Chem. J. Chinese Universities

Cover and Content of Chemical Journal of Chinese Universities Vol.38 No.11(2017)

2017, 38(11): 0-0.

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Hydrothermal Synthesis and Electrochemical Li-storage Performances of NiCo₂O₄@C Nanocomposite^†

LI Fangfang, WANG Hongbin, WANG Runwei, QIU Shilun, ZHANG Zongtao

2017, 38(11): 1913-1920. doi:10.7503/cjcu20170173

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Rodlike NiCo₂O₄ precursor was prepored via one-step hydrothermal method and then a series of NiCo₂O₄ and NiCo₂O₄@C products was prepared by regulating the amount of glucose as well as the calcination conditions such as calcination temperature and atmosphere. The products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and charge/discharge testing, cyclic voltammetry and electrochemical impedance spectroscopy. The results show that proper amount of glucose(0.5 g) in conjunction with appropriate post-calcination conditions can produce NiCo₂O₄@C nanocomposite with good rate capability and cycling stability. At a current density of 100 mA/g, the material demonstrated the charge/discharge capacities of 634.1/767.2 mA·h/g, corresponding to a Coulombic efficiency of 82.7%, and maintained the discharge capacity of 650.1 mA·h/g after five cycles with a retention rate of 84.74%. Furthermore, at a higher current density of 300 mA/g, the material could still afford a high reversible capacity of 225.9 mA·h/g.

Synthesis of Au-Ni Bimetallic Nanoparticles with Tunable Aspect Ratio^†

HAN Tianhao, LIANG Fuxin, YANG Zhenzhong

2017, 38(11): 1921-1926. doi:10.7503/cjcu20170145

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In this paper, the Au-Ni bimetallic nanoparticles with tunable aspect ratio of Au to Ni were synthesized by noble-metal-induced-reduction strategy. Octadecylamine is reducible at high temperatures thus it was used as a reducing agent. As the temperature increased gradually, Au³⁺ was reduced by octadecylamine to form Au⁰. After that, Ni²⁺ was reduced to Ni⁰ by obtaining electrons from Au⁰ at 220 ℃. Octadecylamine provided electrons to Au³⁺ continuously during the reaction. The size of Ni side could be tunable by changing the reaction time at 220 ℃. Au side and Ni side could be selectively etched with aqueous I₂/KI and 0.5%(mass fraction) aqueous HCl, respectively. The size of Au-Ni bimetallic nanoparticles could be tuned continuously by etching for varied time. Au side or Ni side could be completely etched separately, remaining Ni nanoparticles or Au nanoparticles. The fresh surface obtained after etching Au side or Ni side provided a site of chemical reaction for further compositing functional substances. This method is attractive owing to the easiness to continuously tuning aspect ratio of the bimetallic nanoparticles. On the other hand, composition of the bimetallic nanoparticles is also flexibly tunable using different reactants.

Preparation and Drug Release of Anti-cancer Fe₃O₄@ZIF-8@PA System Loaded with Drug^†

WANG Xiaodan, XU Dandan, LÜ Weizhong, LIU Jingyuan, LIU Qi, JING Xiaoyan, WANG Jun

2017, 38(11): 1927-1934. doi:10.7503/cjcu20170176

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An anti-cancer and loading drug system was prepared. Fe₃O₄ nanopartiles prepared by hydrothermal method was chosen as substrate to design and fabricate pH responsive magnetic nanocomposites Fe₃O₄@ZIF-8@PA with core-shell structure. This nanomaterial exhibited high saturation of 35.46 A·m²/g and maintained well magnetic property. Fe₃O₄ nanopartiles showed spherical structure and good dispersion. Compared with the substrate, the particle size of composite microsphere increased significantly, but still conform to the ideal carrier material size. In addition, the carriers with porous structures showed large surface area, high drug loading efficiency and capacity for doxorubicin(DOX) of up to 96.4% and 144.6 mg/g. The drug release of nanopartiles loaded with drug was studied in pH=7.4 and 5.0. The total released percentage of two kinds of pH were 39.8% and 78.6%, respectively. The drug releasing experiment was also to perform to verify the constructed nanocarriers excellent pH-response. The introduction of phytic acid with inhibition to cancer cells made it possible that the carriers could kill tumor cells. The methyl thiazolyl tetrazolium(MTT) test act on human osteosarcoma cell line(MG-63) was also carried out in vitro to demonstrate the combination effect of anticancer between the carriers and DOX.

Synthesis and Biological Evaluation of VPI-7 Zeolite^†

LI Ruiyan, WANG Shuang, LI Dongdong, QIN Yanguo, YU Jihong

2017, 38(11): 1935-1940. doi:10.7503/cjcu20170330

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Porous zincosilicate zeolite, VPI-7, was synthesized through hydrothermal approach, and the size of samples were adjusted by varying amounts of sol. Also, the biological properties of the samples were charactered. The characteristic results showed that the prepared samples were aggregated into microspheres by VPI-7 rod-shaped crystals, and the crystals further cross-linked and formed numerous micron-sized pores, which provided good morphological features for their biological properties. In addition, the surface topography for VPI-7 had the ability to promote the deposition of calcium phosphate, and load/release protein. The in vitro experiments suggested that VPI-7 was conducive to cell adhesion and proliferation, with good biocompatibility. VPI-7 showed excellent biological properties, and has potential to be applied as implant used in bone repair and replacement.

