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10 May 2016, Volume 37 Issue 5

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Cover and Content of Chemical Journal of Chinese Universities Vol.37 No.5(2016)

2016, 37(5):  0-0. 

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Articles: Inorganic Chemistry

Performance of Gas Storage in Carex meyeriana Kunth-based Carbon^†

WANG Yun, BEN Teng, QIU Shilun

2016, 37(5):  801-809.  doi:10.7503/cjcu20160076

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Carex meyeriana Kunth was chosen as raw material to prepare porous carbon material(UlaC-950-HF) by the direct carbonization method without adding exogenous chemical activator. The result of analysis showed that the percentage of carbon in the sample was up to 93% and the product had a trend of part graphitizing. TGA result showed that the sample had high thermal stability(only 3% mass loss from 0 to 400 ℃). N₂ sorption isotherm results showed that the pore structure of porous carbon was mainly microporosity(maximal pore size distribution was 1.1 nm) with a small amount of mesoporous pore. The distribution of pore diameter was narrow. There were slit-like structures in the sample which were beneficial for storaging high-pressure methane. The capacity of methane storage of UlaC-950-HF was up to 208 mg/g(mass fraction, 17%) or volumetric capacity of 232 at 298 K and 3.5 MPa. This paper also explained the reason for the outstanding capacity of storaging high-pressure methane by drawing a theoretical model.



Synthesis and Photoluminescence Properties of β-Ga₂O₃∶Cr³⁺ Persistent Luminescence Nanoparticles with Near-infrared Afterglow^†

ABDUKAYUM Abdukader, ABDURAHMAN Renagul, TUERDI Ailijiang, MAMATIMIN Adil

2016, 37(5):  810-816.  doi:10.7503/cjcu20160006

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Cr³⁺ doped gallium oxide(β-Ga₂O₃∶Cr³⁺) nanoparticles with near infrared(NIR) persistent luminescence properties were prepared by a facile precipitation method with triethylene glycol as a surface ligand. The persistent luminescence properties and crystal structure of the Ga₂O₃∶Cr³⁺ nanoparticles highly depended on pH value of the reaction solution and the sintering temperature. The experimental results showed that pure β-Ga₂O₃∶Cr³⁺ nanocrystal with small grain size(ca. 30 nm) was obtained after pH value of the reaction solution was adjusted to 7 with ammonium hydroxide, and calcined in air at 700 ℃ for 3 h. The maximum afterglow emission wavelength of the β-Ga₂O₃∶Cr³⁺ nanoparticles was 750 nm, which was controlled by the reaction conditions. The NIR afterglow time of the β-Ga₂O₃∶Cr³⁺ nanoparticles was estimated to be longer than 384 h. The β-Ga₂O₃∶Cr³⁺ persistent luminescence nanoparticles with small size, long NIR afterglow time and controllable emission band have great potential application in low background noise and deep tissue in-vivo imaging.



Synthesis of Al₂O₃ Nanofibers with Ionic Liquids as Both the Template and Aluminum Source^†

LIU Tuanchun, TANG Shaokun, JI Xiaowei, HAN Pei

2016, 37(5):  817-821.  doi:10.7503/cjcu20150970

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Al₂O₃ nanofibers were synthesized with aluminum chloride acid type ionic liquids xAlCl₃-[C₁₀mim]Cl([C₁₀mim]Cl is 1-decyl-3-methylimidazolium chloride, x is the molar fraction of AlCl₃ in the ionic liquid) as both the template and aluminum source via sol-gel method. The effects of the molar fraction of aluminum chloride acid and calcination temperature on the alumina morphology were mainly studied. The obtained products were characterized by means of X-ray diffraction(XRD), transmission electron microscopy(TEM) and N₂ adsorption-desorption. The results suggested that xAlCl₃-[C₁₀mim]Cl could act as not only the aluminum sources but also the template to control the alumina morphology. When the molar fraction of aluminum chloride acid was 0.5, Al₂O₃ nanofibers could be synthesized with the diameter of 2 nm, the length of about 200 nm, the surface area of 238.38 m²/g, the pore volume of 0.54 cm³/g and the mean pore diameter of 8.43 nm. The Al₂O₃ nanofibers could maintain the fiber morphology and γ-Al₂O₃ crystalline phase even under 900 ℃, indicating that the Al₂O₃ nanofibers had relatively high thermal stability. Furthermore, the hydrogen bond-co-π-π stack mechanism was proposed to explain the formation of Al₂O₃ nanofibers.



Preparation and Electroswitchable Luminescence Properties of Nanocomposite Films of Polyoxometalates and Ru(phen)₃C\begin{array}{c}{l_2}^{†}\end{array}

WANG Bin, WANG Xiaohong, LIU Zongrui, DUAN Limei, XU Ling, BAI Suozhu

2016, 37(5):  822-828.  doi:10.7503/cjcu20150809

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The red luminescence films [(PEI/P₈W₄₈)_m/PEI/PSS/Ru(phen)/PSS]_n[m=1, 3, 5; PEI=Poly(ethyleneimine); PSS=poly(sodium 4-styrenesulfonate)] were fabricated by layer-by-layer assembling method based on electrochromic polyoxometalate P₈W₄₈ and luminescent complex Ru(phen). The composition and thicking of the films were characterized by UV-Vis spectrophotometry. The electrochemical and luminescent properties were studied by cyclic voltammetry and fluorescence spectrophotometry, respectively. The composite films displayed reversible electrochromic and electroswitchable luminescence properties during redox potential switching. The electrochromic and luminescence switching abilities of the films were almost not changed by double potential steps(-0.85 V/0.85 V) for 50 cycles, suggesting good electrochemical stability of the films.



