Chemical Research in Chinese Universities

Table of Content

24 January 1991, Volume 7 Issue 1

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Articles

Synthesis and Crystal Structure of Cu(Ⅱ) Adduct with N-(4-Chlorophenyl)aza 15-Crown-5

Yan Shiping, Wang Genglin, Yao Xinkan, Wang Honggen

1991, 7(1): 1-5.

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The title compound C₁₈H₂₅NC₄ClBr_{3/sub>Cu crystallizes in space group P 1with a = 1.0105(2)nm b=1.0821(1) nm, c=1. 1007(2) nm, a=80. 00(1)°,β=80. 26(1)° γ=77. 83(1)°. Z=2, D_s = 1. 831 g/cm³, μ=62. 658 cm^-1(Mok_u). The final refinement converged to R=0. 031 for 2547 independent observed reflections. The complex molecule consists of two cationic moieties (HL)⁺ and an anion which appears as a bromide-bridged copper dimer (Cu₂Br₆)^2-. This structural characterization seems to be rare in metal complexes with crown-ether.}

Preparation and Characterization of Heteropoly Octadecamolybdodiphosphates

Wang Enbo, You Wansheng, Liu Jingfu, Hu Changwen, Zhang Baojian

1991, 7(1): 6-10.

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Heteropoly molybdophosphates with general formula M_nP₂Mo₁₈O₆₂ ·xH₂O, where M = H⁺, K⁺, NH₄⁺, Ca²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ and Ag⁺, were prepared and characterlzed by elemental analysis, IR and UV spectrometry and thermal analysis. The solubilities of the compounds were examined. The IR spectra show that the countercations and the crystallization water have an influence upon the vibration frequencies of v_Mo-Oc and v_Mo-Oc-Mo.In the UV spectra, the charge-transfer bands are assigned to e→e and e→b₂ transition. All the compounds decompose at 328～534℃.

Synthesis and Characterization of the Large Pore Molecular Sieves VPI-5 and Si-VPI-5

Yao Shangqing, Qiu Shilun, Pang Wenqin, Yu Long, Li Liyun, Xin Qin

1991, 7(1): 11-17.

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The large pore molecular sieves VPI-5 and Si-VPI-5 were synthesized by using three organic amines (dipropylamine, diisopropylamine and dipentylamine) as the structure-directing agents. Compared with general alumlnophosphate molecular sieves, the synthesis of the molecular sieves of VPI-5 type ls of many unique features. Both VPI-5 and Si-VPI-5 were characterized by XRD, IR, TG-DTA, and MAS-NMR.

Synthesis and Properties of Dinuclear Cu(Ⅱ) Complexes Derived from Oxamidobis(propionato)cuprate(Ⅱ)

Liao Daizheng, Lin Bing, Wang Genglin

1991, 7(1): 18-21.

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Three dinuclear complexes were synthesized and designated as Cu(obp)CuL where obp =oxamidobis(propionato), L=2,2'-bipyridyl(bpy) (1), 1 , 10-phenathroline(phen)(2) and 5-nitro-1, 10-phenathroline(NO₂-phen)(3). The complexes were characterized by elemental analyses, in fared and electronic spectra, magnetic susceptibilities and ESR spectra, indicating antiferromagnetic spin exchange interactions between metal ions.

Emission Spectra of Some Heteropolytungstates Containing Europium

Liu Jingfu, Liu Zhao

1991, 7(1): 22-26.

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The emission spectra of some heteropolytungstates containing europium, K_{17[Eu(XW₁₁ O₃₉)₂](X = P, Ge, As, or Ga), K_{17[EuCAs₂W_{17O_{61)_{2/sup>] and K_{16H_{9EuAs_{4W_{40O_{140 have been investigated and the structures of these compounds are discussed. The emission spectra at room temperature are very similar to each other in terms of both the number of bands and transition frequencies, showing that they have the similar structures to those of K_{16[Ce(P₂W_{17O_{61)₂] and K_{12[U(GeW_{11O_39)₂].}}}}}}}}}}}}}}}

Atomic Emission Spectrometry of Inductively Coupled Plasma with Sample Introduction by Electrothermal Vaporization

Huang Min, Jiang Zucheng, Zeng Yun'e

1991, 7(1): 27-31.

