Table of Content

24 November 2004, Volume 25 Issue 11

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Articles

Synthesis, Characterization and Co-template Role of a New 2-Dimensional Layered Aluminophosphate [Al₆P₈O₃₂][(C₂H₅)₂NHCH₂CH₂NH₃]₂[C₂H₅NH₂CH₂CH₂NH₂C₂H₅]

PENG Li, LI Ji-Yang, YU Ji-Hong, LI Yi, GUO Min, XU Ru-Ren

2004, 25(11):  1981-1985. 

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In this paper, a new layered aluminophosphate, [Al₆P₈O₃₂][(C₂H₅)₂NHCH₂CH₂NH₃]₂·[C₂H₅NH₂CH₂CH₂NH₂C₂H₅], was synthesized in the system Al(OPri)₃-H₃PO₄-N,N-diethyl-ethylenediamine-tetraglycol. Its structure was determined by single crystal X-ray diffraction analysis, and further characterized by XRD, ICP, TG and elemental analysis. The title compound crystallizes in monoclinic space group P2(1)/c , with a=0.909 45(2) nm, b=1.464 24(4) nm, c=1.875 72(5) nm, β=102.672(2)° and Z=4. Its structure constructed by the alternation of AlO₄ and PO₃(=O) units contains the 4,6,8-nets stacked in an ABAB sequence. Two kinds of organic cations, diprotonnated N,N-diethylethylenediamine and its rearranged product N,N′-diethylethylenediamine locate between the adjacent layers. Their co-templating role in the formation of the title compound was also studied in terms of host-guest interaction.

High Density Palladium Nanowire Arrays Synthesized by an Electroless Deposition Route

GU Jin-Lou, SHI Jian-Lin, XIONG Liang-Ming

2004, 25(11):  1986-1989. 

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An electroless deposition route was employed to incorporate high density palladium nanowire arrays into the pore channels of mesoporous thin films(MTFs) which served as templates. The hydrophobic core of direct agent of MTFs was utilized as a carrier to introduce hydrophobic compound of palladium metal into the inner surface of MTFs. After pyrolysis and reduction by hydrogen, the catalysis centers were obtained to initiate the electroless deposition process, which avoid the complicated procedures of conventional electroless deposition. The results indicate that the synthesized nanowires have been fully filled into the pore channels of MTFs with a uniform size and an aspect ratio higher than 60. The diameter of nanowires could be adjusted via the selection of the different mesoporous templates.

In situ Synthesis and Characterization of Chiral Zirconium Phosphonates

HUANG Kun-Lin, YU Ji-Hong, WANG Guang-Mei, GUO Min, XU Ru-Ren

2004, 25(11):  1990-1992. 

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The crystalline chiral zirconium phosphonates with α, γ-type structure, formulated as Zr(PO₄)_0.6(HPO₄)_0.1(O₃PCH₂NHC₄H₇COO^-)_0.55(O₃PCH₂NHC₃H₇COOH)_0.55F_0.55·H₂O(mix-ZrPMP, [α]_D²⁵=-36°) and Zr(PO₄)_0.6(HPO₄)_0.1(O₃PCH₂NHCH₂SC₂H₃COO^-)_0.55(O₃PCH₂NHCH₂S-C₂H₃COOH)_0.55F_0.55·2.0H₂O(mix-ZrPMT, [α]_D²⁵=-39°), were obtained in situ by reaction of N-phosphonomethyl-L-proline(H₃PMP) and N-phosphonomethyl-1,3-thiazolidine-4-carboxylic acid(H₃PMTA) with ZrOCl₂·8H₂O in the presence of HF at 90 ℃, respectively. The heterocycle thiazolidine was integrated onto metal-organic frameworks. Of mix-ZrPMP and mix-ZrPMT, the CO₂H, CO₂^- and NH⁺ groups are remained in layered structures of mixed-type.

Preparation and Luminescence Property of Layer-by-layer Self-assembled Nanometer Multilayer Film Based on Polyoxometalate and Tris(2,2-bipyridine)ruthenium

MA Hui-Yuan, PENG Jun, HAN Zhan-Gang, FENG Yu-Hua, WANG En-Bo

2004, 25(11):  1993-1995. 

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A photo-luminescent multilayer film based on Keggin-type polyoxometalate PMo₁₂O₄₀^3- and transition metal complex tris(2,2-bipyridine) ruthenium [Ru(bpy)₃]²⁺ was prepared by using layer-by-layer assembly(LBL). The formation of multilayer film was monitored by ultraviolet absorption spectra(UV). The absorption intensity of characteristic peaks increases with a four-layer cycle, indicating that the LBL assembly film grows linearly and reproducibly. The composition of the film was measured by X-ray photoelectron spectrum(XPS). The film exhibited photo-luminescence arising from π^*-t_2g ligand-to-metal transition of Ru(bpy).

Synthesis of Rutile TiO₂ Nanowhiskers by Liquid Phase Method at Low Temperature

WEI Yu, YU Jing, LIN Yu-Long, MA Zi-Chuan

2004, 25(11):  1996-1997. 

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By using a simply liquid phase method at a low temperature, rutile TiO₂ nanowhiskers were successfully prepared from TiCl₄ aqueous solution at 70 ℃ after aging for 11 d. The obtained TiO₂ nanowhiskers were characterized by means of TEM,HRTEM and XRD. The results show that the nanowhiskers are rutile crystals growing along c-axis direction with a length of 100_150 nm and a diameter 6_8nm. The simple fabrication method of TiO₂ nanowhiskers will promote practical application of 1D TiO₂.

Immobilization and Property of Penicillin G Acylase in the Channel of Silica Mesoporous Material MCFs

GAO Bo, CHEN Jing, ZHU Guang-Shan, FU Xue-Qi, WANG Chun-Lei, QIU Shi-Lun

2004, 25(11):  1998-2000. 

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Silica mesoporous material MCFs with 16.0 nm pore sizes was prepared by using non-ionic block copolymers and the swelling agents, and was used as the support for the immobilization of enzyme. Penicillin G acylase, an enzyme, was assembled in the channel of MCFs by immersion method. The activity and stability of immobilized penicillin G acylase were studied. It was found that the activity and stability of the immobilized penicillin G acylase increased significantly compared to those of free enzyme. The optimum reaction temperature is 60 ℃. After incubation at 60 ℃ for 1 h, the activity of these immobilized penicillin G acylase remains 69%. These results showed that thermostability and durability on heating of the immobilized penicillin G acylase in MCFs was improved remarkably. The silica mesoporous material MCFs with 3-dimensional channel structure is a good support for the immobilization of enzyme.

Stereoselective Cleavage of DNA by Chiral Ruthenium(Ⅱ) Complexes

WANG Fang, ZHANG Qian-Ling, LIU Jian-Hong, ZHANG Pei-Xin, LIU Yi, REN Xiang-Zhong, LIU Jian-Zhong, JI Liang-Nian

2004, 25(11):  2001-2003. 