Analytical Chemistry

Fabrication of Paper-based Microfluidic Chips and the Application on the Determination of Uric Acid in Serum Based on Gold Nanoparticle-assisted Catalysis^†

ZHAO Tiantian, CHEN Yuqing, ZHANG Min, WANG Yuerong, ZHANG Hongyang, HU Ping

2016, 37(5):  829-834.  doi:10.7503/cjcu20160045

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A simple and fast method for the determiantion of uric acid(UA) in serum was developed using paper-based microfluidic chips and gold nanoparticles(AuNPs) as peroxidase mimic. The paper-based microfluidic chips were fabricated by directly drawing on filter paper with a modified gel pen filled with hydrophobic solution and then dried. When the AuNPs and the mixed solution of TMB and H₂O₂ were droped on the detection zone of paper-based microfluidic chips, the colorless TMB was oxidated to blue substance. Then the sample was added onto the blue zone, the blue-oxidated TMB was reducted to colorless. Finally the picture of detection zone could be captured by a mobile phone camera and the concentration of UA could be caclulated according to the gray value of the detection zone. Parameters influencing the UA determination were investigated, including volume of AuNPs, reaction time and temperature. Under the optimized conditions, the detection limit of UA could be reached to 4.64 mg/L, the linear range was from 10.6 mg/L to 125 mg/L and the recovery was from 94.8% to 108.5%. The method could be applied to determining uric acid in serum.



MWCNTs-rGO/PDDA-AuNPs Nanocomposite Modified Electrode for Sensitive Detection of Ractopamine^†

XUN Yan, CAO Zhong, SONG Tianming, LÜ Chaozhi, LIU Feng, HE Jinglin, YANG Ronghua

2016, 37(5):  835-843.  doi:10.7503/cjcu20160026

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A nanocomposite film of MWCNTs-rGO/PDDA-AuNPs was fabricated through self-assembly method. The surface morphologies of different composite modified glassy carbon electrodes(GCEs) were characterized by means of TEM and UV-Vis spectroscopy, and the cyclic voltammetry behaviors of ractopamine(Rac) were investigated. The results showed that the MWCNTs-rGO/PDDA-AuNPs composite exhibited significantly electrocatalytic activity towards oxidation of Rac. The results of differential pulse voltammetry showed that the electrode possessed a linear range of 0.036—4.5 μmol/L and a detection limit of 6.35 nmol/L(S/N≥3) with good stability, reproducibility and selectivity. The electrode can be well applied to determination of Rac in pork serum and pork urine with a recovery rate of 95.4%—105.9%, suggesting a potential application for actual samples in food security field.



Mechanism of Salvia Miltiorrhiza on the Improvement of Myocardial Function in Patients with Dilated Cardiomyopathy^†

WANG Xiye, SHAN Xiaotong, WANG Yilin, LI Dan, ZHAO Ming, XU Liang

2016, 37(5):  844-851.  doi:10.7503/cjcu20150984

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Metabonomics combined with molecular biology were used to investigate the mechanisms of anti-dilated cardiomyopathy treated by depside salt from Salvia miltiorrhiza. The serum metabolic profiling of control group, model group and treatment group were analysed by principle component analysis(PCA). The potential biomarkers were selected with the help of orthogonal partial least squares discriminant analysis(OPLS-DA). As results, nine potential biomarkers including the PS[16∶0/18∶1(9Z)], LysoPC(16∶0), LysoPC[20∶4(5Z, 8Z, 11Z, 14Z)], LysoPC[22∶6(4Z, 7Z, 10Z, 13Z, 16Z, 19Z)], cholesterol sulfate, taurohyocholate, γ-linolenic acid, docosapentaenoic acid and 9'-carboxy-γ-chromanol were identified respectively. In addition, the relative content of γ-linolenic acid, docosapentaenoic acid and 9'-carboxy-γ-chromanol decreased in the model group, while increased in the treatment group. With the help of western bloting and enzyme-linked immunosorbent method, we confirmed that the depside salt from Salvia miltiorrhiza influenced the expression levels of superoxide disproportionation(SOD), malondialdehyde(MDA), Bcl-2 and Bax protein molecule(the proteins mentioned above were related with γ-linolenic acid and 9'-carboxyl-γ-tocopherol), and then reduced the amount of the apoptosis myocardial cell induced by oxidative stress, and treated the the dilated cardiomyopathy caused by adriamycin finally.



