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    24 August 1995, Volume 11 Issue 3
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    Articles
    Studies on the Steroids of Marine Sponge(Ⅳ)──Steroids from the Marine Sponge Biemna Sp.
    ZENG Zhi, SU Jing-yu, ZENG Long-mei
    1995, 11(3):  185-188. 
    Abstract ( )   PDF (2325KB) ( )  
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    Reported here is identification of a 7-en-sterol and a 5-en-sterol which containsa cyclopropane ring in its side chain and is separated from the South China Seasponge Biemna sp..This leads to the isolation and identification of twelve sterols inthis marine sponge by using gas chromatography-mass spectrometry (GC-MS)analysis.The occurrence of 7-en-sterol and 5-en-sterol with a cyclopropane ring inits side chain from the south China Sea sponge was first reported here.
    Amperometric Glucose Sensor with Tetrathiafulvalene as an Electron Transfer Mediator
    SUN Chang-qing, YANG Xu, LUAN Chai-xia, GAO Qian, XU Hong-ding
    1995, 11(3):  189-194. 
    Abstract ( )   PDF (2411KB) ( )  
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    A glucose oxidase (GOD) electrode with tetrathiafulvalene(TTF) as an elec-tron transfer mediator is described.By means of Nafion, TTFwas modified on aglassy carbon(GC) electrode surface, and glucose oxidase was then immobilized onthe TTF-Na fion film, forming a GOD-TTF-Na fion enzyme electrode.Characteris-tics of the sensor are shown by cyclic voltammetry and constant potential measure-ments.The sensor responds rapidly to glucose, the time required to reach 95% of the steady-state current is less than 60s.The sensor displays a sensitive catalyticcurrent response to glucose and can be operated in a potential range in which theoxidation of common interfering species, such as ascorbic acid and uric acid, doesnot occur.The sensor is stable for more than 30 days at 4℃ and plasma glucose assays were correlated with spectrophotometry(n=10, r=0.995).
    ESR Studies on N-Alkylphenothiazine Radical Cation Salts
    GUO Qing-xiang, LIU Bo, LIU You-cheng
    1995, 11(3):  195-201. 
    Abstract ( )   PDF (2423KB) ( )  
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    The stable radical cation salts of phenothiazine and N-alkyl-phenothiazine(alkyl =methyl, ethyl, isohutyl, isopentyl and benzyl) hexachloroantimonate,per-chlorate, and iodide were prepared by means of one-electron oxidation with 2,2, 6,6-tetramethyl- 4-acetoxypiperidine oxoammonium hexachloroantimonate, perchloricacid, hydrogen peroxide, and molecular iodine, respectively.The radical cationswere characterized using ESRspectroscopy.Conformational analysis based on theESRparameters suggests that the radical cations adopt a planar configuration withthe nitrogen radical as the center.
    An Explanation on the Electron Ionization Mass Spectra of Crown Ethers by MNDO Computational Method
    YUAN Hu-shan, TANG Ming-sheng, WU Yang-jie, TU Ya-ping, MA Fu-qin
    1995, 11(3):  202-205. 
    Abstract ( )   PDF (2326KB) ( )  
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    The bond lengths and bond orders of four kinds of chemical bonds in crownethers(15) were calculated based on the model molecules using MNDO method.With the calculation results, some predictions to the EImass spectral fragmenta-tion behaviour of crown ethers are suggested.The EI mass spectra of studied crownethers are in satisfactory agreenient with the predictions.
    Studies on Systems of Lithium and Potassium Halides from Salt Lake and Bittern Resources ( V)──The Quaternary Reciprocal System Li+,Br-,I--H2O and Boundary Ternary System NH4Br-NH4I-H2O at 25℃
    TANG Zong-xun, ZHANG Feng-xing, GUO Zhi-zhen, HUANG Jing-ying, HAO Zhi-feng
    1995, 11(3):  206-214. 
    Abstract ( )   PDF (469KB) ( )  
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    The solubilities, refractive indexes of saturated solutions of the quaternary re-ciprocal system Li+,NH4+|| Br-,I--H2O and its boundary ternary system NH4Br-NH4I-H2O at 25℃ have been investigated using isothermal method.In the titleternary system which belongs to Roozeboom Ⅳ type, there are two limited solid so-lutions.Entering into the quaternary system, the region of the solid solutions re-duces and disappears with the increase of Li+, and finally, the quaternary systembecomes a simple system.
