Chemical Research in Chinese Universities

Studies on Redox Properties of Heteropoly Compounds Containing Rare Earth Elements

Wang Enbo, Lu Xinghong, Zhao Shiliang, Liu Jingfu, Zhang Baojian

1989, 5(3): 199-205.

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The redox properties of four series of more than one handred acids and salts of rare earth heteropoly compounds, such as LnHSiMo₁₂O₄₀, In (PMo₁₁ O₃₉)₂^11-, Ln (PW₁₁ O₃₉)₂^11-, Ln (AsW₁₁ O₃₉)₂^11-, Ln(GeW₁₁O₃₉)₂^13-, Ln(BW₁₁O₃₉)₂^15-, Ln(GaW₁₁O₃₉)₂^16-, Ln(P₂Mo₁₇O₆₁)₂^17-, Ln (As₂W₁₇O₆₁)₂^17-, Ln₂P₂Mo₁₈O₆₂and Ln₂HP₂Mo₁₇VO₆₂(Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, etc. ) which have Keggin, Daw-son and their derivative structures, were studied by means of potentiometric titration, polarography and cy-clovoltammetry. The mechanisms of the redox reactions were supposed-and the orders of redox ability of the heteropoly compounds were concluded. The periodic changes in reduction potentials of Ln(PMo₁₁O₃₉)₂^11-and Ln(P₂Mo₁₇O₆₁)₂^17- with Ln atomic numbers, and the correlation between E_1/2 of Ln(XMo₁₁O₃₉)₂^n-(X =P, Ge, Si) and nq²(n is the main quantum number of the central atoms and q is their charges) were found.

Directing Role of Cage Structure for Crystallization of Zeolites

Li Shougui, Li Xikai, Xu Ruren

1989, 5(3): 206-211.

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The directing mechanisms of liquid directing agents of zeolite Y and zeolite L were studied by means of light transmission, ultracentrifugation, NMR, XRD and “cross-exchange” experiments. It was discovered that not only microcfystals of zeolites, but also cage structures of zeolites play the directing role for crystallization of zeolites.

Studies on Organo-Phosphorus,-Arsenic and-Antimony Polytungstates and Polymolybdates (Ⅶ)——Preparation and Properties of p-Aminophenylarsenic Polymolybdates

Liu Benyao, Gong Ziqiu, Gu Yidong(Yihtong Ku)

1989, 5(3): 212-218.

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In order to investigate the influence of organic groups on the types of organoarsenic polymolybdates, the reations of p-aminophenylarsonic acid with sodium molybdate were tested at pH=3-5. Six salts were prepared and characterized. (1) (CN₃H₈)₄ [(p-NH₃C₆H₄As)₂Mo₆O₂₅]·H₂O, (2) (CN₃H6)₄ [(p-, NH₃C₆H₄As)₂Mo₆O₂₅ ]·6H₂0, (3) Cs₄ [(p-NH₃C₆H₄As)₂Mo₆O₂₅]·4H₂O, (4) C(CH₃)₄N]₄[(p-NH₃C₆H₄As)₂Mo₆O₂₅]·5H₂O, (5) [(n-C₄H₉)₄N]₃Na[(p-NH₃C₆H₄As)₂Mo₆O₂₅]·2H₂O, (6) Ba₂ NH₃C₆H₄As)₂Mo₆O₂₅]·10H₂O. The IR, UV spectra, and electrochemical behavior are reported and discussed. They should belong to the same type as that for phenyl derivative or the nitrophenyl derivatives. But the ammo groups can accept protons, so that the anion' s charge decreases. Very similar to the tungsten congener (CN₃H₆)₄[(p-NH₃C,H₄As)₂W₆O₂₅]·4H₂O, [(RAs)₂Mo₆O₂₅]^4- type of complexes are formed.

FTIR Spectra of Hexene-1 Adsorbed on ZSM-5 Zeolites

Zhang Jianmin, E. Baumgarten

1989, 5(3): 219-223.

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HZSM-5, Pt-exchanged and impregnated PtHZSM-5 zeolites were prepared, which have different characteristics of OH group, and the IR spectra of hexene-1 adsorbed on these zeolites were investigated.

Spectral Properties of Extracted Complexes of Metal Picrates with Crown Ethers

Zhang Xianxin, Zhou Zhixian

1989, 5(3): 224-230.

