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    10 December 2016, Volume 37 Issue 12
    Content
    Cover and Content of Chemical Journal of Chinese Universities Vol.37 No.12(2016)
    2016, 37(12):  0-0. 
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    Volume Contents of Chemical Journal of Chinese Universities to Vol.37(2016)
    2016, 37(12):  0-0. 
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    Articles: Inorganic Chemistry
    Mechanism in the Preparation of Gold Nanoflowers by Ascorbic Acid Reduction
    YANG Shuang, JI Xiaohui, YANG Wensheng
    2016, 37(12):  2125-2131.  doi:10.7503/cjcu20160608
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    The mechanism in the preparation of gold nanoflowers using the mixture of HAuCl4 and ascorbic acid(AA) as growth solution was investigated. It was identified that the AA concentration affected the attachment of the small gold particles on the seeds and the intraparticle ripening of the gold nanoflowers, thus resulting in the formation of the flowers with different morphologies and optical properties. It is effective to tune morphology and optical property of the gold nanoflowers by optimizing the AA concentration and pH of the growth solution simultaneously. Surface enhanced Raman scattering(SERS) results indicated the as-prepared gold nanoflowers showed good SERS activity to Rhodamine 6G, suggesting the clean surface character of the flowers prepared by AA reduction.

    Design and Bio-evaluation of 64Cu-NOTA-Herceptin for Tumor Targeted Micro-PET Imaging
    ZHU Hua, LI Yilin, ZHAO Chuanke, XIE Qinghua, LIU Fei, HAN Xuedi, GAO Jing, XIA Chuanqin, SHEN Lin, YANG Zhi
    2016, 37(12):  2132-2137.  doi:10.7503/cjcu20160593
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    The precursor compound 2-(p-thiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid-Herceptin(NOTA-Herceptin) was synthesized by the nucleophilic addition reaction of Herceptin and bi-functional chelator NCS-Bz-NOTA. The original Herceptin and NOTA-Herceptin conjugate were investigated by UV-Vis and MALDI-TOF mass spectra. The average number of chelators per Herceptin for the conjugated used in this study was 5.4. The enzyme-linked immunosorbent assay(ELISA) was conducted to compare the biological activity of original Herceptin and NOTA-Herceptin. NOTA-Herceptin kept high immunoreactivity towards HER2 antigen. Then, the PET radio-nuclide 64Cu(T1/2=12.7 h) was labeled to got the novel tumor Immuno-Theranostics probe 64Cu-NOTA-Herceptin. The labeling efficiency of 64Cu-NOTA-Herceptin was tested by Radio-TLC/HPLC. The radiolabeling yield was over 90%, the radio chemical purity was over 98% after PD-10 column purification and the specific activity was 185 MBq/nmol. The immune reactivity and specific activity of radiolabeled Herceptin with HER2 antigen were performed by HER2 positive NCI-N87 cell line and HER2 negative BGC823 cell line. Micro-PET imaging of BGC823 tumor-bearing nude mice revealed that tumor uptake of 64Cu-NOTA-Herceptin got a gradual accumulation from 4 h to 60 h after intravenous injection of 7.4 MBq radiolabeled Herceptin. Uptake in the tumor was clearly visualized by emission computed tomography. 64Cu-NOTA-Herceptin owns a great potential for molecular imaging of PET for diagnosis and follow-up of HER2 expression.

    Synthesis,Crystal Structure and Protein Tyrosine Phosphatase Inhibition of a Copper(Ⅱ) Complex with N-(2-Pyridylmethyl)-L-serine
    LI Yanhong, YUAN Caixia, LU Liping, ZHU Miaoli, FU Xueqi, XING Shu, GAO Zengqiang
    2016, 37(12):  2138-2143.  doi:10.7503/cjcu20160563
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    The reaction of the reduced Schiff base HL [N-(2-pyridylmethyl)-L-serine] with CuCl2·2H2O in molar ratio of 1∶1 in methanol solution afforded a new neutral mononuclear complex [CuLCl(H2O)](Ⅰ). The structure was determined by single-crystal X-ray diffraction and further characterized by elemental analysis, FTIR, electrospray ionization mass spectrometry and powder X-ray diffraction. In complex Ⅰ, the Cu(Ⅱ) ion adopts five-coordinated mode in a square pyramidal configuration which is completed by one oxygen and two nitrogen atoms from the L- anion, one chloride anion and one water molecule. The discrete copper coordination units were extended into a 2D supramolecular network through the intermolecular interactions. The bioactivity of the compound as a potential PTPs(Protein Tyrosine Phosphatases) inhibitory agent in vitro was investigated, displaying potent inhibition against PTP1B(IC50=0.32 μmol/L) and TCPTP(IC50=0.45 μmol/L).