    Studies on HEPES Stabilizing M Intermediate of Bacteriorhodopsin
    FU Xue-qi, LI Zheng-qiang, WANG Jin-dui, WANG BaO-huia, LI Bo-fu, LI Tie-jin
    1995, 11(3):  215-218. 
    Abstract ( )   PDF (270KB) ( )  
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    HEPES has proved to stabilize Mintermediate of Bacteriorhodopsin.Absorp-tion and Raman spectra showed that there was a more stable form of Mintermedi-ate in BR-HEPES solution.It was found by SPSthat there were two main interme-diates .M and O, existing in BR-HEPES solution.
    Theoretical Studies of H2O Adsorption on Pure and Pt Loading TiO2 (Rutile)(110) Surfaces
    XU Wei-xing, Schierbaum, K. D., Goepel, W.
    1995, 11(3):  219-227. 
    Abstract ( )   PDF (582KB) ( )  
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    The binding energy, density of states were calculated for H2O adsorption on aseries of model clusters, such as TiO5-6, Ti4O15-16, 2Pt/Ti4O15-16, etc. using Gaussian 90(ab initio) program.Based on the calculation results, the behaviour of water ad-sorption on these clusters is discussed.It was found that H2O is adsorbed chemical-ly on TiO2(110) surface(binding energy: 2.7 eV-4.7 eV) and Pt loading can pro-mote the water adsorption process and the hole trapping in the adsorbed water.Thesimple one-step kinetic mechanism is proposed for the water cleavage on TiO2 underirradiation.
    Electric Anisotropy and Two-dimensional Energy Band of Undoped and Heavily Doped Polyacetylene
    HUANG Zong-liao, WANG Xiu-jun, TONG La-ga, LI Bai-tao, WANG Rong-shun, BEI YOng-ping
    1995, 11(3):  228-231. 
    Abstract ( )   PDF (2247KB) ( )  
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    Based on the known crystal data, we used the EHMACC(EHMO/CO) methodto calculate the twotlimensional energy band of both undoped and heavily iodine-doped polyacetylene (PA).The results show that (1) I-doping obviously reducesthe niagnitudes of Eg, Eg⊥; (2) in the conducting process along the direction per-pendicular to PAchain, the P-type AOof iodine plays a very important role, i- e.,the conducting bridge to transport the charge between the two neighbor PAchains.I-doping reniarkably increases σT value while the conducting process will reduce theratio magnitude of σ/σ⊥.Therefore, heavily I-doping makes PAchange fromsimeconductor to conductor which obviously has 2-D conductive ability.
    The Electronic Structures of Dimeric Diboroxane and Aldiminoborane
    WANO Zhi-zhong, XU Ming, YANG Zhong-zhi
    1995, 11(3):  232-237. 
    Abstract ( )   PDF (2419KB) ( )  
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    We have studied the electronic structures of dimeric diboroxane and aldiminob-orane by nieans of STO-3G ab iuitio SCF method.The energies and the componentanalysis of niolecular orbitals near to frontier orbital have been given.By both Koopman's theoreni and △Escf mietliod we have calculated the ionization potentialsof 8 higlier occupied orbitals and discussed the electron relaxation effect on IP's cal-culations and the charge distribuuons for the two molecules.
    Rare Earth Polymer Complex Catalyst for Ring Opening Polymerization of Epichlorohydrin
    SHEN Zhi-quan, JIANG Dong-lin, ZHANG Yi-feng
    1995, 11(3):  238-242. 
    Abstract ( )   PDF (329KB) ( )  
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    A novel complex composed of chitosan(CS) and neodymium(Nd) was preparedand the ring opening polymerization of epichlorohydrin(ECH) with a new catalyticsystem comprising this new rare earth polymer complex(CS·Nd) has been suc-cessfully carried out for the first time.It has been found that the new catalytic sys-tem composed of CS·Nd-AI (i-Bu)3-methyl benzoxylate( Ⅲ) is an excellent cata-lyst for the polymerization of epichlorohydrin which shows a catalytic activity 60 times higher tlian that of conventional rare earth catalyst.Under the following re-action conditions: Nd=1 ×10-6 mo1/g monomer, A1/Nd= 60 molar ratio, Ⅲ/A1=0.6 molar ratio, the monomer conversion and PECH molecular weight are as highas 92.9% and 28.2 × 105 respectively and the polymer prepared has a low crys-tallinity.The kinetics investigation revealed that the polymerization has a short in-duction period of several minutes and the rate of polymerization is of first orderwith respect to the monomer concentration and the catalyst concentration.The acti-vation energy of the polymerization reaction was found to be 25.5 kJ/mol which islower than that of conimon rare earth catalvst.
