Chemical Research in Chinese Universities

Crystal and Molecular Structure of an Inclusion Complex of p-tert-Butylcalix[6] arene with Toluene

LU Tong-bu, LI Xiao-yan, JI Liang-nian, HAN Bao-hang, LIU-Yu, YU Kai-bei

1999, 15(1): 1-4.

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An inclusion complex between p-tert-butylcalix[6] arene and toluene was prepared. It crystallized in the monoclinic system with space group P2₁/ n, a =1.734 7(2) nm, b =1.903 2(2) nm, c =1.972 9(2) nm, β =94.74(1)°, V =6.491 2(14) nm³, Z =4. The toluene molecule was included in the macrocycle cavity. The calixanene is of a pinched cone conformation.

Synthesis, Proton Conductivity and Humidity Sensing Property of γ-Type Zirconium Hydrogen Phosphate, Zr(HPO⁴)²·2H²O

FENG Shou-hua, ZHAO Hui, LI Lian-sheng, Martha Greenblatt

1999, 15(1): 5-9.

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A γ type of layered zirconium hydrogen phosphate, Zr(HPO⁴)²·2H²O(γ-ZrP), was synthesized under hydrothermal conditions and characterized by powder X-ray diffraction and thermogravimetric analysis. The temperature dependence of the proton conductivity in γ-ZrP was investigated in a temperature range of 23～413 ℃ by ac impedance spectroscopy. The variation of the conductivity with water loss and phase transitions was observed. The best proton conductivity in γ-ZrP is 6×10^-4 S·cm^-1 at 60 ℃. The proton conductivities in the dehydrated sample are ～10^-5 at 150 ℃ and ～10^-4 S·cm^-1 at 350 ℃, respectively. The conductivities as a function of humidity in the temperature range of 120～200 ℃ were measured.

In Situ Microscopic FTIR Spectroelectrochemistry of Ascorbic Acid in Poly(ethylene glycol)/LiClO⁴ Electrolyte Paste and in the Presence of Dispersed Cobalt Hexacyanoferrate Microcrystalline Powder

GUO Li-ping, LIN Xiang-qin

1999, 15(1): 10-16.

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In situ microscopic FTIR spectroelectrochemical technique(MFTIRs) was applied to studying the electrochemical oxidation of ascorbic acid(AA) in poly(ethylene glycol)(PEG) paste at a 100 Lm diameter Pt disk electrode. Using this technique, the catalytic ability of cobalt hexacyanoferrate(CoHCF) microcrystalline toward AA oxidation was also studied. It was found that the dispersed CoHCF powder in the PEG paste can generate well shaped thin layer cyclic voltammetric waves with the peak height proportional to the scan rate, corresponding to the Fe centered redox reactions. This oxidation step catalyzed the AA oxidation. Also, this pasted CoHCF powder generated well resolved in situ MFTIRs spectra, by which a chemical interaction between C=C bond of AA ring and CoHCF lattice was revealed. A corresponding surface docking mechanism for the catalytic reaction has been proposed.

A Study of the Driving Force for Inclusion Complexation of α-and β-Cyclodextrin with Substituted Benzene

ZHANG Hai-ming, LUO Shuang-hui, CHEN Chao, LIU Lei, GUO Qing-xiang, LIU You-cheng

1999, 15(1): 17-22.

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The driving force for inclusion complexation of α-and β-CD with substituted benzene(PhX) was studied by means of step-wise regression analysis. A set of multiple regression equations was established with correlation coefficients 0.96 and 0.94 for the individual complexation of α-CD and β-CD with PhX. The lnK_a(calc.) values calculated with the aid of the regression equations were close to those determined experimentally. The inclusion complexation is dominantly driven by van der Waals force and hydrophobic interactions.

Synthesizing β-Chiral Carbon Alkanoic Acids and Alcohols via (-)-Bornane-10,2-crotonoylsultam

HUANG Jin-xia, LI Yan, MA Xing-quan, ZHOU Zhong-qiang

1999, 15(1): 23-28.

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(+)-Camphor derived N-crotonoylsultam 2, readily available from chiral auxiliary bornane-10,2-sultam and crotonoyl chloride, reacted with selected Grignard reagent 3(R= n-butyl, n-pentyl, n-hexyl, n-heptyl) under the control of CuI or not being at low temperatures, giving diasteroisomers 4, 5 respectively. After nondestructive cleavage both enantiomers of the acid and alcohol were obtained in high e. e.%. The d. e.% of 4,5 was determined by HPLC, and the assignment of these values was discussed by analyzing ¹H NMR(500 MHz).

Synthesis, Characterization and Biological Activity of (Z)-1-[2-(Triphenylstannyl] Cyclopentanol and Their Phenylhalostannyl Derivativies

YUE Su-mei, LI Xiao-li, SUN Zhen-gang, LIU Jing-fu

1999, 15(1): 29-34.

