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10 February 2006, Volume 27 Issue 2

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高等学校化学学报2006年第27卷第2期目次

2006, 27(2):  0.  doi:

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Contents

Crystal Structures and Fluorescence Property of Rare Earth Complexes {La［o-C₆H₄(NO₂)(CO₂)］₃·(DMF)₂}₂.

LI Li, CHEN Ya-Shao, DIAO Li-Fang

2006, 27(2):  199-203. 

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The o-nitro-benzoic acid(C₇H₅O₄N) and N,N-dimethylformamide(DMF) coordinate with La(Ⅲ) to form a dinuclear complex The onitrobenzoic acid(C₇H₅O₄N) and N,Ndimethylformamide(DMF) coordinate with La(Ⅲ) to form a dinuclear complex The onitrobenzoic acid(C7H5O4N) and N,Ndimethylformamide(DMF) coordinate with La(Ⅲ) to form a dinuclear complex La［oC6H4(NO2)(CO2)］3·(DMF)2}2. The complex resides on an inversion center. The structure of the complex is characterized by IR, ¹H NMR, ¹³C NMR, UV and fluorescent emission spectra. The results show that the complex crystallizes in a triclinic system, space group P1, cell parameter a=1.902(2) nm, b=1.245 0(2) nm, c=1.298 7(2) nm, α=64555(2)°, β=66348(2)°, γ=71.920(2)°, V=1.569 5(5) nm3,  Dc=1.658 Mg/m³, Z=2, μ=1.437 mm^-1, F(000)=784. In the complex, two La(Ⅲ) are bridged by four onitrobenzoic acids liganding with their carboxyl. The coordination number of La(Ⅲ) is nine and the coordinated atoms are all oxygen from the carboxyl and carbonyl. Nine oxygen atoms(seven from a carboxyl of onitrobenzoic acid and two from DMF molecule) occupy the nine coordination sites around La(Ⅲ), respectively. Hydrogen bonds and aromatic π…π stacking interactions assemble the title complex into a three dimensional network. Luminescence measurement shows that the complex emits fluorescence. . The complex resides on an inversion center. The structure of the complex is characterized by IR, ¹H NMR, ¹³C NMR, UV and fluorescent emission spectra. The results show that the complex crystallizes in a triclinic system, space group P1, cell parameter a=1.902(2) nm, b=1.245 0(2) nm, c=1.298 7(2) nm, α=64.555(2)°, β=66.348(2)°, γ=71.920(2)°, V=1.569 5(5) nm³,  Dc=1.658 Mg/m³, Z=2, μ=1.437 mm^-1, F(000)=784. In the complex, two La(Ⅲ) are bridged by four o-nitro-benzoic acids liganding with their carboxyl. The coordination number of La(Ⅲ) is nine and the coordinated atoms are all oxygen from the carboxyl and carbonyl. Nine oxygen atoms(seven from a carboxyl of o-nitro-benzoic acid and two from DMF molecule) occupy the nine coordination sites around La(Ⅲ), respectively. Hydrogen bonds and aromatic π…π stacking interactions assemble the title complex into a three dimensional network. Luminescence measurement shows that the complex emits fluorescence. The complex resides on an inversion center. The structure of the complex is characterized by IR, ¹H NMR, ¹³C NMR, UV and fluorescent emission spectra. The results show that the complex crystallizes in a triclinic system, space group P1, cell parameter a=1.902(2) nm, b=1.245 0(2) nm, c=1.298 7(2) nm, α=64.555(2)°, β=66.348(2)°, γ=71.920(2)°, V=1.569 5(5) nm3,  Dc=1.658 Mg/m3, Z=2, μ=1.437 mm-1, F(000)=784. In the complex, two La(Ⅲ) are bridged by four o-nitro-benzoic acids liganding with their carboxyl. The coordination number of La(Ⅲ) is nine and the coordinated atoms are all oxygen from the carboxyl and carbonyl. Nine oxygen atoms(seven from a carboxyl of o-nitro-benzoic acid and two from DMF molecule) occupy the nine coordination sites around La(Ⅲ), respectively. Hydrogen bonds and aromatic π…π stacking interactions assemble the title complex into a three dimensional network. Luminescence measurement shows that the complex emits fluorescence.

Synthesis of a Novel Complex of Schiff-base and Zinc and Application to Sensitized Nanocrystalline TiO₂ Solar Cell

XIA Jiang-Bin, YANG Hong, LI Fu-You, HUANG Chun-Hui

2006, 27(2):  204-207. 

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AbstractA novel Schiff-base ligand and its Zn complex were synthesized and characterized by UV-Vis absorption and photoluminescence spectroscopies. The Schiff-base ligand and its Zn complex exhibit a good sensitization activity in dye sensitized solar cells(DSSCs). In addition, the complex shows better photo-electro conversion efficiency than that of the free ligand in DSSCs. The photo-electro conversion efficiency of the complex is 1.45%(AM 1.5, 100 mW·cm^-2).

Synthesis and Characterization of  Mesoporous Silica Marterial with Partly-ordered Pore Walls

DIAO Lan, SHU An-Shan, ZHANG Da-Liang, DI Yan, QIU Shi-Lun

2006, 27(2):  208-211. 

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An “improved secondary crystallization” method was firstly proposed to treat mesoporous silica SBA-15. The results of various characterization including XRD, TEM, ED, FTIR and NMR indicate that in the obtained material, the connection of framework atoms are ordered in certain degree, which is different from the conventional amorphous pore wall. Moreover, the highly ordered mesostructure is well maintained via  this method. The obtained material shows much better hydrothermal stability than conventional SBA-15.

Preparation of Cerium(Ⅲ) Fluoride Nanoparticles via Water Solution Method

WU Da-Xiong, WU Xi-Dun, LU Yan-Fei

2006, 27(2):  212-214. 

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Abstract A simple and effective method for preparing cerium(Ⅲ) fluoride nanoparticles was reported, which is suitable for scale production. Cerium (Ⅲ) fluoride nanoparticles were synthesized by direct precipitation from aqueous solution, without any organic solvent or surfactant involved in the whole process.  X-ray powder diffraction analysis showed that the product was a single phase. The grain sizes calculated with Scherrer equation were between 10~17 nm. The images of transmission electron microscopy confirmed that the sizes of the cerium(Ⅲ) fluoride particles were below 20 nm in diameter. Neither organic solvent nor surfactant was involved in the whole process and the particle size distribution was narrow.

Synthesis and Fluorescence Property of BaLiF₃∶Ce³⁺ Nanoparticles

SHU Guo-Xian, Hong-Zhou, MO Feng-Shan, SHI Chun-Shan

2006, 27(2):  215-217. 

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Abstract The complex fluoride BaLiF₃ and BaLiF₃∶Ce³⁺ nanocrystals were synthesized in cetyltrimethylammonium bromide(CTAB)/2octanol/water microemulsion systems. XRD analysis shows that the products were single phase and XPS analysis shows the oxygen content was low. The result of ESEM confirms that the average size of the BaLiF₃ nanocrystals was 28 nm in diameter. The emission peak of the BaLiF₃∶Ce³⁺ nano-particles synthesized by microemulsion shows obvious blue shift in comparison with that of BaLiF₃∶Ce³⁺ synthesized by the reaction at a high temperature and full width at half maximum(FWHM) of emission band was broaden.