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Two enantiomerically pure polypyridyl ruthenium(Ⅱ) complexes Δ- and Λ-[Ru(bpy)₂HPIP](PF₆)₂{HPIP=2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline} were synthesized and characterized. DNA-binding studies indicated that both enantiomers bound to calf thymus DNA by intercalation, the Δ- enantiomer exhibited a stronger binding affinity than the Λ- enantiomer. Upon irradiation at 302 nm, both enantiomers were found to promote cleavage of plasmid pBR₃22 DNA from the supercoiled form Ⅰ to the open circular form Ⅱ, but the Δ-enantiomer exhibited a higher cleaving efficiency for DNA due to the different binding affinities to DNA. The cleaving mechanisms for Δ- and Λ-[Ru(bpy)₂HPIP]²⁺ were identical, the hydroxyl radical(OH^·) was likely to be the reactive specie responsible for the cleavage of plasmid pBR₃22, and the photoreduction of Ru(Ⅱ) complex with concomitant hydroxide oxidation was the important step in the DNA cleavage reaction.

Recognition Method of a New Feedforward Neural Network with Adaptive Structure for QCAR Modeling of Chinese Medicine

FAN Xiao-Hui, CHENG Yi-Yu

2004, 25(11):  2004-2009. 

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In general, the performances of Multilayer Feedforward Neural Network(MFNN), e.g. function approximation accuracy and network efficiency, are not often sufficiently satisfactory, when it is used for modeling of complex non-linear chemical system. In this work, a novel learning approach, which can adaptively construct the optimal architecture of MFNN, is developed for modeling Quantitative Composition-Activity Relationship(QCAR) of Chinese Medicine, and it is successfully applied to predicting the bioactivity of Chuanxiong. The approach taken by the methodology described here is to train an initial neural network that is smaller than necessary and then adaptively increase the number of hidden layer′s neural nodes when the approximation accuracy is insufficient. Once a new hidden node has been added to network, weights of original nodes are frozen. The parameters of the new node, new-added weights as well as the corresponding change of old weights, are determined on the basis of current learning results. It is also verified by simulated experiments that the presented approach can satisfyingly determine the optimal architecture of MFNN, and its learning efficiency is high. As a consequence, the approach can be used for modeling of complex non-linear chemical system.

Application of Fourier Transform Infrared Spectroscopy to Non-invasive Detection of Breast Tumor in vivo and in situ

LI Qing-Bo, XU Zhi, XU Yi-Zhuang, ZHANG Yuan-Fu, ZHANG Neng-Wei WANG Li-Xin, SUN Xue-Jun, ZHANG Li, WANG Fan, YANG Li-Min, ZHAO Ying REN Yu, LIU Zhi, WENG Shi-Fu, ZHOU Wei-Jin, WU Jin-Guang

2004, 25(11):  2010-2012. 

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The non-invasive detection of breast tumor in vivo and in situ was first investigated by FTIR fiber optics technique. The experiment result indicates that there are significant differences between the spectra of skin outside breast tumor and normal breast tissues in the peak position and relative intensity. The in vivo FTIR spectroscopy can provide the information concerning whether the suspected tissue is cancerous or not. This recent result means that in situ FTIR spectroscopic method with fiber optics can be developed as a non-invasive, rapid and in vivo technique for early breast tumor detection.

A Novel Method for Quaternization of Amino Acid/Peptide and Its Product Detection Using Electrospray Ionization Mass Spectrometry

BAO Hui-Min, ZHAI Jian-Jun, ZHANG Guo-An, YANG Peng-Yuan, CHEN Xian

2004, 25(11):  2013-2015. 

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A novel detection method for quaternization of amino acid and peptide was reported. In this method Ag₂CO₃ was employed instead of KHCO₃ to catalyze the occurrence of quaternization reaction. The absence of metal ions in the reaction system enabled us to in situ detect the quaternizing products by using electrospray ionization mass spectrometry(ESI-MS). We analyzed quaternizing products of six amino acids and two peptides in situ, and obtained the ratio of major product to by-product, which suggests the new method possesses prominent advantages over the old one. This method could offer a potential chance to combine quaternization with mass spectrometry which is helpful for the future use of quaternization reaction in quantitative proteomics.

Preparation of Capillary Gas Chromatographic Columns with High Thermal Stability by Sol-gel Method

LIANG Min-Min, QI Mei-Ling, FU Ruo-Nong, SHAO Qing-Long

2004, 25(11):  2016-2018. 

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Perethylated-β-CD, perpentylated-β-CD and 2,6-di-O-pentyl-β-CD were coated onto the fused silica capillary by sol-gel process. The thermal stability of the three sol-gel columns was investigated by pyrolysis gas chromatography(PyGC). The PyGC results show that the sol-gel CDs columns have an outstanding thermal stability, compared with the conventional CDs columns. The temperature of preliminary pyrolysis of the CDs in sol-gel net can be as high as 300 ℃, of the alkylated-β-CDs are at 200℃. The column performances were also studied. The results show that the sol-gel CDs columns have a good separation ability to the disubstituted benzene isomers such as cresols and xylene isomers.

Intramolecular Substitution Reaction of cis-Dicarbonyl Rhodium(Ⅰ) Complexes Containing Tridentate N-Donor Ligand

ZHANG Shu-Feng, QIAN Qing-Li, CHEN Yi, YUAN Guo-Qing

2004, 25(11):  2019-2023. 

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Square planar tetracoordinated Rh(Ⅰ) complex is a typical organometallic complex. In catalytic reactions its four-coordinated structure is the precursor of an active compound. The study on its structure is very important for investigating the catalytic procedure. In this paper, the intramolecular substitution reaction of a novel kind of square planar cis-dicarbonyl rhodium cationic complexes containing different N-coordinated tridentate ligands were studied. \%N,N\%-Bis(2-pyridylethyl)-aniline(DPBA), 1,2,3-tri(2-pyridyl) propane(TPP), tri(2-methylenepyridine) methane(TPM) were resolved in methanol respectively, into which an appropriate amount of [Rh(CO)₂Cl]₂ methanol solution was added under stirring at 0 ℃ and atmosphere of CO to get yellowish carbonyl rhodium complexes respectively. The changes of carbonyl rhodium complexes structures were analyzed by IR and XPS. It is shown that the uncoordinated electron donating nitrogen of the ligand, when heated, may replace the terminal carbonyl to form a new type of tridentate complexes, the weak N—Rh bond can replace the strong Rh—CO σ-π bond. The intramolecular substitution reaction is reversible. The formal cis-dicarbonyl bidentate N-coordinated complex recovers if the newly formed complex is put under the atmosphere of CO. So the rhodium complexes will not decompose for the drop of the terminal carbonyls and their stability is enhanced. There is no such reversible intramolecular substitution reaction in non square-planar cis-dicarbonyl rhodium complexes.