Nanofibrillated Cellulose Derived Hierarchical Porous Carbon Aerogels: Efficient Anode Material for Lithium Ion Battery^†

KONG Xuelin, LU Yun, YE Guichao, LI Daohao, SUN Jin, YANG Dongjiang, YIN Yafang

2017, 38(11): 1941-1946. doi:10.7503/cjcu20170126

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The nanofibrillated cellulose(NFC) with large aspect ratio and uniform size(mean diameter is 230.10 nm) was fabricated from commercial eucalyptus pulps by scale-up nano-grinding. Then the NFC was assembled to NFC aerogels(NFCA) with three-dimensional(3D) frameworks. After carbonization of NFCA under N₂ atmosphere, the carbon nanofiber aerogels(CNFA) were generated with the inherited 3D network structure. With futher KOH-assisted annealing of CNFA, the hierarchical porous carbon aerogels(denoted as CNFA-A) were finally obtained. CNFA-A combined the inherited original 3D network from NFCA and the secondary constructed micropore-mesopore structure. The mean diameter of CNFA-A was diminished to 53.16 nm. The structures of three kinds of cellulose-based aerogels were characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM), and the statistic diameter of nanofibril building-blocks was obtained by Nanomeasure^®. The graphitization degree of cellulose-based aerogels was investigated by X-ray diffraction(XRD) and Raman spectroscopy, and the specific surface area was measured through BET specific surface area test. The specific surface area of CNFA-A is as high as 488.92 m²/g and the total pore volume can reach up to 0.404 cm³/g. In addition, as anode material for lithium ion battery, the CNFA-A exhibits a high reversible capacity(448 mA·h/g at 1 A/g), an excellent rate capability(219 mA·h/g at 20 A/g) and an outstanding cycling performance(409 mA·h/g at 1 A/g after 1000 cycles).

Determination of Serum Urea by Near-infrared Diffuse Reflectance Spectroscopy Using Silver Mirror for Enhancing the Detectability^†

WANG Cuicui, YU Xiaoming, CAI Wensheng, SHAO Xueguang

2017, 38(11): 1947-1952. doi:10.7503/cjcu20170313

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Owing to the low sensitivity or the high detection limit of near-infrared diffuse reflectance spectroscopy(NIRDRS) technique, silver mirror was used as the adsorption substrate to improve the sensitivity. The high reflection ability of silver mirror can not only reduce the background interference, but also enhance the spectral responses. In this study, coupling NIRDRS technique and the silver substrate, the feasibility for rapid and direct analysis of the urea concentration in human serum was studied. Near-infrared diffuse reflectance spectra of silver substrate with sera were directly measured, and then combined with spectral preprocessing and variable selection methods, partial least squares(PLS) regression models were established for fast quantitative prediction. The results demonstrate that the concentrations of serum urea in the range of 2.8—26.1 mmol/L can be accurately determined using NIRDRS technique with the silver mirror as the adsorption substrate. The determination coefficient( $R p 2$ ) between the predicted and reference concentrations is as high as 0.9823, and the recoveries are in a range of 86.0%—117.0%. Moreover, the maximum deviation of the prediction results from the reference values is as low as 1.45 mmol/L. Therefore, the proposed method may be an alternative for routine analysis of serum urea in clinical applications.

SnO₂ Hollow Microspheres Used for Rapid and Sensitive Detection of Hydrogen Sulfide^†

LI Guangyao, WANG Yu, CAO Yinliang, XIAO Zhongliang, HUANG Ying, FENG Zemeng, YIN Yulong, CAO Zhong

2017, 38(11): 1953-1962. doi:10.7503/cjcu20170219

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Tin dioxide hollow microspheres(Sn $O 2$ HMS) were prepared using amino-phenol/formaldehyde resin spheres(APF) as templates. A novel thin-film type hydrogen sulfide(H₂S) gas sensor was constructed by coating SnO₂ HMS onto an alumina ceramic tube based Au electrode. The crystalline phase and microstructure of different nano-materials were characterized by means of X-ray diffraction(XRD) and transmission electron microscopy(TEM), and the gas sensing properties of SnO₂ HMS were studied in detail. The experimental results showed that SnO₂ HMS had good sensing properties for H₂S. At the optimum operating temperature of 200 ℃, the response signal of the prepared sensor to 142.6 mg/m³ H₂S was as high as 97.13%, and the response time was very short, i.e. 22 s. The response linear range to H₂S was from 0.2852 mg/m³ to 142.6 mg/m³, with a detection limit of 0.1549 mg/m³, and the correlation coefficient was 0.9931. Almost no effects on the sensor were observed from the environmental humidity and temperature. Also, the sensor possessed good reproducibility and selectivity. The sensor response signal reduced by 5.4% after 10 months of continuous monitoring of H₂S gas in a pig farm, indicating that the sensor has a long-term stable lifetime with valuable application for remote monitoring in practice.