    Analytical Chemistry
    Photoelectrochemical Response and Application of ZnO Nanorods Photoelectrode to Riboflavin
    HE Yanyan, GE Junying, ZHAO Changzhi
    2016, 37(12):  2144-2149.  doi:10.7503/cjcu20160522
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    In this work, based on the pre-reduction of riboflavin(RF) on the second working electrode, a new photoelectrochemical(PEC) system was fabricated by the reduced RF as an electron donor incorporated into PEC reaction process of zinc oxide nanorods photoelectrode(ZnONRP). After optimizing the electro-chemical preparation for ZnONRP and studying the reaction mechanism of RF with ZnONRP, a PEC method for the determination of RF was developed. Under the optimized conditions of pH=6.5, -0.40 V as pre-reduction potential, illumination at 365 nm and light energy of 450 μW/cm2, the photocurrent at bias voltage 0.1 V is proportional to the logarithm of RF concentration in the range of 1.00×10-5—1.00 μmol/L with sensitivity of 195.6 nA/lg[c(μmol/L)], and the detection limit was estimated to be 6.00×10-7 μmol/L(S/N=3). Determination results for real samples showed that the relative standard deviation is less than 6.25% and the recovery rate is 99.0%—104%. Compared with other methods for the determination of RF, the proposed method has various advantages, such as wide measurement range, high sensitivity, simple equipment and convenient operation. And common biochemical substances were not interfering with the photocurrent response of RF.

    Fragmentation Reaction of Complexes of Alkali Metal Cations with Tripeptides in Gas Phase
    WU Ruofei, CHU Yanqiu, XU Chongsheng, LIU Zhipan, DING Chuanfan
    2016, 37(12):  2150-2158.  doi:10.7503/cjcu20160447
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    For exploring effects of side chain R groups on dissociations of complexes of alkali metal ions with peptides in gas phase, the complexes of Li+, Na+, K+, Rb+, Cs+ and the tripeptides Glycyl-glycyl-glycine(GGG), Glycyl-phenylalanyl-glycine(GFG) and Glycyl-glycyl-phenylalanine(GGF) were chosen to probe the fragmentation reaction process by electrospray ionization mass spectrometry. The experimental results demonstrated that Li+, Na+ or K+ and GGG, GFG or GGF can form complexes in a coordination ratio of 1∶1 or 2∶1, respectively. The mass spectra for competition reactions of GGG, GFG or GGF with Li+, Na+ or K+ showed peak intensity of alkali metallated-tripeptide complexes decrease in the order of Li+, Na+, K+ similarly, indicating that the binding strength of complexes descend with the ascend of the radii of alkali metal ion. Collision-induced dissociation(CID) results showed the center of mass frame collision energy E(CM)50 values were 1.94, 1.76 and 1.63 eV for the precursor of [GGG+Na]+, [GGF+Na]+ and [GFG+Na]+, respectively. The mass spectrometric titrations determined the lgKa1 values were 5.30, 5.25 and 5.17, respectively. Quantitative analyses of mass spectra further confirmed the stability order [GGG+Na]+ >[GGF+Na]+>[GFG+Na]+, indicating binding strength of complexes GFG or GGF with R side chain(benzyl group) were weaker than GGG with R side chain(only hydrogen atom) due to effects of steric hindrance. The tandem mass spectrometric analysis revealed that dissociation of soliated GGG produces most abundant soliated a2, bn, yn ion series, while soliated GGF or GFG ion gives abundant soliated yn and bn ions, but rarely soliated an. Moreover, doubly alkali meallated GGF tends to dissociate to more metallated y ion series. The breakdown graph for the complex [GGF+Na]+ showed the percentage of fragment ion [b2+Na+OH]+ will go up greatly upon the increasing of collision energy. According to Siu’s fragmentation mechanisms of protonated tripeptide, it is inferred that soliated GFG will fragment to [b2+Na]+ ion with an incipient oxazolone. Then [b2+Na]+ will continue to fragment to [a2+Na]+ with a cyclic protonted 4-imidazolidone.