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A system is described in which a graphite furnace electrothermal vaporization device is employed for the introduction of microlitre liquid sample into an inductively coupled argon plasma. The technique provides a picogram detection limit and an adequate precision with a relative standard deviation of 4%. Mechanism of analyte condensation in transport process is explored. As an application, the technique combined with DDTC/CCl₄ extraction is used to enrich and determine non- rare earth impurities in highly pure La₂O₃.

Determination of Trace Silver(Ⅰ) in Basic Aqueous Solution by Electrochemiluminescence of a New Reagent 6-(2-Hydroxy-4-Diethylaminophenylazo)-2,3-Dihydro-1,4-Phthalazine-1,4-Dione

An Jingru, Lin Jinming

1991, 7(1): 32-36.

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The electrochemiluminescence (ECL) of a new reagent 6- (2-hydroxy- 4 diethy laminophenylazo)-2,3-dihydro-1 ,4-phthalazine-1,4-dione (HDEA) in a basic aqueous so lution was studied by using the apparatus designed by ourselves. Trace amounts of silver (Ⅰ) shows a significant effect on the efficiency of light emission of HDEA during a positive trigonometrical wave pulse was exerted on the solution. The linear relationship between the light intensity and the concentration of silver(Ⅰ) occurs in the range of 5. 0×10^-8 to 3. 0×10^-6 mol/L Ag(Ⅰ) in a medium of KOH-KCl-HDEA (pH= 12. 8). The detection limit of the method is 2. 0×10^-8 mol/LAg(Ⅰ), and the r. s. d. for 1.0×10^-7 mo)/L Ag (Ⅰ) is 5%. Of 21 metal ions concerned, only nickel(Ⅱ), cerium(Ⅳ) and cobalt(Ⅱ) interfere the silver detection seriously; I^- and B^- also have some interference.

Speciation Study of Trace Elements by Reversed Phase-High Performance Liquid Chromatography (Ⅰ)——Simultaneous Determination of Cr(Ⅲ) and Cr(Ⅵ)

Yao Xingdong, Liu Jinchun, Cheng Jieke, Zeng Yun'e

1991, 7(1): 37-41.

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Reported here is the Cr-speciation study by High Performance Liquid Chromatography (HPLC) using precolumn derivatization with ammonium pyrolidinyldithiocarbamate (APDC) and spectrophotometric detection. The rapid and sensitive method has been successfully applied to the analysis of environmental water. The chromatographic behavior of the two Cr-APDC chelates are illustrated with "Solvophobic Theory".

Fourier Transform Infrared Study on the Melting Phase Transition of Octadecanoic Acid

Jiang Yutao, Tian Yongchi Liang Yingqiu

1991, 7(1): 42-46.

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Fourier transform Infrared (FT-IR) spectroscopy was used to study the melting phase transition of anhydrous octadecanoic acid. The phase transition occurs at 69℃(T_c). In solid phase, the alkyl chains take the all-trans zigzag conformation and the C_B-C_a= 0 group adopts trans configuration in the dimers. In liquid state, the alkyl chains convert to gauche conformation and the C_B-C_a= 0 to cis configuration.

ESR Study of the Reaction Between Cp₂Ti(CO)₂ and Cp₂TiBr₂

Wang Jitao, Liu Fengquan Bai Lingjun

1991, 7(1): 47-50.

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FT-IR Study on Crosslin king Reaction of Acrylates Copolymer Emulsions

Li Jianzong, Cheng Shiyuan, Xu Zushun

1991, 7(1): 51-56.

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