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10 August 2013, Volume 34 Issue 8

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Cover and Content of Chemical Journal of Chinese Universities Vol.34 No.8(2013)

2013, 34(8):  0-0. 

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Article: Inorganic Chemistry

Praperation of Fe₃O₄ Hexane Ferrofluid with Phase-transfer Method

CHEN Ming-Jie, XIONG Xiao-Min, SHEN Hui, LIU Hai-Feng

2013, 34(8):  1801-1805.  doi:10.7503/cjcu20130317

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A novel and facile phase-transform method has been presented for the preparation of double-coated Fe₃O₄ hexane ferrofluid. Firstly, the double-coated Fe₃O₄ nanoparticles were synthesized via chemical coprecipitation and excess sodium oleate were used as surfactant to yield a stable water-based magnetic fluid. Based on this, hydrophilic Fe₃O₄ nanoparticles were transformed into hydrophobic ones which were extracted to hexane by adding acetic acid. Fourier transform infrared(FTIR) spectra show that -COO^- at the outer layer of Fe₃O₄ nanoparticles transforms into -COOH at proper pH value adjusted by acetic acid, which makes Fe₃O₄ nanoparticles hydrophobic and dispersive in polar or nonpolar carrier liquid. X-Ray diffractometer(XRD), vibrating sample magnetometer(VSM) and transmission electron microscope(TEM) were also used to characterize the magnetic nanopartieles and the ferrofluid. Our method ensures that Fe₃O₄ nanoparticles are coated compactly and mono-dispersive state without any agglomeration, which makes the thus obtained hexane ferrofluid stable and less delamination after several months. The ferrofluid with different solid content and dispersed in other oil-based carriers can be obtained through evaporating n-hexane.



Synthesis of Divalent-metal-containing Open-framework Aluminophosphates M(Ⅱ)-CJ50 Using Ether Amine as the Organic Template

SHAO Lang, LI Yi, WANG Xiao-Fang, YU Ji-Hong

2013, 34(8):  1806-1811.  doi:10.7503/cjcu20130309

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Three divalent-metal-containing open-framework aluminophosphates, designated M(Ⅱ)-CJ50, (|C₆H₁₇N₂O₂| [MAl₃P₄O₁₆], M=Mg, Mn and Fe), have been hydrothermally synthesized using 2,2'-(ethylenedioxy)bis(ethylamine) as the organic template. Single crystal and powder X-ray diffraction analyses show that their structures are similar to those of trivalent-metal-containing aluminophosphates M(Ⅲ)-CJ50 synthesized by using imidazole as template. The differences between M(Ⅱ)-CJ50 and M(Ⅲ)-CJ50 are: hetero-metal atoms in M(Ⅱ)-CJ50 have lower oxidation states owing to the usage of ether amine; in M(Ⅱ)-CJ50, hetero-metal atoms are coordinated to the two O atoms in each ether amine molecule, whereas in M(Ⅲ)-CJ50 hetero-metal atoms are coordinated to pairs of imidazole molecules through single N atoms. Moreover, magnetic measurements reveal that the hetero-metal atoms in M(Ⅱ)-CJ50 are high-spin whereas those in M(Ⅲ)-CJ50 are low-spin owing to the differences in ligand molecules and oxidation states of hetero-metal atoms.



Controlled Preparation of Te Nanowires/Nanorods by Low Temperature Wet Chemical Methods

HONG Xiao-Jie, FAN Xi-An, ZHANG Hui-Xuan, CAI Xin-Zhi, YANG Fan, LU Lei

2013, 34(8):  1812-1817.  doi:10.7503/cjcu20130117

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In the present work, Te nanowires/nanorods were prepared by low temperature wet chemical methods. The effects of reaction temperature and the dropping rate of reducing agent on the phase and microstructure of the products were investigated. The results showed that the diameter of Te nanowires increased and the length decreased with the increase of reaction temperature. With decreasing the dropping rate of hydrazine hydrate, the length and diameter of the Te nanowires all increased. The growth principle of Te nanowires could be inferred by observing the morphology and structure of the products during different reaction stages. At early stage of the reaction, the TeO₂ dissolved in ethylene glycol were reduced into the metastable activated α-Te and stable τ-Te. As the reaction proceeded, metastable α-Te would be re-dissolved and be reduced into the stable τ-Te. The axial growth characteristic along [001] direction of τ-Te crystal should be ascribed to its significant crystal anisotropy.



Study of Interaction Between Bovine Serum Albumin and Cobalt Complexes of Phenanthroline and Nitrilotriacetate by Fluorescence Spectrometry

LIN Hai-Bin, ZHENG Lin, LIN Yu-Qin, ZHOU Zhao-Hui

2013, 34(8):  1818-1825.  doi:10.7503/cjcu20130098

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Cobalt complexes [Co(phen)₂Cl₂(1), Na[Co(nta)]·H₂O(2), [Co(phen)₂(H₂O)₂]·[Co(nta)(phen)]₂·12H₂O([STHZ]3[STBZ])] (phen: phenanthroline, nta: nitrilotriacetate) were synthesized in solution, and the structure of complex 3 was characterized by single-crystal X-ray diffraction analysis(XRD). It crystallized in the triclinic system, space group P1 with a=1.2448(2) nm, b=1.5898(3) nm, c=1.7412(3) nm, α=91.746(3)°, β=97.807(3)°, γ=103.745(3)°, V=3.309(1) nm³. The interaction between bovine serum albumin(BSA) and complexes 1-3 was investigated with fluorescence spectra at room temperature. Fluorescence quenchings were shown as static quenching for complexes 1 and 3 based on the fluorescence spectrum at different temperatures. The binding constant, binding sites and thermodynamic functions were calculated. The interaction sites, binding force and distance for BSA with complexes 1 and 3 were discussed respectively.