Synthesis and Biological Activity of Novel 1-(Substituted-pyrazole-4-carbonyl) Pyrazoles

CHENG Yong-Hao, ZOU Xiao-Mao, GAO Ying, YANG Hua-Zheng

2004, 25(11):  2024-2027. 

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A series of new 1-(substituted-pyrazole-4-carbonyl)-pyrazoles were synthesized by the reaction of 5-amino-1-methyl-3-(methylthio)-¹H-pyrazole-4-carbohydrazide and 5-amino-1-methyl-¹H-pyrazole-4-carbohydrazide respectively with 2-cyano-3,3-bis(alkylthio) acrylates or 2-[bis(alkylthio)methylene] malononitriles. All the compounds were structurally confirmed by elemental analysis and ¹H NMR. Their herbicidal activities were tested. Bioassay results showed that some of them had herbicidal activities. The structure-activity relationship was discussed, which indicated the substituents on the pyrazole ring have influence on the title compounds activities.

Sythesis of a Kind of Recoverable and Reusable Ligand and Its Application in AD Reaction

JIN Ying, SUN Xiao-Li, ZHANG Sheng-Yong, YAO Zhi-Jun, WANG Qiao-Feng

2004, 25(11):  2028-2030. 

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Dichoropyridazine was reacted with quinidyl and dihydroquinidyl in the presence of NaH in DMF to give compound 2. The side of quinidyl was reacted with 2-mercaptoethanol, then was oxidized to give ligand 1. Ligand 1 delivers excellent enantioselectivity as well as specific chemoselectivity in the asymmetric dihydroxylation(AD) of six olefins(88%—99% e.e). and 74%—91% isolated yields were obtained in AD reaction. Furthermore this ligand can be recovered and reused. Its enantioselectivity and chemoselectivity were unchangeable when it was reused for four times in AD reaction with cinnamic ethyl as the substrate.

3D-QSAR Study on N-(4-Substituted pyrimidin-2-yl) Benzyl Sulfonylurea and Phenoxy Sulfonylurea

MA Yi, JIANG Lin, LI Zheng-Ming, LAI Cheng-Ming

2004, 25(11):  2031-2033. 

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Comparative molecular field analysis(CoMFA) method was applied to the study of the three-dimensional quantitative structure activity relationship(3D-QSAR) on two series of N-(4-substituted pyrimidin-2-yl)-2-methyl carboxylate-benzyl sulfonylureas and N-(4-substituted pyrimidin-2-yl)-2-substituted phenoxy sulfonylureas. A reasonable model with predictive ability was obtained from the investigation. According to the resulting contour map of electrostatic field, compounds with enhanced activity could be designed by introduction of more negative charged group into the red region, and positive charged substituent in the blue region will lead to more herbicidal activity. For the steric field, the introduction of smaller groups into the yellow region gives a compound with a higher activity and larger groups in the green region will improve the activity. The models were used to explain why the sulfonylureas with a modified bridge still remain a high herbicidal activity and will help us in our further study.

Isolation and Structural Analysis of the Polysaccharides of Limonium bicolor and the Inhibition to Hela Cell

ZHANG Lian-Ru, CHEN Ka-Lin, LI Ni, ZOU Guo-Lin

2004, 25(11):  2034-2037. 

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Soluble polysaccharides were isolated from Limonium bicolor Kunge(Bge.) and purified by conventional method. IR, GC-MS, ¹³C NMR and ¹H NMR were used to analyze the structures of the polysaccharides. The result showed that glucose and glucose acid were the main components of the polysaccharides, and the bond between GlcA and Glc was α-(1→6), then the disaccharide unit was connected by α-(1→4) linkage. The polysaccharides were fluorescent with the biggest emission peak at 460 nm, and Zn²⁺ or Ca²⁺ enhanced the fluorescence intensity of LP. Much more research proved that LP had the function of inhibiting the growth of Hela cells, with the IC₅₀ being 62.2 μg/mL.

Inclusion Complexation Between Cucurbit[n]uril(n=5,6,7,8) and Two Diazonium Tetrafluoroborates

LIU Si-Min, WU Xiao-Jun, LIANG Feng, YAO Jun-Hua, WU Cheng-Tai

2004, 25(11):  2038-2041. 

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Inclusion complexation between cucurbit[n]uril(CB[n], n=5,6,7,8) and two diazonuim salts in various acid solutions was investigated by ¹H NMR spectroscopy and UV-Vis spectrophotometric titration. The binding constants were obtained by using a non-linear least squares curve fitting. The inclusion of diazonuim ions in the cavity of CB[n] made ¹H NMR spectra of diazonuim ions moving towards a higher magnetic field. The results indicated that CB[5] and CB[8] couldn′t include the two kinds of diazonium ions efficiently. The cavity of CB[6] was too small to accommodate 4,4′-biphenylene-bis-diazonium ions. CB[7] could contain both p-methylbenzene diazonium and 4,4′-biphenylene-bis-diazonium ions. In contrast to CB[6], CB[7] was more suitable for holding p-methylbenzenediazonium ion, showing that the complex stability is dominated by the size/shape-matching between the host and guest. With increasing the concentration of the acid, the measured binding constants decreased notablely, due to the competitive complex of protons with carbonyls of CB[n].

Interactions Among Various Functional Macromolecules and Its Application

PANG Jie, ZHANG Fu-Sheng, KANG Bin-Bin, TIAN Shi-Ping

2004, 25(11):  2042-2047. 

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The interactions among three polysaccharides and the interaction between polysaccharide and protein were studied by using konjac glucomannan, κ-carrageenan, xanthan and soybean protein isolation as the raw materials. The results showed that the substantial molecular synergisms existed. Its integrative function was improved, such as gel strength, gel plasticity, gel transparency and so on. Based on the findings, a new food containing dietary fiber and protein was developed. The effects of temperature, time, mass fraction on polysaccharide interactions as well as electrolytes on polysaccharide and protein were studied. As a result, a polysaccharide healthcare product and an imitation shellfish product were formulated.

Penta-coordinated Phosphorous Structure Analysis on Molecular Motors

LI Wu, ZHAO Yu-Fen

2004, 25(11):  2048-2050. 

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The mechanisms of molecular motors are still unresolved problems. Based on our experiments on amino acids, the activated process of molecular motors was analyzed and original software using the method of penta-coordinated phosphorous structure was designed. Via the software, the hotspots from different molecular motors′ phosphorous activated area were obtained. It was found that the types of hotspots discovered with above methods were highly conserved. This founding provides new perspectives to study the intrinsic relationship of motion in molecular motors and also helps understanding the evolution of molecular motors.

Synthesis of 1,2-Dihydroquinazolin-4(3H)-ones Promoted by Low-valent Titanium

SHI Da-Qing, RONG Liang-Ce, WANG Ju-Xian, WANG Xiang-Shan, TU Shu-Jiang, HU Hong-Wen

2004, 25(11):  2051-2053. 