Preparation and  Application of Cross-linked Polyacrylamide Coated Column  for Capillary Electrophoresis

TIAN Hong-Zhe, Yang Bing-Cheng, Guan Ya-Feng

2006, 27(2):  218-221. 

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Abstract A method was developed for the preparation of static coating onto the fused-silica columns with cross-linked polyacrylamide. The coated columns were effective to suppress the electroosmotic flow and prevent the absorption of basic proteins on the column wall. The basic proteins were separated by using the coated columns at pH=4.0,  with retention time variation of less than 2.1% RSD. The average separation efficiencies were 2.4×105 plates/m for alkaloids. The cross-linked polyacrylamide coated columns can be prepared reproducibly by using this method.

Comparison Studies of Constituents Between Dangguibuxuetang and
Its Single Medicines via Hyphenated Chromatography and
Multicomponent Spectral Correlative Chromatography

WANGYa-Li, LIANG Yi-Ceng,Hu-Yun, LI Bo-Yan, CENG Zhong-Da, XU Shu-Bing

2006, 27(2):  222-226. 

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AbstractIn this study, a compound medicine of Dangguibuxuetang and its two involved single medicines of Danggui(Radix Angelica sinensis) and Huangqi(Radix Astragali) were compared for their relevant constituents after the combination of hyphenated chromatography and multicomponent spectral correlative chromatography, based on the two-dimensional spectrochromatographic fingerprints of the three medicinal objects obtained from HPLC-DAD. It was found that of twenty-one high peaks in Dangguibuxuetang, eight originate from Radix Angelica sinensis, six from Radix Astragali, and seven from both Radix Angelica sinensis and Radix Astragali. A little of other components in the investigated overlapping peaks varied. Moreover, new chemical ingredients appeared just in spectrochromatographic fingerprints of Dangguibuxuetang, and some existing in those of single medicines contrarily disappeared after the compatibility, as opposite in Radix Angelica sinensis and Radix Astragali. It suggested that there are certain interactions of the chemical ingredients in compound medicine besides their total sum effect of single medicines. This proposed approach was quite convenient and reliable to make a quick comparison and analysis of the relevant constituents in spectrochromatographyic fingerprints of the compound and single medicines, especially for the comparison of two overlapping peaks.

Rapid Determination of Pesticide Multiresidues in Vegetable by Gas Chromatography\|mass  Spectrometry and Compensation for Matrix Effect with Protectants

HUANG Bao-Yong, PAN Can-Beng, WANG Yi-Ru, CAO Zhe, ZHANG Wei, LI Wen-Ming, JIANG Shu-Ren

2006, 27(2):  227-232. 

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Abstract A multi-residue method is described for rapid determination of 52 multi-class pesticides, including  their isomers, in vegetables by gas chromatography-mass spectrometry(GC-MS) with the aid of analyte protectants. Addition of different  combinations of  protectants before injection for compensation of matrix effect was demonstrated. Pesticides were extracted from samples with acetonitrile and the extract was cleaned up by using dispersive method by primary-secondary amine sorbent. Pesticides was injected into GC with the aid of analyte protectants [3-ethoxy-1,2-propanediol(20 mg/mL)and D-sorbitol(1 mg/mL)] , followed by MS detection under EI ionization and selective ion monitoring mode. Good linear and lower limits of detection were obtained, the linear range are between 0.01 and 1.00 mg/L, correlation coefficients are better than 0.98, and the detection limits are mainly between 0.2 and 9.4 μg/kg. All compounds have mean recoveries of 81.8%-119.5% and the relative standard deviation is between 0.8% and 17.6%.

Fabrication and Characterization of Au Disk Mircoelectrodes

ZHU Ming-Zhi, JIANG Zhuang-De, JING Wei-Xuan

2006, 27(2):  233-235. 

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AbstractAu fiber disk microelectrodes with well defined geometries were fabricated by low temperature  plasma enhanced chemical vapor deposition(PECVD). Silicon nitride thin films with thickness of 0.7 μm were deposited concentrically on the cylindrical length of 25 μm Au fibers. To form microelectrodes devices, the coated gold microfibre was connected to a copper leader with Ag epoxy. The thin film deposition was performed in a PECVD instrument with substrate temperature (340±10) ℃. Comparing with chemical vapor deposition and resistive heating (CVD\|RH), the insulation by the PECVD can be performed to metal microfibres with the low melting or softening points for the fabrication of microelectrodes as it offers the possibility to fabricate a surface coating at low temperature (≤450 ℃). The quality, thickness and adhesion to the fiber substrates of films were characterized by scanning electron microscopy. The films are found to be free of microcracks and have a quality seal with Au fibers. Cyclic voltammograms were obtained in electrolyte of 0.5 mmol/L K₃Fe₃ (CN)₆ in 0.5 mol/L KCl solution. The electrochemical responses are sigmoidal in shape and indicate that the radial diffusion is the primary mode of mass transport at different scan rates. As a result, the silicon nitride coated disk microelectrodes exhibit an excellent microelectrode electrochemical response without  using an epoxy sealant.

Periodate-oxidized Heparin Inhibiting P-selectin-mediated A375 Cell Adhesion

WEI Min, Zhou-Xi-Fa, Tian-Mei-Hong, Chen-Lin, Zeng-Xian-Lu

2006, 27(2):  236-239. 

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Abstract Numerous experiments  show that heparin affects tumor metastasis in various ways, and one of the mechanisms by which heparin inhibits metastasis is by blocking the P-selectin-based interaction of platelets with tumor cells. However, heparin′s significant anticoagulant properties and the potential of bleeding complications may contraindicate its use as an anti\|metastasis compound.  RO-heparin with low anticoagulant activity was tested as the inhibitor of human malignant melanoma A375 cells adhering to surface-immobilized platelets expressing P-selectin. Then we demonstrate that RO-heparin can block P-selectin-mediated A375 human melanoma cell adhesion, suggesting that it may has a potential value as a anti-metastatic, therapeutic agent.

Chemical Synthesis and Esterification of a Precursor Dipeptide of RGD as a Site for Cell Adhesion

WANG Hua, Zhao-Mi-Feng, Li-Gang, Huang-Yi-Bing, Hou-Rui-Zhen, Ceng-Hong-Bin, Xu-Li, Zhang-Xua-Zhong

2006, 27(2):  240-243. 