Fractionation of Azaphilones from Secondary Metabolites of Marine-Derived Fungus Penicillim pinophilum and Their Antibacterial Activity^†

MA Yangyang, CAI Hui, DU Min, CAO Fei, ZHU Huajie

2017, 38(11): 1963-1967. doi:10.7503/cjcu20170304

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Bioassay-guide fractionation of the marine-derived fungus Penicillim pinophilum led to the isolation of three azaphilones derivatives: Pinophilins G(1), Pinophilins B(2) and Sch 725680(3), which were separated by silica gel column chromatography, octadecylsilyl(ODS) column chromatography, Sephadex LH-20. Compound 1 is a new compound. The plane structure of compound 1 was determined based on HR-ESI-MS, ¹H NMR, ¹³C NMR, heteronuclear multiple bond correlation(HMBC), nuclear overhauser effect spectroscopy(NOSEY) and heteronuclear singular quantum correlation(HSQC). The absolute configuration of compound 1 was determined by comparing its experimental electronic circular dichroism(ECD) with the calculated ECD spectra using quantum methods. The results indicated that compounds 1 and 3 showed antibacterial activities against four spices of pathogenic bacteria.

C₂-Symmetric Bisprolinamide Chiral Polymer Catalyst with Double Decker Silsesquioxane in Main Chain for the Asymmetric Aldol Reactions^†

SHEN Jinrui, ZHOU Zhe, ZHOU Yuan, LU Cuifen, YANG Guichun, CHEN Zuxing

2017, 38(11): 1968-1973. doi:10.7503/cjcu20170298

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Double-decker silsesquioxane(DDSQ) and tert-butyl oxygen carbonyl(Boc) protection of C₂-symmetric bisprolinamide were used to prepare C₂-symmetric bisprolinamide chiral polymer catalyst with DDSQ in the main chain. The chiral polymer catalyst was prepared by silicon hydrogen addition reaction and Boc deprotection. The structure of the prepared polymer catalyst was characterized by means of ¹H NMR, ¹³C NMR and ²⁹Si NMR. The molecular weight and thermal property of the prepared polymer catalyst were characterized by means of GPC and TGA. The polymer catalyst was applied in asymmetric Aldol reaction to study the catalytic function, and the products were obtained in good yields and stereoselectivities. Moreover, the polymer catalyst could be readily recovered and recycled for further transformations at least six cycles without observing significant decrease in yield and stereoselectivity.

Preparation, Characterization and Release Properties of β-Cypermethrin Microcapsules^†

FENG Jianguo, YANG Guantian, YUAN Xiaoyong, CHEN Qicheng, SUN Chencheng, YUAN Shuzhong

2017, 38(11): 1974-1981. doi:10.7503/cjcu20170249

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The solvent evaporation method was adopted to prepare β-cypermethrin microcapsules, using β-cypermethrin as core material, ethylcellulose as wall materials. The physical and chemical properties of microcapsules were characterized. The effects of process conditions on appearance, mean particle size and distribution, encapsulation efficiency, loading content and controlled release were studied by single factor experiments. The results indicated that emulsifier types and shearing duration time had significant influence on appearance of microcapsules. The particle size and size distribution decreased with the increasing of emulsifier concentration. When the dosage of Tween-80 increased from 4% to 8%, the average particle size of microcapsules decreased from 59.9 μm to 29.8 μm, and the span reduced from 1.21 to 0.72. As the core-wall ratio decreased, there was a gradual increase in both particle size and encapsulation efficiency, but a decrease in loading content. When the core-wall ratio was 1:1.75, the encapsulation efficiency was more than 70%. The most fitted drug release kinetics model was the Ritger-Peppas model(lgQ=lgk+nlgt). For microcapsules with similar mean particle sizes and different loading content, the sample with minimum loading content tended to have a lower release rate and cumulative release rate. For microcapsules with similar loading content and diffe-rent mean particle sizes, the sample with largest size tended to have a lower release rate and cumulative release rate.

Interaction of Pyrimidine Derivatives with Human Serum Albumin^†

TANG Qian, SU Jinhong, CAO Hongyu, WANG Lihao, SHI Fei, WANG Ailing, GONG Tingting, JIN Xiaojun, ZHENG Xuefang

2017, 38(11): 1982-1992. doi:10.7503/cjcu20170063

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The interaction of eight pyrimidine derivatives(PDs, 5-FU marked as A is the positive control, other seven samples have been made in our laboratory and numbered from B to H, respectively) with human serum albumin(HSA) have been investigated by means of steady state fluorescence, laser flash photolysis(LFP), UV-Vis absorption spectroscopy and molecular docking techniques under simulative physiological coditions. The fluorescence quenching mechanism of HSA and different pyrimidine derivatives have been analyzed by the Stern-Volmer equation and laser flash photolysis techniques. From these results, we can know that pyrimidine derivatives numbered from A to E are static quenching, but pyrimidine derivatives numbered from G to H are dynamic quenching. Depending on double reciprocal curve, we can obtain the binding constants(K_a) and the number of binding sites(n) of the five pyrimidine derivatives of static quenching and HSA. These data show that the protein and pyrimidine derivatives combinate with weak binding force and the number of binding site are equal to one. Fitting the thermodynamic parameters ΔH, ΔS and ΔG can faciliate to understand the binding force types for pyrimidine derivatives and HSA, and pyrimidine derivative B, C and E are the electrostatic and hydrophobic interactions, while for pyrimidine derivatives A and D are hydrogen bond and van der Waals force, and these experimental results are consistent with molecular docking results. According to non-radiative energy transfer theory(FRET), the binding distance(r) between HSA and pyrimidine derivaties can be obtained, which are less than 4 nm, and these results are conform to the energy transfer theory. With synchronous fluorescence, three-dimensional fluorescence and circular dichroism spectroscopy, the space conformation changes of HSA in the drugs combining process can be investigated. The results show that pyrimidine derivatives B, D and E have no influence on the secondary and tertiary structure of HSA. pyrimidine derivative A and C have no effect on secondary structure of HSA, but the hydrophobicity around the aromatic amino acids for the tertiary structure are slightly enhanced. Therefore, HSA can be used as an excellent carrier to transport and store these five pyrimidine derivatives.