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Dihydroquinazolin-4(3H)-ones were synthesized by the reaction of o-nitrobenzamides with aromatic aldehydes or cyclones promoted by the low-valent titanium reagent(TiCl₄-Zn system). The products were characterized by elementary analysis, IR, ¹H NMR and X-ray single crystal diffraction. This method possesses the advantages of easily accessible starting materials, convenient manipulation and moderate to high yields.

Synthesis of 5-Fluoro-4-deoxy-β-L-uridine

DONG Chun-Hong, QI Xiu-Xiang, YU Xue-Jun, CHANG Jun-Biao,

2004, 25(11):  2054-2056. 

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We now report the syntheis here in a full account of 5-fluoro-4-deoxy-β-L-uridine. The structures of compounds were identified by the MS, UV, IR, ¹H NMR spectra and elemental analyses. It is of interest to sythesize the L-nucleosides in anticipation of promising antiviral agents.

Chemical Constituents of Anemone raddeana Regel(Ⅱ)

XIA Zhong-Ting, LIU Da-You, WANG Xiao-Ying, YANG Xiu-Wei, LIU Ke-Feng

2004, 25(11):  2057-2059. 

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Chinese folk medicine “Liang Tou Jian”(Anemone raddeana Regel) is the important medicine used to treat rheumatism, neuralgia, cancer and so on. Its chemical constituents were studied by chromatographing on silica gel and HPLC. A new triterpenoid saponin, raddeanoside 18, along with two known triterpenoid saponins, Hederacholichiside F and Leontoside D, was isolated from the ethanolic extrant of the rhizoma of Anemone raddeana Regel. Their structures were elucidated as 3-O-β-D-glucopyranosyl(1→4)[β-D-glucopyranosyl(1→2)]-α-L-arabinopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl(1→4)-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside(1), 3-O-β-D-glucopyranosyl(1→4)[α-L-rhamnopyranosyl(1→2)-]-α-L-arabinopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl(1→4)-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside(2), 3-O-β-D-glucopyranosyl(1→4)-α-L-arabinopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl(1→4)-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside(3) by 1D and 2D NMR ESI-MS and IR spectrometries, respectively.

Promotion Effect of Cationic Gemini Surfactants on 1-Dodecene Hydroformylation in Biphasic Catalytic System

XU Bin, LI Min, YANG Min, ZHENG Hong-Jie, HE Yu-E, CHEN Hua, LI Xian-Jun

2004, 25(11):  2060-2064. 

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New cationic gemini surfactants with a rigid spacer group of xylene were synthesized, their compositions and structures were characterized. The cmc and the solubilizations of 1-dodecene in micellar solution were determined by surface tension method and UV-Vis spectrometry respectively. The cmc of new gemini surfactants are lower than CTAB by about an order, but the solubilizations of 1-dodecene in gemini surfactants solution are higher than that in CTAB solution. The promotion effect of cationic gemini surfactants on 1-dodecene hydroformylation in biphasic catalytic system was studied. The results indicated that in the biphasic system containing the catalysts RhCl(CO)(TPPTS)₂ and TPPTS, [TPPTS=tris(sodium-m-sulfonatophenyl) phosphine], the reaction rate of 1-dodecene hydroformylation in the presence of gemini surfactants was faster than that in the presence of conventional surfactant CATB, e.g., the conversion of 1-dodecene is 90% when G(o-xyl) C₂₂ concentration in aqueous solution was 2×10^-3 mol/L, however, the conversion was only 20.4% when the concentration of CTAB was 3×10^-3 mol/L. The greater acceleration of gemini surfactants in 1-dodecene hydroformylation could be attributed to that cationic gemini surfactants had lower cmc and better solubilization for the substrate. The lower cmc and surface tension are favorable for increasing the interfacial area of two phases, breaking phase barrier and promoting the substrate transfer to interface where the substrates coordinate with the active rhodium complex anion species. The regioselectivity for olefin hydroformylation in gemini surfactants.

Delamination and Intercalation of Layered Microporous Aluminophosphate [Al₂P₃O₁₀(OH)₂][C₆NH₈]

HUANG Qiong, Wang Wen-Han, HUA Wei-Ming, YUE Ying-Hong, GAO Zi

2004, 25(11):  2065-2069. 

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Layered microporous aluminophosphate [Al₂P₃O₁₀(OH)₂][C₆NH₈](AlP) was delaminated to form a well dispersed colloid in water-ethanol solution. New C₂_C₁₂ alkylamine intercalated materials of the aluminophosphate were reassembled in the solutions with dielectric constants in the range of 50—70 and an amine amount of 10 mmol/g AlP. The saturated C₂_C₁₂ alkylamine intercalated materials of AlP were packed with alkylamine bilayers tilted at an angle of about 42.6° in the interlayer region. The delamination and intercalation processes were followed by XRD and SEM measurements. The influence of layer structure on the delamination and reassembly processes was discussed.

Theoretical Studies on the Insertion Reaction of Silylenoid H₂SiNaF with R—H(R=F, OH, NH₂, CH₃)

WANG Huan-Jie, XIE Ju, FENG Da-Cheng, FENG Sheng-Yu

2004, 25(11):  2070-2073. 

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The insertion reaction of silylenoid H₂SiNaF with RH(R=F,OH,NH₂,CH₃) was studied at B3LYP/6-31G^* level by using density functional theory. The mechanism of these four reactions was analogical. The reaction goes through three stages: electrophilic approach, nucleophilic insertion and substitution, then the intermediate formed. Accounting to zero-point vibration energy, the potential barriers of the four reactions are 0.9, 61.7, 114.6 and 190.6 kJ/mol respectively. The intermediate could dissociate to substituent silane and NaF. This dissociating process has no transition state. The reaction energies for the four reactions are -122.6, -96.3, -6.8 and 50.2 kJ/mol respectively.

Laser-induced Luminescence Spectroscopy of ZnO/SiO₂

CHEN Jun, FENG Zhao-Chi, YING Pin-Liang, LI Can

2004, 25(11):  2074-2077. 

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ZnO/SiO₂ materials with different ZnO loadings were prepared by incipient wetness impregnation method in different calcination atmospheres. A home-built laser-induced luminescence spectroscopy setup was applied to studying the luminescent behavior of these materials. The continuous wave He-Cd laser(λ=325 nm) was used as the excitation source. It is found that the samples calcined in air mainly show the orange luminescence band(centered at about 670 nm), but the samples calcined in Ar mainly exhibit the green luminescence band(centered at about 540 nm). Interestingly, the orange luminescence band is changed into the green luminescence band after the ZnO/SiO₂ was treated in air and calcined in Ar again, and the green luminescence band is changed into the orange luminescence band after the ZnO/SiO₂ was treated in Ar and further calcined in air. These results suggest that the visible luminescence bands of ZnO are ascribed to the oxygen vacancies in ZnO. The green luminescence band is ascribed to the state with a high density of oxygen vacancies; and the orange luminescence band is attributed to the state with less oxygen vacancies. The XRD patterns show that ZnO in these materials exists as a wurtzite structure. UV-Vis and Raman spectra indicate that most ZnO is formed in the form of macrocrystal on SiO₂. Our results also demonstrate that the laser-induced luminescence spectroscopy is a powerful technique to characterize the defect sites, particularly the oxygen deficient in semiconductor materials.

