Table of Content

24 April 2001, Volume 17 Issue 2

Previous Issue    Next Issue

Articles

Syntheses, Characterization and Anti-HIV Activity of Charge Transfer Heteropolycomplexes

LIU Shu-xia, LI Yang-guang, HAN Zeng-bo, HUANG Ru-dan, WANG En-bo, ZENG Yi, LI Ze-lin

2001, 17(2):  127-133. 

Abstract ( )   PDF (480KB) ( )  

Related Articles | Metrics

Each of Keggin type heteropolytungstosilicic and heteropolytungstogermanic acids reacted with 8-quinolinol, p-aminodimethylaniline and pyridine, respectively, yielding six charge trans fer heteropolycomplexes(CTHPCs), which were purified and characterized by elemental analy sis, IR, UV and ¹⁸³W NMR. The anti-HIV-1 activities of CTHPCs were evaluated by ELISA of HIV-P24 antigen. The toxicity against MT-4 cells was measured by MTT. The results show that median inhibitory concentration(IC₅₀) for each CTHPC to inhibit HIV-P24 antigen in cell culture was lower than 5 g/mL, while median toxicity concentration (IC₅₀) against MT-4 cells was higher than 268 g/mL. The following mechanisms might be considered for their anti-HIV 1 activity, namely, (1) inhibiting the penetration of HIV-1 virus into target cells for it can blockade CD4 receptor of MT-4 cells and (2) inhibition of syncytium formation.

Isolation and Spectroscopic Characterization of Protonated Mixed [Tetrakis (4-pyridyl)porphyrinato] (phthal ocyaninato)Rare Earth (Ⅲ)Double-decker Compounds

JIANG Jian-zhuang, LIU Wei, SUN Xuan, ZHANG Xian-xi, NG Dennis K. P.

2001, 17(2):  134-142. 

Abstract ( )   PDF (299KB) ( )  

Related Articles | Metrics

The treatment of tetrakis(4-pyridyl)porphyrin H₂TPyP with a hydrated rare earth (Ⅲ) acetylacetonate RE(acac)₃·nH₂O (RE=Y, Eu, Gd) in 1,2,4-trichlorobenzene (TCB) pro duced a monomeric porphyrinato rare earth compound RE(TPyP)acac, which further reacted with dicyanobenzene in amyl alcohol in the presence of 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU), giving HRE(TPyP)(Pc) in a good yield. Upon exposure to air, part of the protonated mixed double-deckers in CHCl₃ solutions converted slowly to the corresponding neutral complexes RE(TPyP) (Pc). These protonated complexes were characterized by means of UV-Vis, IR, NMR, mass spectroscopies. The quaternarization of these protonated mixed double-deckers with methyl iodide produced the salts of tetramethylated cations [HRE (TMPyP)(Pc)]⁴⁺.

Synthesis of Nanometer-sized Mesoporous Oxide Spheres

LUO Qian, LI Li, XUE Zhi-yuan, ZHAO Dong-yuan

2001, 17(2):  143-147. 

Abstract ( )   PDF (433KB) ( )  

Related Articles | Metrics

A few hundreds nanometer-sized mesoporous silica and alumina spheres were synthesized in organic solvents. The impacts of ammonia, N,N-dimethylformamide (DMF) and stirring speed were also investigated.

Synthesis, Properties and Structure of a Novel Unsymmetrical Bis (phenoxo) Bridged Binuclear Copper (Ⅱ) Complex

LU Tong-bu, LI Yan-wu, FENG Xiao-long, CAl Ji-wen, LI Xiao-yan, JI Liang-nian

2001, 17(2):  148-152. 

Abstract ( )   PDF (325KB) ( )  

Related Articles | Metrics

A novel bis(phenoxo) bridged binuclear copper (Ⅱ) complex with dissimilar coordination environments was synthesized and characterized by spectroscopies and X-ray crystallography. It crystallized in the monoclinic system with space group C2/c, a=2.241 1 (2) nm, b=1.834 2 (2) nm, c=1.877 9(2) nm, β=122.861(2)°, V=6.484 3(11) nm³, Z=8. It consists of two unsymmetrical Cu(Ⅱ) centers bridged by two phenolic oxygen atoms to yield a Cu₂O₂ core with the Cu-Cu separation of 0. 310 2 nm, in which Cu1 and Cu2 ions exhibit distorted N₂O₃ and N₃O₂ square pyramidal geometries, respectively.