Highly Sensitive Colorimetric Sensing for Cu²⁺ by Inverse Opals of Photonic Crystal Hydrogels^†

LIU Shirong, QIN Liyan, ZHANG Xiaodong, CHEN Mingqing

2017, 38(11): 1993-1998. doi:10.7503/cjcu20170519

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Inverse opals of photonic crystal hydrogels(PCHs) composed of acrylamide(AM) and N-vinyl imidazole(NVI) copolymers were fabricated for the specific detection of Cu²⁺. A “sandwich” structure was used to control the precursor infiltration in order to endow PCHs with highly ordered three-dimensional interconnected macroporous structure. The acquired PCHs produced the characteristic Bragg diffraction peak when immersed into Cu²⁺ buffers, and exhibited a rapid response. With the increase of concentration of Cu²⁺ from 0 mol/L to 10^-4 mol/L, Bragg diffraction peak of PCHs blueshifted 66 nm and the color change was visible to the naked eyes(from brown to kelly green). Furthermore, PCHs exhibited efficient recognition to Cu²⁺ in the multicomponent metal ion solution. Such a specific recognition, rapid response and signal self-reporting of PCHs to Cu²⁺ provide great potential for the real-time monitor of Cu²⁺.

NiFe₂O₄/NiO Nanocomposites as Electrocatalysts for Oxygen Evolution Reaction^†

FENG Xiaolei, QU Zongkai, CHEN Jun, WANG Dengdeng, CHEN Xu, YANG Wensheng

2017, 38(11): 1999-2005. doi:10.7503/cjcu20170426

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NiFe₂O₄/NiO nanocomposites were prepared by the thermal treatment of a single-source NiFe-layered double hydroxide precursor and were used as electrocatalysts for electrooxidation of water(oxygen evolution reaction, OER). The NiFe₂O₄/NiO nanocomposites exhibited much higher water oxidation activity and better stability than pure NiFe₂O₄, NiO and a physical mixture of NiFe₂O₄ and NiO synthesized by chemical coprecipitation method. A current density of 10 mA/cm² was reached at an overpotential of 364 mV in alkaline media. The good electrocatalytic performance for OER could presumably be attributed to that the well-dispersed heterogeneous structure of the nanocomposites prevented the aggregation of NiFe₂O₄ and resulted in a higher surface area and a smaller charge transfer resistance compared with the control samples.

Effect of Potassium Loading on the NO_x Storage and Reduction Performance of the CuO/K₂CO₃/MgAl₂O₄Catalyst at High Temperature^†

LIU Yaoyao, DING Tong, ZHAO Dongyue, GAO Zhongnan, GUO Lihong, TIAN Ye, LI Xingang

2017, 38(11): 2006-2014. doi:10.7503/cjcu20170192

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We designed a new NO_x storage and reduction(NSR) CuO/K₂CO₃/MgAl₂O₄ catalyst operating at high temperature. The effect of potassium loading on the NO_x storage and reduction performance of the catalyst was studied. In the catalyst, the K₂CO₃ exists as highly dispersed K₂CO₃ and bulk K₂CO₃. In the lean-burn period, the nitrates formed on the bulk K₂CO₃ have high thermal stability at high operating temperature, while the thermal stability of the nitrates formed on the highly dispersed K₂CO₃ is low. When the K loading is low, the K₂CO₃ mainly exists as highly dispersed K₂CO₃, the limited NO_x storage capacity and the low thermal stability of the nitrates result in the low NSR activity at high temperature. While too much K₂CO₃ loaded on the catalyst can decrease the redox ability of CuO by covering it, which will decrease the NSR activity of the catalysts. When the K loading is 10%, the best NSR activity is obtained with the highest NO_x reduction percentage of 99. 9% at 450 ℃. Therefore, the CuO/K₂CO₃/MgAl₂O₄ catalyst is a promising high-temperature NSR catalyst.

Synthesis of Polystyrene/silver Nanoparticels Composite Spheres and Their Catalytical Application^†

SHEN Xiaohua, HU Jiawen

2017, 38(11): 2015-2022. doi:10.7503/cjcu20170159

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This study reports the preparation of polystyrene/Ag nanoparticles(PS/Ag NPs) composite spheres and their catalytic application toward MB conversion. The composite spheres were prepared by synthesis of PS speres, their sulfonation, and finally reduction of [Ag(NH₃)₂]⁺ ions absorbed on sulfonated PS spheres using polyvinyl pyrrolidone. The resultant PS/Ag NPs composite spheres were characterized using scanning electron miscroscopy, transmission electron microscopy, UV-Vis spectroscopy, Infrared spectroscopy and X-ray diffraction spectroscopy, and their catalytic properties were examined. These results show that small Ag NPs with diameter of about 9—18 nm were well dispersed on the PS spheres and the PS/Ag NPs composite exhibits excellent catalytic activity towards MB conversion without obvious deteriorating after five cycles of running. This study, thus, may have impact on the degradation of organic contaminants in water.