Determination of Cr(Ⅵ) by Ratiometric and Visual Fluorescence Method Based on Formaldehyde Functionalized Polyethyleneimine-rhodamine B Hydrazide System^†

YANG Chuanxiao, YU Mengwen, SONG Duoduo, SUN Xiangying

2016, 37(5):  852-859.  doi:10.7503/cjcu20150962

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Formaldehyde functionalized fluorescent polyethyleneimine(FPEI) were prepared via microwave-assisted synthesis. In H₂SO₄ media, the amine groups on the FPEI surface would be protonated and adsorb Cr(Ⅵ) via electrostatic attraction, and the fluorescence intensity of the FPEI at 480 nm decreased accordingly. At the same time, potassium dichromate can oxidize rhodamine B hydrazide(RBH) to rhodamine B in acidic aqueous conditions, resulting in recovery of rhodamine B fluorescence and absorbance, the absorption bands of which ranged from 250 nm to 600 nm, fully covering the emission and excitation bands of FPEI. Thus, the inner filter effect occurring in FPEI/RBH system led to further decrease of the fluorescence intensity of the FPEI. The fluorescence change ratio(F₅₈₀/F₄₈₀) between the fluorescence intensity of rhodamine B at 580 nm and that of FPEI at 480 nm has a good linear correlation with the concentration of Cr(Ⅵ), and a noticeable blue to orange color change was detected under an ultraviolet lamp if Cr(Ⅵ) solution was mixed with the FPEI/RBH. Based on the phenomena, a novel rapid ratiometric and visual fluorescence method for determination of Cr(Ⅵ) was developed. Under optimal conditions, the ratio fluorescence intensity F₅₈₀/F₄₈₀ increased linearly with the concentration of Cr(Ⅵ) ranging from 0.1 μmol/L to 3.6 μmol/L with a detection limit of 12 nmol/L. In addition, the change of fluorescence color was related to the concentration of Cr(Ⅵ) in the range of 0.4—2.8 μmol/L. The proposed method, being highly selective, simple and rapid, could be applied to determine the concentration of Cr(Ⅵ) samples with recovery of 90%—109%.



Preparation and Properties of Doxorubicin Hydrochloride Sensor Based on Molecularly Imprinted Polymer^†

ZHANG Yan, ZHENG Jing, WANG Juan, GUO Mandong

2016, 37(5):  860-866.  doi:10.7503/cjcu20150938

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An electrochemical sensor was developed for the determination of doxorubicin hydrochloride(DOX) using the molecularly imprinted technique. A molecular imprinted polymer(MIP) on the surface of a gold electrode was prepared by electropolymerization of 3,4-ethylenedioxythiop-hene(EDOT) in the presence of DOX in the phosphate buffer solution. Under the optimum conditions, the properties of the electrochemical sensor modified with DOX-imprinted membrane were characterized by cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy. A linear relationship between oxidation peak current and DOX concentration was obtained over the range of 4.0×10^-7—1.0×10^-6 mol/L with a correlation coefficient of 0.9967 and a detection limit(S/N=3) of 6.5×10^-8 mol/L. After regeneration by washing with electrochemical method, the sensor showed excellent reproducibility and good stability. The MIP electrode exhibited very weak response to vinblastine, actinomycin D and fluorouracile, proving a good selectivity. The imprinted sensor was applied to the determination of doxorubicin hydrochloride in human blood serum samples with the relative standard deviation(RSD) below 4% and recovery ranging from 96.0% to 106.7%.



Detection of Common Transition Metal in Water by Microwave Plasma Torch Mass Spectra in Negative Ion Mode^†

XIONG Xiaohong, ZHANG Yan, ZHOU Runzhi, WANG Shangxian, JIANG Tao, ZENG Bin, QI Wenhao, ZHU Zhiqiang

2016, 37(5):  867-872.  doi:10.7503/cjcu20150927

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The microwave plasma torch(MPT) is a novel ambient ion source with multi-advantages, including low-power consumption, easy operation, simple construction, strong excitation ability, and so on. Previous studies showed that the MPT ion source coupled with a mass spectrometer is a promising analytical tool in various fields. Adopting the desolvation unit and the central-tube injection of MPT, the MPT mass spectrometer can detect directly the metal ions in water, without tedious sample pretreatment. And this instrumental method is sensitive enough for some toxic heavy metals with limit of detection(LOD) down to the level of several 10^-8 g/L. For instance, for lead and cadmium, the LOD values can reach 20×10^-9 and 71×10^-9 g/L, respectively. Thus the MPT mass spectrometer can be used as the supplementary of ICP-MS and have potential applications in field analysis. To expland the applications of microwave plasma torch(MPT)-MS in metal element analysis in water, the further researches about the feature MPT mass spectra of transition metal elements are necessary. This article presented firstly the MPT mass spectra of some common transition metal elements in negative ion mode of linear ion trap(LTQ) mass spectrometer and clarified the regularity of the metallic anions. These metals include: manganese, iron, cobalt, nickel, copper and zinc. Moreover, primer results showed that the LOD for these transition metal ions in water are the levels of 10^-5 g/L. These results established the basic of the practical applications of MPT mass spectrometer in the fields of environment controlling and the water quality inspection.



New Method for Identifying Different Teas Based on Liquid Colorimetric Sensor^†

HUO Danqun, FU Beibei, LI Junjie, YANG Mei, SHEN Caihong, LUO Huibo, HOU Changjun

2016, 37(5):  873-880.  doi:10.7503/cjcu20150922

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A liquid colorimetric sensor array was presented for cross-reactive discrimination of tea fusions based on complexation reaction and redox reaction of tea polyphenols with ferric ions and ceria nanoparticles, respectively. Hydrothermal reaction was applied to synthesize different kinds of ceria nanoparticles, hollow nanospheres and nanorods of zinc silicate to immobilized ferric thiocyanate[Fe(SCN)₃], which were subsequently combined to construct a 3×3 colorimetric sensor array. Performance of the colorimetric sensor array was evaluated using 5 kinds of tea polyphenols and 14 kinds of tea fusions with 5 repeated parallels. Hierarchical clustering analysis(HCA) and principal component analysis(PCA) of the colorimetric profiles suggested that all 5 kinds of tea polyphenols can be easily differentiated with good reproducibility. Correct discrimination of 14 kinds of tea fusions was also realized according to individual quality grade and categories. Our preliminary study provides a potential alternative for fast visible detection and discrimination of teas within different qualities and grades.