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Abstract A precursor dipeptide of RGD as a site for cell adhesion,  GD(Gly-Asp),  was synthesized by a novel chemical method in two steps including chloroacetylation of L-aspartic acid and ammonolysis of chloroacetylated L-aspartic acid.  GD dipeptide ethyl ester and methyl ester were synthesized by ROH-HCl method.  The condition of the  esterification was optimized by examining the effects of some key factors, such as the molar ratio of GD to ethanol/methanol,  reaction temperature and reaction time,  on the yields of GD esters.  The optimal esterification condition for the two GD esters was established being the molar ratio of GD dipeptide to ethanol/methanol(1∶40),  30 ℃,  for 1—2.5 h, under which  the maximum yield of 80%—85% was obtained.  The two GD esters were confirmed as Gly-Asp-(OEt)₂ and Gly-Asp-(OMe)₂ by mass spectrographic analysis.

Theoretical Study, Synthesis and Characterization of the ［60］ Fullerene
Sulfurbridge Linked 2-Thioxo-1,3-dithioles Derivatives

LU Mei-Xiang, ZENG He-Ping

2006, 27(2):  244-249. 

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Abstract To attaining longlived charge separated states, the new compounds 7 and 8 of C₆₀-S-2-thioxo-1,3-dithioles derivatives were synthesized by Diels-Alder cycloaddition reaction. The structures generated by AM1 were used as the initial configurations for the density functional optimization(DFT)at the B3LYP/3-21G level for all carbon and sulfur clusters, and some geometry conformation indexes were obtained. We found that C60 has been halfpacked by the curved 2-thioxo-1,3-dithioles derivatives. The distant space between donor and acceptor is shorter than no sulfur-bridge covalent bond linked and the energy gap is smaller. A longlived charge separated states may occur in the ［60］fullerene sulfur-bridge covalent bond linked tetrathiafulvalene derivatives when it is excited. The medial and final molecular structures were identified and characterized by TOF-MS, ¹H NMR, ¹³C NMR, FTIR, UV-Vis and Fluorescence spectra.

Synthesis of a Novel Soluble Polymer\|bound Chiral Ligand and It's Application in Catalytic Asymmetric Dihydroxylation of Olefins

CHENG Ci-Kun, ZHANG Sheng-Yong, WANG Beng-An, SUN Xiao-Chi, DIAO Yan

2006, 27(2):  250-253. 

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The osmium catalyzed asymmetric dihydroxylation(AD) of olefins in the presence of cinchona alkaloid derivatives provides one of the most effective methods for the preparation of chiral vicinal diols. Although this reaction has had a widespread application to organic and pharmaceutical synthesis,  there have been few large\|scale industrial products due to the complicated synthetic manipulations required to produce the chiral ligands. Attachment of the cinchona alkaloid to polymers and recycling of catalyst are of great interest. To realize homogeneous catalysis,   in this paper,  1,4-difluoroanthraquinone was nucleophilically mono\|substituted by HO-OPEG-OMe in the presence of KOH and K2CO3 in dry toluene,  to give intermediate F-AQN-OPEG-OMe in 88% yield. Then,  QN-AQN-OPEG-OMe was obtained in 95.6% yield by reaction of F\|AQN\|OPEG-OMe with the lithium salt of quinine. The homogeneous catalyst that QN\|AQN\|OPEG\|OMe complexed with osmium tetroxide in situ delivered excellent enantioselectivities(92%-99% e.e.) and good yields(80%-94%) in AD reactions of four olefins,  comparable to that of the homogeneous catalyst with Sharpless ligand(DHQ)2AQN reported. This ligand was recovered almost quantitatively by a simple filtration and reused for five cycles without obvious decreased and catalytic activities,  with 95%-97% recovery of ligand.

Studies on  Synthesis of 2\|Carboxylic Acid Phenyl Heptaglucoside and Its Phytoalexin\|Elicitor Activity

MEI Xiang-Dong, ZHANG Zhi-Beng, YI Yue-Chao, LI Bao-Ju, NING Jun

2006, 27(2):  254-257. 

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The elicitor-active heptaglucose (2) acts as a regulatory molecule in plants, which can stimulate biosynthesis of phytoalexins in quantities sufficient to inhibit growth of microbial pathogens. Salicylic acid can also stimulate plants to produce phytoalexin as a defense response to the pathogen. In order to investigate the synergic effect of the heptaglucose (2)  and salicylic acid, 2\|carboxylic acid phenyl gluco\|heptasaccharide (1)  was synthesized by condensation of the hexasaccharide donor (7)  and 2\|methylcarboxylate phenyl glucoside acceptor (6), which was obtained by 6-O-deacetylation of 2-methylcarboxylate phenyl 6-O-acetyl-2,3,4-tri-O-benzoyl-α-D-glucopyranoside (5). Compound 5  was synthesized by coupling of 6-O-acetyl-2,3,-|tri-O-benzoyl-α-D-glucopyranosyl trichloroacetimidate (3)  with methyl salicylate (4). The structures of all compounds synthesized were determined by NMR and elemental analysis. The ability of elicitor to stimulate phytoalexin accumulation in soybean tissue has been used as the basis for biological assays of its activity. Bioassay indicates that the heptaglucose derivative synthesized here has slightly more phytoalexin-elicitor activity than its corresponding heptaglucose, heptaglucose 2 and salicylic acid have a synergic effect.

Synthesis and Biological Activity of a Series of Poly-substituted Purines

YUAN De-Kai, LI Zheng-Ming, DIAO Wei-Guang, FAN Zhi-Jin, WANG Su-Hua

2006, 27(2):  258-262. 

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urine plays very important roles in life process, such as metabolism and heredity, while purine nucleosides and nucleotides are the key components of some important co\|enzymes nucleic acids.  Lots of compounds containing purine ring have been developed into drugs in treating cancer, virus infection and vascular disease.  In recent years, nucleic acid chemistry is also developed into a focused field.  And  derivation and selective modification of purine ring have attracted great attention of researchers.  Although N\|benzyl adenine was found to possess a good plant growth regulation (PGR) activity and used in agriculture for a long time, there is much less attention paid on purine ring than other heterocycles in agro\|chemistry field.  In order to study the synthesis and biological activities of multi-substituted purines, new poly\|substituted purine-8-thiones (6) were obtained from 4\|chloro\|5\|nitropyrimidine (3) via  a series of reactions as amination, reduction and cyclization.  After alkylation of compounds 6, 7 and 8 were obtained in high yields.  The preliminary  bioassay indicates that some of compounds  6, 7 and 8 possess moderate herbicidal and anti-TMV activities.

Analysis of E6 Variants of Human Papillomavirus Type 18, 45 Isolated from Cervical Cancer Patients in Sichuan Province

WU En-Qi, REN Yuan, QIU Ai-Dong, ZHANG Guo-Nan, JIANG Chun-Lai, FAN Ying, XU Xiang-Hui, WU Yong-Ge, CHA Xiao, Kong Wei

2006, 27(2):  263-267. 

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The E6 genes of human papillomavirus(HPV) 18 and 45 variants were isolated and amplified by PCR from the tumor tissues of patients with cervical cancer in Sichuan Province of China, and the E6 genes were sequenced for investigating their structural characteristics and variability. The same two point silence mutations were found in three samples of HPV18, and six point mutations were found in one sample of HPV45, resulting in changes of the translated amino acids at two points(T19I and C53F) which are located in the HPV E6 epitope regions. Some point mutations of the HPV45 are identical to those nucleotides found specifically in the HPV18 from these samples, the diversity between HPV18 and HPV45 of Sichuan variants is less by 4.05% than between HPV18 and HPV45 of wild types, this value is lower than that of variants isolated from Africa, which support the hypothesis that the phylogenetic root of HPV18 and 45 is in Africa.