Growth and Luminescence Properties of Ce,Mn: YAG Single Crystal

ZHANG Zhi-Min, LIANG Xiao-Juan, ZHAO Bin-Yu, CHEN Zhao-Ping, LIU Bing-Feng, ZHONG Jia-Song, XIANG Wei-Dong, LÜ Chun-Yan

2013, 34(8):  1826-1832.  doi:10.7503/cjcu20130097

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Ce,Mn: YAG single crystal for white light emitting diode(LED) was grown by Czochralski method. The structure, valence states of doped Mn and optical properties of the samples were characterized by X-ray diffraction(XRD), X-ray absorption fine structure(XAFS), absorption and photoluminescence spectra. The photoelectric parameters of white LED were also measured by changing the thickness of single crystal and the driving current. Ce,Mn: YAG single crystal shows a broad emission band peak around 526 nm and 566 nm under blue light of 460 nm. The XAFS result shows that the valence states of doped Mn are mostly Mn²⁺ in the Ce,Mn: YAG. Due to the effective energy transfer between Ce³⁺ and Mn²⁺ in YAG single crystal, the bright orange luminescence in the bands peaked at 566 nm are caused by the ⁴T₁→⁶A₁ radiative transitions of Mn²⁺.



Syntheses, Structures and Surface Photo-electric Properties of Cd(Ⅱ)-btec Coordination Polymers

JIN Jing, DING Yu, LI Dan, CHI Yu-Xian, NIU Shu-Yun

2013, 34(8):  1833-1839.  doi:10.7503/cjcu20120905

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Two Cd(Ⅱ) coordination polymers [Cd₃Na₂ (btec)₂(H₂O)₂]_n(1) and {[Cd₃Na₂(btec)₂·(H₂O)₂]·4H₂O}_n(2)(H₄btec=1,2,4,5-benzenetetracarboxylic acid) were synthesized by hydrothermal method. The structures were determined by single crystal X-ray diffraction. Structural analyses show that the asymmetric units of polymers 1 and 2 contain two crystallographically unique Cd(Ⅱ) ions with six- and eight-coordinate, respectively, and they possess 3D structures bridged by btec^4- groups. The structure differences between them are that the coordination environment around Na(Ⅰ) ions is different and polymer 2 has lattice water molecules. The photo-electric properties of the two polymers were investigated by surface photovoltage spectroscopy(SPS). The results of SPS show that the two polymers exhibit obvious photovoltage responses in the range of 300-500 nm, which indicates that they all possess certain photo-electric conversion properties. The SPS and UV-Vis spectra of the polymers were interrelated, and XRD patterns and TG curves of the two polymers were measured and analyzed.



Analytical Chemistry

Detection of Hydroxylated Metabolites of Polycyclic Aromatic Hydrocarbons by Electrospray Ionization Ion Trap Tandem Mass Spectrometry

LI Xue, FANG Xiao-Wei, LI Yin-Ping, CHEN Huan-Wen

2013, 34(8):  1840-1844.  doi:10.7503/cjcu20130427

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Hydroxylated metabolites of polycyclic aromatic hydrocarbons(OH-PAHs) are the mostly widely used biomarker of carcinogenic PAHs to assess health risk caused by exposure to PAHs. Among present strategies used for detecting OH-PAHs, electrospray ionization tandem mass spectrometry(ESI-MS²) shows advantages in both high sensitivity and selectivity; however, fragment ions cannot be obtained for some OH-PAHs(e.g. 3-OHBaP, 2-OHFlu). In this work, ESI-MS² analysis of nine OH-PAHs(2- to 5-rings) was achieved with ion trap MS²(IT-MS²); by optimizing collision-induced dissociation conditions of activation Q(AQ) and normalized collision energy(NCE), 3-OHBaP and 2-OHFlu were effectively fragmented meanwhile fragmentation efficiencies of other seven OH-PAHs were also improved. AQ was proven to be the critical parameter for fragmenting OH-PAHs when IT-MS² is used.



High Sensitive Glutathione and Cysteine Detection by Au Nanoparticles Enhanced Electrochemical Biosensor

