Table of Content

10 June 2015, Volume 36 Issue 6

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Articles: Inorganic Chemistry

Interaction of Human Serum Albumin and Water Soluble Cationic Pyridyl Corrole Gallium Complex^†

WEN Jinyan, LÜ Biaobiao, ZHANG Yang, WANG Jiamin, YING Xiao, WANG Hui, JI Liangnian, LIU Haiyang

2015, 36(6):  1033-1041.  doi:10.7503/cjcu20150044

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The interaction between gallium 5, 10, 15-tris(4-methylpyridiniumyl)corrole(1-Ga) and human serum albumin(HSA) was investigated using UV-Vis spectra, fluorescence spectra, circular dichroism(CD) spectra and molecular docking simulation. The results reveal that the fluorescence quenching of HSA by 1-Ga is a static quenching process. The binding constant of complex 1-Ga with HSA is 2.82×10⁴ L/mol, and bin-ding distance r=3.342 nm. Thermodynamic parameters show the interaction is mainly driven by hydrophobic and hydrogen binding forces. Site marker competition experiment indicates 1-Ga preferably bind to ibuprofen site Ⅱ of HSA. Also, α-helix content of HSA will decrease upon binding 1-Ga as indicated by UV-Vis and CD spectroscopy. Molecular docking simulation confirmed 1-Ga bind to the hydrophobic pocket site Ⅱ in domain ⅢA of HSA.



Synthesis and Characterization of Titanium-containing Periodic Mesoporous Organosilicas^†

WANG Donglong, ZHOU Jinghong, SUI Zhijun, ZHOU Xinggui, SCOTT L. Susannah

2015, 36(6):  1042-1051.  doi:10.7503/cjcu20150035

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Titanium-containing periodic mesoporous organosilicas(Ti-PMO) were hydrothermally synthesized using triblock copolymer P123 as the template, 1,2-bis(trimethoxysilyl)ethane as the silica precursor and titanocene dichloride as the titanium precursor. The crystal and textural properties of Ti-PMO were characterized by X-ray diffraction(XRD), transmission electron microscope(TEM) and N₂ physisorption. The influence of different titanium precursors, prehydrolysis time of titanium precursor, acid concentration and molar ratio of Si/Ti on the form of titanium in PMO were investigated by means of diffuse reflectance UV-Vis spectroscopy. It was revealed that Ti atoms could be incorporated into the framework of PMO materials in the form of tetrahedral coordination by finely controlling the synthesis condition. The hydrolysis rate of titanium and silica precursors should be precisely balanced to bring the oligomer titanium species and oligomer silica species, which are the hydrolysis intermediates of titanium precursor and silica precursor, into intimate contact and then co-condensate to form Ti—O—Si structure. Tetrahedral-coordinated Ti-containing PMO with good thermal and hydrothermal stability can be successfully obtained using titanocene dichloride as the titanium precursor at the ratio of n(Si)/n(Ti)>20 and prehydrolyzed for 6 h at acid concentration of 0.18 mol/L.



Analytical Chemistry

Non-linear Chemical Analysis of Throng Component and Simultaneous Determining Contents of Cow and Mare Milks Mixed with Goat Milk^†

WANG Erdan, LU Lili, ZHANG Taiming, DONG Wenbin, LU Hongmei, LIANG Yizeng, XU Tianshu, ZHANG Juan, CHEN Chunnan

2015, 36(6):  1052-1060.  doi:10.7503/cjcu20150049

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A method was proposed to determine the contents of raw milks in mixed milks. At first, non-linear chemical fingerprints of standard samples of goat milk and mixed milks with different contents of raw milks were determined at different temperatures, and via the multiple linear relationship between the contents of raw milks and the fingerprint-inductive-time difference of the mixed milks relative to goat milk, an analysis system model to predict the contents was fitted through classical least squares(CLS). And then, using the inductive-time difference between the sample and goat milk, the raw milk contents were calculated by the model. Lastly, according to the raw contents, the authenticity and quality of the sample were identified and evaluated. The results show that the correlation coefficient between the measured values and true values is 0.9991, the RSDs are 0.77%—4.3%, the recoveries are 93.2%—105.5%, and the detection limits of cow and mare milks doped in goat milk are 1.93% and 2.81%, respectively. The method has good reproducibility and accuracy, and is a practical and exact one for determining the raw milk contents in mixed milks, identifying the authenticity of dairy, and evaluating the quality of mixed milk. The method can be used for reference in research on determining throng component in other samples.