Diagnostic Classification of Normal Persons and Cancer Patients by Using Neural Network Based on Trace Metal Contents in Serum Samples

ZHANG Zhuo-yong, HONG Zhe, ZHOU Hua-lan, LIU Si-dong

2001, 17(2):  153-158. 

Abstract ( )   PDF (406KB) ( )  

Related Articles | Metrics

Artificial neural network with the back-propagation(BP-ANN) approach was applied to the classification of normal persons and various cancer patients based on the elemental contents in serum samples. This method was verified by the cross-validation method. The effects of the net work parameters were investigated and the related problems were discussed. The samples of 72, 42, and 52 for lung, liver, and stomach cancer patients and normal persons, respectively, were used for the classification study. About 95% of the samples can be classified correctly. There fore, the method can be used as an auxiliary means of the diagnosis of cancer.

Anion Adsorption on an Au Colloid Monolayer Based Cysteamine-Modified Gold Electrode

HU Xiao-ya, XIAO Yi, CHEN Hong-yuan

2001, 17(2):  159-167. 

Abstract ( )   PDF (622KB) ( )  

Related Articles | Metrics

Anion adsorption behavior on Au colloid surface was investigated in virture of depositing monolayers of Au colloid on the self-assembled monolayers of cysteamine on a gold electrode. Po tential-dependent anion adsorption-desorption waves via the nonfaradaic current were obtained by means of cyclic voltammetry at Au colloid-modified gold electrodes in the potential range of -200-600 mV. The adsorption sequence in the order of adsorption peak potentials(Epa) is OH^->citrate^3->H₂PO₄^->Cl->SO₄^2->ClO₄^->NO₃^-. Among them, citrate3-exhibited an en tirely irreversible adsorption. A rise in temperature can increase the rates of adsorption-desorp tion and improve the reversibility of the adsorption-desorption of CI^-, SO₄^2-, CIO₄^-, NO₃^- and H₂PO₄^-. The adsorption peak potentials shifted more negatively for ca. 63 mV as the anion con centrations were increased by a decade factor. The change of pH from 7 to 1 slightly affected the adsorption peak potentials of Cl^- and NO₃^-. Au colloids with a smaller size (16 nm) gave rise to a better reversibility of the adsorption-desorption process and lower adsorption currents. The ex perimental results of citrate ions adsorption on Au colloid surface show that Au colloids with a smaller size prepared by sodium citrate method exhibited a higher stability in the solution in com parison to those with larger sizes because of its higher ratio of charge/mass. In other words, the smaller gold nanoparticles are covered with citrate ions monolayer that can also be formed at larg er gold nanoparticles by means of electrochemical scan.

Synthesis and Efficiency of a Spherical Macroporous Epoxy-dicyandiamide Chelate Resin for Preconcentrating and Separating Trace Au, Hg, Pd and Ru from Samples

GONG Bo-lin, LI Xue-qiang, WANG Feng-rong, CHANG Xi-jun

2001, 17(2):  168-174. 

Abstract ( )   PDF (462KB) ( )  

Related Articles | Metrics

A novel spherical macroporous epoxy-dicyandiamide chelate resin was synthesized simply and rapidly from epoxy resin and used for the preconcentration and separation of trace amounts of Au(Ⅲ), Hg (Ⅱ), Pd (Ⅳ) and Ru (Ⅲ) ions from solution samples. The analyzed ions can be quantitatively concentrated by the resin at a flow rate of 2.0 mL/min at pH 4, and can also be desorbed with 15 mL of 4 mol/L HCl+0.3 g thiourea from the resin column with recoveries of 96.5%-99.0%. After the chelate resin was reused for 7 times, the recoveries of these ions were still over 92%, and 400-1 000 times of excess of Fe(Ⅲ), Al(Ⅲ), Ni(Ⅱ), Mn(Ⅱ), Cr (Ⅲ), Cu (Ⅱ), Cd (Ⅱ) and Pb(Ⅱ) caused little interference with the determination of these ions by an inductively coupled plasma optical emission spectrometer (ICP-OES). The capacities of the resin for the analytes are in the range of 0.35～0.92 mmol/g. The RSDs of the proposed method are in the range of 1.1%～4.0% for each kind of the analyzed ions. The recoveries of a standard added in real solution samples are between 96.5 % and 98. 5 %, and the results for the analyzed ions in a powder sample are in good agreement with their reported values.

Syntheses of α-Hydroxyarylacetic Acids in the Presence of Different Phase Transfer Catalysts Under Sonication

XU Wei-liang

2001, 17(2):  175-177. 