WANG Qing, LIU Wei, YANG Xiao-Hai, WANG Ke-Min, LIU Pei, HE Lei-Liang

2013, 34(8):  1845-1850.  doi:10.7503/cjcu20130424

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Glutathione(GSH) and cysteine(Cys) are biological thiols that play vital roles in maintaining cellular functions. GSH is a thiol-group-containing tripep-tide, which has a pivotal role in maintaining the redu-cing environment in cells. Cys is a biomarker for various medical conditions, and a disease-associated physiological regulator. In this work, a high sensitive electrochemical biosensor for GSH and Cys detection was constructed using Au nanoparticles enhanced signal amplification. DNA1 and DNA2 were all poly-T DNA probes. Firstly, DNA1 was modified on the surface of electrode, and then DNA2 was modified on the AuNPs. In the presence of Hg²⁺, the binding of Hg²⁺ with thymine(T) was employed to form T-Hg²⁺-T structure and thus DNA2 modified AuNPs could be captured on the electrode surface. The added GSH(or Cys) could selectively coordinate with Hg²⁺ of the T-Hg²⁺-T structure, which resulted in the departure of AuNPs from the electrode surface. Since DNA modified on AuNPs could bind a large number of electric active RuHex via electrostatic interaction, the chronocoulometry signal was reduced obviously, and then GSH(or Cys) could be detected according to the change of chronocoulometry signal. The results showed that the electrochemical biosensor was highly sensitive, and it could detect as low as 10 pmol/L for GSH(or Cys). It was about 2-3 orders of magnitude lower than those of fluorescent and colorimetric methods. Moreover, eight kinds of amino acids were used as control to investigate the selectivity of this electrochemical biosensor, and the results showed that this electrochemical biosensor showed good selectivity.



Simulation of a Single-channel Separation System Based on Brownian Ratchets

CHEN Li-Li, FU Ying-Qiang, ZHAO Jian-Wei, ZHANG Wen-Wei

2013, 34(8):  1851-1857.  doi:10.7503/cjcu20130244

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Research on diffusion behaviors in micro-scale confined space is of significant value in micro-chemistry. In this work, we have constructed a model of miniature single-channel separation system, which was made of inversely asymmetric Brownian ratchets, and conducted simulations of molecular diffusion in this system based on random walk theory. The separation mechanism and the influence of different conditions on the diffusion behaviors were discussed based on the simulation results. It was concluded that, interaction between the particle and the Brownian ratchets could be adjusted by the switching time of the external force properly, which enables different particles separated into two different directions in the single-channel system. The applicable conditions of this separation system was provided as well. Furthermore, it was demonstrated that with adjustment of the structural parameters of the separation device, time cost of the separation process could be saved effectively while achieving optimal separation. The simulation method has certain reference significance for the development of micro-separation devices and optimization of the operating parameters.



Organic Chemistry

Total Synthesis of Chelerythrine

HUANG Kang-Lun, XIE Long-Guan, LÜ Pei, GUO Cui, XU Xiao-Hua

2013, 34(8):  1858-1862.  doi:10.7503/cjcu20130279

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Chelerythrine is an isoquinoline alkaloid isolated from Herba Chelidonii that possess complex structure and remarkable activities. In this work, its total synthetic approach was investigated. Key meditate methyl 6-iodo-2,3-dimethoxybenzoate(7) was obtained in six steps with(6-bromo-2,3-dimethoxyphenyl)methanol(1) as starting material. The core structure was efficiently constructed by palladium-catalyzed tandem reaction in one step. At the same time, a proposed mechanism of palladium-catalyzed tandem reaction was suggested and the chelerythrine was synthesized in 10 steps with a total yield of 60.9%. All compounds were confirmed by IR, ¹H NMR, ¹³C NMR and high resolution mass spectrometer(HRMS).



Microwave-assisted Synthesis of Arene Ru(Ⅱ) Complex [(η⁶-C₆H₆)Ru(H₂iiP)Cl]Cl in SiC Vessel

WU Qiong, MEI Wen-Jie, WU Wei-Li, CHEN Yan-Hua, ZENG Ling-Li, ZHENG Wen-Jie

2013, 34(8):  1863-1867.  doi:10.7503/cjcu20121112

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Arene Ru(Ⅱ) complex [(η⁶-C₆H₆)Ru(H₂iiP)Cl]Cl(1) was synthesized using [(η⁶-C₆H₆)·5RuCl₂]₂ and 2-indole-3-imidazole[4,5-f][1,10] phenanthroline(H₂iiP) as raw material under microwave irradiation. The target compound was characterized by means of elemental analysis, ESI-MS, IR and NMR. The best craft condition determined by orthogonal test is that reactant molar ratio of 1.0: 2.2, the reaction tempe-rature of 90℃ and the microwave irradiation time of 30 min. Then the average yield of 96.0% and RSD of 1.28% confirmed that microwave-assisted synthesis of arene Ru(Ⅱ) complex in SiC vessel gives a good stability and reiteration. The antitumor activity of arene Ru(Ⅱ) complex 1 was determined by MTT assay and the results showed that complex 1 could selectively inhibit the growth of MCF-7, indicating its potential utility in chemotherapy.



Synthesis and Antifungal Activity of N-(4'-Substituted aromatic pyrimidin-2'-yl)-2-ethoxycarbonyl phenyl Sulfonylurea Derivatives

LIU Zhuo, PAN Li, YU Shu-Jing, LI Zheng-Ming

2013, 34(8):  1868-1872.  doi:10.7503/cjcu20121094

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The innovative research by DuPont’s George Levitt on sulfonylureas had been acknowledged as a milestones in herbicidal chemistry due to the ultralow dosages and ecofriendly characteristics. In order to carry out the systematic research of novel mono- and disubstituted heterocycles within sulfonylurea structures to study the structure-activity relationship(SAR), 14 novel sulfonylurea derivatives containing aromatic substituted moieties at the 4th position of the pyrimidine ring were designed and synthesized based on the commercial herbicide Chlorimuron-ethyl. Their structures were characterized by ¹H NMR and HRMS. The preliminary in vitro bioassay results indicated that most of the title compounds exhibited moderate fungicidal activity against Botrytis cinerea, Sclerotinia sclerotiorum and Rhizoctonia solani at 50 mg/L. Three title compounds 7g, 7h and 7i displayed satisfactory fungicidal activity against them, which are higher than the other compounds. Compounds 7j-7n containing heteroaromatic ring at the 4th position of the pyrimidine ring indicated the moderate fungicidal activity against Sclerotinia sclerotiorum.