Polydopamine Nanoparticle-based Fluorescence Resonance Energy Transfer Assay for microRNA Detection^†

MA Lina, LIU Fuyao, GAO Jiaxue, WANG Zhenxin

2015, 36(6):  1061-1066.  doi:10.7503/cjcu20150016

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A simple, rapid and low-cost polydopamine nanoparticle(PDA NP)-based fluorescence resonance energy transfer(FRET) assay with deoxyribonucleaseⅠ(DNaseⅠ)-assisted target recycling signal amplification was developed for microRNA(miRNA) detection. Under the optimized experimental conditions, the recovery ratio of Cy5 fluorescence intensity increased linearly with logarithm of miR-21 concentration from 10 pmol/L to 100 nmol/L, with a detection limit of 7 pmol/L. Moreover, satisfactory results were obtained while the proposed method was applied to detect miRNA in 10% human serum.



Direct Analysis of Micro Area on Tooth Surface by Surface Desorption Atmospheric Pressure Chemical Ionization Mass Spectrometry^†

WANG Jiang, LI Qian, GU Haiwei, GUO Xiaotun, YANG Shuiping, WANG Zhihao

2015, 36(6):  1067-1073.  doi:10.7503/cjcu20150008

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A novel analytical platform based on a nanoliter needle for sampling and surface desorption atmospheric pressure chemistry ionization mass spectrometry(SDAPCI-MS) for analysis was developed for the direct, fast and micro-area analysis of different parts of a human tooth, including cavity, cavity edge, tooth cusp and tooth sulcus. The results showed that the mass spectra from the four sampling spots on the same tooth were different, and that SDAPCI-MS detected lactic acid, pyruvic acid, phenylacetic acid and propanoic acid were confirmed using tandem mass spectrometry(MS/MS). Principal component analysis(PCA) of the mass spectral data successfully differentiated the different sampling spots, levels of tooth decay and levels of gum disease. Therefore, our nano-SDAPCI-MS approach provides a promising way for micro-area analysis with fast, minimal pretreatment sampling, enabling rapid, simple and reliable surface MS investigation.



Global Survey of Mouse Liver Protein Expression Using Liquid Isoelectric Focusing Prefractionation of Tryptic Peptides and LC-MS/MS^†

LI Ying, YAO Jun, YANG Pengyuan, FAN Huizhi

2015, 36(6):  1074-1081.  doi:10.7503/cjcu20141120

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To comprehensively and quickly identify proteins of mouse liver, the tryptic peptides were pre-fractioned and enriched by isoelectric focusing technigue using Agilent 3100 OFFGEL Fractionator into 24 fractions, followed by RPLC and MS/MS analysis. Each MS/MS spectrum was searched for mouse species against the Swissprot database. The results were analyzed which resulted in the identification of proteins in mouse liver. Finally, 3474 proteins were identified from mouse liver, 832 of them were new identified proteins. Bioinformatic analyses were performed to demonstrate the physicochemical properties, cellular locations and functions of the proteins. The combined use of liquid fractionation and LC-MS allows a considerable increase in proteome coverage of very complex samples prepared from the tissues extracts and supports the low-concentrated protein identification. This study can provide useful data to research C57 mouse liver proteins.



dentification of Glyphosate and Butachlor by Detecting Chlorella Pyrenoidosa with Raman Microspectroscopy^†

SHAO Yongni, JIANG Linjun, PAN Jian, HE Yong

2015, 36(6):  1082-1086.  doi:10.7503/cjcu20140938

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This study investigate the method to identify two herbicides using Chlorella pyrenoidosa as a carrier and obtained the Raman spectral information of β-carotene of Chlorella pyrenoidosa grown in glyphosate-polluted water, butachlor-polluted water and normal water, respectively. The partial least-squares(PLS) model and linear discriminant analysis(LDA) classification model were established by the spectral signal after preprocessing. When the threshold is ±0.3, the correct prediction rate to glyhosate and butachlor reached 83.33% by using the PLS model based on the whole band, and correct classification rate of the two herbicides can reach 100% by using LDA classification model based on characteristic peaks. The results show that using Chlorella pyrenoidosa as a carrier to identify heribicides glyphosate and butachlor is feasible and LDA classification model is more suitable for classification of the two herbicides.