    Organic Chemistry
    Synthesis and Antitumor Activities of Rhein-Valine Adducts
    ZHANG Jie, ZHOU Changjian, XIE Jianwei, DAI Bin
    2016, 37(12):  2159-2167.  doi:10.7503/cjcu20160568
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    In order to search for novel leading compounds endowed with better antitumor activities, twelve novel rhein-valine derivatives were designed and synthesized by modification of position-1, 3 and 8 of rhein nucleus, and their structures were confirmed by 1H NMR, 13C NMR and HRMS. All the target compounds were tested for cytotoxic activity against five cancer cell lines including Hela, MCF-7, HepG2, KB and HEK293T by methyl thiazolyl tetrazolium(MTT) method in vitro. The results demonstrate that compound 5l displayed a broad spectrum of cytotoxic activities with IC50 value of lower than 10 μmol/L against all tumor cell lines, compounds 5e, 5i and 5j only demonstrated moderate cytotoxic activities(IC50<50 μmol/L). Primary structure-activity relationships(SARs) analysis indicated that the 3-phenylpropoxyl substituents in position-1,8 of rhein nucleus were the suitable pharmacophoric group giving rise to significant antitumor agents. In addition, compound 5l was found to exhibit remarkable DNA intercalating effects.

    Extraction, Separation, Structural Analysis and Antioxidant Activity in vitro of Arabinoxylans(AX-Ⅰ-1) from the Residue of Astragalus Root
    LIU Lei, LI Ke, HAO Xia, WANG Guizhen, QIN Xuemei, DU Guanhua, ZHANG Xiang
    2016, 37(12):  2168-2175.  doi:10.7503/cjcu20160500
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    Four fractions(AX-Ⅰ-1, AX-Ⅰ-2, AX-Ⅰ-3 and AX-Ⅰ-4)from the residue of Astragalus root were extracted by sequential chemical extraction, and purified by DEAE-Cellulose 52 anion-exchange and Sepharcryl S-400 high resolution gel-permeation chromatography. A combination of chemical and instrumental analysis was performed to investigate the structural characterization and antioxidant activity of AX-Ⅰ-1. The results demonstrated that AX-Ⅰ-1 was mainly composed of rhamnose, arabinose, xylose, mannose, glucose and galactose, and the molar ratio was 0.006∶14.113∶8.284∶0.116∶0.468∶1. Backbone of AX-Ⅰ-1 composed of arabinose and xylose by β-(1→2), β-(1→3)and β-(1→4)glycosidic bond. The branches were composed of (1→4)-linkedArap, (1→3)-linkedGalp, (1→2)-linkedManp, and the terminal residues were αRhap, βGclp, βGalp.The four fractions had a certain scavenging effect on hydroxyl radical, superoxide anion radical and DPPH radical. When the concentration is 0.1 mg/mL, scavenging rate of AX-Ⅰ-2, AX-Ⅰ-3 and AX-Ⅰ-4 on superoxide anion is about 2 times higher than the positive control vitamin C.

    Physical Chemistry
    Three-dimensional N-Doped Graphene Aerogel Supported Cobalt Phthalocyanine as High-efficiency Catalyst for Oxygen Reduction Reaction
    YU Dingling, ZHANG Bowen, HE Xingquan
    2016, 37(12):  2176-2183.  doi:10.7503/cjcu20160607
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    A two-step solvothermal approach for the synthesis of three-dimensional(3D) N-doped graphene aerogel and cobalt tetrapyridyloxyphthalocyanine composite(CoTPPc/NGA) as a novel and efficient non-precious catalyst in the oxygen reduction reaction(ORR) was reported. The resulted hybird exhibited impressive ORR catalytic activity and superior stability as well as excellent methanol crossover to commercial Pt/C, which could be used as an alternative Pt-free catalyst in alkaline direct methanol fuel cells(DMFCs).

    Oxidative Desulfurization of Gasoline Catalyzed by Organic-inorganic Heteropoly Acid Ionic Liquids Under Ultrasound
    YU Fengli, XIE Panhui, ZHU Guoqiang, YUAN Bing, XIE Congxia, YU Shitao
    2016, 37(12):  2184-2190.  doi:10.7503/cjcu20160539
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    A series of Organic-inorganic heteropoly acid ionic liquids was synthesized and used for catalyzing oxidative desulfurization of simulated gasoline under ultrasound. With the help of ultrasonic wave, the reaction time was largely reduced, and the desulfurization efficiency was also raised. The results showed that Zr0.25[BMIM]HPW12O40 exhibits the best catalytic activity. The effects of ultrasonic power, ultrasonic/clearance time, the amount of catalyst, reaction temperature, reaction time, and the amount of H2O2 on the desulfurization rate were fully investigated. The selected optimal conditions were as follows: n(Cat.)=0.008 mmol, V(H2O2)=40 μL, V(simulated oil)=10 mL, V(acetonitrile)=1 mL, reaction temperature 25 ℃, reaction time 10 min, the ultrasonic power 300 W, the ultrasonic time 2 s, and the ultrasonic off-time 1.5 s. Under the optimal conditions, the sulfur removal of DBT could reach 97.8%. The solid catalyst Zr0.25[BMIM]HPW12O40 could be directly separated out after the reaction, and could be reused after the vacuum drying. The results showed that Zr0.25[BMIM]HPW12O40 also exhibited good recyclability. After 5 recycles, the desulfurization rate still could reach 81.9%. By using Zr0.25[BMIM]HPW12O40 as catalyst, the reaction activity decreased in the order of DBT>4,6-DMDBT>ethyl thioether>phenyl thioether>n-butyl mercaptan>methyl phenyl thioether>BT>thiophene.