Investigation on Redox Mechanism of p-Nitrophenol in Aprotic Media^†

LI Yuying, LI Dan, CHENG Longjiu, JIN Baokang

2017, 38(11): 2023-2030. doi:10.7503/cjcu20170107

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The mechanism of electrochemical reduction of p-nitrophenol in acetonitrile was explored by means of in situ FTIR spectroelectrochemistry, cyclic voltabsorptometry(CVA) and derivative cyclic voltabsorptometry(DCVA). Also, the possible structures of free radical anions and dimers in the reaction were calculated by the B3LYP method at the 6-311++G^* level. Electrochemical experimental results showed that CV curve changed with the change of p-nitrophenol concentration. When increasing the number of CV scan turns, the entire electrochemical process was chemically reversible by observing 3D IR spectra. Both CV and rapid-scan IR spectra(CVA and DCVA) supported that for p-nitrophenol in acetonitrile solvent, complex self-protonation reaction occured during electrochemical reduction. The self-protonation reaction took place after PNP was reduced to free radical anion; when the PNP concentration was high, the dimerization reaction happened from the free radical anion and products of self-protonation reaction, followed by the p-nitrophenol anion being reduced to the corresponding radical dianion. At the same time, when the concentration of p-nitrophenol was decreased, the electrochemical process would also change, that is, the dimerization phenomenon disappeared, and the anion free radical would continue to reduce.

Preparation of NF/rGO/Co₃O₄/NiO Electrode and Its Application in Supercapacitor^†

LI Yingying, ZHANG Qi, ZHANG Yiheng, WANG Lei

2017, 38(11): 2031-2037. doi:10.7503/cjcu20170056

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The electrochemical deposition method was used to prepare NF/rGO/Co₃O₄ and NF/rGO/Co₃O₄/NiO electrodes(NF=nickel foam; rGO=reduced graphene oxide). Here, with NF as a current collector, rGO, Co₃O₄ and NiO were grown on NF directly without any binder under specific conditions including optimized potential, time and concentration. NF/rGO/Co₃O₄ and NF/rGO/Co₃O₄/NiO electrodes were used as the electrode of supercapacitor, and three-electrode system was employed in cyclic voltammetry, galvanostatic charge-discharge and electrochemical impe-dance spectroscopy characterization of the electrodes. The results showed that the capacitance of NF/rGO/Co₃O₄/NiO electrode was 1188.6 F/g at 2 A/g; its rate capability was 75.7% when the current density varied from 2 A/g to 12 A/g; and its cycling stability was 80.5% after 2000 times. Compared with NF/rGO/Co₃O₄, the supercapacitor performance of NF/rGO/Co₃O₄/NiO electrode improved a lot, which can be attributed to the synergistic effect of Co₃O₄ and NiO. What’s more, rGO could enhance the electroconductivity of electrodes to a large extent.

Influence of Au Doping on the Surface States and Charge Transport in TiO₂ Films^†

ZHENG Jiawei, JIANG Ling, DING Yong, MO Lie, DING Youcai, HU Linhua, DAI Songyuan

2017, 38(11): 2038-2044. doi:10.7503/cjcu20170021

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Nanoblocky TiO₂ with different contents of Au doping was synthesized by two-step method. Cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the influence of Au doping on the number and distribution of surface states in the films. Meanwhile, intensity-modulated photocurrent/photovoltage spectroscopy was used to study the electron transfer and recombination process. The results show that Au doping can effectively reduce the surface states in TiO₂ films and optimize the energy distribution. Furthermore, in-depth characterizations indicate that Au doping(molar fraction, 0.2%) can increase the charge transfer resistance at the interfaces of dyed-TiO₂/electrolyte. Overall, the cell performance was relatively dependent on the effect of surface states essentially.

One-step Synthesis of Hydrangea-like BiOCl/Br Solid Solution Photocatalyst with Co-template Method^†

CHEN Ying, ZHAO Yu, LI Jing, HAN Xingyue

2017, 38(11): 2045-2052. doi:10.7503/cjcu20160894

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Hydrangea-like BiOCl/Br solid solution photocatalysts were prepared by using glycol/dodecyl trimethyl amonium bromide(EG/DTAB) co-template in one step. The catarysts were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, N₂ adsorption-desorption, and UV-Vis diffuse reflectance spectroscopy. The results showed that the BiOCl/Br solid solution obtained by the EG/DTAB co-template method had a layered structure like hydrangea, different from BiOCl hierarchical microspheres prepared by solvothermal method; the Br^- of DTAB was inserted into the lattice of BiOCl to form a solid solution, reducing the band gap of BiOCl. Hydrangea-like BiOCl/Br solid solution showed excellent photocatalytic activity for degradation of rhodamine B(RhB) and methyl orange(MO) under visible light irradiation. When the molar ratio of DTAB to KCl was 0.75, the photocatalytic degradation rate of RhB was 97.2% within 8 min, and that of MO was 83.6% with 1 h.