Organic Chemistry

Design, Synthesis and Activity Screening of Isopeptide Bond-tethered N Peptides as HIV-1 Fusion Inhibitors^†

LI Xue, LAI Wenqing, JIANG Xifeng, WANG Chao, LIU Keliang

2016, 37(5):  881-885.  doi:10.7503/cjcu20160125

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Peptides derived from the N-terminal heptad repeat(N-peptides) of HIV-1 gp41 can exhibit highly potent anti-HIV-1 activity when presented in a trimeric coiled-coil conformation. In this paper, the NHR trimeric coiled coils were designed based on a naturally occurring N-peptide, e.g. N38, on which engineered acyl transfer active sites were incorporated at the e/g-positions of heptad repeats to generate isopeptide bond cross-links. These isopeptide bond-tethered N-peptides exhibited exceptional thermal stability and possessed promising inhibitory activity on HIV-1 env-mediated cell-cell fusion.



Synthesis of ILs 1-Alkyl-3-carboxymethyl Benzimidazole Double Trifluoromethanesulfonimide and Application in Desulfurization of Fuels^†

LIU Zhiqing, XUE Fei, LEI Zhenkai, LIU Chenjiang

2016, 37(5):  886-891.  doi:10.7503/cjcu20160124

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A new class of ionic liquids(ILs) 1-alkyl-3-carboxymethyl benzimidazole double trifluoromethanesulfonimide was synthesized and characterized. Ionic liquids and hydrogen peroxide were tested in extraction-oxidative desulfurization system, the sulphur removal efficiency of S-compounds in the model oil was investigated. The results showed that the 1-butyl-3-carboxymethyl double trifluoromethanesulfonimide salt([C₂O₂OBIM][Tf₂N]) was both extractant and catalyst, n(H₂O₂)∶n(DBT)=5∶1, m(Model oil)∶m(Ionic liquid)=5∶1, at 75 ℃ for 1 h. The ratios of desulfurization to the model oil of dibenzothiophene(DBT) reached 98.8%. All oxidation desulfurization processes conformed to the pseudo first-order kinetics equation. The sulfide removal rate of the order of five sulfide is dibenzothiophene(DBT)>4,6-dimethyldibenzothiophene(4,6-DMDBT)>thianaphthene(BT)>2,5-dimethylthiophene(2,5-DMT)>thiophene(T). The apparent activation energy of removal of DBT and BT is 44.16 and 52.10 kJ/mol, respectively. Ionic liquid can be recycled for 14 times with an unnoticeable decrease in desulfurization activity. The method can realize deep desulfurization the depth and have the advantages of both simple operation and mild reaction condition.



Synthesis, Structural Characterization, Insecticidal and Fungicidal Activity of (1H-1,2,4-Triazol-5-yl)carbamates^†

JIA Changqing, YANG Dongyan, CHE Chuanliang, MA Yongqiang, RUI Changhui, YAN Xiaojing, QIN Zhaohai

2016, 37(5):  892-901.  doi:10.7503/cjcu20160065

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A series of novel (1H-1,2,4-triazol-5-yl)carbamates(5 and 6) was synthesized via the method of combining the crucial sub-structures of carbamates and 1H-1,2,4-triazole-5-amines in one molecules. Their structures were characterized by nuclear magnetic resonance(NMR), infrared(IR) spectrometry, high resolution mass spectrometry(HRMS) and elemental analysis. The preliminary insecticidal activity assays indicated that the lethal rates of target compounds to Myzus persicae were good at the concentration of 500 μg/mL. And the lethal rate of several compounds was more than 90%. Further research of these compounds against Myzus persicae indicated that compound 5b showed considerably high activity with a LC₅₀ of 9.49 μg/mL, which confirmed that these compounds are valuable for further study. The preliminary fungicidal activity assays indicated that these compounds exhibited low fungicidal activity against tested fugi in vitro. At a dose of 50 μg/mL, only a few of compounds gave limited inhibition on mycelium growth. In addition, the structure-activity relationship was also discussed.



Regiospecific Aminobromination of β-Nitrostyrene Derivatives with Acrylamide and N-Bromobutanimide^†

DU Manfei, HOU Dan, HUI Wenping, CHEN Zhanguo

2016, 37(5):  902-911.  doi:10.7503/cjcu20150883

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A new protocol for the high regioselective aminobromination of β-nitrostyrene derivatives with acrylamide and N-Bromobutanimide(NBS) as nitrogen/bromine sources was developed. β-Nitrostyrene derivatives reacted with acrylamide and NBS promoted by CH₃CH₂ONa at room temperature(without the protection of an inert gaseous atmosphere) in CH₂Cl₂, offered vicinal haloamine products in good yields(up to 83%). For the β-methyl-β-nitrostyrene, the good yields(up to 98%) were also achieved in CH₃OH promoted by Na₂CO₃. Although the strong electron-donating substituents(e.g., OCH₃) on the 4-position of benzene ring could deactivated the reaction activity of β-nitrostyrenederi-vetives, the vicinal haloamines were also afforded as the sole addition product. Whereas strong electron-withdrawing substituents(e.g., NO₂) could activated reaction activity remarkably and the vicinal haloamines were afforded as the sole addition product, too. The result revealed that the addition reaction has a nucleophilic addition feature. The aminobromination of 25 examples of β-nitrostyrenes were investigated and the structure of all products were confirmed by the corresponding nuclear magnetic resonance(NMR) spectra and high resolution mass spectrometer(HRMS). A possible mechanism involving a nucleophilic conjugate addition was proposed.