Abstract ( )   PDF (212KB) ( )  

Related Articles | Metrics

The syntheses of a-hydroxyarylacetic acids with a good yield in the presence of different phase transfer catalysts(PTC) under sonication were studied. The results obtained are superior to those by other similar methods. The data show that β-cyclodextrin(β-CD) is more efficient than other PTC. The preliminary reaction conditions are also discussed.

Synthesis of Conformationally Locked 2'-Deoxy-2'-nucleobase-5'- Isonucleosides: 2'-Deoxy-2'-nucleobase-5'deoxy-1', 4':3', 6'-dianhydro-D-mannitol

TIAN Xiao-bing, ZHANG Ling, MIN Ji-mei, ZHANG Li-he, LU Yang, JIANG Reng-wang, ZHENG Qi-tai

2001, 17(2):  178-185. 

Abstract ( )   PDF (589KB) ( )  

Related Articles | Metrics

Novel bicyclic isonucleosides, 2'-deoxy- 2'-nucleobase- 5'-deoxy- 1', 4': 3', 6'-dianhydro D-mannitol 10a-10c, were synthesized from D-glucose. The computer-assisted molecular simu lation indicated that the sugar conformations of compounds 10a-10c were restricted to N-con formation.

The Promoting Effect on the Activities of Fe Doped TiO₂ Photocatalysts

YU Xi-bin, WANG Gui-hua, LI He-xing

2001, 17(2):  187-192. 

Abstract ( )   PDF (395KB) ( )  

Related Articles | Metrics

The particles of titanium-iron (Ti/Fe) complex with different Fe contents were prepared by means of the sol-gel method and used as a photocatalyst. The activity of the catalyst was investi gated as a function of the Fe content during the liquid-phase oxidation of tetracycline, which showed an enhancement at the low Fe content. The XRD, Raman, XPS, and UV-Vis absorp tion spectra indicated that the crystalline structure of the Ti/Fe complex particles changed from anatase phase to rutile phase when the Fe content increased. The isolated Fe₂O₃, Fe₃O₄, FeO species were observed and Fe³⁺ ions were highly dispersed in the TiO₂ matrixes, then Ti--O--Fe species were formed. These species increased the surface defects of the Ti/Fe particles. Also, ac tive hydroxyl radicals could be generated in the catalytic transformation, which led to the higher activity of the catalyst than bare TiO₂ for the degradation of tetracycline.

Nanostructured Columns from Self-assembly of Complementary Molecular Components

YANG Wen-sheng, YANG Bai-quan, JIANG Yue-shun, LI Tie-jin, LIU Ya-Juan

2001, 17(2):  193-197. 

Abstract ( )   PDF (421KB) ( )  

Related Articles | Metrics

Nanostructured columns with a length about several tens of micrometer and a diameter of about 80 nm were obtained by molecular recognition directed self-assembly of a pair of comple mentary molecular components, 4-amino-2,6-didodecylamino-1,3,5-triazine (M) and 5- (4-dode cyloxybenzylidene)-(1H, 3H)-2,4,6-pyrimidinetrione (B) in chloroform. In this system, with positive cooperativity, r-aromatic stacking and van der Waals interactions as well as hydrogen bonds cause the formation of the nanocolumns.

Molecular Component Structures Mediated Formation of Self-assemblies

YANG Wen-sheng, LU Ran, TANG Xin-yi, LI Tie-jin, FU Lian-she, ZHANG Hong-jie

2001, 17(2):  198-201. 

Abstract ( )   PDF (348KB) ( )  

Related Articles | Metrics

Molecular recognition directed self-assemblies from complementary molecular components, melamine and barbituric acid derivatives were studied by means of NMR, fluorescence, and TEM. It was found that both the process of the self-assembly and the morphologies of the result ed self-assemblies could be mediated by modifying the structures of the molecular components used. The effect of the structures of the molecular components on the formation of the self-as semblies was discussed in terms of intermolecular interactions.

A Theoretical Study of the Mechanism for the Photodecomposition of AgN₃

SHI Shou-heng, SHI Chuan, Zhang Shao-yin, Dai Hong-yi

2001, 17(2):  202-206. 