Investigation of the Effect of 5-FU on p33^ING1 mRNA Level Based on Molecular Beacon

WANG Wei, LIU Bin, LI Jun, WANG Ke-Min, TAN Wei-Hong, TANG Hong-Xing

2006, 27(2):  268-270. 

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Abstract In order to conduct the fundamental investigation of the effect of 5-FU on HNE1 cells,  p33^ING1 mRNA level in cellular total RNA was detected quantitatively based on MB assay.  During the operation,  the effects of 5-FU concentrations and treatment time in HNE1 cells and HNE1 cells transfected with p33^ING1 were measured in vitro.  The results were as follows: p33^ING1 mRNA expression level in tumor cells was enhanced not only by the 5-FU concentration but also by lapse of time.  The MTT results also proved that high expression of p33^ING1 mRNA can increase cell's sensitivity to chemical drug 5-FU.  The detection method based on MB can be used to provide useful evidence quickly and quantitatively for gene expression and new chemical drugs development.

Quantum Dots Labeled Immune Peptide and Characterization of the Interaction with T Cell

WANG Li-Feng, WANG Li-Ping, CHEN Jie, FANG Xue-Xun, LI Wei

2006, 27(2):  271-273. 

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Abstract Semiconductor quantum dots(QDs) were used for labeling many biomacromolecules and small molecules, but it remains a challenge to couple it  with short active peptides without any limitation, which play critical roles in many physiological processes. Several coupling methods known about QDs and short peptides  have some limitations. In this research, we report a method for the synthesis of QDs labeled  peptides to be appropriate to any short peptide. The QDs(CdTe)-labeled short peptides were verified and characterized by RP-HPLC. The result shows that the surface of the T cell treated with QDs-TP5 emits yellow fluoresence. These results indicate that QDs-TP5  tends to aggregate on the surface of T cells. They were applied to monitoring the specific binding between the  immune peptides and T cell surface receptors. The binding and the resultant fluorescence were observed and monitored by fluorescence microscope in vitro. The QDs-labeled immune peptides provide a powerful method for studying  the immune modulating activity of TP5  in vivo.

Continuum Medium Model of Non-equilibrium Solvation and Solvent Effect for Ultra-fast Process

ZHU Quan, FU Ke-Xiang, LI Xiang-Yuan

2006, 27(2):  274-286. 

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n the 1950s of the 20th century, the non-equilibrium solvation theory for ultra-fast processes such as electron transfer and light absorption/emission was paid particular attention to. A number of scientists made efforts to study this area and various models, which give reasonable qualitative descriptions for solvent reorganization energy in electron transfer and spectral shift in solution, were developed within the framework of continuous medium theory. However, in a series of publications by the authors (see for example J. Comput. Chem. 2004, 25: 500; J. Comput. Chem. 2004, 25: 835; J. Comput. Chem. 2005, 26: 399; Chinese Sci. Bull. 2003, 48: 965; J. Mole. Struct.Theochem 2005, 715: 157), it was clarified that the expression of the nonequilibrium electrostatic free energy, which is at the dominant position of nonequilibrium solvation and serves as the basis of various models, was incorrectly formulated. In this work, the authors argue that reversible charging work integration δW=∫_VΦδρdV  was inappropriately applied to an irreversible path linking the equilibrium state and the non-equilibrium one in the past. Because the step from the equilibrium state to the non-equilibrium one is factually thermodynamically irreversible, the conventional expression for nonequilibrium free energy, G^non₂(M)=(1/2)∫_V(ρ₂Φ^non₂+ρ₂Φ^eq₁-ρ₁Φ^non₂)dV  that was deduced in different ways, is unreasonable. Here the authors derive the non-equilibrium free energy to a quite different form of  G^non₂=(1/2)∫_V ρ₂Φ^non₂dV according to Jackson integral formula,dG= (1/2)∫_V(Φδρ+ρδΦ)dV. Such a difference throws doubts to the models including the famous Marcus two-sphere model for solvent reorganization energy of electron transfer and the Lippert-Mataga equation for spectral shift. By introducing the concept of “spring energy” arising from medium polarizations, the energy constitution of the non-equilibrium state is highlighted. For a solutesolvent system, the authors separate the total electrostatic energy into different components: the selfenergies of solute charge and polarized charge, the interaction energy between them and the“spring energy” of the solvent polarization. With detailed reasoning and derivation, our formula for non-equilibrium free energy can be reached throughdifferent ways. Based on the new expression of nonequilibrium free energy, the generalized form for solvent reorganization energy,λ_av=(1/4)∫_VΔρ(Δφ_op-Δφ_s)dV, has been attained. A new twosphere model for solvent reorganization energy is proved to have the form of  λ_av=(1/2)Δq²(1/ε_op-1/ε_s)(1/(2r_D)+1/(2r_A)-1/d). Compared with Marcus′ expression, this new formula estimates the solvent reorganization energy only one half of the latter. This difference provides a pretty explanation for why Marcus′ theory often overestimated the solvent reorganization energy by a factor about two in the past. With the single-sphere model and point dipole approximation, the authors argue that the total spectral shift should look like Δhν_total=(1/2)R_slow(μ₁-μ_m)², and this is also one half of the Lippert-Mataga result. The novel expressions for the spectral shifts for individual absorption and emission have also been given. Finally, a numerical algorism for the solution of Poisson equation is presented and the total nonequilibrium solvation energy is deduced to a quite different and much more compact form as ΔF^non₂=〈Ψ^non₂|H⁰+(1/2H''|Ψ^non₂〉-〈Ψ^gas₂|H⁰|Ψ^gas₂〉+(1/2)∑_i∑_j［q₂,_fast(i)+q_1,slow(i)］Z_j/(|r_i-R_j|) when compared with the most recently developed expression by other authors. As an application, the numerical algorism incorporated with COSMO was applied to a model system, and the solvent reorganization energy is found in excellent agreement with the experimental fitting,while the conventional theories always estimate twice this quantity.


3D-QSAR Study of a Series of Novel Benzofuran NMT Inhibitors

ZHU Jie, SHENG Chun-Quan, ZHANG Min, SONG Yun-Long, CHEN Jun, YU Jian-Xin, YAO Jian-Zhong, LIAO Zhen-Yuan, ZHANG WAN-Nian

2006, 27(2):  287-291. 