    Kinetics and Mechanism of Decontamination Reaction of CEES in H2O2/[CnMIm]HCO3
    WANG Zhicheng, XI Hailing, KONG Lingce, ZHAO Sanping, ZUO Yanjun
    2016, 37(12):  2191-2198.  doi:10.7503/cjcu20160487
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    A series of environmentally benign 1-n-alkyl-3-methylimidazolium bicarbonate ionic liquids(ILs)([CnMIm]HCO3, n=2, 4, 6, 8) was synthesized and hydrogen peroxide was employed in decontamination against 2-chloroethyl ethyl sulfide(CEES, a mustard agent simulant) in these ILs. The influencing factors such as ILs alkyl chain length, oxidant/CEES molar ratio and temperature were tested and the activation energy, reaction product in H2O2/[BMIm]HCO3 was analyzed. The results indicated that the solvents species can affect decontamination efficacy against CEES and they were in the following sequences: [BMIm]HCO3>[EMIm]HCO3>[HMIm]HCO3>[OMIm]HCO3>C2H5OH> H2O. In H2O2/[BMIm]HCO3 system, 99.58% of the CEES was oxidized mainly to corresponding sulfoxide after 30 min at the concentration of 20 mg/mL and O/S molar ratio of 10. The apparent activation energy of CEES oxidized by H2O2/[BMIm]HCO3 was 15.59 kJ/mol. Moreover, the superoxide radical anion(·O-2) could be produced and oxidized ILs to 2-imidazolone, which inhibited the formation of corrosive sulfone. The result indicated that H2O2/[BMIm]HCO3 system may be a new option for decontamination against CEES.

    Theoretical Studies on the Mechanisms of Transfer Hydroformylation Between Hydrocinnamaldehyde and Norbornadiene Catalyzed by Rh(Xantphos)L Complexes
    YANG Yongsheng, YANG Xin, TIAN Zhiyue, XUE Ying
    2016, 37(12):  2199-2205.  doi:10.7503/cjcu20160489
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    The mechanism of transfer hydroformylation reactions of hydrocinnamaldehyde with norbornadiene(nbd) catalyzed by the catalyst a[Rh(Xantphos)L] complex at M11-L/6-31G(d,p) was calculated(Pathway A). The α-C in the reactive aldehyde molecules actually bonds with one hydrogen atom at least to reduce the steric interaction between the aldehyde reactant and counterion section in C—H oxidative addition step. A little of alkane products observed experimentally, the mechanism of reactive course of decarbonylation of hydrocinnamaldehyde(Pathway B) was calculated. The theoretical study indicates that decarbonylation reaction is suppressed and the selectivity for dehydroformylation is calculated to be(styrene∶phenylethane>99∶1) with benzoate as counterion. The calculation results show that simple aldehyde propanal would prefer dehydroformylation reaction rather than decarbonylation reaction catalyzed by active catalyst a. Based on the reactive energy barrier profile, the hydroformylation of acceptor nbd accelerated the occurrence of dehydroformylation and made the whole transfer hydroformylation irreversible.

    Ca, Sr co-Doped Ceria and Its Application in Oxidative Coupling of Methane
    YANG Yanling, DONG Lingyu, XIA Wensheng, WAN Huilin
    2016, 37(12):  2206-2214.  doi:10.7503/cjcu20160467
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    The Ca and Sr co-doped ceria catalysts were synthesized with a citric acid method and their performances in oxidative coupling of methane(OCM) were significantly enhanced when compared with the single or none doped ceria catalysts. By X-ray diffraction(XRD), CO2 temperature programmed desorption(CO2-TPD), O2 temperature programmed desorption(O2-TPD), X-ray photoelectron spectroscopy(XPS) characterizations, we found that the Ca and Sr co-doped catalysts were consisted of the phases CeO2 and SrCO3, along with Ca highly dispersed or doped in ceria. They exhibited the decreased size of ceria particles and the medium basicity. The number of electrophilic oxygen species and the ratio of electrophilic oxygen species to lattice oxygen species on the catalyst surfaces were changed in the order of CeSrCa>CeSr>CeO2, corresponding to the C2 selectivity in OCM. In addition, the presence of SrCO3 was beneficial to improve on catalytic performances of OCM over Ce-based oxide catalysts.