Expression and Purification of DEPTOR and Its Interaction with mTOR-TRD2^†

WANG Nan, CHENG Xiaoheng, ZHENG Jimin, CHEN Guangju, JIA Zongchao

2016, 37(5):  912-919.  doi:10.7503/cjcu20150817

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The inhibition of mammalian target of rapamycin(mTOR) is important to cancer treatment. DEPTOR is currently known as an endogenous mTOR inhibitor and could interact with mTOR FAT domain to suppress mTOR activity in vivo. It showed that MBP fusion mTOR TRD2 subdomain could be expressed in BL21(DE3) with conversional protocol and DEPTOR-G270P mutation could be expressed 5-fold more than wild-type DEPTOR in BL21(DE3). Adding glycerol(volume fraction 10%) in purification buffer would improve DEPTOR-G270P purity. CD spectra assay showed that this purification protocol could produce DEPTOR in large quantity without affecting its secondary structure. Gel-filtration assay indicated possible interactions between mTOR-TRD2 subdomain and DEPTOR, which may provide insights into mTOR-DEPTOR interaction and give new information about mTOR inhibition.



Physical Chemistry

First-principle Calculations on Electronic Structures and Optical Properties of α, β, γ, δ, ε, η-Bi₂\begin{array}{c}{O_3}^{†}\end{array}

LI Tan, ZHANG Xiaochao, WANG Kai, LI Rui, FAN Caimei

2016, 37(5):  920-927.  doi:10.7503/cjcu20160028

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A theoretical investigation on the geometric structures, band structures, densities of states and optical properties of Bi₂O₃ in six crystalline phases(α, β, γ, δ, ε and η) was carried out using CASTEP(Cambridge Sequential Total Energy Package) module based on the density functional theory. The calculation results show that the α, ε and η phases belong to the layered structure, in which α and ε phases are —Bi—O— single-layer structure and η phase is consisted of the —Bi—O— double-layers structure, while the β, γ, and δ phases are —Bi_m—O_n— staggered structure, in which the δ phase is intensively staggered and its band structure exhibits the conductor characteristic. The conduction bands of all the six crystalline phases are mainly generated by Bi_6p states, while the valence bands are contributed by O_2p states. The potential of the six phases are lower than the H₂O/O₂, indicating that they have the higher oxidative ability, which is in good agreement with the reported experimental result(γ-Bi₂O₃>β-Bi₂O₃>α-Bi₂O₃>δ-Bi₂O₃) of the photocatalytic oxidative ability. The reduction potential of the conduction band is lower than H₂/H₂O, we thus speculate that pure Bi₂O₃ has hardly the catalytic ability of hydrogen production. The γ and δ phases have the longer initial response wavelengths, implying that they should have the infrared excitation property. Our calculations can provide basic and reliable theoretical data for the synthesis and study of Bi₂O₃ materials with partial infrared excitation and wide spectral response range, and afford significant guidance for the development and application in the Bi₂O₃-based materials.



Molecular Dynamics Simulation of the Inhibition Against Arginase Ι Catalyzed Reaction by L-Val

HUANG Yiling, GAO Xuefeng

2016, 37(5):  928-931.  doi:10.7503/cjcu20160007

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Molecular dynamics simulation and mutation were used to get the influence at activity and kinetics of enzyme catalyzed reaction by L-Val on W-Arginase Ι and R-Arginase Ι. There is a big cavity C2 near the activity pocket of Arginase Ι. The result of molecular dynamics simulation shows that the mutation of Ile156Arg narrows the cavity volume of C2. The experimental result shows that influenced by L-Val the half maximal inhibitory concentration(IC₅₀) of R-Arginase Ι has been risen obviously, the IC₅₀ by 3.06 mmol/L rises to 6.26 mmol/L. Therefore, Arginase Ι does exist a regulatory site in C2 and L-Val can combine on this site to disturb the activity of Arginase Ι.



Theoretical Studies on the Intrinsic Defects in ZnO and ZnS Crystal^†

MA Changmin, LIU Tingyu, CHANG Qiuxiang, LUO Guoyin

2016, 37(5):  932-937.  doi:10.7503/cjcu20150973

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The stability of the intrinsic point defects in ZnS and ZnO crystal over a range of temperature and the partial pressure \begin{array}{c}{p}_{S_2}\end{array} and \begin{array}{c}{p}_{O_2}\end{array} was studied with the approach that integrates first-principles, thermodynamic calculations and the contributions of vibrational entropy. The results indicate that the contribution of the vibrational entropy to the defect formation energy could not be ignored under high temperature condition. The vacancy-type defects are the predominant intrinsic point defects in ZnS and ZnO crystal. The anion vacancy(V_O) forms more easily in ZnO crystal, however, the V_Zn has the lowest formation energy in ZnS under most conditions. Therefore, ZnS crystal is easier to perform p-type doping than ZnO crystal. The defect formation energies of the complex point defect, including Frenkel pairs, anti-Frenkel pairs and Schottky pairs, were calculated to predict relative stability. The calculated results show that the Schottky defect pairs are the most unstable, the Frenkel defect pairs are the most stable. Except anti-Frenkel pairs in ZnS, the combinations of charged defects produce lower defect formation energies than combinations of neutral defects.