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AbstractUsing comparative molecular field analysis(CoMFA) and comparative molecular similarity indices analysis(CoMSIA), three dimensional structureactivity relationship(3D-QSAR) studies were carried out on a series of benzofuran N-myristoyl transferase(NMT) inhibitors. Variation of grid spacing was used during the optimization of the CoMFA model. For the CoMSIA study, the influence of the combination of different field types was evaluated and the best combination was considered to be steric, electrostatic, hydrophobic and Hbonding acceptor fields. Variation of grid spacing and attenuation factor was used to obtained the best CoMSIA model. The resulting CoMFA and CoMSIA models had a cross validated coeffiecient(q²) of 0.759 and 0.730 respectively, which showed a strong predictive ability on both test-set and trainingset. The tri-dimensional contour maps of CoMFA and CoMSIA provided smooth and interpretable explanation of the structure-activity relationship of the compounds. The analysis of the tri-dimensional contour maps permitted interesting conclusions about the effects of different substituents of different positions of the benzofuran group on the antifungal activity, which will guide the design of novel NMT inhibitors with a higher activity.

Theoretical Investigations on Molecular Conducting Wire under Electric Field

LI Yan-Wei, ZHANG Yan, YIN Ge-Ping, ZHAO Jian-Wei

2006, 27(2):  292-296. 

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AbstractPolyacetylene, as a model molecular conducting wire, was studied theoretically at HF/6.31G, HF/6.31G*, HF/6.31G**, HF/6.31+G, HF/6.31++G, HF/6.31+G*, HF/6.31+G**, HF/D95+*, B3LYP/6.31G*, B3LYP/6.31+G* levels, respectively. The influences of the external electric field intensity on the molecular conducting wire were discussed in terms of molecular geometry, SCF energy and molecular orbital energy. A quantitative relationship between the above factors and electric field intensities was revealed.

Adsorption and Vibration for H Atom on Fe Low-index and High-index(211) Surfaces

FENG Hui, DIAO Zhao-Yu, WANG Ze-Xin, ZHANG Jing

2006, 27(2):  297-302. 

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AbstractThe 5-parameter Morse potential(5-MP) of the interaction between H atom and Fe surface was constructed. The absorption and diffusion of H on Fe low-index surface and Fe(211) high-index surface were investigated with 5-MP in detail. All the critical characteristics of the system were obtained, such as adsorption site, adsorption geometry, binding energy, eigenvalues for vibration, etc. And our calculated results are in good accordance with the experiments. The calculated results show that H atom is located at the fourfold hollow site of the intact Fe(100) surface, the vibrational frequency is 1 009 cm^-1; and on Fe(110) and Fe(211) surfaces, H atom trends to occupy quasi-3-fold site without exception, the vibrational frequencies are 1 054 and 1 046 cm^-1, respectively. However ,the most stable site on Fe(111) surface is bond site, the vibrational frequency is 1 030 cm^-1.

Multireference Theoretical Calculation of Photodissociation of SSCH₃

YAN Bing, PAN Shou-Fu, WANG Zhi-Gang, YU Jun-Hua

2006, 27(2):  303-305. 

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Abstract The vertical excitation energies of SSCH₃ were calculated by using multireference MΦller-Plesset theory. The adiabatic and diabatic potential-energy curves of the two types of bond cleavage, S—C and S—S, were calculated with multireference MΦller-Plesset theory, the photodissociation dynamics of SSCH₃ under 193 nm laser was investigated and the results are in good agreement with those of the previous experiments.

Spatial Ordered Structure Originated in Metallomicelle System Beyond Turing Bifurcation and Its Catalytic Activity

ZHANG Wen-Hua, Luo Jiu-Li

2006, 27(2):  306-309 . 

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Abstract Based on the ternary complex kinetics model for metallomicelle catalysis, the special dynamic behavior of this kind of super-molecular system related to the capable self-organization formed in it is analyzed in this paper. It is found that a kind of spatial ordered structure in metallomicelle catalytic reaction system can emerge beyond Turing bifurcation if a set of relationships between the characteristic parameters and the externally controlled parameters are satisfied. This self-organization of the concentrations in the metallomicelle system induced by the chemical reaction-diffusion coupling and the non-ideality of the components results in a special spatio-ordered catalytic activity distribution with a maximum. The theoretic results reported in this article will be helpful to explain the ordered catalytic activity characteristic of the metallomicelle system.

Studies on the Thermochemisry for Scattered Metal Compound  InCl₃

GUAN Wei, LI Lei, WANG Heng, HU Wei-Guo, YANG Jia-Zhen

2006, 27(2):  310-313. 

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AbstractThe molar solution enthalpies of scattered metal compound InCl₃  with various molalities were determined at 298.150 K in water by the solution reaction isoperibol calorimeter.  According to Pitzer′s electrolyte solution theory,  the molar solution enthalpy of InCl₃  at infinite dilution,  Δ_sH^∞_m ,  and Pitzer′s parameters  β^(0)L_MX and   β^(1)L_MX were obtained.  Then the values of apparent relative molar enthalpy ΦL,  hydration heat and relative partial molar enthalpy of solute(InCl ₃),  L₂,  were calculated,  respectively.  At last,  the interaction of InCl₃ with water was discussed.  In terms of the crystal lattice energy of InCl₃ and the hydration heat of Cl^-,  the values of the hydration heat of InCl₃ and In³⁺ were obtained. 

The Order of Surface Adsorption and Micella Formation of Binary Surfactant Systems Containing Dodecyl Polyglycoside

WANG Zhong-Ni, LI Gan-Zuo, ZHANG Gao-Yong, LIU Feng, MU Jian-Hai, WANG Zheng-Wu

2006, 27(2):  314-318. 

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Abstract Surface tension, dynamic surface tension and molecule exchange energy in mixed monolayer formation(ε) and mixed micellization(ε_m) were determined, for binary mixtures of a multidegree polymerized dodecyl polyglycoside C₁₂G_1.46 with C₁₂E₃S(trioxyethylenated dodecyl sulfonate), C₁₂TAC(dodecyl trimethylammonium chloride), BE-6(hexa-oxyethylenated trisilaxane surfactant), and TMN-6(hexa-oxyethylenated-2,6,8-trimethyl-nonanol), respectively, in 0.1 mol/L NaCl solution at 25 ℃. From the results obtained two conclusions are drawn: (1) C₁₂G_1.46 is more surface-active than pure C₁₂G₁ and C₁₂G₂, which is interpreted by the energy results calculated by using MM2 force field method; (2) for C₁₂G_1.46/BE-6 and C₁₂G_1.46/TMN-6 systems, the mixed monolayer formation is prior to the mixed micelle formation, in which ε-ε_m<0 and the dynamic surface tensions reach the meso-equilibrium with 15 s; while for C₁₂G_1.46/C₁₂E₃S and C₁₂G_1.46/C₁₂TAC systems, surface adsorption and micellization processes occurred at the same time, in which ε-ε_m≥0 and the meso-equilibrium are reached within about 50 s.

Electrochemical Synthesis of Diamond and Diamond-like Material at  Ambient Temperature and Pressure

ZHANG Bo, QIU Ri, ZHANG Juan, DIAO Xiao-Hui, ZHANG Shu-Yong

2006, 27(2):  319-322. 