    Hydrodealkylation of Trimethylbenzene over Silicon-based Catalyst
    XIA Yanyang, BU Tiantong, WANG Licheng, ZHU Wanchun, YANG Xuwei, BAO Qiang, HAO Mengmeng, CHENG Dongdong, WANG Zhenlü
    2016, 37(12):  2215-2220.  doi:10.7503/cjcu20160461
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    A series of Ni/SiO2 catalysts, prepared via sol-gel and impregnation methods, respectively, was tested in the reaction of hydrodealkylation of 1,2,4-trimethylbenzene(1,2,4-TMB). The results showed that the volume of citric acid anhydrous(CA) have great influence on the structure, surface properties, particle size and catalytic properties. 1,2,4-TMB hardly reacted disproportionation and isomerization reaction on Lewis acid sites. The hydrogenation of benzene ring was main adverse reaction on Ni/SiO2 catalysts. The particle size of Ni on the catalyst could be adjusted in a certain range by changing the amount of CA, and the resultant catalysts exhibited high selectivity for Benzene-Toluene-Xylene(BTX). With the optimum reaction conditions, the highest conversion of 1,2,4-Trimethylbenzene was 29.4% and the selectivity of BTX was 99.9% on the 10Ni/Si-2.0 catalyst.

    Removal Research of Selenite in Wastewater with the Ferrous Hydroxyl Complex(FHC)
    FU Mao, WU Deli, ZHANG Yalei, ZHANG Yong
    2016, 37(12):  2221-2227.  doi:10.7503/cjcu20160435
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    Se(Ⅳ) and Se(Ⅵ) were found in treatment of industrial wastewater, especially toxicity and highly radioactivity of Se(Ⅳ) are seriously hazardous to the natural environment. The ferrous hydroxyl complex(FHC), structural Fe(Ⅱ), was synthesized by precipitation method, and for the treatment of industrial wastewater containing selenite were investigated by FHC. The results showed that Se(Ⅳ) removal rate was 40% by FHC when pH value was 8. Se(Ⅳ) removal rate were 80%, 90%, 53% by FHC when pH values were 6.5, 8, 9.5, respectiverly, and Cu(Ⅱ) concentration was 0.5 mmol/L. In other conditions being the same, Se(Ⅳ) removal rate was 93%, 99%, 98% when Ag(Ⅰ) concentration was 0.3 mmol/L. However, in the pH value of 8, Se(Ⅳ) removal rate was 30%, 24% and 21% when nitrite concentration was 0.2, 2 and 20 mmol/L. This result showed that the nitrite has an obviously inhibition in Se(Ⅳ) removal. The samples were characterized via X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD), which indicated silver ions converted into elemental silver, copper ions were reduced into cuprous oxide, selenite were fixed onto the structure state ferrous surface and reduced for oxidation state of selenium. By sequential extraction procedure, analysis on selenium in sediments has been found that selenide and element Se was the main reduction product, which indicated the reduction immobilization was mainly selenite removal envelope. Owing to FHC strong coagulation and reduction ability, it should be of practically potential for treatment of industrial waste water.

    Preparation and Electrochemical Performance of Polyaniline Film Formed on Acid-activated Stainless Steel 316L
    LIU Ming, TIAN Ying, FU Jie, XU Hongfeng
    2016, 37(12):  2228-2235.  doi:10.7503/cjcu20160432
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    Ni-Cr enrichment on stainless steel 316L(SS316L) was achieved by adjusting the concentration and distribution of Cr and Ni on the surface of the SS316L substrate through in situ oxidation processes. Aniline monomers were absorbed and polymerized on the surface of modified SS316L, and a polyaniline(PANI)/Ni-Cr enriched SS316L composite was prepared using chronopotentiometry(CP) technique. Under both reducing(anode simulated) and oxidizing(cathode simulated) conditions of proton exchange membrane fuel cell(PEMFC), the results of potentiodynamic test showed that the PANI coating increased the free corrosion potential of the steel by more than 470 and 500 mV, respectively, with a passivation current density more than 2—3 orders of magnitude lower than that of the bare steel. Under the PEMFC environment, the corrosion currents of the anode and cathod of PANI/Ni-Cr enriched SS316L electrode were decreased by 1 and 2 orders of magnitude, and corrosion rates of the anode and cathode were about 6—9 μA/cm2 and <5 μA/cm2, respectively. Furthermore, the interface contact resistance between the PANI film and carbon paper was reduced by about 250.0 mΩ·cm2 at a compaction pressure of 1.4 MPa. Polyaniline/Ni-Cr enriched SS316L bipolar plate was remarkably more stable in simulated PEMFC environments, and more conducting compared to the bare SS316L.