XPS Valence Band of ZnO Films

LI Wan-Cheng, DU Guo-Tong, YANG Xiao-Tian, LIU Bo-Yang, ZHANG Yuan-Tao, ZHAO Bai-Jun, JIANG Xiu-Ying

2004, 25(11):  2078-2081. 

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ZnO films are grown by the plasma-assisted metal organic chemical vapor deposition(MOCVD) on c-sapphire and are measured by XPS. The results show that comparing with O_1s and Zn_2p, Zn_3d has more obvious chemical displacement which can help us study the characteristics of ZnO film more effectively. The binding energy of Zn_3d electron becomes larger along with the strengthening of coupling between Zn_3d or Zn_3d+Zn_4s and O_2p. The temperature of DEZn is an important factor which affects the formation of covalent bond between Zn and O atoms.

Electrochemical Performances of Fuorinated Polymer Graphite

DONG Quan-Feng, ZHENG Ming-Sen, JIN Ming-Gang, YOU Jin-Kua, LIN Zu-Geng

2004, 25(11):  2082-2085. 

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Using FGs(fluorinated polymer graphite) as novel cathode additives for conventional alkaline batteries were investigated. It is demonstrated that FG as a cathode additive in alkaline batteries can improve the discharge performances significantly. The discharge performance of the cells in which the cathode contains a different mass fractions of FG and that contain a fixed mass fraction of FG but with different contents of fluorine in the FG were explored in detail. Furthermore, the electrochemical behavior of pure FG cathode(i.e. the FG exclusive cathode) was studied, as well as normal graphite cathode. The storing stability of the batteries in which the cathode is made of pure FGs (FG exclusive cathode) or the cathode contained FG as additives were explored. XRD studies are carried out on fluorinated polymer graphites and some normal graphites before and after discharging and the results are discussed.

Theoretical Study on the Reaction Mechanism of (CH₃)₃C+NO₂

SUN Cheng-Ke, ZHAO Hong-Mei, Liu Kun, Li Zong-He

2004, 25(11):  2086-2089. 

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The reaction mechanism of (CH₃)₃C· radical with NO₂ is theoretically investigated at the B3LYP/6-31G^* level. The results show that the reaction is a multi-channel reaction in singlet state and triplet state with different products, and the reaction occurs more easily in single state than in triplet state. To the open system, such as atmosphere, the reaction of (CH₃)₃C +NO₂ mostly produces the stable complex (CH₃)₃CONO and (CH₃)₃CNO₂ at a normal temperature, which could play a role in eliminating air pollution.

Electrochemistry of Ru-Fe Heterobimetallic Complexes and the SAM on Au Surface

LI Zhao-Hui, Fehlner T. P., FU Xian-Zhi

2004, 25(11):  2090-2094. 

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Heterobimetallic Ru-Fe complex trans-RuCl(dppm)₂(C≡CFc)(1)(Fc=C₅H₄FeC₅H₅, dppm=(C₆H₅)₂PCH₂P(C₆H₅)₂) was functionalized to give Ru(dppm)₂(C≡CFc)(C≡CPhOCH₃)(2), [Ru(dppm)²(C≡CFc)(N≡CCH₂CH₂NH₂)][PF₆](3) and[Ru(dppm)₂(C≡CFc)(N≡CCH₂CH₂NH·C(O)(CH₂)₁₀SH)][PF₆](4) for surface binding. Cyclic voltametric techniques were performed on these complexes to study the extent of perturbation of the surface binding “tail” on the overall electrochemical peroperties. It is found that the substituent on the Ru center adjusts the electron density on the Ru atom and affects the redox properties of the Ru center. However, this substituent effect is not transferred through the acetylene bond to the ferrocenyl moiety. Complex 4 forms a stable and order SAM on the Au surface and CV was used to study the film growth and surface coverage.

Adsorption Thermodynamics and Kinetics of 2-Thiopheneacetic Acid on Three Types of Resin

WEI Rui-Xia, CHEN Jin-Long, CHEN Lian-Long, FEI Zheng-Hao, LI Ai-Min, ZHANG Quan-Xing

2004, 25(11):  2095-2098. 

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The adsorption thermodynamics and kinetics of 2-thiopheneacetic acid by XAD-4, NDA-100 and ND-90 resins were carried out through static experiments. The results showed that the adsorption of 2-thiopheneacetic acid on XAD-4 resin is Langmuir monolayer, and the adsorption rate appears to be the first order kinetics. The adsorption data of 2-thiopheneacetic acid on NDA-100 and ND-90 resin were also discribed well by the Langmuir isotherm, which is caused by the capillary condensation and the volume filling of micropores besides monolayer adsorption. The adsorption of 2-thiopheneacetic acid on NDA-100 and ND-90 resin passed through two processes: macropores and mespores area and micropores area. And the adsorption rates of the two processes are the first order kinetics.

Interaction Between Bovine Serum Albumin and Berberine Chloride Extracted from Chinese Herbs of Coptis Chinensis Franch

LIU Xue-Feng, XIA Yong-Mei, FANG Yun, LIU Ling-Ling, ZOU Lu

2004, 25(11):  2099-2103. 

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The interaction between bovine serum albumin(BSA) and berberine chloride(BC) extracted and purified from coptis chinensis franch was studied by using UV and fluorescence spectroscopy. The phenomenon that fluorescence spectra of BSA splitted and shifted from a simple peak to double peaks in the presence of BC was explained, and the double peaks responding to tyrosine and tryptophan residues respectively was prospected. Fluorescence quenching was thought to be deduced by combining static quenching with nonradiative energy transfer. The values of the apparent association constant(K_A) at 30 ℃ and 37 ℃ are 8.66×10⁴ L·mol^-1 and 8.72×10⁴ L·mol^-1 respectively, and the binding sites of BC molecules on BSA(n) are (3.1±0.2). The stereo-distance(r) between BC and fluorescent amino acid residues of the BSA is 3.75 nm at 30 ℃ and 3.62 nm at 37 ℃, which affirms that part of BC segments have inserted into the hydrophobic pockets of BSA. Binding BC to BSA is a spontaneous supramolecular interaction in which entropy increases and Gibbs free energy decreases, and the main driving force of the above interaction is hydrophobic force.

Synthesis of Hydroxypivalic Acid via Direct Electrooxidation of Hydroxypivalaldehyde

YU Jian-Guo, ZHANG Heng-Bin, LI Fei, CAO Xue-Jing, LIN Ying-Jie

2004, 25(11):  2104-2107. 

