as a model molecule of cyclic 3Hg roups was calculated by ab initio method. It is explored by the results of ab initio electrostatic potential calculations that there is a positive electropotential region at the direction of the three axial hydrogen atoms. This points out the collective effect of the cyclic 3Hgroup and the cause for easily understanding its larger interaction with the atom carrying negative.FTIRspectra of solution of diphenyl ketone in hexane and paraldehyde are determined. The peak of streching mode of C=O group shifts 7. 9 cm-1to the low frequency in the latter case. PMR peak of CHfor paraldehyde in acetone solution shifts 0. I 5 ppm up to the high field in comparison with that in CC14and CHC13solution.Evidences of 3Hgroup for 666 are also obtained by FTIR, PMR. All the experimental evidences support the results of computation and confirm the existance of cyclic 3Hgroups.
    Synthesis of Novel Non-ester Pyrethroids and Studies on Their Biologic Activity (Ⅰ)
    Li Ying-fu, Zhou Chang-hai
    1991, 12(4):  479-481. 
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    Ten N-aryl-3-methyl-3-(p-ethoxyphenyl)butyramide were synthesized and screened as new pyrethroids. The structures of the compounds were confirmed by 1HNMR, IRand elemental analysis. All of the compounds showed a moderately insecticidal activity and a knockdown effect against house-flies. For different compounds, the mortality is about 5%～30% and the knockdown percent is about 10%～42. 5% at the dose of 0. 952 μg/housefly.
    Stereoselective Syntheses of　1-O-Aroyl-β-D-Glucopyranose Tetraacetates and 1-O-Aryl-D-Glucopyranose
    Wang Shi-yu, Chen Yun-dong, Li Cui-juan, Jin Sheng
    1991, 12(4):  482-484. 
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    l-O-Aroyl-β-D-glucopyranose tetraacetates (Ⅰ-Ⅶ) were obtained by the condensation of tetra-O-acetyl-α-ZJ-glucopyranosyl bromide with aromatic acids in K2CO3-Me2CO　at room temperature. Exclusive production of β-D-anomers was confirmed by measurement of their specific rotation and also by observing their 1R　and NMR　spectra. Reaction of α-acetobromoglucose with methyl o- or p-hydroxybenzoate in aq. KOH-Me2CO　gives the corresponding β-D-glucopyranoside(Ⅶ-Ⅷ). Control of the stereochemistry in obtaining α-D-anomers (Ⅷ-Ⅸ) could also be satisfactorily achieved by employing penta-O-acetyl-D-glucopyranose and methyl o-or p-hydroxybenzoate in ZnG2-AcOH-Ac2O.
    Synthesis of Some Novel Pyrethroids Containing Pyrimidines and Their Biological Activity
    Chen Fu-heng, Yu Zhong-sheng
    1991, 12(4):  485-487. 
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    Eighteen novel pyrethroids containing pyrimidines have been synthesized. Their structures were confirmed by IR, 1H NMR and elementary analysis. The preliminary biological test shows that some of the novel compounds are effective against housefly.
    Synthesis and Structure of 1,1'- (Tetramethyldisilandiyl) η5-Dicyclopentadienyl Zirconium Dibromide
    Wang Ying, Zhou Xiu-zhong, Yao Xin-kai, Wang Hong-gen
    1991, 12(4):  488-490. 
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    The title compound was prepared by acidolysis of μ-O-bis[1, 1'-(tetramethyldisilandiyl) η5-dicyclopentadienyl chlorozirconium] with concentrated hydrobromic acid. It' s structure was confirmed by X-ray diffraction method. The crystal is monoclinic, space group P21/n, with α=1. 1880(1) nm, 6=1.8739(2) nm, c=0. 8370(1) nm, β=98.37(1)°, V=1.8434 nm3, Z=4, final R=0. 054. Some selected bond lengths and bond angels have been compared with related compounds.
    Alkylation of Isopropyl 4-Chlorobenzenesulfonyl Acetate Under Phase Transfer Catalysis Condition
    Zhang Li-kang, Zhang Zheng
    1991, 12(4):  491-493. 