Effect of Hydrophilic Ionic Liquid [EMIM]BF₄ on the Catalytic Activity of Immobilized β-Glucuronidase

CAO Hong, SUN Qian, LI Chun, LI Kai-Xiong, LI Jun

2013, 34(8):  1873-1879.  doi:10.7503/cjcu20121082

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To improve hydrolysis of glycyrrhizin(GL) to glycyrrhetinic acid monoglucuronide(GAMG) possessing best biological function, Penicillium purpurogenum Li-3 strains highly expressing β-glucuronidase was screened by our workgroup in the initial research period. This enzyme was capable of promoting biotransformation process of GL to GAMG. With chitosan as carrier, immobilized β-glucuronidase was prepared by adsorption-crosslink technology in this work. With the purpose of studying the effect of hydrophilic ionic liquid BF₄ on catalytic activity of immobilized β-glucuronidase, the [EMIM]BF₄/buffer homogeneous system was used as bio-catalytic medium for immobilized β-glucuronidase to catalyze hydrolysis of GL to GAMG. The results showed that under the conditions of 16%(volume fraction)[EMIM]BF₄, pH value of 5.4, the reaction temperature of 50℃ and the shaker rotate speed of 200 r/min, the enzyme activity could reach its maximum, and obviously higher than the highest enzyme activity in pure buffer medium system. After repeated recycling experiment, compared with that in pure buffer medium system, the immobilized β-glucuronidase showed excellent stability to repeated use in containing [EMIM]BF₄ homogeneous medium system. The appa-rent kinetic parameters and activation energy data showed that the affinity between β-glucuronidase and its substance was enhanced by [EMIM]BF₄ in biocatalytic medium, and the enzyme-substrate in the transition state was effectively stabilized, and the activation energy of the catalytic reaction was lowered, so that immobilized β-glucuronidase showed higher catalytic activity. This study provided the basis for design and application of new clean biological reactors and technology to improve the efficiency of enzymatic hydrolysis of GL to GAMG.



Aggregation-induced Emission Enhance and Electrical Storage Properties of 1,2,4,5-Tetra{4-[N,N-di(4-iodophenyl)amino]styryl}benzene

YANG Hua, QI Qi, WANG Bin-Bin, QIAN Ying

2013, 34(8):  1880-1886.  doi:10.7503/cjcu20120257

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A conjugated dendrimer based triphenylamine, 1,2,4,5-tetra{4-[N,N-di(4-iodophenyl)amino]styryl}benzene(TPAB-I), was synthesized through Wittig-Horner reaction. The maximum emission wavelengths of TPAB-I were 451, 464, 478, 481 and 511 nm in toluene, THF, ethyl acetate, CH₂Cl₂ and DMF, respectively. The maximum emission wavelengths of solid and film of TPAB-I were 526 and 488 nm, respectively. Aggregation-induced emission enhancement of TPAB-I had been found. The possible mechanism of this phenomenon was discussed. An organic electrical memory device having the Al/TPAB-I/indium-tin oxide(ITO) sandwich structure was fabricated firstly. The device exhibited a flash memory effect with a high ON/OFF current ratio nearly 10⁴, a long retention time above 10⁴ s and a read voltage 1.0 V. The read voltage and erase voltage were 1.5 and -2.0 V, respectively. The results demonstrated that the synthetic TPAB-I possessed a high potential to become dendrimeric memory device.



Virtual Screening and Antibacterial Activity of Novel Inhibitors Targeting the DNA Gyrase with New Mechanism

HUANG Zhen-Gui, LIN Ke-Jiang, YIN Hong-Ping, YE Bo-Ping, WENG Xing-Bei, YOU Qi-Dong

2013, 34(8):  1887-1893.  doi:10.7503/cjcu20130312

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A new class of DNA gyrase inhibitors such as GSK299423 with new mechanism was reported as potent antibacterial activity against multidrug-resistant bacteria. In this work, crystal structure of GSK299423 in complex of DNA gyrase and DNA(PDB code: 2XCS) was utilized for drug design of novel DNA gyrase inhibitors. A pharmacophore model was constructed via the crystal structure of complex. By decoy set validation, the pharmacophore model was demonstrated to possess favorable ability to recognize novel DNA gyrase inhibitors from library. The pharmacophore model and docking method were applied to virtual screen the Screening Compounds library to obtain hit compounds. The hit compound LTH02 was demonstrated to significantly inhibited multidrug-resistant Escherichia coli by antibacterial activity assay, thus the LTH02 as a novel DNA gyrase inhibitor was finally achieved. The pharmacophore model developed could be applied to design more novel DNA gyrase inhibitors and it also provided theoretical basis for further structural modification and synthesis of the inhibitors.