Organic Chemistry

Isolation and Structural Identification of Neutral Human Milk Oligosaccharides^†

LIU Shilong, LANG Yinzhi, ZHU He, YAN Lina, LÜ Youjing, ZHAO Xiaoliang, CAI Chao, YU Guangli

2015, 36(6):  1087-1093.  doi:10.7503/cjcu20150118

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Eighteen natural oligosaccharides were obtained from the defatted and deproteinated human milk using a combination isolation process including anion exchange chromatography(AEC), gel permeation chromatography(GPC) and porous graphitized carbon(PGC) liquid chromatography. Meanwhile, the structures of these oligosaccharides were identified by electrospray ionization collision-induced dissociation tandem mass spectrometry(ESI-CID-MS/MS). The major building blocks of neutral human milk oligosaccharides were consisted of tri- to nonasaccharides through the regular assembly of glucose(Glc), galactose(Gal), N-acetylglucosamine(GlcNAc) and fucose(Fuc). Lactose(Galβ1-4Glc) core was located at the reducing end in all of these oligosaccharides while the lactosamine(Galβ1-3/4GlcNAc) was determined at the non-reducing end. In addition, some of Gal, Glc and GlcNAc residues on the backbone of oligosaccharides were fucosylated in α1-2, α1-3 and α1-4 linkages, respectively.



Synthesis and Properties of Symmetrical Donor or Acceptor Unit Conjugate Linked BODIPY Derivatives^†

PENG Zaixi, LIAO Junxu, XU Yongjun, ZHAO Hongbin, PENG Min, CUI Yunzeng, NING Jingheng

2015, 36(6):  1094-1099.  doi:10.7503/cjcu20150034

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Four novel symmetrical 4,4'-difluoro-4-bora-3a,4a-diaza-sindacene(BODIPY) derivatives were synthesized. These BODIPY derivatives bear different donor or acceptor units as conjugate bridge, and the BODIPYs meso-position substituted by thiophene or benzene as the termini groups. The structures of all the compounds were identified by ¹H NMR, ¹³C NMR and MS techniques. The photophysical properties of these compounds were measured by the UV-Vis absorption and the fluorescence emission spectrophotometer. And the electrochemical properties were investigated by the cyclic voltammetry. The results of absorption spectra confirmed that these BODIPYs had a characteristic absorption peak, and the conjugate bridges had little influence on the intramolecular charge-transfer(ICT) interaction neither used as donor nor acceptor. On the other hand, meso-position substituentes have a weak influence on the ICT interaction in the BODIPYs, and meso-position thiophene substituted ones have raised more intensive ICT than the meso-position benzene substituted ones. Both the absorption spectra and cyclic voltammetry data indicate that BODIPYs with meso-thiophene substitutuents possess a lower oxidation potential and a narrower band gap than those meso-position benzene ones.



Synthesis of Lipiophilic Cations of Anthraquinone and Their Anticancer Activities^†

LIU Dan, HU Xiufang, ZHENG Yanyan, PAN He, LUO Shuwei, HONG Fang, ZHAO Wenna, JIANG Meihong, ZHU Yunhui, SHAO Jingwei, WANG Wenfeng

2015, 36(6):  1100-1106.  doi:10.7503/cjcu20141145

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Seven emodin quaternary ammonium salts, two aloe emodin quaternary ammonium salts, one water soluble emodin quaternary ammonium as well as a quaternary ammonium salt of α-naphtholbenzein were synthesized and the in vitro anticancer activities were tested. Emodin quaternary ammonium salts containing one long carbon chain showed very low anticancer activities, and emodin and aloe emodin quaternary ammonium salts containing two carbon chains exhibited high anticancer activities. Using hydrophilic long chains to replace lipiophilic long carbon chains made emodin quaternary ammonium salts lose anticancer activities. Quaternary ammonium salt of α-naphtholbenzein showed a moderate anticancer activity, which indicated that the introduction of lipiophilic cations to a molecule with ability to transfer electrons could increase its anticancer activity.