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Hydroxypivalic acid was synthesized by oxidation of hydroxypivalaldehyde at PbO₂ electrode in sulfuric acid solution with proton exchange membrane. The change trends of the selectivity and the current efficiency with changing the concentration of hydroxypivalaldehyde, pH, reaction temperature and anode potential were studied. It was found that the effect of pH on the selectivity and the current efficiency is the largest. The highest selectivity is 92.6%, the highest current efficiency is 61.4%. High performance liquid chromatography was used to analyze the concentrations of products and reactants. The melting point, elemental analysis and IR spectrum were used to characterize the product after the separation and purification.

New Room-temperature Molten Salt Based on LiTFSI with Acetamide and Ethyleneurea

CHEN Ren-Jie, WU Feng, LIANG Hong-Ying, ZHANG Cun-Zhong,

2004, 25(11):  2108-2111. 

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Thermal and electrochemical properties of new room-temperature molten salt based on LiTFSI with acetamide or ethyleneurea were studied by differential scanning calorimetry, ac impedance spectroscopy and cyclic voltammertry, respectively. These molten salts appear as liquid at room temperature though they are composed of two solids. DSC analysis shows that the molten salt has a excellent thermal stability and its eutectic temperature is about -62.18 ℃. The conductivity of LiTFSI-acetamide molten salt at molar ratio 1:6.5 is 1.08×10^-3 S/cm at 25 ℃ and 5.35×10^-3 S/cm at 60 ℃, and the electrochemical window of the sample at molar ratio 1:4.0 is about 3 V.

Theoretical Studies on the Potential Energy Surface of the HCCN+NO Reaction

WEI Zhi-Gang, HUANG Xu-Ri, SUN Yan-Bo, SUN Chia-Chung

2004, 25(11):  2112-2115. 

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A doublet potential energy surface for the reaction of HCCN radical with molecular NO is worked out at the CCSD(T)/6-311G(d,p)//B3LYP/6-311G(d,p) +ZPE level to give four products: P1(HCN+NCO), P2(OH+NCCN), P₃[HCN+(CNO)] and P4(HCN+CNO). It is shown that product P1 is the major one, product P2 is the minor one, and products P₃ and P4 are hard to be obtained. For the pathways to the major product P1 and the minor product P2, the single point energies are also calculated at the G2(B3LYP/MP2/CC) level of theory for precision. On the other hand, the quartet potential energy surface for the reaction is also considered, but there is no favorable pathway in it.

New Room-temperature Molten Salt Based on OZO of Neutral Molecule with LiTFSI

CHEN Ren-Jie, WU Feng, LUAN He-Lin, WU Meng, YU Hui-Fang

2004, 25(11):  2116-2118. 

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The new room-temperature molten salt was prepared based on LiTFSI[LiNC(SO₂CF₃)₂] with OZO(C₃H₅NO₂) which were not reported in literature. Its thermal and electrochemical properties were studied by differential scanning calorimetry, ac impedance spectroscopy and cyclic voltammertry respectively. The results indicated that the structure symmetry of the molecule was depressed and the extent of charges delocalization was expanded, because of introducing oxygen atom of differential electronegativity in OZO molecule. DSC analysis showed that the LiTFSI-OZO molten salt has the excellent thermal stability and its eutectic temperature is below about 223.15 K. Meanwhile, the conductivity of LiTFSI-OZO molten salt at a molar ratio of 1:4.5 is 0.75×10^-3 S/cm at 298.15 K and 3.50×10^-3 S/cm at 333.15 K. CV analysis showed that the electrochemical window of the sample is about 4 V.

Rearrangement Reaction of (-)-Verbenone by Photocatalysis

SONG Zhi-Guang, LI Ye-Zhi, HUANG Hua-Min

2004, 25(11):  2119-2121. 

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We reported a facile synthesis of (-)-isochrysanthenone(2) from (-)-α-pinene in a high yield. When(-)-α-pinene reacted with O₂ in the presence of Co[4-Me(C₅H₄N)₂]Br₂ used as a catalyst, the crude product of (-)-verbenone(1) was formed, and the crude product 1 was directly irradiated with ultraviolet light and converted into the (-)-isochrysanthenone(2). The structure of compound 2 was converted to a cyclic ester(4) by Baeyer-Villiger oxidation, the compound 4 was hydrolyzed to form a crystal 2,2,4-trimethyl-5-oxy-3-cyclohexenyl carboxylic acid 5. Compound 5 was confirmed by IR, ¹H NMR and X-ray crystal analysis. In summary, we found that under the condition of photochemical rearrangement of (-)-verbenone and (+)-verbenone, different compounds were obtained, they are not enantiomers.

Crystallization and Surface Photovoltage Properties of Polystyrene Coated by TiO₂ Nanoparticles

ZHANG Ming, GAO Ge, ZHAO Da-Cheng, ZHANG Dan, YANG Min, WANG De-Jun, LIU Feng-Qi

2004, 25(11):  2122-2124. 

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Hybrid microballs with polystyrene cores coated by titania nanoparticles were prepared by miniemulsion polymerization. The crystallization morphology and photovoltage properties of the hybrid particles after calcination were characterized by Scanning Electron Microscope(SEM), X-ray diffraction and surface photovoltage spectra(SPS). The crystal morphology has a critical effect on the threshold. It is found that the materials become prous, the thresholds of TiO₂ particles blue-shift with their particle sizes decreasing and crystal phase changing from anatase TiO₂ to rutile TiO₂. The SPS results showed that the peak height was three times the height of common TiO₂ nanoparticles.

Highly Effective Hydrogen Production from Steam Reforming of CH₃OH over Cu/ZnO/Al₂O₃ Catalysts Promoted by Nanostructured Carbon Materials

ZHANG Xin-Rong, WANG Lu-Cun, YAO Cheng-Zhang, CAO Yong, DAI Wei-Lin, FAN Kang-Nian, WU Dong, SUN Yu-Han

2004, 25(11):  2125-2127. 

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A number of nanostructured carbon materials were proposed as new effective promoters for preparing modified Cu/ZnO/Al₂O₃ catalyst system for efficient hydrogen production from methanol steam reforming. Compared to the catalysts modified by other type of carbon materials, the ACF-promoted catalyst prepared via carbonate-coprecipitation method exhibit the highest performance in the low-temperature steam reforming of methanol. It was suggested that the intrinsic high surface area nature of ACF material may favor the generation of modified catalysts with a high surface area and improved component dispersion, thus leading to improved performance for methanol steam reforming.

Quantum Chemical Studies on the Reaction Mechanism of OXO(X=Cl, Br) with H(²S)

ZHAO Min, LIU Peng-Jun, Chang Ying-Fei, SUN Hao, PAN Xiu-Mei, SU Zhong-Min, WANG Rong-Shun

2004, 25(11):  2128-2130. 