Theoretical Study on Charge Transport Properties of Copolymers of Diketopyrrolopyrrole and Oligo-thiophene^†

FAN Jianxun, JI Lifei, REN Aimin

2017, 38(11): 2053-2060. doi:10.7503/cjcu20170321

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The electronic structures and charge transport properties of the oligomers of diketopyrrolopyrrole(DPP) with the thiophene were investigated with ab initio density functional theory and classical Marcus charge transport theory. The results show that with the increase of the DPP concentration(or decrease of the thiophene numbers) in the polymer unit both the HOMO and LUMO energy levels of the polymers decrease, and the band gaps narrow. As the DPP concentration increased, the intrachain overlap of the electron wave functions of the DPP acceptor units was improved, that facilitates the intrachain electron transport. Moreover, the increase of DPP concentration strengthens the rigidity of the molecular backbone and enhances the interchain overlap of LUMO orbitals, which strengthens the electron transfer integrals and the system is converted from p-type into ambipolar materials.

Molecular Docking, QSAR and Molecular Dynamics Simulation on Phosphorus Containing Pyrimidines as CDK9 Inhibitors^†

TANG Guanghui, ZHANG Ya, ZHANG Yuping, ZHOU Pengpeng, LIN Zhihua, WANG Yuanqiang

2017, 38(11): 2061-2069. doi:10.7503/cjcu20170237

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The interaction modes between phosphorus containing pyrimidine cyclin dependent kinase 9(CDK9) inhibitors and the protein were studied using the combination of molecular docking and three-dimensional quantitative structure-activity relationships(3D-QSAR). The interaction mode obtained by molecular docking revealed that the molecule conformation, hydrophobic interaction and H-bond, as well as Cys106 played an important role in the binding of phosphorus containing pyrimidines and CDK9. Based on the result of molecular docking, 3D-QSAR models were established by comparative molecular field analysis(CoMFA), comparative molecular similarity indices analysis(CoMSIA) and Topomer CoMFA techniques. With the best CoMSIA-SEH model, the cross-validated value(Q²) was 0.557, the non-cross-validated value(R²) was 0.959. The predictive power of the CoMSIA-SEH model was determined from external test sets that were excluded during model development(r²=0.863). Ten new compounds were obtained based on the above modeling, and the results of molecular docking and molecular dynamics simulation suggested they could act as potential CDK9 inhibitors, especially compound 64d with more potent inhibitory activity proved by molecular dynamics simulation and binding free energy analysis. It was expected that these results could help establish the binding mechanism between phosphorus containing pyrimidines and CDK9, and provide a valuable reference for future anti-CDK9 drug design.

Effect of Force Fields and Water Models on EGFRvⅢ-MR1(scFv)Complex by Molecular Dynamics Simulation, MM-PBSA Calculation, and ITC Experiment^†

REN Jiayi, YANG Zhiwei, ZHENG Nianjue, LI Junqi, YANG Chunlong, LIN Shujian, YANG Bing, HUANG Junqing, LIAO Huaxin, YUAN Xiaohui, OU Shiyi

2017, 38(11): 2070-2076. doi:10.7503/cjcu20170212

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Six commonly used force fields and three commonly used solvent water models were employed, respectively, for EGFRvⅢ and its corresponding scFv antibody(MR1) complex, and total 16 antigen-antibody complex moleaular(MD) simulations were carried out. The molecular mechanics/Poisson-Boltzmann surface area(MM-PBSA) calculations were performed and the thermodynamic parameters of antigen-antibody interaction were measured by isothermal titration calorimetry(ITC) experiment. The RMSD analysis show that all the MD simulations were stable, but the binding free energy values from MM-PBSA are different under 6 force fields and 3 water models. The recommended calculation models are given by comprehensive analysis of structural changes, energy changes, consistency of experiment and combining calculation and experimental verification with two antibody humanization mutants(huMR1-2 and huMR1-G). At the same time, the calculation accuracy of different force fields and solvent water models were discussed. The conclusions of this study can be used in the subsequent antibody humanization, antibody affinity maturation, and other related computer-aided antibody drug design.

Sol-gel Preparation of Hydrophobic Silica Coating-materials with Ultralow Refractive Index^†

HE Meiying, LUO Jianhui, YANG Bowen, XIA Bibo, LI Yuanyang, ZHANG Shuming, JIANG Bo

2017, 38(11): 2077-2081. doi:10.7503/cjcu20170148

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Using methyltriethoxysilane(MTES), tetraethylorthosilicate(TEOS) as co-precursors and hydroxypropyl-β-cyclodextrin(HPCD) as porogen, ultralow refractive index films were prepared based on a base-catalysed sol-gel process. After further modification by hexamethylisilazane(HMDS), the lowest refractive index of these silica coatings obtained from the hybrid sol were 1.05 and the static water contact angles of the coatings increased from 66.4° to 128.7°. The data showed that the films prepared with HPCD as porogen got a pore diameter around 4 nm. Compared with those templates such as poloxamer(F127), HPCD not only perform well in decreasing the refractive index of films, but also eliminate light scattering caused by mesopore of the film, will have potential value in the field of surfactant-templated methods.