    Effect of Acid-treatment of Graphitized Carbon Supports on Performance of Fuel Cell Catalysts
    YAN Haixu, YANG Meini, ZENG Hao, PU Hongting, LIN Rui
    2016, 37(12):  2236-2245.  doi:10.7503/cjcu20160426
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    The graphitized carbon black(GCB) was obtained by a high temperature(1700 ℃) treatment of the XC-72 commercial carbon black(XC-72 CB). The functional groups of GCB were modified by acid treatment. Transmission electron microscopy(TEM), X-ray diffraction, Raman spectrum and infrared spectroscopy displayed the GCB with acid treatment had a higher degree of graphitization. Oxygen-containing functional groups were introduced into the GCB surface and the ordered structure of the GCB was maintained at the same time. Nitrogen adsorption and desorption experiment showed the GCB had smaller specific surface area and less micropore compared to XC-72 CB. Thermogravimetric analysis showed that GCB had the better heat stability. Cyclic voltammetry and linear sweep voltammetry test showed that the electrochemical specific activity area(ECSA)(75.25 m2/g) and the mass activity(MA)(0.093 A/mg) of conc. H2SO4 and conc. HNO3 treated GCB(abbreviated as OGCB) were higher than those of the commercial one. TEM showed the Pt/OGCB had an average particle diameter of 2.28 nm, smaller than the commercial one. After durability test of 5000 cycles, the ECSA and MA of Pt/OGCB decreased by 17.3% and 29.5%, respectively, smaller than those of Pt/C(JM)(25.1% and 42.5%). Both activity and durability performance of Pt/OGCB catalyst were better than those of commercial Pt/C(JM) catalyst in oxygen reduction reaction. In addition, in single cell test, the durability of Pt/OGCB catalyst was also better than that of the commercial catalyst. The results show that OGCB has a promising application prospect in the field of proton exchange membrane fuel cell(PEMFC) catalyst support.

    Preparation and Photoelectrocatalytic Performance of CuO/V2O5/FTO Composite Nanofibers Electrode
    LIN Xiao, LI Youji, LI Ming, TANG Ningmei, LI Ziqin, HAN Zhiying
    2016, 37(12):  2246-2252.  doi:10.7503/cjcu20160428
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    CuO/V2O5/FTO composite nanofibers photoelectrode was fabricated by electrospinning method with polyvinyl pyrrolidone(PVP) as fiber skeleton, copper(Ⅱ) nitrate hydrate and vanadium(Ⅳ)-oxy acetylacetonate as raw materials. The structure of the samples was characterized by thermogravimetry-differential thermal analysis(TG-DTA), X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electronic microscopy(TEM) and X-ray photoelectron spectroscopy(XPS). The photoelectrocatalytic performance of the samples was analyzed by the degradation of methylene blue(MB) solution. The results show that the heterojunctions between CuO and V2O5 were formed, and the separation of photogenerated electron-hole pairs on CuO/V2O5/FTO was promoted, which made the degradation rate of MB catalyzed by CuO/V2O5/FTO much higher than that catalyzed by pure V2O5/FTO. The different molar ratios of n(Cu)/n(V) had influence on photoelectrocatalytic activity, and the CuO/V2O5/FTO with n(Cu)/n(V)=1∶1 had the highest catalytic activity(degradation rate of MB was 96%).

    Photoconversion of γ-Hexachlorocyclohexane in the Presence of Humic Acid in Ice
    BAO Siqi, KANG Chunli, ZHONG Yubo, ZHOU Lin, YAO Zhifu, HUANG Dongmei, WANG Yuhan, TIAN Tao
    2016, 37(12):  2253-2259.  doi:10.7503/cjcu20160414
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    The photoconversion regularity of γ-hexachlorocyclohexane(γ-HCH) in snow and ice in the presence of humic acid(HA) were studied. The results showed that the photoconversion efficiency of γ-HCH was promoted at low initial concentration of HA, but inhibited at high concentration of HA. Salt ion concentration, NO2- and NO3- all promoted the photoconversion efficiency of γ-HCH. The photoconversion efficiency of γ-HCH was promoted at low initial concentration of Fe3+, but inhibited when the concentration of Fe3+ reached 50 μmol/L. The sequence of photoconversion rate of γ-HCH at different pH was alkaline>neutral>acidic. HA accelerated the photoconversion of γ-HCH by producing singlet oxygen(1O2), hydroxyl free radical(·OH) and triple excited state(HA*) in ice. Photoproducts of γ-HCH in the presence of HA are mainly pentachloro-cyclohexene, p-dichlorobenzene and o-dichlorobenzene, 1-chlorobenzene, and 1O2 indirectly accelerated the photoconversion of γ-HCH by consuming the intermediate products.