Loading of Myoglobin into Layer-by-layer Films Assembled Through Boronic Acid-diol Specific Recognition and Its Electrochemical Study^†

YAO Huiqin, HUANG Shan, SU Qiaoling, SHI Keren, GAN Qianqian, WANG Mingke

2016, 37(5):  938-945.  doi:10.7503/cjcu20150943

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A polyelectrolyte PAA-PBA containing both phenylboronic acid(PBA) moieties and carboxylic acid groups[PAA=poly(acrylic acid)] was synthesized. PAA-PBA and dextran(Dex) were then assembled into {PAA-PBA/Dex}_n layer-by-layer(LbL) films by LbL assemble technique on pyrolytic graphite(PG) electrode surface through boronic acid-diol specific recognition between them. Myoglobin(Mb) in a buffer solution(pH=5.0) was loaded into the films, forming stable {PAA-PBA/Dex}_n-Mb films. By cyclic voltammetry(CV) technique, the {PAA-PBA/Dex}_n-Mb film electrodes demonstrated the direct electrochemistry of Mb and could be used to electrocatalyze reduction of various substrates(e.g. O₂ and H₂O₂).



Adsorption Mechanisms of TMPDO and 4-NOH-TMPD in HTS/H₂O₂ System and Effects on the Stabilization of Ti—OOH^†

YAN Shan, ZHANG Shengjian, ZHAO Yingxian, LI Xianming, ZHANG Yongming, ZHANG Hong, WANG Jian, FU Jianqiong

2016, 37(5):  946-955.  doi:10.7503/cjcu20150779

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The adsorption mechanisms of 2,2,6,6-tetramethyl-piperdin-4-one(TMPDO) and 2,2,6,6-tetramethyl-piperdin-4-one-oxime(4-NOH-TMPD) in HTS/H₂O₂ system were investigated by thermogravimetry analysis(TG), NH₃ temperature programmed desorption(NH₃-TPD), Fourier transform infrared spectrum(FTIR) and in situ IR. The results showed that there were Si—OH and Ti—OOH active sites on the surface of the catalyst in HTS/H₂O₂ system. Two-site adsorption was formed by the interaction of alkali group ═N—H of TMPDO or 4-NOH-TMPD with strong acid center Si—OH, and para group —C═O in TMPDO or —N═OH in 4-NOH-TMPD with Ti—OOH center. Such two-center adsorption of TMPDO or 4-NOH-TMPD on surface of HTS significantly increased the stability and concentration of active site Ti—OOH in HTS/H₂O₂ system, and thus caused an evident decrease of strong acid sites and an increase of weak acid sites on surface of the catalyst. Therefore, it is expected to improve the catalytic activity and selectivity of HTS/H₂O₂ system by modifying the surface properties of catalyst with adsorption of appropriate organic bases.



Preparation and Characterization of Ti—O Units Anchored on Silica by Surface Organometallic Chemistry Method^†

LI Jinling, GAO Ziwei

2016, 37(5):  956-963.  doi:10.7503/cjcu20150707

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Based on the surface organometallic chemistry method, four surface organtitanium complexes anchored on silica were obtained by the reaction of spacer ligand (phenol, benzoic acid, 1-naphthol and 1-naphthol acid as spacer ligand, respectively), Ti(NMe₂)₄ and silica in one pot reaction system. Then, the four products were calcined respectively to obtain the titanum oxide anchored on silica. The surface organtitanium complexes and surface titanum oxides were characterized by Fourier transform infrared spectrum(FTIR), thermogravimetry analysis(TG-DTA), X-ray photoelectron spectrometry(XPS) and atomic force microscopy(AFM). The results showed that after calcination of surface organtitanium complexes at high temperature in O₂, not only were the organic ligands removed, but also the surface hydroxy was regenerated, which ensured that the four coordination forms of Ti were not changed. Meanwhile, titanium oxides anchored on silica surface by Si—O—Ti bonds, and existed as isolated, dispersed and ordered form. In addition, the skeleton structure of the silica was kept well after calcination of surface organtitanium complexes.



Synthesis of Light Olefins from CO₂ Hydrogenation Catalyzed over Rare Earths Modified CuO-ZnO-ZrO₂/SAPO-34^†

LIU Rong, ZHA Fei, YANG Aimei, CHANG Yue

2016, 37(5):  964-971.  doi:10.7503/cjcu20150693

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Y₂O₃, La₂\begin{array}{c}{O_3}_{}\end{array}and Ce₂O₃ modified CuO-ZnO-ZrO₂ catalysts were prepared by co-precipitation method. The samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), Brunauer-Emmett-Teller(BET), temperature programmed reduction(TPR) and thermogravimetry(TG). Rare earth metals modified CuO-ZnO-ZrO₂ catalyst have good dispersion and higher specific surface area. The activity of biofunctional prepared by mechanical mixing of modified CuO-ZnO-ZrO₂ with SAPO-34 for the hydrogenation of carbon dioxide to light olefins was investigated.Under the conditions of reaction temperature of 400 ℃, pressure of 3.0 MPa, space velocity(SV) of 1800 mL·\begin{array}{c}{g}_{\mathit{cat}}^{-1}\end{array}·h^-1, CO₂/H₂(volume ratio) of 1∶3, mass ratio of Ce-CuO-ZnO-ZrO₂/SAPO-34 to 1∶1 and the quality of multiple catalyst of 1.0 g, the conversion of CO₂ could reach to 54.6%, with a light olefins selecti-vity and yield of 51.1% and 27.9%, respectively.