Abstract ( )   PDF (348KB) ( )  

Related Articles | Metrics

Recently some new apparatuses have been developed to study the thermal decomposition and the photodecomposition mechanism of silver azide with some new experimental results. We anal ysed the experimental results with ab initio calculations (CASSCF, valence CI, MC-CEPA, ACPF and CEPA), assigned the spectrum structure of AgN₃, plotted the potential energy curves of AgN₃ and reinterpreted the photodecomposition mechanism of silver azide. The poten tial energy curves of the two lowest singlet and the two lowest triplet valence states of AgN₃ a long AgN-NN distance R2 show that the two singlet valence states are involved in the photodisso ciation of AgN₃, proved by the two peaks at 2.18 and 2.23 eV which are the results of the elec tron transition from the ground state to the two singlet valence states respectively.

SOS Calculation of Nonlinear Optical Properties of Synthesized ASPBPh₄

ZHAO Xian, TIAN Yu-peng, ZHOU Yu-fang, JIANG Min-hua, LIU Yong-jun, HU Hai-quan

2001, 17(2):  207-211. 

Abstract ( )   PDF (339KB) ( )  

Related Articles | Metrics

The two-photon absorption induced lasing spectrum shows that the synthesized ASPBPh₄, trans-4-[P-(N-methyl-N-(hydroxyethyl) amino) styryl]-N-methylpyridinium, has a distinct ef ficiency of laser frequency up-conversion. This nonlinear optical property of such a kind of com pounds is related to two-photon absorption (TPA). In our work, we used the intermediate ne glect of differential overlap (INDO) plus single-excitation configuration interaction (SCI) method to get the basic properties of the molecule, and calculated the second hyperpolarizability and the cross section of two-photon absorption by means of sum-over-state (SOS) expression. The rela tionship between the structure and the properties is discussed.

Molecular Similarity Based on Super-Ball Algorithm

GUO Ming, LIU Wen-jie

2001, 17(2):  212-218. 

Abstract ( )   PDF (454KB) ( )  

Related Articles | Metrics

The molecular similarity of 139 organic compounds was calculated by the topologic index method, the flexible super-ball algorithm was used to scan similar molecules and structures. The results show that the properties of organic compounds estimated from this method are reliable.

DFT Thermodynamic Research of the Pyrolysis Mechanism of the Carbon Matrix Precursor Toluene for Carbon Material

WANG Hui, YANG Hai-feng, RAN Xin-quan, WEN Zheng-yi, SHI Qi-zhen

2001, 17(2):  219-225. 

Abstract ( )   PDF (487KB) ( )  

Related Articles | Metrics

Based on the experiments, the standard enthalpy △H^Θ of the possible pyrolysis reactions of the carbon matrix precursor toluene was investigated by means of DFT method UB3LYP/ 3-21G^* (based on semi-empirical method UAM1 and ab initio method UHF/3-21G^*). The com putation results with UB3LYP/3-21G^* coincide with the experimental values well. Then, the mechanism for all types of the pyrolysis reactions of toluene was studied by UB3LYP/3-2lG^*. The geometries of the reactant and the product radicals were optimized, meanwhile, the standard thermodynamic parameters of the pyrolysis reaction at different temperatures (298, 773, 843, 963 and 1 073 K) were calculated. The thermodynamic computation result shows that when the pyrolysis temperature of toluene is lower than 963 K, the reaction path supported by thermody namics is that the C-H bond of the methyl on the benzene ring breaks and bitoluene form, while the temperature increases (about 1 073 K), the thermodynamic calculation result turns to sup port the reaction path producing phenyl radicals and methyl radicals. This mechanism is in accord with the experiments.

Synthesis and Characterization of One-dimensional and Two-Dimensional Porphyrin Polymers^*(Ⅰ)

LI Xiang-qing, WANG Xing-qiao, GUO Jing-fu, MENG He, LIU Guo-fa

2001, 17(2):  226-227. 

Abstract ( )   PDF (243KB) ( )  

Related Articles | Metrics

Research Notes

Influence of The P,O-Bidentate Ligand on Ethylene Oligomerization Catalyzed by Iron Complexes

WANG Mei, YU Xiao-min, QIAN Ming-xing, HE Ren

2001, 17(2):  228-232. 

Abstract ( )   PDF (335KB) ( )  

Related Articles | Metrics

Shear-induced Stabilization of the Nematic Phase in a Side Group-containing Poly (aryl ether ketone) Copol ymer

SUN Hui, MA Jia, BEN Teng, WANG Han-fu, CHEN Chun-hai, ZHANG Wan-jin, JIANG Zhen-hua, WU Zhong-wen, XU Ying-kai, ZHENG Qiang, LI Li-wei

2001, 17(2):  233-236. 

Abstract ( )   PDF (277KB) ( )  

Related Articles | Metrics