Copolymerization of Ethylene and Methyl Methacrylate with Salicylaldiminate Nickel(Ⅱ) Complexes^†

ZHANG Danfeng, ZHANG Yujun, YU Guocong, GAO Wenhao

2017, 38(11): 2082-2088. doi:10.7503/cjcu20170256

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Four salicylaldiminate-based nickel(Ⅱ) complexes: bis[N-(2,6-diisopropylphenyl)salicylaldiminate]-nickel(Ⅱ)(C1), bis[N-(2,6-diisopropylphenyl)-3-methylsalicylaldiminate]-nickel(Ⅱ)(C2), bis[N-(2,6-diisopropylphenyl)-3-isopropylsalicylaldiminate]-nickel(Ⅱ)(C3) and [N-(2,6-diisopropyl-phenyl)-3-isopropylsalicylaldiminate]-nickel(Ph)(PPh₃)(C4), in the presence of methylaluminoxane(MAO), were applied in copolymerization of ethylene and methyl methacrylate(MMA). The influences of polymerization parameters, such as molar ratio of Al/Ni, polymerization temperature and time, on the copolymerization were studied with complex C3 as a model catalyst. Based on these results, the effect of the structure of the nickel complexes on the copolymerization was explored under optimized polymerization conditions. Complex C2 exhibits higher catalytic activity of 13.1 kg/(mol Ni·h) than C1 and C3, while C3 gives the lowest comonomer MMA incorporation of 14.1% in the obtained copolymers. For complexes C3 and C4, with the same ligand but different structures, C3 displays better catalytic activity than C4, but their comonomer MMA incorporations are similar. The microstructures and thermo-properties of the obtained copolymers were characterized by means of FTIR, ¹H NMR,¹³C NMR, GPC and DSC.

Effect of Co-stabilizers on the Properties of Ba/Zn System

LI Wei, WU Suhua, Ren Xinxin

2017, 38(11): 2089-2094. doi:10.7503/cjcu20170156

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The transparency of polyvinyl chloride(PVC) stabilized with barium isooctoate and zinc isooctoate(Ba/Zn) was discussed. Then formulations based on Ba/Zn with hydrotalcite(LDH), phosphite ester and β-diketone were fully characterized which showed good initial color and obvious increase in transparency respectively. Afterwards, the thermal stability of PVC in the presence of Ba/Zn and LDH was studied by testing the static and dynamic stabilities, thermalaging properties and conductivity. The results showed that LDH used as costabilizer could enhance the thermal stabilities of PVC significantly, which also indicated that a strong synergistic effct between Ba/Zn and LDH. Finally, evaluation of the use of three different co-stabilizers for PVC stabilization were carried out by thermogravimetric analysis. The curves presented that all of them could improve the primeval thermal stabilities of PVC.

Modification of SSBR/BR with Trans-1,4-Polyisoprene Alloy Rubber for High Performance Passenger Car Radical Tire Tread Stock^†

WANG Hao, ZHANG Jianping, MA Yunsheng, WANG Riguo, HE Aihua

2017, 38(11): 2095-2101. doi:10.7503/cjcu20170152

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The crystalline characteristics, processing and mechanical properties of trans-1,4-polyisoprene alloy rubber(TPIR) were studied. Then TPIR incorporated with solution polymerized butadiene-styrene rubber(SSBR)/cis-1,4-polybutadiene rubber(BR) blends were further investigated as passenger car radical(PCR) tire tread stocks. Compared with amorphous SSBR and BR, TPIR raw rubber showed improved green strength due to its crystallizability at room temperature. The capillary extrusion behavior of TPIR indicated that TPIR presented good extrusion behavior with smooth extrusion appearance and low extrusion swelling ratio. SSBR/BR/TPIR compounds showed increased green strength and 100% modulus with the increase in TPIR, when compared with SSBR/BR blends. After vulcanization, SSBR/BR/TPIR vulcanizes showed excellent physical and mechanical properties, such as increased wet skid resistance, wear resistance, compressive strength, and outstanding tensile fatigue resistance(increased by more than 4 times). Carbon blacks and silica were proved to be dispersed much more uniformly in SSBR/BR/TPIR vulcanizates with much smaller aggregates than in SSBR/BR vulcanizates. So comprehensive speaking, TPIR as a novel synthetic rubber has the potentional application in PCR tire tread stock with superor performance.

Preparation and Adsorption Properties of Molybdate Anion Imprinted Ceramic Membrane^†

ZENG Jianxian, DONG Zhihui, ZHANG Zhe, LIU Guoqing, ZHOU Hu

2017, 38(11): 2102-2110. doi:10.7503/cjcu20170143

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A novel imprinted ceramic membrane(IIP-PVI/CM) for adsorbing selectively molybdate anion[Mo(Ⅵ)] was prepared with surface imprinting technology and graft-polymerization using an alumina ceramic membrane as the supporting material, Mo(Ⅵ) as the template ion, 1-vinylimidazole as the functional monomer and 1,6-dibromohexane as the cross-linking agent. The obtained samples were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis and scanning electron microscopy. Effect of pH value on adsorption performance of IIP-PVI/CM was investigated. The results indicate that IIP-PVI/CM shows a good adsorption capacity in the pH range of 2—4. The adsorption behaves of IIP-PVI/CM toward Mo(Ⅵ) were studied through adsorption kinetics and thermodynamics. The kinetics curve meets pseudo-second-order model. The adsorption isotherm can be described by Langmuir isotherm model. The selective adsorption experiment for IIP-PVI/CM was carried out at pH of 4.0 and temperature of 30 ℃ by a mixed solution containing 4 mmol/L Mo(Ⅵ) and 4 mmol/L W(Ⅵ). It was found that IIP-PVI/CM has specific selectivity for Mo(Ⅵ), and the selectivity coefficient is 7.48 for Mo(Ⅵ) to W(Ⅵ). A dynamic adsorption experiment was done by a membrane apparatus. The results indicate that IIP-PVI/CM also shows good selectivity for separation of Mo(Ⅵ) and W(Ⅵ). The values of the saturated adsorption time of W(Ⅵ) and Mo(Ⅵ) anions are 24 and 47 min, corresponding to the saturated adsorption amounts of 0.163 mmol/100 g for W(Ⅵ) and 0.672 mmol/100 g for Mo(Ⅵ), respectively. After nine adsorption-desorption cycles, the adsorption capacity of IIP-PVI/CM towards Mo(Ⅵ) still reaches 92% of the initial capacity. The IIP-PVI/CM has good regeneration and recycling performance.