    Ionic Conduction of A Novel Comb Polvmer Electrolyte Based on Maleic Anhydride Copolymerwith Oligo-oxyethylene Side Chains
    DING Li-ming, LIN Yun-qing, YANG Cheng-zong
    1995, 11(3):  243-249. 
    Abstract ( )   PDF (2489KB) ( )  
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    A comb-shaped polynier (BM350) with oligo-oxyetliylene side chains of thetype-O (CH2CH2O)7CH3 was prepared from methyl vinyl ether /maleic anhydridecopolymer- Honiogeneous aniorplious polymer electrolyte cornplexes were madefrom the conib polymer and LiCF3SO3 by solvent casting from acetone, and theirconductivities were nieasured as a function of temperature and salt concentration.Maxiniuni conductivity close to 5.08 ×10-5 Scm-1 was obtained at room tempera-tureancl at a [Li]/[EO] ratio of about 0.12.The conductivity which displayednon-Arrheni us behaviour was analyzed using the Vogel-Tammann-Fulcher equationand interpreted on the basis of the configurational entropy model.The results of mid-IR sliowed that the coortlination of Li+ to side chains made the C-O-C bandbecome broader and shift sliglitly- X-ray photoelectron spectroscopy analysis indi-cated that the oxygen atonis in the two situations could coordinate to Li+ and thiscoortlination resulted in the reduction of the electron orbit binding energy of FandS.
    Studies on the Mechanism of Methyl Methacrylate Polymerization Initiated by Volatile and Nonvolatile Products of Methyl Methacrylate Plasma
    LIU Xiao-dong, LI Jing, MA Yu-guang, SHEN Jia-cong
    1995, 11(3):  250-255. 
    Abstract ( )   PDF (2406KB) ( )  
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    The volatile (VPP) and nonvolatile (NVPP) products of methyl methacrylate(MMA) reaction in plasma chamber were used as initiators of MMA polymeriza-tion.From the structure analyses of the two initiators, the measurement of poly-merization kinetics, and the determination of the molecular weight of resultantpolymers, we found tliat MMA polymerization initiated by NVPP is a typical radical mechanism of polymerization which undergoes a process of continuous initiationand bifunction termination, while VPP-initiated polymerization suggested a mech-anism of living radical process fpolymerization with instantaneous initiation, chain-transfer to monomer, without termination).
    Catalytic Oxidation of Cyclohexene with Molecular Oxygen on Hydrotalcite-like Compounds
    GUO Jun, WANG Ning, JIAO Qing-ze, JIANG Da-zhen, YANG Guang-hu, MIN En-ze
    1995, 11(3):  256-258. 
    Abstract ( )   PDF (2255KB) ( )  
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    Synthesis and Structure of Schiff Base Complex Containing 'Cu4O'Core
    MA Chang-qin, YU Zheng-gang, ZHANG Wen-xing, WANG Xu-ning, JIANG De-hua
    1995, 11(3):  259-263. 
    Abstract ( )   PDF (2345KB) ( )  
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    Photochromism of Hexatungstic Acid in DMF
    YUE Bin, LIN Xin-rong, ZHU Si-san
    1995, 11(3):  264-265. 
    Abstract ( )   PDF (2220KB) ( )  
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    Chemiluminescence Determination of 6-Mercaptopurine in Pharmaceuticals
    HE Zhi-ke, LIU Xing-lian, LUO Qing-yao, YU Xi-mao, ZENG Yun'e
    1995, 11(3):  266-270. 
    Abstract ( )   PDF (2359KB) ( )  
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    Electrochemical Studies on Some Tetracomponent Molybdovanadophosphate with Keggin Structure
    ZHANG Heng-bin, WU Fang, YU Jian-feng, WU TOng-hao, LI Shu-jia
    1995, 11(3):  271-275. 
    Abstract ( )   PDF (2303KB) ( )  
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    Syntheses and Characterization of Metal Complexes of L-Lysine-N, N, N', N'-tetraacetic Acid and L-Lysine-N, N, N',N '-tetramethylenephosphonic Acid
    ZHUO Ren-xi, LU Zheng-rong, WEN Jie
    1995, 11(3):  276-278. 
    Abstract ( )   PDF (189KB) ( )  
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Editor-in-Chief:
Jihong YU
ISSN 1005-9040
CN 22-1183/O6
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