Isolation and Identification of Two New Compounds from Aspergillus Aculeatus^†

XU Yan, TIAN Shasha, YU He, YANG Wenzhi, ZHU Huajie

2015, 36(6):  1107-1111.  doi:10.7503/cjcu20141146

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In order to investigate new bioactive compounds, a piece of fungi Aspergillus aculeatus was obtained from the Jinyun mountain soil in Chongqing, China. By fermentation using Potato Dextrose(PD) within 14 d at 28 ℃, the extraction of ethyl acetate(103 g) was obtained. The extraction was then used for isolation of compounds through a series of study by classical separation methods, for example Octadecyl Silane(ODS) and Sephadex LH-20. Two new compounds 2-(2',4',6'-trihydroxy phenyl)benzene-(7-hydroxy-5-methyl) chromone(1) and (E)-4-hydroxy-3-[(4-hydroxy-3-methylbut-2-en-1-yl)oxy] benzoic acid(2) were obtained. The structures were elucidated using mass spectrometry(MS), one demensional nuclear magnetic resonance spectroscopy(1D NMR), heteronuclear multiple bond correlation(HMQC), heteronuclear single quanturn correlation(HMBC) and rotating-frame overhauser effect spectroscopy(ROESY). Other two known compounds 2-(2'-hydroxypropyl)-5-methyl-7-hydroxychromone(3) and (3R, 4S)-8-hydroxy-3,4,5- trime-thyl-6-oxo-4,6-dihydro-3H-isochromene-7-carboxylic acid(4) were obtained. Compounds 2 to 4 exhibited some 2,2-diphenyl-1-picrylhydrazyl(DPPH) antioxidant activity.



Synthesis Method of β-Aminophosphonate Derivatives^†

XIONG Zhen, JI Siping, CHUAN Yongming, JIANG Lin, YUAN Minglong

2015, 36(6):  1112-1116.  doi:10.7503/cjcu20141126

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The Mannich reaction of Ohira-Bestmann reagent and α-amino sulfone was preliminary studied with tetrabutyl ammonium iodide(TBAI) as a phase transfer catalyst. Under the optimal reaction conditions, the Mannich reaction between Ohira-Bestmann reagent and a series α-amino sulfone derived from substituted aromatic aldehyde can be smoothly achieved. Moderate to good yields(52%—93%) were obtained and the structure of β-aminophosphonate derivatives 5a—5k were confirmed by ¹H NMR, ¹³C NMR and MS. By the Mannich reaction of Ohira-Bestmann reagent and α-amino sulfone, an effective method for the preparation of β-amino phosphonate derivatives was developed.



High Regioselective Aminobromination of β-Nitrostyrene Derivatives with 1,3-Dibromo-5,5-dimethyl Hydantoin^†

LIU Yali, LIU De’e, DU Manfei, CAO Chenxi, CHEN Zhanguo

2015, 36(6):  1117-1125.  doi:10.7503/cjcu20141110

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A new protocol for the high regioselective aminobromination of β-nitrostyrene derivatives with 1,3-dibromo-5,5-dimethyl hydantoin(DBDMH) as nitrogen/bromine sources was developed. Two kinds of β-nitrostyrene derivatives got different reaction results under different reaction conditions. For the β-nitrostyrene derivatives, this protocol offered vicinal haloamine products in good to excellent yields(up to 97%) at room temperature in CH₃CN catalyzed by Na₂CO₃. For the β-methyl-β-nitrostyrene, the good to excellent yields(up to 95%)were also achieved refluxed in CH₃CN catalyzed by KOH. The strong electron-donating substituents(e.g., CH₃O) on the 4-position of benzene ring could deactivated the reaction activity of β-nitrostyrenederi-vetives with DBDMH. However, the vicinal haloamines were also afforded as the sole addition product. Whereas strong electron-withdrawing substituent(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 20 examples of β-nitrostyrenes were investigated in this work and the structure of all products were confirmed by the corresponding ¹H NMR, ¹³C NMR spectra and HRMS(ESI). A possible mechanism involving a nucleophilic conjugate addition was proposed.