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    Alkylation of isopropyl 4-chlorobenzenesulfonyl acetate (1) with alkyl halides R1X(R1=n-Bu, CH2=CHCH2, p-CiC6H4CH2, C6H5CH2CH2, C6H5CH2; X=Cl, Br) in the system of K2CO3/DMF was carried out under solid-liquid phase transfer catalysis and five α-substituted products (2a-e) were obtained. The monoalkylated products directly reacted with active alkyl halides R2X (R2: CH2=CHCH2, p-ClC6H,CH2, C6H;CH2; X=Cl, Br) in one-pot to give dialkylated compounds 3n-t. This method has the advantage of moderate reaction conditions and high yields.
    The Structure and Excited State Proton Transfer Process of 9-Hydroxyphenalenone
    Feng Ji-kang, Liu Tian-hua, Li Zhi-ru
    1991, 12(4):  494-497. 
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    Using INDO series methods, the structure and excited state proton transfer process of 9-hydroxyphenalenone have been studied, and the potential energy surfaces of ground state and excited states, barriers, transition states have been gotten. The mechanism of reaction and the possibility of applications have been discussed too.The stable structure of 9-hydroxyphenalenone should be C8, structure. The fluorescence spectra correspond S2→S0From the characters of ground state and excited state barriers, we think it hopeful to use this molecule and its derivatives for molecular electronic devices.
    A Study of Kinetics of Oxidation Reaction of Uranium (Ⅲ) with Oxygen in the Air
    Zhou Zu-ming, Zhao Lei-hong, Qin Qi-zong
    1991, 12(4):  498-501. 
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    The oxidation reaction of uranium (Ⅲ) in the hydrochloric acid solution with oxygen in the air was investigated. It was found that the oxidation rate was proportional to [U(Ⅲ)] and [Cl-]-1/2in hydrochloric acid solution and [O2](6)1/4 in air. Moreover, the rates were nearly independent of [H+] in the range of 0. 2-2 mol/L. The oxidation rate increased with increasing temperature. The apparent activation energy was found to be 3-1. 3 kJ/mol in the temperatures of 10 to 40℃ region. It is suggested that the reaction may be a catalytic oxidation process.
    Synthesis, Characterization and Catalytic Activity of Saponites and Their Pillared Analogues
    Liu Zi-yang, Jiang Da-zhen, Zhang Ai-jun, Fan Shu-guang, Min En-ze, He Ming-yuan, Zhao Xue-bin
    1991, 12(4):  502-505. 
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    Saponite clays (S) were synthesized by hydrothermal mathod. The pillared saponite clays (Al-CLS) were prepared by intercalating the saponite with aluminum hydsoxy polymer [A113O4(OH)24·(H2O)12]7+. Saponite clays and their pillared clays were characterized with XRD, 27A1 and 29SiMASNMR and the amount of adsorped pyridine. The catalytic activity of saponites and their pillared anologues were evaluated for cumene cracking. The results show that the synthetic products were of good crystallinity and the aluminum amount in the tetrahedral layer of T-O-Tsheet of saponite could be controlled by synthetic condition. The crosslinking density is correlative with aluminum amount in the tetrahedral layer. Compared with saponite, the activity for cumene cracking on the Al-CLS is higher but activity decay is lower. The catalytic activity of the sample is correlated with the number of strong acid sites on the surface where the probe molecule can arrive.
    Investigation on Purification of Polluted Water Containing Oil by Magnetofluid
    Kang Hong-ye, Wang Yun-jun, Shi Zhan, Gao Guo-rong, Zhao Mu-yu
    1991, 12(4):  506-509. 
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    The oil content in the polluted water can be decreased from hundreds ppm to dozens ppm throuth treating the emulsified water containing oil with magnetofluids or Fe3O4fine particles; The influences of properties of the fine particle and the surfactant on the purification were studied. The mechanism of waste water purification with Fe3O4fine particles and magnetofluids is also proposed.