    Density Functional Theory Study of the Structural and Spectrum Properties for PdSin(n=1—15) Clusters
    ZHANG Yu, WANG Chong, ZHANG Shuai, LI Genquan
    2016, 37(12):  2260-2267.  doi:10.7503/cjcu20160349
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    The possible geometrical structure of the PdSin(n=1—15) clusters were optimized with density-functional theory(DFT) approach at B3LYP level, based on the crystal structure analysis by particle swarm optimization(CALYPSO). The electronic properties, infrared and Raman spectrum were also studied. The calculated results indicate that the most stable structures of PdSin clusters develop from planar to three-dimen-sional structure; when n≤4, vibrational frequencies are in a range of 450—500 cm-1; when n≥5, vibrational frequencies are in a range of 50—500 cm-1, the strong peak modes are found almost to be an breathing vibration of the Si atoms.

    Synthesis of Pd/PEI-GNs Composites as Electrocatalyst for Reduction of p-Nitrophenol
    LUO Minghong, XIA Kejian, ZHOU Guanghua, GE Wen
    2016, 37(12):  2268-2274.  doi:10.7503/cjcu20160338
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    Pd/PEI-GNs composites were prepared by the electrochemical deposition technique with poly(ethyleneimine) functionalized graphene(PEI-GNs) as the support. The as-prepared composites were characterized by FTIR, XRD, XPS and SEM. The results showed that Pd/PEI-GNs composites were prepared and Pd particles were uniformly dispersed on the PEI-GNs support. Cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS) and chronoamperometric curves were used to investigate the electrocatalytic activities of the Pd/PEI-GNs composites. The results indicated that the as-prepared composites presented better electrocatalytic activity and stability towards p-nitrophenol reduction. The enhancement in electrochemical performance of the Pd/PEI-GNs composites can be attributed to the synergistic effect of highly dispersed Pd nanoparticles on the PEI-GNs and higher electron transfer of PEI-GNs.

    Investigation of Topology-distinct Stable Structures for Hydrogen Fluoride Clusters (HF)n(n=2—8) by the Methods of Graph Theoretical Enumerations and Quantum Chemical Calculations
    MAHMUTJAN Jelil, ABLAT Mamat, ALIMJAN Abaydulla, MAMAT Tursun
    2016, 37(12):  2275-2283.  doi:10.7503/cjcu20160275
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    A graph theoretical procedure to generate all the possible topology-distinct structures for hydrogen fluoride(HF) clusters was presented and all the possible topology-distinct structures for hydrogen fluoride (HF)n(n=2—8) clusters were enumerated in this work. On the basis of the restrictions found, FORTRAN program was designed and executed by Python program, and the corresponding diagraphs or restrictive digraphs were drawn by means of free graph visualization software, GraphViz 2.38 for HF cluster (HF)n(n=2—8) . Within the theoretical framework of the corresponding digraphs or restrictive digraphs, all the topology-distinct local minima for (HF)n(n=3—7) were optimized and analyzed by means of ab initio method and density functional theory(DFT) method at the level of MP2/6-31G**(d,p) and B3LYP/6-31G**(d,p), respectively. The local minimum structures for (HF)n(n=3—7) are the same as those in the previous works. For HF pentamer, hexamer and heptamer, some new local minimum structures were obtained.

    Polymer Chemistry
    Research on Silicone-modified Boric Phenolic Resin
    GUO Anru, LI Jie, LIU Chang, XIAO Dehai
    2016, 37(12):  2284-2290.  doi:10.7503/cjcu20160662
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    (2-Hydroxyphenyl)propyl silicone oil(Si-phenol) was obtained via Williamson ether synthesis, Claisen rearrangement, and hydrosilylation, and then was mixed with phenol. The silicone-modified boric phenolic resin(SBPF) was synthesized via borate esterifieation. The structure of SBPF was analyzed by means of 1H NMR and FTIR, and the heat-resistance and mechanical performances of SBPF were characterized by TGA, shearing test, tensile test, and impact test. The effects of Si-phenol content on various performances of SBPF were investigated, and the mechanisms were researched. The result shows that the synthesized resin has good heat-resistance, and the introduction of appropriate proportion siloxane segments could improve its adhesive property and enhance its mechanical strength.