Effects of Lipids and Heparin Sulphate on Formation of Amyloid Fibril from α_s1-Casein

YIN Jian-Yuan, John A. Carver, David C. Thorn, LIU Ji-Hua

2013, 34(8):  1894-1898.  doi:10.7503/cjcu20121124

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α_s1-Casein is the major protein in milk and has a molecular chaperone action. With the interest in that, whether κ-and α_s2-casein can form amyloid fibrils or not, we investigated amyloid fibril formation from α_s1-casein by means of ThT assay, transmission electron microscopy and circular dichroism(CD) spectra. The results show that amyloid fibrils formed from α_s1-casein at pH=5.0-5.4 and 65℃ under heating for 144 h. The CD spectra show that the structure of α_s1-casein has changed from α-helical to β sheet core, which are the special structure characters of fibrils. Lipids of D6PC promoted amyloid fibril formation from α_s1-casein in the concentration of 0.3 and 1 mmol/L. Heparin sulphate did not influence the fibril formation from α_s1-casein in the test. It is concluded that although α_s1-casein has the effects of molecular chaperon, but it could still form fibrils under harsh conditions. Lipids can influence amyloid fibril formation from α_s1-casein, depanding on concentration. It suggests that there is relationship between lipid in membrane and amyloid fibril formation. The results are helpful to exploring the mechanism of fibril formation from α_s1-casein.



Physical Chemistry

Degradation of Nitrobenzene Wastewater with Modified Ti/SnO₂-Sb Electrode

LIU Miao, LENG Su, CHEN Song-Yue, ZHANG Liang, ZHANG Mei-Xiu, LIU Wan-Yi, SHEN Li, ZHANG Zhen-Bin, LIU Nan, JIAO Xin-Qian, CHEN Li-Ke, QUAN Fu-Min

2013, 34(8):  1899-1906.  doi:10.7503/cjcu20130294

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By thermal decomposition, Ti/SnO₂-Sb electrodes modified with metals on Ti substrates were prepared. The morphology and crystal structure of the electrodes were analyzed by SEM and XRD. The stability and electric catalytic activity were studied by strengthening the electrode life and the electric catalytic experiment. The degradation rate of the electrodes was analyzed by dynamic equation, the degradation mechanism of nitrobenzene was explored with mass spectrum, and the concentration of OH · was measured by salicylic acid capturing hydroxyl radicals with high performance liquid chromatography. The experimental results show that metal doping improved the surface morphology, changed the diffraction peak intensity of SnO₂, prolonged the electrolytic life, and ameliorated the catalytic ability of the electrodes. The degradation of nitrobenzene was identified with quasi first order reaction dynamics equation. The aniline absorption peak was generated on the mass spectrogram at top 5-10 min, after 15 min there was no other absorption peak indicated that the nitrobenzene degraded rapidly after deoxidizing to aniline. The higher concentration of free radicals was, the faster nitrobenzene degradation rate would be. Since it reacted for 60 min, the OH· concentration of the blank electrode fell by one-fifth, comparing to the one mixed with Cu.



Preparation of CuO/CeO₂ Catalysts from Metal-organic Frameworks Precursor for Preferential CO Oxidation

XU Li, CHEN Chao, WANG Rui, LUO Jia-Huan, LIU Yun-Ling, ZHANG Ning

2013, 34(8):  1907-1912.  doi:10.7503/cjcu20130260

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Employing metal-organic frameworks(MOFs)as precursors, a series of CuO/CeO₂ catalysts was prepared and applied for CO-PROX(preferential oxidation of CO) in H₂-rich stream. Compared with previously reported A-600 catalyst, we can conclude that different precursors lead different catalytic activity. The X-ray diffraction, temperature-programmed reduction in H₂(H₂-TPR), transmission electron microscope and X-ray photoelectron spectroscopy analysis characterization indicated the as-synthetic catalysts presented more bulk CuO species on the surface than that of the A-600 catalyst, which resulted in the negative catalytic activity for preferential CO oxidation. But this also prevented the deactivation of catalysts in H₂O and CO₂ steam, indicating that the catalysts were promising in the CO-PROX process for proton exchange membrane fuel cell(PEMFC) application.



Porous Phosphate Heterostructure Materials as Green Catalysts in Prins Condensation

WANG Xue-Yan, HUA Wei-Ming, YUE Ying-Hong, GAO Zi

2013, 34(8):  1913-1918.  doi:10.7503/cjcu20130268

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Various ion-exchanged porous phosphate heterostructure(PPH) materials were prepared and characterized by SEM, N₂ adsorption and infrared spectra of pyridine adsorption(Py-IR). Their catalytic behavior for the Prins condensation of β-pinene with paraformaldehyde was investigated. All catalysts exhibit good activities and selectivities towards nopol. Zn-ZrP is a more selective one in comparison to others, due to abundant Lewis acid sites and less Brnsted acid sites on the surface. The conversion of β-pinene and the yield of nopol on the catalyst reach 91% and 83% at 80℃. The catalyst is stable and reusable, and the product yield is only reduced by 12% after five runs. The reduction in activity is probably caused by deposition of coke on the active sites and partial collapse of porous structure.



NO Selective Reduction by H₂ over Pt Supported ZSM-35/MCM-49

YU Qing, WANG Zhong-Wei, LI Lan-Dong, WU Guang-Jun, GUAN Nai-Jia

2013, 34(8):  1919-1923.  doi:10.7503/cjcu20130203

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Composite zeolite was used as support in NO_x elimination. The catalytic performances of Pt/ZSM-35/MCM-49, Pt/ZSM-35 and Pt/MCM-49 were studied on the condition of 0.1%NO, 0.5%H₂, 6.7%O₂, He as balance gas and GHSV=8×10⁴ h^-1. The results show that the activity of Pt/ZSM-35/MCM-49 is higher than the other two catalysts: the maximum NO conversion and N₂ selectivity reaches 84% and 74%, respectively. XRD, H₂-TPR, CO adsorption and in situ FTIR were employed to characterize these three catalysts. The results indicate that the enhancement of activity comes from the co-crystallization, which is benefit for the formation and stabilization of key intermediates, ammonium species.