    Formation of Excited CH Fragments and Its Kinetic Study
    Guo Jing-zhong, Gu Yue-zhu, Liu Chuan-pu, Fang Xiao-dong, Yin Yong-jia, Cao De-zhao, Liao Chang-huan
    1991, 12(4):  510-513. 
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    In this paper the energy transfer reaction of He(23S) with CHDr3and CH2Br2has been investigated by the flowing afterglow technique. Based on the emission spectra of excited fragments we estimated the relative populations and formation rate constants of CH(A, B, C). The rotational distribution of CH(A2△, v'=0) and reaction mechanism were discussed.
    Studies on States and Dispersion Rules of Active Component on Supported Oxide Catalyst Using TPR,XRD and Chemical Analysis Methods
    Tang Xin-shuo, Huang Shao-ming, Jin Song-shou
    1991, 12(4):  514-518. 
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    The methods of TPR, XRD phase quantitative analysis and chemical analysis were used in this paper to study systematically the existing states, maximum degree of dispersion and dispersion rules of NiOsupported on various supports including γ-Al2O3, SiO2, TiO2by impregnation, and compare the results of the three methods in order to provide a simple and effective method for studing solid-solid adsorption.
    Studies on Coordination and Remodifination of POAP Film
    Chen Yan-zhen, Zhang Ai-qiang, Tian Zhao-wu
    1991, 12(4):  519-522. 
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    In this paper the coordination and remodification of poly-o-aminophenol (POAP) film are reported. Fe2+,Co2+and Ni2+can be separated and exchanged by POAPfilm. POAP-Fe(CN)63- film has a stable redox current peak, a small potential drift and a good repeatability, and it can be used as a new model reference electrode. The remodified POAP film also has excellent pHcharacters.
    Roles of Ce in Potassium-Promoted Iron Oxide Based Catalysts for Dehydrogenation of Ethylbenzene to Styrene
    Zhu Yi-xian, He Dan-yun, Lin Ren-cun, Chai Qing-die
    1991, 12(4):  523-527. 
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    The roles of cerium in Fe-K-Ce mixed oxide catalysts were investigated. Cerium increases very obviously the activity of the catalysts with high content of potassium but only had a little influ ence on that of the catalysts with low content of potassium in the case of this work. No evident influence of cerium on the selectivity of these catalysts was observed. From XRD, XPS, EDAX. TEM and the activity tests of these catalysts, it was found that cerium nitrate is a better precursor of the cerium promoter than CeO2because Ce promoter would be located on the surface of the catalysts as micro crystals when the nitrate is used to prepare the catalysts and it would tend to be covered by iron ox ide if the CeO2is used. According to the viewpoints that K2Fe2O4is the active phase of the potassium-promoted iron oxide catalysts and that both the direct catalytic dehydrogenation and the catalytic deby drogenation by oxygen-transfer pathway are included in the process of the dehydrogenation of ethyl benzene to styrene, it is suggested that although the K2Fe2O4is a good active phase for the direct dehy drogenation, it is not a good one for the oxygen-transfer dehydrogenation because of the poor mobility of the lattice oxygen in the K2Fe2O4and that the role of the Ce promoter is transforing oxygen from steam to the K2Fe2O4and creating many active sites for the oxygen transfer dehydrogenation. There fore, the contribution of the oxygen-transfer dehydrogenation mechanism in the overall Eli dehydru genation and then the activity of the overall EBdehydrogenation arc increased. Our experimental re suits could be satisfactorily explained based upon these suggestions.
    A New Kind of Surfactant:Long-Chain-Alkyltriphenylphosphonium Salt (Ⅰ)--The Synthesis of n-Dodecyltriphenylphosphonium Bromide and the Preliminary Study of Its Surface Activity in Aqueous Solution
    Jiang Yun-bao, Xu Jin-gou, Chen Guo-zhen(K. C. Chen)
    1991, 12(4):  528-531. 