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The possibility of electrochemical synthesis of diamond from CCl₄-Nacl-BMIM]BF₄ system at ambient temperature and pressure was testified by using the linear sweeping voltammetry(LSV), X\|ray diffraction(XRD), and Raman spectroscopy. It was found by LSV that CCl₄ could be directly reduced on Pt electrode without NaCl serving as electron medium. A substance with black color formed on Pt electrode during the potentiostatic electrolysis between -1.5 and 2.4 V vs. Ag/AgCl. The characteristic diffraction peaks of diamond  with d = 2.03, 1.23 and 1.07  could be observed in the XRD pattern of the product with another compound of unknown composition distinguished. In the Raman spectrum, the characteristic Raman shift of diamond at 1 332 cm^-1 could be observed. Both XRD and Raman spectroscopy confirmed the presence of diamond or diamond\|like material in the product. This suggested that to synthesize diamond or diamond-like material from CCl₄-[BMIM]BF₄ system at ambient temperature and pressure is possible.     The formation mechanism of diamond or diamond-like material from CCl4 electrochemically was discussed.

Photovoltaic Polarity Inversion in Thin Filma of Titanoxophthalocyanine/N,N-Bistolylperylene Tetracarboxylic Dimimide Composite Films

SUN Jing-Zhi, CAO Jian, XU Hai-Feng, HONG Huang

2006, 27(2):  323-326. 

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Surface photovoltaic behavior of titanoxophthalocyanine(TiOPc)/N,N-bistolylperylene tetracarboxylic diimide(ToPTCDI) composite films was investigated with surface photovoltaic spectroscopy(SPS) and field induced surface photovoltaic spectroscopy(FISPS).  It was found that the introduction of  ToPTCDI into TiOPC could result in negative SPS response both in visible and in near-infrared spectral regions,  which was assigned to the phenomenon of photovoltaic polarity inversion.  The polarity of the SPS signals could be tuned by external bias,  showing the characteristic of surface electronic states.  Based on the n\|type nature of ToPTCDI,  the energy space between the optical transitions from valence band to surface state and from surface state to conduction band,  as well the bias-direction dependent FISPS signals,  the origin of the surface electronic state was ascribed to ToPTCDI component.

Studies on the Desulfurization Kinetics of Shell Sorbent Using Thermogravimetric Analysis Method

HAN Kui-Hua, LU Chun-Mei, CHENG Shi-Qiang, WANG Yong-Zheng, DIAO Jian-Li

2006, 27(2):  327-331. 

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The general desulfurization sorbent, limestone is limited in sulfation temperature range and suffers from rapid loss of reactivity and incomplete utilization. However, plentiful shells are generally abandoned as garbage especially in coastal area, which consist of CaCO₃ similar to limestone. Desulfurization with shell shows a higher calcium utilization and better sulfation property than limestone under various experimental conditions. The desulfurization reaction process of calcium\|based sorbent including four species of shell and a sort of limestone were investigated by thermogravimetric analysis method. The kinetic behavior was expressed by the  modified grain model. The activation energy (E_a) and the pre-exponential factor (k₀) of surface reaction, the activation energy (E_p) and the pre\|exponential factor (D₀) of product layer diffusion reaction were calculated and explained according to the model. It is shown that   the modified grain model can describe the desulfurization course of shells and limestone. Additions of alkali metal salts may improve microstructure and product diffusion of sorbent during high temperature sulfation, and enhance the initial reaction rate and the final CaO conversion of sorbents. The kinetic parameters of shell desulfurization show a compensation effect. There are linear relationships between logarithms of the pre-exponential factor lnk0, lnD₀ and activation energies E_a, E_p respectively. The method based on the isokinetic temperature Ts to estimate sorbent activity is applied to different control stage. Alkali metal salts can enhance the initial reaction rate, at the same time can accelerate the high temperature sintering of sorbent, so there is optimal content in sorbent. The advisable molar ratio of alkali metal cations (mainly Na ⁺ and K ⁺) to Ca²⁺ in the sorbent is best kept to 2% approximately at the desulfurization temperature range of 1 073-1 273 K.

Density Functional Theory Studies on Interaction Between Calix[4]bipyrrole and Halide Anions

CHEN Dong-Hui, CHEN Pei-Quan, SUN Hong-Wei, CHEN Lan, CHEN Rong-Xin, YUAN Jing, YUAN Man-Xue, LAI Cheng-Meng, LI Zheng-Ming

2006, 27(2):  332-335. 

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A new class of calix[4]pyrrole analogue containing bipyrrole show a good affinity for halide anions.  calix[4]bipyrrole and its complexes with the halide anions were investigated by density functional theory(B3LYP) at the 6\|31G* and LANL2DZ level.  It was shown that  calix[4]bipyrrole and halide anions can form highly symmetric complexes by eight intermolecular hydrogen bonds.  The interaction between calix[4]bipyrrole and halide anions decreased along the halide elemental period.  The calculated results of frequency, charge distribution and front molecular orbital show that there are linear correlations between the BSSE correct binding energy and charge transference, N─H bond length, N─H stretch frequency shifts.

Recognition of Halide Anions by Strapped Calix[4]pyrroles

DIAO Pei-Chi, SUN Hong-Wei, CHEN Lan, CHEN Rong-Xin, CHEN Pei-Quan, YUAN Jing, YUAN Man-Xue, LAI Cheng-Meng

2006, 27(2):  336-339. 

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Anion\|binding chemistry has emerged in recent years as one of the most intensely explored areas of supramolecular chemistry.  The binding of different halide anions to four strapped calix[4]pyrroles was  studied by means of molecular mechanics and molecular dynamics simulations methods.  The results indicate that the anion binding ability of calix[4]pyrrole-type systems could be effectively tuned by modifying the length and nature of the bridging straps. In this process,  it was the most stable conformation upon anion binding due to the formation of four NH\|halide hydrogen bond,  simultaneity,  the difference of cavity by modifying straps adapted themselves to different halide anion.

Studies on Electron Transfer on Pt^ⅣCl_x /TiO₂ Induced by Irradiation of  Visible Light

CHEN Yi-Lin, LI Dan-Zhen, WU Qing-Ping, FU Xian-Zhi, WANG Xu-Xu

2006, 27(2):  340-342. 

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AbstractA TiO₂ modified with Pt^Ⅳ chloride was  investigated by diffuse reflectance UV\|Vis spectra (DRS), X\|ray photoelectron spectroscopy (XPS),  surface photovoltage spectroscopy(SPS) and electric field\|induced surface photovoltage spectroscopy(EFISPS). XPS showed that a Ti-O-Pt^ⅣCl_x surface complex between Pt^Ⅳ chloride and TiO₂ appears to be responsible for visible light absorption. An electron transfer from the surface-complexed Pt^ⅣClx to the conduction band of TiO₂ upon absorbing visible light was confirmed by SPS and EFISPS.

Studies on ab initio Principle of Electronic Structure of New-diamond  

WEI Na-Ran, WEN Bin, GONG Chang-Wei, MA Hong-Jun, LI Ting-Ju

2006, 27(2):  343-345. 