Polymer Chemistry

Highly Aligned Ultrafine Fibers of Graphene/Poly(L-lactic acid)(Gr/PLLA) Composite for the Construction of Nerve Conduit^†

ZHANG Huilan, YI Bingcheng, WANG Xianliu, LI Biyun, YU Zhepao, LOU Xiangxin, ZHANG Yanzhong

2016, 37(5):  972-982.  doi:10.7503/cjcu20150958

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Highly aligned ultrafine fibers of graphene/poly(L-lactic acid)(Gr/PLLA) composite were prepared for studying the synergistic effect of fiber orientation degree and Gr incorporation on nerve cell growth and differentiation, from which nerve conduits by reeling-heating the aligned Gr/PLLA fibers were fabricated for potential neural tissue engineering applications. The results showed that the Gr/PLLA fibers made by stable jet electrospinning(SJES) had higher degree of fiber alignment. Incorporation of Gr improved the thermal and mechanical properties of the PLLA fibers. Increasing the Gr content and fiber orientation degree gave rise to increased adhesion number and elongation percentage of the Schwann cells(SCs). All the fiber scaffolds could promote SCs to proliferate well and cells growth reached the best state at 96 h, indicating appropriate cytocompatibility of the Gr/PLLA fibers. In addition, it was found the aligned Gr/PLLA fibers also promoted the neural differentiation of PC12 cells. The nerve conduits with inner diameter of 2 mm made of Gr/PLLA fibers showed good axial fiber orientation degree and pressure-resistance ability, and could promote cell growth directionally.



Synthesis and Characterization of Trimesoylamidoamine^†

CHEN Xiaolin, WU Hao, LIU Lifen, GAO Congjie

2016, 37(5):  983-988.  doi:10.7503/cjcu20150957

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Trimesoylamidoamine(TMAAM) is a novel compound, which can be used as a key functional monomer to fabricate antifouling and chlorine-tolerant polyamide reverse osmosis membrane by interfacial polymerization. Trimesoyl chloride(TMC) and 1,3-diamino-2-propanol(DAP) were used as raw materials to synthesize TMAAM via three-step method including esterification, amidation and ester aminolysis reactions successively. The effects of methanol dosage, type and amount of the acid binding agent, and DAP dosage on the reactions were discussed. The reaction mechanism of ester aminolysis was also explored. The chemical structure of TMAAM was identified via infrared spectra(IR), nuclear magnetic resonance(NMR) and high-resolution mass spectragraph(HRMS). This three-step method has some advantages including mild reaction conditions, easy operation, convenient post treatment and favorite reaction economy. The top total product yield of three reactions was 57%.



High Tempreture Fuel Cell Performance and Anisotropy of Carbonyl and Sulfone Groups Co-crosslinked Sulfonated Polyimides Proton Exchange Membranes^†

CHEN Kangcheng, JI Mengdie

2016, 37(5):  989-995.  doi:10.7503/cjcu20150950

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Anisotropic properties of membrane swelling and proton conductivity of carbonyl and sulfone groups co-crosslinked sulfonated polyimides(SPI) proton exchange membranes(M1C, M2C) were reported in this paper. Fuel cell performance and durability under high temperature and relative low humidification were investigated in detail. The results showed that dimensional changes of M1C and M2C were lower than that of sulfone group crosslinked R1C in thickness and no obviously change in plane direction. The through-plane proton conductivities of M1C and M2C were significantly larger than that of R1C. The operation conditions of temperature, back pressureand relative humidity largely affected the proton exchange membrames of fuel cell(PEMFC) performance in connection with each other. The PEMFC performance of M1C was better than that of R1C in the similar conditions. At 90 ℃ and relatively high humidification of 82%RH, the crosslinked PEMs showed high fuel cell performances which were comparable to NR212. As the humidification reduced to 27% RH, the fuel cell performance of M1C largely decreased, but still kept in a reasonably high level and higher than that of R1C. With the operation temperature increased from 90 ℃ to 110 ℃, cell performances of all the SPI PEMs decreasedlargely. At 0.2 MPa and 49%RH, the maximum output of M1C was 21% higher than R1C. The maximum output of M1C largely increased from 0.17 W/cm² at 0.2 MPa to 0.38 W/cm² at 0.3 MPa. The PEMFC with M1C operated at 110 ℃ for 330 h without obviously degradation in cell performance. The result indicated that carbonyl and sulfone groups co-crosslinked SPI PEMs have high temperature fuel cell durability.