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The synthesis and characterization, by elementary analysis, IR and ¹H NMR of (Z)-1-[2 (triphenylstannyl)vinyl]-1-cyclopentanol, CH²(CH)³C(OH)CH=CHSnPh³ are described together with its halodemetallation by I², Br² and ICl to yield derivatives of the types CH²(CH²)³C(OH)CH=CHSnPh_3-n Xⁿ (n =1, 2; X=I, Br, Cl). The solid state structures of the dibromide were determined by X-ray diffraction analysis. In the crystal of CH²(CH²)³C(OH)· CH=CHSnBr², the Sn atom has a destorted trigonal bipyramidal geometry, in which Sn—O interaction is noted[0.244 6(8) nm]. The biological activity of the title complexes was also investigated.

Isolation and Characterization of C-phycocyanin from Spirulina Platensis

YIN Gang, LIU Zheng, LIU Fei, LI Chen, DING Fu-xin, YUAN Nai-ju

1999, 15(1): 35-38.

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The isolation of biliproteins from the Spirulina platensis cultured in southern China was accomplished with gel filtration on Sephacryl S-200 and chromatography on hydroxylapatite. The spectrophotometry, isoelectric point, and amino acid composition of C-phycocyanin were determined, respectively.

Synthesis of Novel Hydrophobic Media and Purification of Recombinant HBsAg

WANG Yan, WANG Qun, XIAO Neng-qing, LIU Da-wei, YE Shi-de, LUO Xuan, GUAN Gui-fan, WEI Zi-li, CHEN Wan-ge, BAI Fang

1999, 15(1): 39-46.

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A novel hydrophobic medium with propyl as functional group and Sepharose 6B as matrix was designed and synthesized. The comparison of the hydrophobic medium synthesized with the commercial products was made by hydrophobic interaction chromatography(HIC) in isolating recombinant hepatitis B surface antigen(r-HBsAg). r-HBsAg was further purified to the final products by following a downstream procedure^[1]. The results indicate that the synthesized hydrophobic medium possesses a stable structure and desired physical and chemical properties. They were used to purify r-HBsAg with a high yield and purity. Both the immunity and stability of hepatitis vaccine made by the r-HBsAg products have reached the same level as other similar kinds of products.

Microcalorimetric Character of Inhibition of Salicylaldehyde Glucosamine Schiff Base SG on Bacterial Metabolism

HUANG Zai-ying, QU Song-sheng, FENG Ying

1999, 15(1): 47-51.

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The power time curves of the reaction of E. coli with SG at different temperatures were determined by microcalorimetric method and the mutliplication rate constant k, generation time G, ratio I, and thermogenetic quantity Q, Q₀ and Q₀ were calculated.The function formulas have been established. It was found that P_max, t_g, t and Q₀ can be used to characterize the bacterial growth metabolism of E. coli and the antibacterial activity of SG.

Nonorthogonal Tight binding Study of the Geometries and Electronic Properties of Ge n (n =2—20) Clusters

LI Si-dian, ZHAO Ji-jun, WANG Guang-hou 

1999, 15(1): 52-57.

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The universal-parameter nonorthogonal tight-binding scheme proposed by Menon and Subbaswamy was used to optimize the geometrical structures, binding energies and electron affinities of small germanium clusters Ge_n (n =2—20). A complete agreement with available ab initio results from the lowest energy structures for Ge₂—Ge₆ was obtained and reasonable structures for these clusters were predicted and compared with those of corresponding silicon clusters in the range of n =7—20. The averaged discrepancy with experiments in binding energies for n =2—7 is about 6% and the calculated electron affinities agree well with the measured values in the range of n =2—8 as well.

Studies on ζ-Potential of Positive Sol of Magnesium Aluminum Hydroxide

HAN Shu-hua, HOU Wan-guo, DONG Qian, SUN De-jun, HUANG Xi-rong, ZHANG Chun-guang

1999, 15(1): 58-62.

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The IEP of magnesium aluminum hydroxide was predicted with the modified Yoon's equation, and the effect of electrolyte on the ζ-potential of the sol was studied by electrophoresis method. The results showed that the calculated IEP values with the modified Yoon's equation agreed well with the experimental ones. With the increase of the ionic radius of monovalent anions (Cl^-, Br^-, I^-) the ζ-potential decreased. The same was true for CO₃^2-, SO₄^2- but the sign of the ζ-potential reversed from positive to negative. For Al³⁺, Ca²⁺, Mg²⁺, however, the ζ-potential increased with the increase of the concentration of Al³⁺, Ca²⁺, Mg²⁺.

Crystal Structures of Cu(Ⅰ) and Cu(Ⅱ) Complexes of Tris(N-n-propylbenzimidazol-2-ylmethyl)amine

SU Cheng-yong, ZHOU Qin, ZHANG Wei-jun, LU Zhong-ling, KANG Bei-sheng

1999, 15(1): 63-66.

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Two New Bisabolane Sesquiterpenes from Ligularia Thyrsoidea

LIAO Jian-chun, YANG Li, JIA Zhong-jian

1999, 15(1): 67-69.

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