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The investigation on UV-visible spectra of species formed by extracting some metal picrates with benzo-15-crown-5(B15C5) and dibenzo-18-crown-6(DB18C6) verified that there are some interactions of picrate anion with K⁺, Na⁺ and rare earth ions in loaded organic phase. By the study of the charge transfer band and absorption spectra of picrate anion, it can be determined whether an ion pair has been formed and either a 1 : 1 contact ion pair or a 1 : 2 crown-separated ion pair involved in organic phase can be distinguished for an ion-pair extraction.

Extraction of Gold by Di(2-ethylhexyl)Sulfoxide and N-Octyl Sulfoxide

Lu Zhong'e, Que Haoquan, Liu Guoxing, Wang Hanzhang, Zhu Qinhua

1989, 5(3): 231-236.

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Elution Behaviour of Monocarboxylic Acids on a Cation-exchange Resin Column

Zhao Guoliang, Liu Zhiguang

1989, 5(3): 237-243.

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The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic process. On the basis of the proposed mechanism, an equation was derived for correlating distribution coefficient, K_d, dissociation constant, A_a, and adsorption equilibrium constant, K, of the analyzed acid. By this approach, retention data for some aliphatic acids under different operating conditions were predicted. Results are reasonably in agreement with experiment.

Studies on the Combined Derivative Spectrophotometry

Shi Huiming, Xi Changsheng, Li Jinhe, Ren Hongji

1989, 5(3): 244-249.

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The combined derivative spectrophotometry developed in this paper is a new method, which can be used to determine multicomporent mixture simultaneously and may improve the sensitivity and accuracy of the measurement remarkably. Two practical tests were carried out to verify the correctness of the theory, and the results are satisfactory.

Diterpenoids from Rabdosia Nervosa

Bai Guang, Chen Yaozu, Meng Xianjun

1989, 5(3): 250-254.

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Six ent-kaurene type diterpenoids were isolated from the leaves of Rabdosia nerwsa. Among them.ganer-vosin A and B are new compounds, the structures of which were elucidated as 1 and 2 respectively by spectral and chemical methods. The other four were identified as odonicin (3), novelrabdosin (4), nodosin (5) and shikokianal acetate (8). Compounds (1), (2), (5) and (8) have not been found in this herb previously.

Electronic Structures of Mono- and Bi-nuclear Benzene-Transition Metal Sandwich Complexes

Wang Zhizhong, Shen Erzhong, Wang Liqun

1989, 5(3): 255-260.

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We report here the calculations on electronic structures of mono- and bi-nuclear benzene - transition metal sandwich complexes by means of CNDO/2 program, on the basis of molecular orbital components, atomic net charges and bond orders, the bonding pictures are analysed and discussed.

Kinetics of the Reaction of Abstracting Hydrogen from Ethylene by Hydrogen Atom

Ye Song, Dai Shushan

1989, 5(3): 261-264.

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Hydrogen abstraction reaction, H+C₂H₄ ——H₂+C₂H₂ was studied by using A initio SCF method. Ge-ometries were fully optimized at SCF level and energies were computed at STO-3G basis set for reactants and transition state. Vibrational analysis was performed thereupon. Finally, the rate constant calculations were carried out at different temperatures for all range of reaction temperature according to Eyring's sbwlute reaction rate theory. The calculated activation energy is 12. 68 kcal/mol, lower than observed value (H. S kcal/mol) by 1. 82 kcal/mol only. The agreement of the calculated rate constants with the experiments is satisfactory.

Raman Spectroscopic Studies on the Complexation and Adsorbed Behaviour of Thiourea

Tian Zhongqun, Fleischmann, Martin

1989, 5(3): 265-269.

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Raman spectroscopic studies on thiourea (TU) in highly acidic media (e. g. >3 mol/L HC1O4) show that TU as a solution species is protonated through its sulphur atom and forms complex with anions. However, as an adsorbed species, TU is protonated via the nitrogen atom and adsorbed at the silver electrode surface through the sulphur atom. The distinct effects of pH and anions of the solution on the surface enhanced Raman (SER) spectra of TU were investigated. In acidic and neutral solutions, TU is coadsorbed with anions through its NH³⁺ and - NH₂ groups respectively.

Investigation of Absorption Spectra of Bis(alkylxanthato)-platinum(Ⅱ) Complexs

Zuo Bencheng, Shi Tiesheng, Chen Guoru, Wang Shuenqing

1989, 5(3): 270-275.

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Studies on the Thin Film of TiO₂, Fe₂O₃ and SnO₂ by the Organometallic-CVD Technique

Luo Wenxiu, Tan Zhongke

1989, 5(3): 276-278.

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Excimer and Micellization of a Merocyanine

Tian Yongchi, Liang Yingqiu, Ge Gang, Wang Shangtian

1989, 5(3): 279-281.

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