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AbstractAfter the pyrogenation of carbon black and nanometer-sized iron catalyst at atmospheric pressure and a temperature of 1 100 ℃, new-diamond nanometer-particles were synthesized. The new-diamond was analyzed by X-ray diffraction(XRD). The lattice constant of the new-diamond is determined as 0.359 4 nm. Based on the ab initio principle of density functional theory, the electronic structure of the new-diamond was investigated. The results indicate that the new-diamond is a metallic form of carbon.

Preparation and Characterization of Sr-doped TiO2 Nanocrystal  Microspheres

LV Yao-Jun, DAN Ge-Yu, GUO Xian-Zhi, CHEN Hong-Jian, ZHANG Cheng, HE Chang-Jin, DU Zong-Jie, ZHANG Bao-Long

2006, 27(2):  346-348. 

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Sr\|doped nanostructured crystalline TiO₂ microspheres were fabricated by modifying the bare microspheres with the method of soaking in strontium nitrate solution and heat treatment.  The morphology, crystal structure and photoabsorption ability were characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD) and UV-Vis spectrophotometer.  The observation of SEM showed that both the bare and Sr\|doped microspheres presented the same honeycomb porous morphology.  The XRD spectra affirmed that the incorporation of Sr was in the form of strontium titanate(SrTiO₃) as eutectic structure with anatase TiO₂.  The photocatalytic efficiency of Sr\|doped TiO₂ microspheres was assessed by monitoring the photodecomposition of KN-R dye.  The results reveal that Sr-doped microspheres provided a higher efficiency than the unmodified, which was consistent with the analysis results of UV-Vis absorption spectra.  Obvious phenomenon of red-shift on UV-Vis spectrum was seen in comparison with the bare microspheres.  Both the phenomena of red-shift and the photocatalytic activity improvement were attributed to the synergistic action between SrTiO3 and anatase TiO₂.

Thermodynamic Partitioning Behavior for Solutes into Immobilized Artificial Membrane or an n-Octano/Water System

SUN Jin, ZHANG Tian-Gong, LI Ji, MAO Jing-Jing, HE Zhong-Gui

2006, 27(2):  349-351. 

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The thermodynamic partitioning behavior of solutes into immobilized artificial membrane(IAM) and n-octanol/water systems was investigated, including acidic, basic, and amphoteric substances. In an n\|octanol/buffer system, partitioning process was entropy\|dominated for the most studied drugs, while partitioning of oxolinic and nalidixic acids into n-octanol phase was enthalpy\|driven. In IAM chromatography, partitioning into membrane for the studied solutes was enthalpy\|driven and  an exothermal process. In conclusion, there is a significant difference of solutes′ partitioning mechanism into either IAM or an n-octanol phase, therefore, presenting the theoretical basis for differing lipophilicity measuring scale. 

Stereoselective Polymerization of rac-Lactide Initiated by Achiral Schiff-base Isopropoxide Aluminum Complex

YANG Yong-Kun, Tang-Chao-Hui, PANG-Hui, Du-Hong-Zhi, Chen-Xue-Si, Jing-Xia-Bin

2006, 27(2):  352-355. 

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Abstract An achiral Schiff-base isopropoxide aluminum complex(Ⅱ) was used for the stereoselective ring-opening polymerization of rac-lactide. The kinetics studies indicated that rac-lactide polymerization was first order kinetics to monomer concentration. There was linear relationship between the monomer conversion and molecular weights(Mn) of the polymer with a narrow molecular distribution. These phenomena indicated that the polymerization was well controllable. Moreover, the obtained poly(rac-lactide) was crystalline polymer with relative high tm(179 ℃). 13C NMR and homonuclear decoupled ¹H NMR spectra revealed that the polymerization of rac-lactide initiated by complex(Ⅱ) resulted in the isotactic stereoblock polymer, which contained blocks with an average of 11 units of enantiomerically pure lactic acid.

Polymerization Characteristics of ε-Caprolactone at Low Temperature by Lanthanum Tris(2,6-di-tert-butyl-4-methylphenolate) and the Block Copolymerization of ε-Caprolactone with Cyclic Carbonates

ZHU Gui-Xiang, TAN Guo-Hua, LING Jun, CHEN Wei, SHEN Zhi-Quan

2006, 27(2):  356-359. 

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Abstract The polymerization characteristics of ε-caprolactone(CL) with lanthanum tris(2,6-di-tert-butyl-4-methylphenolate) at a low temperature was reported. The polymerization system shows some living character below -10 ℃. That is the length of polymer chain increases with the increase of  the molar ratio of monomer to initiator or polymerization time. The block copolymers of CL and cyclic carbonate(TMC or DTC) were prepared after CL had been polymerized for a period at a low temperature and were characterized by GPC, DSC and 1H NMR.

Synthesis and Characterization of Biodegradable Poly(butylene succinate-co-butylene methyl succinate)

SUN Yuan-Bi, Xu-Jun, Xu-Yong-Xiang, Yan-Li-Tang, Guo-Bao-Hua

2006, 27(2):  360-364. 

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Abstract A series of polyesters PBSM, poly(butylene succinate-co-butylene methyl succinate), were obtained by direct melting polycondensation of  succinate and methyl succinic acid with 1,4-butanediol. The compositions and physical properties of the resulted homopolyester and copolyesters were investigated by ¹H NMR, differential scanning calorimetry(DSC)and X-ray diffraction. The results suggest that the introduction of comonomer containing a side-chain methyl group led to a change in thermal properties and crystallization behavior. The DSC analysis indicates that with the increase of comonomer content, the T_g, T_m, T⁰_m and crystallinity were decreasing gradually, and the depression of Tm followed Flory′ prediction for random copolymer. Furthermore, an Avrami method was used to analyze the kinetics of isothermal crystallization of PBS and PBSM-20. The Avrami exponents, estimated by Avrami plots, ranging from 2.8 to 3.0 for PBS and 2.7 to 3.0 for PBSM-20 indicate that the mechanism of crystallization for both homopolyester and copolyester was a tridimensional growth with heterogeneous nucleation. Meanwhile, X-ray analysis shows that there was almost no effect of the methyl succinate unit on the crystal structure.

Rheological Properties of Liquid-solid Transition in Isothermal Crystallization for High-density Polyethylene

CHEN Qing, FAN Yu-Run, LI Wen-Chun, Zheng-Qiang

2006, 27(2):  365-368. 

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AbstractThe rheological properties of liquid-solid transition during the crystallization for high-density polyethylene(HDPE) was investigated through the static and dynamic rheological measurements.  It is found that with the crystallization proceeding,  a tensile force upon the parallel-plates is induced by volume  contraction of the sample.  In the case of static test with the motionless parallel plates,  this tensile force relaxes quickly in liquid states,  while starts to accumulate after certain time.  Accordingly,  a new method to determine the liquid-solid transition depending on the static tensile force is proposed.  A comparison between it and the classic dynamic one for detecting liquid\|solid transition evidences that the dynamic method is preferred to slow crystallization,  and static method is more appropriate for the crystallization at moderate rates.  Furthermore,  the latter has the advantage of no disturbing the crystallization behavior of HDPE before the transition.