Volumetric and Viscous Properties for Binary Mixtures of N-Methylpiperazine with Ethyl Acetate or Butyl Acetate from 298.15 K to 313.15 K

LI Dan, FANG Wen-Jun, LIU Li, WU Qian, ZHANG Hong-Yan, SUN Xiao-Ri

2013, 34(8):  1924-1928.  doi:10.7503/cjcu20130182

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Density and viscosity data for binary mixtures of N-methylpiperazine+ethyl acetate and N-me-thylpiperazine+butyl acetate were measured over the entire range of molar fraction at 298.15, 303.15, 308.15 and 313.15 K. Excess molar volume and viscosity deviations were calculated. Excess molar volumes were fitted to the Redlich-Kister equation. The viscosities were correlated with four semi-empirical equations. Thermodynamic functions of activation of the binary systems were correlated. The results show that the excess molar volumes are positive and the viscosity deviations are negative at given temperature, and ΔH^≠ plays a major role in the mixing process.



Effects of Mg Substitution on Structure and Hydrogen Storage of LiBH₄(010) Surface

GONG Xue-Jing, CHENG Li-Ping, XU Bao-En, ZENG Yan-Li, LI Xiao-Yan, MENG Ling-Peng

2013, 34(8):  1929-1935.  doi:10.7503/cjcu20130177

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The geometry, electronic structure, dehydrogenation energy and hydrogen atom migration on the clean and Mg doped LiBH₄(010) surfaces were studied with first-principles calculations based on density functional theory(DFT). The lengths of B-H bond increase, and H atoms are easy to dissociate. Based on the H1 vacancy, we found that the presence of H vacancy is helpful to the formation of other kinds of H vacancy. Electronic structure reveals that the B-H bonds are weakened. By calculating the diffusion pathway of H atom from one [BH₄] to the nearby [BH₄] on the clean and Mg doped LiBH₄(010) surfaces, we find that the migration barrier energy comes down from 4.03 eV to 3.09 eV. This indicates that the H atoms are easier to diffuse on the Mg doped LiBH₄(010) surface.



Three-way Catalytic Acitvities and Thermal Stabilities of Pd@SiO₂/Ce_0.4Zr_0.6O₂ Nanocatalysts with Core-shell Structure

LIU Bei-Bei, ZHANG Gui-Zhen, HE Hong, LI Jin-Zhou, ZI Xue-Hong, QIU Wen-Ge, DAI Hong-Xing

2013, 34(8):  1936-1944.  doi:10.7503/cjcu20130137

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A New type of Pd@SiO₂/Ce_0.4Zr_0.6O₂ three-way nanocatalyst with core-shell structure was prepared from the colloidal Pd nanoparticles. For comparison, the corresponding reference catalyst Pd/Ce_0.4Zr_0.6O₂ was synthesized. The catalysts were characterized by powder X-ray diffraction(XRD), transmission electron microscopy(TEM), nitrogen gas adsorption-desorption and temperature programmed reduction by H₂(H₂-TPR). The three-way catalytic activities and the thermal stabilities of the two kinds of catalysts with different structure were investigated. It was found that the silica shell could prevent the aggregation of Pd nanoparticles. At the same time, the silica could inhibit the redispersion of Pd species so that the loss of precious metal Pd was reduced. All results showed that the Pd@SiO₂/Ce_0.4Zr_0.6O₂ nanocatalyst with core-shell structure possessed good three-way catalytic activities and high thermal stabilities.



Theoretical Study on Structure-property Relationship of Oligothiophene Dyes for Dye-sensitized Solar Cells

SU Xin, ZHANG Ji, WU Yong, GENG Yun, SU Zhong-Min

2013, 34(8):  1945-1952.  doi:10.7503/cjcu20130090

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In order to discuss the differences in the performance of dye-sensitized solar cells(DSSCs) based on two D-π-A organic dyes, which only differ in the donor part, theoretical parameters closely related to the short-circuit photocurrent density(J_sc) and the open-circuit photovoltage(V_oc) were computed with the density functional theory(DFT) and time-dependent DFT calculations, including absorption spectrum, light harvesting efficiency, injection driving force, vertical dipole moment and number of photoinjected electrons and so on. The results reveal that the lower dye regeneration efficiency of dye 2 lead to the lower J_sc of DSSCs, when the dyes have comparative light harvesting efficiency and electron injection efficiency. Meanwhile, under the condition that the dyes have comparative number of photoinjected electrons and the extent of charge recombination, the higher vertical dipole moment of dye 1 could be the crucial factor leading to the higher V_oc. The calculated results are in good agreement with the experimental one. Finally, we hope that our results could provide certain guidance for the future works on the synthesis and design of new efficiency dyes.