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The reaction mechanism of OXO(X=Cl, Br) with H(²S) was studied theoretically by using the B3LYP/6-311+G(3df, 3pd) and the high-level electron-correlation QCISD(T)/6-311+G^** at single-point. The results show that the mechanism for the title reaction involves three channels, from which OH+XO, HO₂+X and HX+O₂ products could be obtained, respectively. Therefore, the channel to yield the products OH+XO is the dominant one in agreement with the experiments.

UV-Vis and XPS Spectroccopic Studies on Self-assembled Metalloporphrin Films

LI Xiao-Ling, XU Wei-Qing, JIA Hui-Ying, WANG Xu, ZHAO Bing, LI Bo-Fu

2004, 25(11):  2131-2133. 

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We investigated the fabrication of self-assembled monolayers of 5,10,15,20-tetra-(p-methonphenyl)porphyrin metal hydroxyl compound(MTPPOH; M=Ho, Yb) on amino-terminated quartz surfaces by mesns of UV-Vis spectrum and X-ray photoelectron spectroscopy(XPS). The results indicate that the central metal is crucial in the formation of the self-assembled porphyrin films.

Electron Transfer Laser Flash Photolysis Between Nucleosides and Probe Triplet N-(2’-Hydroxyethyl)-1,8-naphthalimide

LI Hui-Qing, JIANG Zhi-Qin, Wang Xin, PAN Yang, WANG Feng, YU Shu-Qin

2004, 25(11):  2134-2136. 

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The time resolved transient absorption property, kinetics and mechanism of electron transfer(ET) process of the fluorescence probe, N-(2-hydroxyethyl)-1,8-naphthalimide(NPI) were studied. The transient absorption spectra of NPI in H₂O-CH₃CN solution were successfully detected upon pulsed excitation at 355 nm. ³NPI was proved as the primary excited state with lifetime of 147 μs. ³NPI underwent the T-T energy transfer with β-carotene and ET with triphenyl amine to produce NPI^-·. In the absence of quenchers, the self-quenching of ³NPI by the ground states of NPI took place via ET. The ET from nucleosides to ³NPI was also explored. NPI showed a strong electron-accepting capability and the absorbance of ³NPI was strongly quenched by the nucleosides. The formation of NPI^-· was facilitated to a great extent simultaneously. The bimolecular quenching rate constants of NPI by GUA and DGUA were determined as k₃=8.8×10⁶mol^-1·L·s^-1, k₄=2.1×10⁷ mol·L·s^-1. The ET between NPI and nucleosides was verified and the mechanism was proposed.

Heterogeneous Electrocatalytic Reduction of p-Nitrobenzoic Acid on Nanocrystalline TiO₂ Film Modified Electrode

CHU Dao-Bao, YAO Wen-Li, GU Jia-Shan, LI Xiao-Hua, SHEN Guang-xia

2004, 25(11):  2137-2139. 

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Redox behavior and electrocatalytic activities of the Ti/nano-TiO₂ electrode were investigated by cyclic voltammetry(CV) and bulk electrolysis. The results indicate that there are two pairs of well-defined redox peaks for Ti/nano-TiO₂ film electrode in the 1 mol/L H₂SO₄ and 1 mol/L NaOH at 0.1 V/s corresponding to TiO₂/ Ti₂O₃ and TiO₂/Ti(OH)₃ reversible electrode process. In 1 mol/L NaOH medium the peak potential evidently shift to the negative value with E_1/2^r being -1.38 and -1.72 V(vs.SCE), and the heterogeneous electrocatalytic reduction activities of TiO₂/Ti₂O₃ redox for p-nitrobenzoic acid (PNA) is very high. The indirect electroreduction of PNA to p-aminobenzoic acid (PAA) by Ti^Ⅳ/Ti^Ⅲ redox system on nanocrystalline TiO₂ film surface was found, and the electrode reaction mechanism is called electro-catalytic(EC) mechanism. In the preparative electrolysis, the current efficiency was over 90%.

Relationship Between Rheology Behavior of TLCP/PEI Blend System and Its Multi-scales of Structure

YU Ruo-Bing, ZHOU Chi-Xing, YU Wei

2004, 25(11):  2140-2143. 

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Structural rheology of multi-scales of Vectra A950/PEI blend was studied. The prediction of the dynamic rheological behavior of Vectra A950/PEI blend according to Palierne model is consistent with the experiment results during the period of low frequency, while at high frequency, the prediction is deviated from the experiment results. The cause is that dispersed phase is deviated from sphere at a high frequency, which is related to rheological response of multi-scales of structure. The explanations are: (1) at the higher frequency, molecules orientation of Vectra A950 is hard to relax completely, and global anisotropy appears, so that the dispersed TLCP particles are easy to be deformed; (2) the relaxation process of dispersed phase droplet is slow, therefore, the deformed dispersed TLCP droplets are not able to retract at the high frequency. Affected by the two factors metioned above, Vectra A950 droplets in Vectra A950/PEI blend are deviated from sphere, resulting in different structural rheology properties from flexible polymer blends.

Theory of Polymer Solutions Based on Volume Fraction at Chain-end

QIAO Bao-Fu, YANG Zai-Zhou, ZHAO De-Lu

2004, 25(11):  2144-2147. 

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The concept of volume fraction at chain-end is presented to overcome the mean-field approximation in Flory-Huggins(FH) theory. With the concept of interval-continuous chain introduced to replace multi-chains mathematically, some thermodynamical quantities can be written in path integral method. The entropy of polymer/solvent system is divided into two parts. Based on the conditions metioned above and the approximation that the interaction energy doesn′t affect the entropy of the system, a new theory of polymer solutions is built. The calculated FH interaction parameter and the spinodal curves with different molecular weights of PS are all quite well consistent with the experimental data, and much better than those of FH theory.

An Acid-base Controlled Fluorescence Switch Based on a Free-base-porphyrin-perylene-diimide Molecular Array

SUN Jing-Zhi, YANG Xin-Guo, LI Han-Ying, HUANG Ji, WANG Mang

2004, 25(11):  2148-2152. 

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The variations of the fluorescent spectral features with respect to a molecular array, N,N-bis[p-5′-(m-10′,15′,20′-triphenylporphyrin)phenyl]-perylene-3,4:9,10-tetracarboxyl-diimide(TrPP-PTCDI-TrPP), were investigated at different concentrations of trifluoroacetic acid, the molecular array displays the characteristic emission of the protonated free-base-porphyrin subunit upon the photo-excitation of both the protonated free-base-porphyrin(λ=439 nm) and perylene-diimide subunits(λ=491 nm), because the excited state of protonated free-base-porphyrin in the molecular array was a relative stable species in comparison with other excitations. The incorporation of the acid leads to the closure of the efficient charge transfer decay, while results in the open of the radiation decay. Addition of triethylamine into the solution affords the reverse processes, i.e. the open of the efficient charge transfer decay while the closure of the radiation decay. Thus the molecular array provides a proton-type of fluorescent switch based on acid-base control. Such a molecular array switch has advantages of facility due to the acid-base neutralization and broad-band sensitivity due to the simultaneous response to different excitation wavelengths.