    Synthesis and Performance of Novel Modified Polycaprolactone Polyurethane Elastomers
    CHEN Chao, BAO Chunyan, YUAN Min, LIN Qiuning, ZHU Linyong
    2016, 37(12):  2291-2298.  doi:10.7503/cjcu20160528
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    Polycaprolactone(PCL) is a kind of excellent histocompatible and biodegradable materials due to the presence of amounts of esters that can be hydrolyzed by water or enzyme, which made PCL as one of Pure Food and Drug Administration(FDA) certified medical materials. However, the high crystallinity and poor hydrophility of polycaprolactone induce slow biodegradation rate, poor tenacity and fatigue durability although it has high mechanical strength. Therefore, modification on polycaprolactone was necessary. Herein, we used isocyanates[hexamethylene diisocyanate(HDI) and isophorone diisocyanate(IPDI)] to modify polycaprolactone and the phosphorylated prepolymers were reacted with bifunctional epoxy to form crosslinked and biodegradable elastomers. The test and analysis of mechanical properties, water contact angle, degradation/swelling and cell cytotoxicity in vitro indicated that the introduction of isocyanate helped to improve flexibility, fatigue resistance and degradation rate of the elastomers with no increased cytotoxicity.

    Preparation and Characterization of Thermo-sensitive N-Acetyl Glycol Chitosan Hydrogel for Sustained Drug Release
    LI Zhengzheng, XU Ziyang, GAO Liuyi, ZENG Wei, ZHAO Linlin
    2016, 37(12):  2299-2305.  doi:10.7503/cjcu20160513
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    A novel thermo-sensitive polymer N-acetyl glycol chitosan(NAGC) by N-acetylation of glycol chitosan with acetic anhydride was prepared. The chemical structure, thermo-sensitive property, morphology and in vitro drug release properties of NAGC hydrogel were investigated by means of 1H NMR, FTIR, tube inverting method, SEM and UV-Vis spectroscopy. The results show that the degree of acetylation(DA) of NAGC is increased along with the increase of the feed molar ratio of acetic anhydride to glycol chitosan and reaction time. NAGC hydrogel shows reversible thermo-sensitive sol-gel transition behavior, and the sol-gel transition temperature is well controlled from 25 ℃ to 37 ℃ by controlling the DA and polymer concentration. NAGC hydrogels show macroporous structure with the pore size of 1—40 μm. The pores are well-interconnected to each other and the pore size could be controlled by changing the DA and concentration of NAGC. NAGC hydrogel(DA=89.90%, 5%—7%, mass fraction) shows sustained release behavior for anticancer drug gemcitabine, and the release time could be controlled from 3 d to 5 d. NAGC shows great promise for various biomedical applications, such as drug delivery and tissue engineering.

    Preparation and Filtration Performance of Antifouling PVA/PVDF Composite Ultrafiltration Membrane Based on Electrospinning Technology
    WU Linghui, WANG Bin, WANG Jiaona, LI Congju
    2016, 37(12):  2306-2314.  doi:10.7503/cjcu20160429
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    A composite ultrafiltration membrane containning polyethylene terephthalate(PET) non-woven fabric substrate and poly(vinylidene fluoride)(PVDF) nanofibers as support layer, polyvinyl alcohol(PVA) nanofiber membrane for barrier layer was prepared using electrospinning method. A mixture of acetone and water solution was used for crosslinking treatment to form the dense barrier layer. The ultrafiltration membranes were characterized by Fourier transform infrared(FTIR) spectroscopy, scanning electron micrograph(SEM) and water contact angle(WCA). Filtration performance of the resulting PVA/PVDF composite ultrafiltration membranes was evaluated by the oil/water emulsions separation system. The results showed that the optimal composite ultrafiltration membrane possessed general flux[(42.50±4.78) L/(m2·h)] and high rejection rate[(95.72±0.33)%] at very low feeding pressure(0.02 MPa), after 5 times recycled, it still has good filter performance. The pure water flux using the dead-end filtrationof composite ultrafiltration membrane at atmospheric pressure was [(3469±28) L/(m2·h)].

    Crystallization Kinetics of trans-/cis-Polyisoprene Blends
    YAO Kuncheng, NIE Huarong, MA Yunsheng, WANG Riguo, WANG Xiaojian, HE Aihua
    2016, 37(12):  2315-2322.  doi:10.7503/cjcu20160394
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    Isothermal and non-isothermal crystallization kinetics of cis-1,4-polyisoprene(CPI)/trans-1,4-polyisoprene(TPI) binary blends were investigated by differential scanning calorimetry method. The results were analyzed by Avrami equation and MO theory. It was found that the presence of CPI suppressed the crystallization rate of TPI component during both isothermal and non-isothermal crystallization. The crystallinity of TPI component was enhanced by CPI during the isothermal crystallization. For non-isothermal crystallization, the relative content of β crystal form increased, while the crystallinity of TPI component changed little with the incorporation of CPI component.