Preparation and Hydrogen Generation for Al-LiBH₄ Composite Materials

LIU Hao, XU Fen, SUN Li-Xian, CAO Zhong, ZHOU Huai-Ying

2013, 34(8):  1953-1958.  doi:10.7503/cjcu20121095

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Al-LiBH₄ composite materials were prepared by the mechanical ball milling. The results of the hydrogen-production curves and X-ray diffraction patterns show that when the reaction temperature is higher, the mutual promotion effect between aluminum and LiBH₄ will be more intensed, and the generation of hydrogen will be more. The milled materials have good properties of hydrogen generation in water at room temperature, especially for the Al-25%LiBH₄(mass fraction of LiBH₄ is 25%) material milled for 5 h with a ball/material ratio of 30: 1, which can produce 720 mL/g hydrogen. At 90℃, the Al-25%LiBH₄ material can produce 2026 mL/g hydrogen with the hydrogen yield of 95% while the Al-30%LiBH₄ material can produce 2211 mL/g hydrogen with the hydrogen yield of 96%.



Study on the Electrochemical Redox Mechanism of 2-Hydroxy-1,4-naphthoquinone

LI Dan, JIN Bao-Kang

2013, 34(8):  1959-1964.  doi:10.7503/cjcu20121045

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In situ IR spectroelectrochemistry, cyclic voltabsorptometry(CVA) and derivative cyclic voltabsorptometry(DCVA) techniques were used to study the electron transfer mechanism of 2-hydroxy-1,4-naphthoquinone(2-HNQ) in acetonitrile. When the scan range is from 0.2 V to -1.8 V, the voltammogram of 2-HNQ in acetonitrile shows two couples of anodic and cathodic peaks. When the scan range is from 1.0 V to -2.0 V, there is another anodic peak in cyclic voltammetry(CV) at more positive potential. Tracing the change of some IR absorption peaks during CV scan, there are two kinds of intermediates in the electrochemical process. Radical dianion formed by the reduction process of deprotonated quinine(Q-O^-) continues to reduce, i. e., Q-O^- reduces by an electrochemical reaction-electrochemical reaction mechanism(EE pathway). In addition, it involves the formation of strong hydrogen bonding.



High Yield NiO Nanocubes from Bulk Nickel by Millisecond Pulse Width Laser Ablation

TIAN Fei, AN Jun-Chao, CAO Hong-Mei, GUO Shi-Zhen, SUN Jing

2013, 34(8):  1965-1970.  doi:10.7503/cjcu20120996

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Long-pulse-width laser was used to ablate bulk nickel target immersed in circulating water to obtain NiO nanocubes in high yield. Transmission electron microscopy(TEM), X-ray diffraction(XRD), selected area electron diffraction(SAED) and energy dispersive spectromety(EDS) were employed to characterize the morphology and structure of the NiO nanocubes. The formation of NiO nanocubes is ascribed to the high temperature and high pressure(HTHP) conditions produced by high power density laser. The results show that when the laser power density is above 10⁴ W/cm², NiO nanocubes can be fabricated under laser ablation. The metal droplet is first generated by the laser with a power density higher than 10⁴ W/cm², which boil the surrounding liquid and produce a HTHP vapor due to the confinement of the liquid layer, and finally the surface reaction between the metal droplet and liquid take place to form NiO nanocubes. The laser ablating of bulk nickel target immersed in circulating water is a simple, green, high efficient method for the preparation of NiO nanocubes.



Photoconversion of Hexachlorobenzene in Water, Ice and Organic Phase

LIU Han-Fei, YANG Ting, KANG Chun-Li, LI Lin-Lin, LI Zhe, LIU Jia, CHEN Bai-Yan

2013, 34(8):  1971-1978.  doi:10.7503/cjcu20120974

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The photoconversion kinetics of hexachlorobenzene(HCB) was studied under UV irradiation by using low-pressure mercury lamp as light source. The photoproducts were analyzed and on this basis the photoconversion mechanism was proposed. Also, the effects of H₂O₂, NO₂^-, Fe²⁺ on the photoconversion in water/ice were investigated, respectively. The results show that the photoconversion rates of HCB in the three systems under the irradiation changed as follows: organic phase>water>ice; H₂O₂ promotes the photoconversion of HCB in water but inhibits it in ice; NO₂^- has inhibition effect on the photoconversion of HCB both in water and in ice; Fe²⁺ promotes the photoconversion of HCB in water but has no effect in ice; the photoconversion mechanism of HCB is a step-by-step dechlorination process.



Polymer Chemistry

Long Chain Bismaleimide Modified Cyanate Ester Resin and Its Composites

MA Peng-Chang, LIU Jing-Feng, FAN Wei-Feng, MENG Xiang-Sheng, YANG Ming

2013, 34(8):  1979-1984.  doi:10.7503/cjcu20130281

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A kind of long chain bismaleimide-modified cyanate ester resin and the relevant composites were prepared and characterized. The results indicate that when the resin content of the long chain maleimide-terminated thioetherimide(MIMTI) reached 37.5%(mass fraction), the T_5%of the modified cyanate ester resin(MTI/T₃) was 414℃. Tensile strength and flexural strength of the MTI/T₃ composite were 431.2 and 331.0 MPa, 631.5 and 278.4 MPa at room temperature and 200℃, respectively. And its coefficient of thermal expansion(CTE) in X-Y axis and the moisture absorption were 18.1×10^-6℃^-1 and 1.4%, respectively. Compared to the common bismaleimide-modified cyanate ester resins, and the 20% and 30% MIMTI-modified cyanate ester resin MTI/T₁ and MTI/T₂, respectively, the obtained cyanate ester resin MTI/T₃ exhibited good processing, excellent heat resistance and mechanical properties, low moisture absorption and low CTE.