Synthesis of Novel Homogeneous Chromium-based Catalysts and Catalyze Ethylene Oligomerization^†

LI Ping, MI Puke, GU Jinjing, XU Sheng

2017, 38(11): 2111-2117. doi:10.7503/cjcu20170109

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Three novel [NNN]-1,3,5-triazacyclohexane ligands containing O or N atom in the N-substituent of the type [NNN] were synthesized and characterized by ¹H NMR,¹³C NMR and electron ionization-mass spectrometry(EI-MS). Three kind of catalysts were prepared through the coordination of ligands with Cr(Ⅲ), and characterized by electrospray ionization-mass spectrometry(ESI-MS) and elemental analysis. Upon activation with methyl silane oxygen aluminum(MAO), Cr(Ⅲ) complexes were evaluated the activity to catalyze ethylene oligomerization as catalyst precursor. The effects of polymerization temperature, polymerization pressure and the molar ratio of Al to Cr on the activity and the selectivity for 1-hexene and 1-octene were investigated. The results showed that at the reaction temperature of 50 ℃ and ethylene pressure of 0.8 MPa and n(Al)/n(Cr) of 500, catalyst with 3-(dimethylamino)propy substituent possesses higher catalytic activity of 15.71×10⁵ g/(mol Cr·h) and the selectivity for 1-hexene and 1-octene can reach 91.02%. Otherwise catalyst with 3-ethoxypropyl substituent shows lower catalytic activity of 11.54×10⁵ g/(mol Cr·h), and the selectivity for 1-hexene and 1-octene is higher reaching 93.05% under the same polymerization condition.

Adsorption Kinetics/Thermodynamic Behavior and Adsorption/Desorption Mechanism of Crystal Violet by Semi-interpenetrating Sodium Alginate/Polyacrylamide Hydrogel^†

LI Zhigang, ZHANG Yixuan, ZHANG Qingsong, MA Youwei, HU Tao, BAI Haihui, LIU Pengfei, WANG Ke, ZHANG Xiaoyong

2017, 38(11): 2118-2127. doi:10.7503/cjcu20170101

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The sodium alginate(SA), a kind of polyanion electrolyte including many carboxylic acid(—COO^-), was introduced into polyacrylamide hydrogel network to prepare the SA/PAM hydrogels with semi-interpenetrating network structure via free-radical solution polymerization. The pore morphology and chemical composition of SA/PAM hydrogels before and after adsorption of crystal violet(CV) were comparative analyzed by scanning electron microscope(SEM), X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared spectroscopy(FTIR). All kinds of models were used to study adsorption kinetics and thermodynamics behavior for the adsorption of crystal violet(CV) on the SA/PAM hydrogel. Meanwhile, the desorption efficiency was discussed, and the mechanism of adsorption and desorption was proposed. The results showed that, with the introduction of SA, the pore size reduced, but pore numbers increased. The SA/PAM-10 hydrogel shows the maximum adsorption amount, about 13.5838 mg/g. Four kinds of SA/PAM hydrogels agree with pseudo first-order kinetic model, and the adsorption rate depends on both film diffusion and particle diffusion. The isothermal adsorption process is consistent with the Temkin and the D-R model, which belongs to the microporous multi-layer adsorption. Thermodynamic analysis results show that the adsorption process is driven by entropy rather than chemical factor. The desorption was achieved by adding HCl, the maximum desorption rate reached up to 94.18%, and reversible adsorption of SA/PAM hydrogel could be found by adding NaOH. The high adsorption capacity can be ascribed to the electrostatic interaction between COO^- of SA molecular chain and —C=N⁺— of CV molecules. Due to protonation of —COO^- and —NH₂ under low pH value, leading to increased electrostatic repulsion with CV molecules. Accordingly, the desorption rate was naturally increased.

Effect of Hot Stretching on the Structure of Polypropylene Microporous Membranes with in situ Small Angle X-Ray Scattering^†

WANG Wei, XU Jiali, LIN Yuanfei, LI Xueyu, MENG Lingpu, LI Liangbin

2017, 38(11): 2128-2134. doi:10.7503/cjcu20170184

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With in situ small angle X-ray scattering and scanning electron microscopy measurements, effects of hot stretching temperatures and draw ratios on the lamellae and pore structure of the polypropylene microporous membrane were studied. The results show that the lamellar clusters are separated during the cold stretching and heat setting process, while the internal structures do not undergo separation during the hot stretching process. With the increase of the hot stretching ratio, the bridge length of microporous membrane after hot stretching process increases substantially. Also, it has better periodicity along the equatorial direction compared with the cold-stretching and heat-setting samples. The results of different stretching temperatures show that the length of the bridge increases with the increase of the stretching temperature. When the temperature is too high, the bridge will partially melt. This work can provide guidance for the structural control during preparation of polypropylene microporous membranes.

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