Thermal Polymerization of Urethane Vinyl Ethers Initiated by Diaryldiodonium Salt

PANG Lai-Xing, ZENG Zhao-Hua, YANG Jian-Wen, CHEN Yong-Lie

2004, 25(11):  2153-2156. 

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Two solid vinyl ether terminated aliphatic urethanes, named PUE1 and PUE2, were synthesized and characterized. PUE1 is a crystalline compound with a melting point of 101 ℃; PUE2 is a prepolymer with glass transition temperatures of 30.8 and 17.2 ℃. Both compounds undergo rapid thermal polymerization in the presence of diphenyliodonium hexafluorophosphate(PI810) at different temperatures. The thermal polymerization temperatures for these systems are much lower than the thermal decomposition temperature of neat PI810. The initiation mechanism is presumably based on the electron transfer from electron-rich vinyl ether to electron-dificient diphenyliodonium salt, forming an intermediate charge transfer complex, which can undergo rapid electron transfer or decompose to give radical-cationic vinyl ether or protonic acid, both of which are responsible for the initiation of vinyl ether cationic polymerization.

Synthesis of a Novel Sulfonated Poly(ether ether sulfone)s Used as Proton Exchange Membrane Fuel Cell(PEMFC)

LI Xian-Feng, NA Hui, LU Hui

2004, 25(11):  2157-2160. 

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A novel sulfonated poly(ether ether sulfone) derived from 3,3′,5,5′-tetramethylbiphenyl-4,4′-diol was synthesized by direct aromatic nuelecphilic condensation of 3,3′,5,5′-tetramethylbiphenyl-4,4′-diol with various ratios of 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone to 4,4′-dichlorodiphenylsulfone. The polymers have a good thermal stability and solubility in some polar solvents. Most of them can be cast into tough membranes, and the properties of the membranes will be studied in future.

Influence of Temperature Effect on Phase Separation of Epoxy Resin Modified with Polyetherimide

GAN Wen-Jun, LI Hua, LI Shan-Jun

2004, 25(11):  2161-2165. 

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The phase separations of epoxys resin modified with phenyl terminated and fluorocarbon chain polyetherimide at different temperature has been studied by using DSC, SEM and time-resolved light scattering(TRLS). It was found that for F-blend, the phase separation occurred and curing rate and phase separation rate were slower than those for P-blend which leads to smaller periodic distance. As the temperature increased, the larger periodic distance resulting from the higher phase separation rate and the difference between the two systems caused by fluorocarbon terminated chain became smaller. It suggests that the phase structure can be controlled by lowering the surface energy of polyetherimide and it is a possible way to obtain co-continuous structure with a smaller periodic distance.

Synthesis of Branched Polyethylene via Copolymerization in situ Catalyzed by (α-diimine)nickel(Ⅱ) Complex-TiCl₄ Combined and Supported Catalyst

ZHANG Qi-Xing, LIN Shao-Quan, WU Zhi-Yong, WANG Hai-Hua

2004, 25(11):  2166-2170. 

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The (α-diimine)nickel(Ⅱ){[C₆H₅—NC(CH₃)—C(CH₃)N—C₆H₅]NiBr₂}—TiCl₄(abbreviated as NiL-TiCl₄) combined catalyst which was supported by the MgCl₂-SiO₂ carrier was prepared. With alky aluminum(AlR₃) as a cocatalyst, in place of methylaluminoxane(MAO), it can catalyze ethylene polymerization and copolymerization in situ. The influences of the procedure for supporting NiL-TiCl₄, the molar ratio of NiL to TiCl₄, cocatalyst type and polymerization temperature on the catalytic performance were studied. The branching degree and the composition of the branched chain of polymerized product were investigated by IR and ¹³C NMR spectra. The experiment results show that the combined catalyst can be used to catalyze the synthesis of the branched polyethylene with various banched chains. The polymerization reaction was monitored by gas chromatography and mass spectrometer(GC-MS). The results show that this catalyst has the function to catalyze the oligomerization and copolymerization in situ for ethylene.

Synthesis and Anti-cataract Activity of a Novel Peroxidase Mimetics

WANG Li-Ping, LIU Ya-Li, YANG Hui, LI Wei

2004, 25(11):  2171-2173. 

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Cataracts are one of the most important causes of blindness. As the mechanism of oxidative damage to cataracts was understood, anti-oxidants, especially peroxidase mimetics, were used to develop the agents to protect the eye and cure cataracts. We have designed and synthesized a nonapeptide (DhHP-6) containing deuterohaemin and histidine, which showed a peroxidase activity by degrading H₂O₂ and tert-butyl hydroxyl radical in ascorbate-specific peroxidase test. The specific activity is 4.0×10³ U/μmol with H₂O₂ and ascorbate as the substrate. DhHP-6 is capable of protecting cultured rat lenses from cataracts induced by galactose. In the absence of the DhHP-6 big change on lenses was observed.

Synthesis of a Novel Water-soluble Poly(p-phenylene vinylene-co-methacrylic acid) with Blue Photoluminescence

AN Li-Juan, LIU Jun-Song, XIE Bin, TANG Jun, CHI Yuan-Bin, WANG Ce

2004, 25(11):  2174-2175. 

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A new water-soluble poly(p-phenylene vinylene-co-methacrylic acid) copolymer was synthesized based on the introducing non-conjugated water-soluble group to conjugated backbone, which was different from previous works by functionalizing the fully conjugated group side chains to obtain water-solubility. The synthesized copolymer exhibits efficient blue emission.

Methyl Methacrylate Miniemulsion Polymerization via RAFT Mechanism Using β-Cyclodextrin as Solubilizer

SHAO Ya-Jun, NI Pei-Hong, JI Xiao-Li, YU Zhang-Qing

2004, 25(11):  2176-2178. 

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The methyl methacrylate(MMA) reversible addition-fragmentation chain transfer(RAFT) miniemulsion polymerization in the presence of β-cyclodextrin(β-CD) was investigated. β-CD is found to act both as an efficient solubilizer for RAFT agent(2-cyanopro-2-yl dithiobenzoate) and as a stabilizer for heterogeneous polymerization. The RAFT miniemulsion polymerizations with or without β-CD were compared in terms of kinetics and the molecular weight distribution. The problem of poor latex stability was observed in this system. A good result of the control over RAFT miniemulsion polymerization of MMA was obtained with β-CD. The increase of the molecular weight of poly(methyl methacrylate) shows a linear relationship with the monomer conversion. The polydispersity index of the polymer with β-CD(PDI=1.18—1.21) is smaller than that without β-CD. TEM photographs showed that the PMMA particles produced with β-CD had smooth surfaces and uniform particle size. Higher amount of sodium dodecyl sulfate and hexadecane was found in favor of improving the controllability of the system. Oil soluble initiator is beneficial to the controllability of the polymerization.