Preparation of PLMA/PU Blend Fiber and Its Absorption Properties

HU Xiao, XIAO Chang-Fa, ZHAO Jian, FENG Yan, XU Nai-Ku

2013, 34(8):  1985-1992.  doi:10.7503/cjcu20130222

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Polylauryl methacrylate(PLMA) was synthesized via aqueous suspension polymerization using polyvinyl alcohol(PVA) as a dispersing agent and benzoyl peroxide(BPO) as an initiator. PLMA/PU(polyurethane) blend fibers were prepared via blending, pelleting and melt spinning. The structure and properties of the as-spun fibers were investigated by Fourier transform infrared spectrometer(FTIR), scanning electron microscopy(SEM), electronic tensile tester and optical contact angle measuring apparatus. We also studied the absorption rate and reusability of fibers. The results demonstrate that the as-spun fibers exhibit good hydrophobicity and lipophilicity, the fibers are obviously swollen after oil adsorption; the fibers have impressive oil absorbency for light organic liquids, the maximum oil absorbency are 4.86, 8.1, 2.42, 2.04 and 3 g/g for toluene, trichloroethylene, diesel, kerosene and 10% mass fraction of crude oil, respectively. The oil-absorptive fiber could be reused after adsorption-desorption. PLMA played a dominant role during adsorption process; PU played a skeletal role in both organic liquid adsorption and spinning.



Synthesis and Properties of Sulfonated Poly(phthalazinone ether ketone ketone)s Containing Pendant Phenyl Groups

ZHANG Shou-Hai, JIANG Yi-Wen, CHEN Li-Yun, JIAN Xi-Gao

2013, 34(8):  1993-1998.  doi:10.7503/cjcu20130210

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Poly(phthalazinone ether ketone ketone)s with pendant phenyl groups(PPEKK-P) were synthesized via high temperature polycondensation from 4-(4-hydroxyphenyl)-2,3-phthalazin-1-ketone, 4-(3-phenyl-4-hydroxyphenyl)-2,3-phthalazin-1-ketone and 1,4-bi(4-fluorobenzoyl)benzene(BFBB). A series of sulfonated poly(phthalazinone ether ketone ketone)s containing pendant phenyl groups(SPPEKK-P) was prepared from PPEKK-P with concentrated sulfuric acid as the sulfonating agent. The chemical structures of PPEKK-P and SPPEKK-P were characterized by FTIR and ¹H NMR. SPPEKK-Ps proton exchange membranes were obtained by solution casting method. Water uptake, swelling ratio and proton conductivities of SPPEKK-Ps membranes increased with the increase of ion exchange capacity. The membranes exhibited good oxidative stability. The methanol permeability values of SPPEKK-Ps membranes were much lower than that of Nafion117 membrane. The proton conductivity of SPPEKK-P-100 membrane reached 7.44×10^-2 S/cm at 95℃.



Superhydrophobic Polyaniline Micro/Nano Structures as Anticorrosion Coating

XING Cui-Juan, YU Liang-Min, ZHANG Zhi-Ming

2013, 34(8):  1999-2004.  doi:10.7503/cjcu20130214

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A "template-free" method was used to prepare the polyaniline micro/nano structures with different wettability by changing the dopant. The corrosion protection performance of the PANI with different wettability was evaluated in 0.1 mol/L H₂SO₄ using the potentiodynamic polarization curves and electrochemical impe-dance spectroscopy(EIS). The effect of the wettability on the anticorrosion performance was investigated. Superhydrophobic PANI micro/nano structures show good anticorrosion properties. This is due to the superhydrophobic conducting PANI coating not only inhibited water from being absorbed by the coating, thus preventing the corrosive chemicals and corrosion products from diffusing through the coating, but also promoting a thin oxide film on the electrode surface.



Synthesis of Branched Polyethylene and Characterization of Their Structures and Properties

ZHANG Dan-Feng, FAN Shuai, FU Yan, LI Sen

2013, 34(8):  2005-2010.  doi:10.7503/cjcu20121085

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The branched polyethylene(br-PE) were synthesized by [ArNC(An)-C(An)NAr]NiBr₂[An=acenaphthyl, Ar=2,6-C₆H₃(^emPr)₂] in the presence of the modified methylaluminoxane(MMAO) and methylaluminoxane(MAO). The effects of experimental conditions in which ethylene pressure, temperature and time were varied on ethylene polymerization were investigated. The structures of the obtained polyethylene were characterized by high-temperature NMR, high-temperature GPC and DSC. It was found that the activities from MMAO were higher than that from MAO about 10 times, which reaches 10⁷ g/(mol Ni·h). The branches of polyethylene prepared from MMAO were about (45-64)/1000C, while that from MAO were about (82-88)/1000C. The mechanical properties of the br-PE were analyzed and compared with low density polyethylene(LDPE) and ethylene propylene methylene(EPM). It was shown that br-PE exhibits high tensile strength(27.90 MPa), which is much higher than LDPE(14.40 MPa) and EPM(5.44 MPa). The elastic modulus of br-PE is 2.10 MPa, almost same as EPM(2.11 MPa). The elongation at break of br-PE is 774.6%, little higher than that of LDPE(725.6%), but lower than that of EPM(1770.1%).)