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    The synthesis of n-dodecyltriphenylphosphonium bromide was described and its surface activity in aqueous solution was studied with the fluorescent probe method. Using pyrene as a fluorescent probe based on the relativity between the intensity ratio of the third vibronic band to the first vibronic band in its monomer fluorescence spectrum and the polarity of its environment, the CMC of the newly synthesized surfactant was determined to be 2. 08×10-3moI/L, and the micropolarity of the micellar core was obtained to be 16. 1 (expressed by the dielectric constant).
    The Charge Transfer Mechanism at the Interface of the Electrodeposited n-CdSe/Polysulfide Solutions
    Tang Rui-ping, Sun Bi-rou
    1991, 12(4):  532-536. 
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    From the determination of the flat-band potentials of the n-CdSe anodes in various polysul-fide solutions, the adsorption of OH-ions on the anodes under different conditions and the preferential adsorption of sulfide ions in S-, S2-, OH-electrolytic solutions are clarified. The charge transfer mechanism at the interface of n-CdSe in the pojysulfide solution is elucidated with the help of rotating ring-disk electrode measurements.
    Model of Electrochemical Hydrogen-Permeation in Nonequilibrium Entry Condition
    Wu Hui-huang
    1991, 12(4):  537-540. 
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    A mathematical model is proposed for the electrochemical hydrogen-permeation under the nonequilibrium entry condition, and the corresponding expressions for the permeation-current transients are derived. The new model is characterized by the boundary condition at the cathodic side of metal specimen, the so-called "constant hydrogen concentration" and "constant hydrogen flux" boundary conditions in the literature are considered as its special cases. It is pointed out that the kinetics of entry process can be determined by the relation between the steady-state permeation currents and the specimen thickness. The dependance of apparent values of hydrogen diffusion coefficient on the cathodic polarization is also discussed.
    The Effect of Electrical Field Modulation on Surface Photovoltage Spectroscopy
    Wang De-jun, Jiang Lei, Li Ping, Liu Xue-ying, Bai Yu-bai, Li Tie-jin
    1991, 12(4):  541-542. 
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    A new method of photovoltage measurcnment, Field-Modulated Surface Photovoltage Spec-troscopy(FMSPS), has been created by combining the principle of field-effect with the photovoltage technique. Some materials are investigated by using FMSPS. The results show that the method will be helpful to attestation and analysis of surface photovoltage spectroscopy.
    The IRC Method in Chemical Reactions (Ⅸ)--Reaction Ergodography for the Dehydrogenation of Silylthiol
    Han Yun-zhu, Zhao Cheng-da, Chen Bin
    1991, 12(4):  543-544. 
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    The reaction ergodography was performed for the dehydrogenation pathway of silylthiol, and the comparing study was made for this result with that of the dehydrogenation of methanethiol. It reveals both of these two reaction pathways to be concerted, but nonsynchronous. The activation energy is favour to the dehydrogenation of silylthiol, however, the activation entropy and frequency factor are favour to the dehydrogenation of methanethiol.
    A Study on the Inclusion Phenomena of Cedrol with Phenol Type Compounds
    Guo Wen-sheng, Lu Zhai-gao, Guo Chang-wu, Fu Xing-ji
    1991, 12(4):  545-547. 
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    It is reported that cedrol(1) complexed with phenol type compounds, such as phenol(2), o-cresol(3), w-cresol (4), p-cresol(5) and formed new clathrate compounds. Melting points of these crystal clathrate compounds, (l)+(2), (l)+(3), (1)+(4) and (1)+(5) are 54-56℃, 43- 44℃, 48-49℃ and 56-58℃, and their molar ratios(cedrol/phenol, in the same sequence) are 1: 1, 1: 1, 1: 0. 79, 1: 0. 77, respectively. The results of X-ray and IRof the inclusion compounds were given.
    Studies on the Kinetics of the Metal Exchange Reaction Between o-Hydroxybenzylamine-N,N,O-Triacetic Acid Complex of Mo (Ⅵ) and Cu2+
    Wang Yong-wei, Zhang Hua-lin
    1991, 12(4):  548-550. 