Synthesis and Characterization of Poly-L-glutamic Acid with a High Molecular Weight

CAO Tian, YIN Jing-Bo, LUO Kun, CHEN Hong-Dan, CHEN Xue-Si

2006, 27(2):  369-371. 

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Abstract Poly-L-glutamic acid with a high molecular weight  was prepared by chemical synthesis.  The structures of PBLG and PLGA were confirmed by FTIR and 1H NMR spectroscopies and their molecular weights were measured by GPC and viscosity measurements.  The results show that the average molecular weight of poly-L-glutamic acid is about 7×104\_35×104.   Furthermore,  when the anhydride-initiator malar ratio n(A)/n(I)>50,  the average molecular weight was independent of the amount of triethylamine initiator. 

Properties of a Novel Phenoxy Resin Containing Biphenyl Groups

CA Gong-Chi, NA Hui

2006, 27(2):  372-374. 

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Abstract A kind of novel phenoxy resin derived from 3,3′,5,5′-tetramethyl-4,4′-dihydroxybiphenyl and the epichlorohydrin was synthesized with catalyst and dispersant. FTIR and ¹H NMR spectra were performed to characterize the structure of the resin. The analysis results indicate that the structure answers our design. In addition, the   thermal properties of the resin were studied by DMA and TGA analysis. According to these results, due to the molecular structure containing biphenyl groups in the resin the conformational entropy of chain segment of the polymer depressed effectively and the  T_g increased. The resin characterized in the article also has adequate physical property and good solubility in some solvents.

Synthesis of Complex(1,2\|Ph₂-4-MeCp)₂ZrMe₂ and Catalysis for Ethylene Polymerization         

LV Chun-Qing, ZHANG Fan, MU Ying, LI Hua-Fu

2006, 27(2):  375-379. 

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AbstractA new dialkylzirconocene type of  complex, (1,2-ph₂-4-MeCp)₂ZrMe₂(2),  was synthesized by reaction of (1,2-Ph₂-4-MeCp)₂ZrCl₂(1) and with 2  equivalent of methyl lithium at -78 ℃. Complex 2 was charcterized by elemental analysis,  ¹H NMR and  ¹³C NMR.  The structure of complex 2 was determined by single crystal X-ray structural  analysis. Upon activation with Al( ⁱ Bu)₃/Ph₃C⁺B(C₆F₅)^-₄,  complex 2 showed a high catalytic activity for the ethylene polymerization reaction at  lower  n(Al)/n(Zr) ratios and high molecular  weight polyethylene samples with high melting transition temperatures were  produced. The polyethylene samples were characterized by molecular weight determination, DSC and XRD analysis.

Cloromethylation for Polystyrene under Micellar Catalysis

LIU Qi-Fa, Gao-Bao-Jiao, Yang-Yun-Feng, An-Fu-Jiang

2006, 27(2):  380-385. 

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The solubilization properties of ionic surfactants for polystyrene that was dissolved in carbon tetrachloride were determined by using a UV  method. The chloromethylation reaction of polystyrene was carried out in a micellar catalysis system, and the structure of chloromethylated polystyrene(CMPS) was characterized  by means of  FTIR and its composition was measured via  the  Volhard method. The catalysis effects of two types of anionic and cationic surfactants were compared; the catalysis effects of different cationic surfactants with different structures were examined; and the mechanism of micellar catalysis for chloromethylation reaction of polystyrene was explored. The experiment results show that a micellar solution of the surfactant can solubilize polystyrenes dissolved in CCl₄, namely, polystyrene can be transferred  into a micellar solution of surfactant along with solubilization of CCl₄ in the micellar solution of the surfactant. Micellar catalysis is an effective way to realize the  chloromethylation for polystyrene, and only 3.35 g/L  CTAB is needed for the  chloromethylation of  polystyrene with a 37%  chloromethylation degree at 65 ℃ within 5 h. The reaction mechanism of the reaction among polystyrene, formaldehyde and hydrochloric acid consists of two steps:  electrophilic substitution and nucleophilic substitution. The cationic surfactants are more effective than anionic surfactants, and the nucleophilic substitution step is a rate-controlling step. So it is appropriate to use cationic surfactants for realizing the chloromethylation of polystyrene. For cationic surfactants, the longer the hydrophobic carbon chain is, the better the solubilization property of surfactant is, so that its catalysis effect is better.                 

Studies on Polycondensation of BHEN

QIAO Qian, HAN Yi-Jun, CHEN Yan-Mo, LIU Gui-Yun, ZHAOYa-Juan, LIU Ruo-Wang

2006, 27(2):  386-388. 

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Abstract BHEN intermediate was synthesize via transesterification between NDC and EG and the effect of processing conditions on synthesis of PEN was studied via BHEN polycondensation and by using orthogonal experiment method. Zinc acetate was optimized as the catalyst and steric phenol WZF1010 as the antioxidant and the optimum processing conditions for BHEN polycondensation are as follows: reaction temperature 568 K, the catalyst concentration is about 4×10^-4 mol pet one mol of BHEN, reaction time 180 minutes and the antioxidant concentration is about 1×10^-5 mol pet one mol of BHEN.

Investigation on the Crystalline Transition of Nylon-6 18

XIAO Dan, CUI Xiao-Wen, LI Wei-Hua, YA De-Yue

2006, 27(2):  389-393. 

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The Brill transition of even\|even nylon-6 18 was investigated by using differential scanning calorimetry(DSC),  temperature-dependent wide angle X-ray diffraction(WAXD) and Fourier transform infrared(FTIR). The X-ray diffraction results indicate that the melt-crystallized sample of nylon-6 18 transforms from the triclinic unit cell to the pseudo-hexagonal phase in the  temperature range of 120—180  ℃. In this range,  the thermograph of nylon-6 18 presents a broad endothermal peak. From the FTIR spectra,  it can be found that,  during the transition process of nylon\|6 18,  the intensity of the intrasheet hydrogen bonds  becomes weak. At the same time,  the CH₂-amide bonds twist and the all\|trans conformation of methylene sequences is disordered by inserting the gauche conformation. The CH₂ segments are in a mobile state because of the enhanced stretching and twisting vibrations of  C—CO and C—N bonds.

Dispersion Polymerization of Acrylic Acid  in Aqueous Media

LIU Xiao-Guang, Chen-Dong-Nian, Zhang-Wen-De, Wang-Pi-Xin

2006, 27(2):  394-396. 

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Abstract Dispersion polymerization of acrylic acid was  successfully carried out in aqueous ammonium sulfate media at 30 ℃. The polymerization behavior  with varying concentrations of stabilizer,  ammonium persulfate,  and ammonium sulfate were investigated.  Polydisperse spherical particles were formed in the system. The particle sizes increase first, then decrease with the increase of the initiator concentration. The increase of the stabilizer concentration resulted in a decrease in particle size and an increase in the intrinsic viscosity.   The results show that the reaction conditions for the stable dispersion polymer are as follows: the mass fractions are 0.64%-1.92% for the stabilizer,  and 24%-31% for the salt respectively.