Preparation and Performance of Composite Hydrogel Crosslinked by Surface Grafting Method of Thermo-sensitive Microsphere^†

XU Tiantian, XU Kun, ZHOU Chao, TAN Ying, LU Cuige, WANG Pixin

2016, 37(5):  996-1002.  doi:10.7503/cjcu20150912

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To improve slow response rate and poor toughness of microsphere composite hydrogel(MCH), the MCH gels were prepared by grafting polyacrylamide chains onto the surface of thermo-sensitive polymer microspheres in the absence of crosslinking agent. Herein, polymer microspheres without chemical cross-linking structure were obtained by assembly of amphiphilic thermo-sensitive graft copolymer and employed as cross-linking junctions. MCH gels own excellent toughness(strain at break: 2800%, fracture energy: 80 kPa) and can adjust the mechanical properties according to temperature stimuli. Moreover, the results of investigation suggest that MCH gels exhibit thermo-sensitive property and their response rate are 5 to 10 times faster than the traditional poly(N-isopropyl acrylamide) organic gel.



pH-Responsive PEGylated Gene Delivery System^†

LIU Yajie, ZHANG Peng, DU Jianwei, WANG Youxiang

2016, 37(5):  1003-1009.  doi:10.7503/cjcu20150907

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The pH-sensitive polyethylene glycol-grafted polyethylenimine(mPEG-CH═N-PEI) was synthesized via benzoic imine linker according to the acidic environment of endosomal. The corresponding stable PEGylated polyethylenimine(mPEG-PEI) without pH-sensitivity was synthesized as control. The results showed that both PEGylated polycations could condense DNA into tight spherical nanoparticles about 80 nm in size and 10 mV in ξ-potential, which showed excellent stability under physiological conditions. The benzoic imine linkers were easily cleaved under the pH of 5, which was similar with the endosomal pH. Human hepatoblastoma cell line(HepG2) cell culture results indicated that the cytotoxicity and cellular uptake efficiency of both PEGylated gene nanoparticles decreased remarkably because of the shielding effect of PEG shell. Due to the cleavage of benzoic imine linker at acidic environment of endosomal, the PEG shell of mPEG-CH═N-PEI/DNA polyplexes was detachable and lead to quick endosomal escape. So mPEG-CH═N-PEI/DNA polyplexes showed higher gene expression than the mPEG-PEI/DNA polyplexes. Based on these results, we concluded that PEGylated polyplexes via benzoic imine linkers showed high extracellular stability, intracellular DNA release and effective gene transfection.



Monte Carlo Simulation on Self-assembly of AB Diblock Copolymers/Nanoparticles Complex Confined in Parallel Walls^†

WANG Yingying, CUI Jie, HAN Yuanyuan, JIANG Wei, SUN Yingchun

2016, 37(5):  1010-1017.  doi:10.7503/cjcu20150868

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The self-assembly behavior of the A₁₅B₅ asymmetric diblock copolymers/nanoparticles composite confined in parallelwalls which attract A blocks was studied using Monte Carlo simulation. The simulation results indicates that the volume fraction of the nanoparticles in diblock copolymers/nanoparticles composite and the interactions between nanoparticles and each blocks are crucial to the self-assembled structures formed by diblock copolymers/nanoparticles composite and the distribution of nanoparticles. When the distance between the two parallel walls keep constant, A₁₅B₅ asymmetric diblock copolymers can self-assemble into parallel layers in which the mid-layer formed by B blocks are hexagonally perforated. When the nanoparticles which are incompatible with blocks A, while compatible with blocks B are added into the system, increasing the attractive interaction between nanoparticles and blocks B can effectively maintain the hexagonally perforated structure and the pore size in the layer. At this time, the nanoparticles are homogenously distributed in the domain formed by blocks B. However, when the nanoparticles which are incompatible with both blocks are added into the system, a decrease in the repulsive interaction between nanoparticles and block copolymers can benefit for maintaining the hexagonally perforated structure. In addition, when the interaction between nanoparticles and block copolymers is rather weak, the nanoparticles cannot aggregate even if the volume fraction of the nanoparticles is very large, and the nanoparticles homogenously disperse in the interface between A and B phases.



Synthesis of Amidic Alginate Derivatives Modified Silica Nanoparticles via Ugi Multicomponent Reaction^†

YAN Huiqiong, CHEN Xiuqiong, LI Jiacheng, FENG Yuhong, WU Jianbo, LIN Qiang, SHI Zaifeng, WANG Xianghui

2016, 37(5):  1018-1024.  doi:10.7503/cjcu20150831

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To wider applications of silica(SiO₂) nanoparticles, the Ugi multicomponent reaction was proposed to prepare the novel polymers-silica(Oct-Alg-SiO₂) nanoparticles using amidic alginate derivatives. The structure and surface elemental composition of Oct-Alg-SiO₂ were confirmed by ¹H Nuclear Magnetic Resonance(¹H NMR) spectrometer and X-ray photoelectron spectroscopy(XPS). Additionally, the morpho-logy, size and colloid stability of Oct-Alg-SiO₂ were also investigated via transmission electron microscope(TEM), zeta potential and laser particle size analyzer. The characterization of the materials revealed that Oct-Alg-SiO₂ nanoparticles were successfully fabricated via the Ugi reaction. The amidic alginate derivatives were covalently bonded onto the surface of amino-functionalized silica(SiO₂-NH₂) nanoparticles, increasing their average diameter and tuning their zeta potential, which could exhibit good dispersion stability performance in the aqueous media. The Pickering emulsions were prepared by Oct-Alg-SiO₂ using 10% liquid paraffin as the oil phase. It is worth noting that the stable Pickering emulsions with an average size of 5.7 μm could form between the oil-water interfaces. With the increase of pH value, the volume fraction of the emulsions increased and the stability of the emulsions also improved. The cytocompatibility experimental results showed that Oct-Alg-SiO₂ nanoparticles possessed excellent biocompatibility. Oct-Alg-SiO₂ nanoparticles combined excellent colloid stability performance of SiO₂ nanoparticles and good biological properties of amidic alginate derivatives, possessing great potentials in biomedical applications.