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    The kinetics of the metal exchange reaction between o-hydroxybenzylamine-N,N,O-tri-acetic acid(H3L) complex of molybdenum (Ⅵ) and cupric ion has been studied by means of stopped-flow technique over the pHrange of 3. 3l-4.16 at 10℃, I=0. 5 mol/L(NaCl). The variation of the pseudo-first order rate constant kobs with [H+] and CCu indicates a SN1 IP mechanism and the following rate equation and reaction scheme were derived on it:(这里有图片199104-500-3.gif).
    Photon Correlation Spectroscopy Study of 4-Arm Star Polystyrene Molecular Diffusion in Good and θ Solvents
    Li Jun-bai, Ma Rong-jiu, Yin Rui, Lin De-hou, Shen Jia-cong
    1991, 12(4):  551-554. 
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    The paper reports the concentration and temperature dependence on diffusion coefficients for 4-arm star polystyrene in a good and a 0 solvents (THF and CH)studied by cumulent method. In0solvent, when T>0 or T<0, the molecular diffusion behaves as in a good solvent and a poor solvent. Extrapolating concentration to zero, we obtained the molecular diffusion coefficients at infinite dilution at various temperatures. With Stokes-Einstein equation, we gave the hydrodynamic radii of 4-arm star polystyrene in different solvents. InDwas plotted against 1/T, we got the values of diffusion activation energy EnTHF=7. 07 kJ/mol, EnCH=14. 06 kJ/mol, for 4-arm star polystyrene in THFand CHrespectively.
    The Synthesis and Antitumor Activity of 5-Fluorouracil-N1-Carbonyl Aminoacids and Oligopeptides
    Zhuo Ren-xi, Liu Gao-wei, Peng Pu-ping
    1991, 12(4):  555-559. 
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    Seven5-fluorouracil-N1-carbonyl amino acid benzyl esters(1a-g) were respectively prepared by the reaction of 5-fluorouracil-N1-carbonyl chloride with benzyl esters of glycine, valine, leucine, phenylalanine and bisbenzyl esters of aspartic and glutamic acids. These esters were then hydrogenated to obtain the corresponding5-fluorouracil-N1-carbonyl aminoacids (2a-c). 2Cand 2ewere further coupled with aminoacid methyl esters or dipeptide methyl esters by DCC-mediated coupling reaction to afford 5-fluorouracil-N1-carbonyl dipeptide or tripeptide methyl esters (3a-d, 4a,b). 5-Fluorouracii-N1-Carbonyl dipeptide methyl esters (5n-d) were also obtained directly by the reaction of 5-fluorouracil-N1-carbonyl chloride with dipeptide methyl esters. The antitumor activity of some of the above compounds was tested against EAC or S180in mice.
    Preparation of Microparticles of Narrow Distributed Diameters and Their Usage in Amino Acid Analysis
    Wang Bu-sen, Zhang Yu-ge, He Bing-lin
    1991, 12(4):  560-563. 
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    The narrow distributed polymeric microparticles with diameters of,3-10 μm were prepared by suspension polymerization when PVA and DBS-Na were used as the mixed dispersant with the rate of stirring 1500-2000 r/min. The effects of the conditions of the polymekrization reactions on the diameters and their distributions of the microparticles were examined. Thereafter, the authors studied the properties of the sulfonated polymeric microparticles which were used as the stationary phases of an amino acid analyzer.
    Studies on Mechanical Properties of Cryo-Hydrogel
    Huang Guang-lin, Feng Yu-ding, He Jian-ye, Lu Zhong-heng
    1991, 12(4):  564-567. 
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    In this paper,a cryo-hydrogel elastomer, containing, more than 85% water, was prepared by freezing aqueous solution of poly(vinyl alcohol)(PVA). The mechanical properties of cryo-PVA-hydrogel were studied by one way extension and compression. The experimental results show that the mechanical strength is increased with increasing the polymer concentration and the freezing time. The relationship between the elastic modulus and the gel concentration is in accordance with the scaling law It is suggested that the mechanical strength of the cryo-hydrogel is based on the contribution of physical crosslinking networks.
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