Physical Chemistry

Cellulose Generated Carbon Materials with Nitrogen Doping for the Desulfurization of Flue Gas^†

CHENG Shangzeng, GUO Qianqian, HUANG Zhanggen, SHEN Wenzhong, HAN Xiaojin

2015, 36(6):  1126-1132.  doi:10.7503/cjcu20150130

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Nitrogen-doped carbon materials with well developed pore structure and high nitrogen content were prepared from cellulose and characterized by N₂ adsorption, element analysis and X-ray photoelectron spectroscopy, then applied to SO₂ removal. The role of nitrogen-containing groups in the desulfurization was studied by changing the calcination temperature and amount of urea. It is found that the nitrogen-containing groups, especially pyridine nitrogen, could effectively improve the activity of carbon materials towards SO₂ removal. Such a result is closely related to the pyridine nitrogen enhancing SO₂ adsorption and its oxidation to SO₃.



Relationship Between Interfacial Dynamics and Chain Entanglement in Confined Polymer Films^†

LI Sijia, ZHANG Wanxi, YAO Weiguo, SHI Tongfei

2015, 36(6):  1133-1139.  doi:10.7503/cjcu20150077

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We investigated the relationship between the interfacial dynamics and chain entanglement of polymer melts in confinement by means of the lattice Monte Carlo simulations using the bond-fluctuation model, combining the primitive path analysis. When the wall-polymer interaction varies from weakly attractive interaction to strongly repulsive interaction, chain mobility in the interfacial region is higher than that in the inner region. Only when the wall-polymer attraction is stronger than a critical adsorption strength will chain mobility in the interfacial region be lower than that in the inner region. The facilitation or retardation of interface dynamics may be directly related to the degree of entanglement in the interfacial and inner regions: the entanglement degree in the interfacial region retains the bulk level despite of the wall-polymer interaction; the entanglement degree in the inner region is lower than that in the interfacial region when the polymer film is confined between strongly attractive walls, but it is higher when the film is between weakly attractive or repulsive walls. The variations of the confinement degree of polymer chains in both interfacial and inner regions also have an impact on the interface dynamics. Analysis on chain density distribution in the film as a function of the wall-polymer interaction provides a certain explanation for the related physical mechanisms.



Temperature-responsive Expansion of Self-crosslinked Ufasomes of Conjugated Linoleic Acid^†

DAI Jining, FAN Ye, FANG Yun

2015, 36(6):  1140-1145.  doi:10.7503/cjcu20150079

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Self-crosslinked ufasomes of conjugated linoleic acid(SCLA ufasomes) were obtained from CLA ufasomes through intravesicular polymerization initiated by mild UV irradiation. Temperature-responsive size and morphology evolutions of the SCLA ufasomes were traced by dynamic light scattering(DLS) and cryo-transmission electron microscope(cryo-TEM), and it was found that not only the vesicular structure of the SCLA ufasomes was stable but also the vesicular volume was expansive hugely with increasing temperature. In vitro release of 5-Fluorouracil(5-FU) from the SCLA ufasomes was evaluated and the results demonstrated that the drug-loading SCLA ufasomes possessed temperature-responsive sustained and controlled release of 5-FU.



Investigation on Structures and Nonlinear Optical Properties of PPV and Its Derivatives Systems with Adsorbing Alkali Metal Atom^†

LI Shaochen, YU Guangtao, CHEN Wei, ZHOU Zhongjun, HUANG Xuri

2015, 36(6):  1146-1155.  doi:10.7503/cjcu20150055

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By means of the density functional theory(DFT) method, we investigated detailedly the structures and nonlinear optical(NLO) properties of the adsorbed phenylenevinylene(PPV) polymer with the alkali metal Li atom and its corresponding derivatives systems decorated with the donor/acceptor group. In these PPV-based systems, the Li atom can be adsorbed stably on the surfaces of PPV and its derivatives, as revealed by their considerable adsorption energies(62.3—78.2 kJ/mol). It is revealed that when adsorbing the Li atom on the [PPV]_n(n=2—4), the evident charge transfer can occur between them, and this effect of lithium salt can effectively enhance the first hyperpolarizabilities β₀ values of PPV systems from original 249—756 a.u. to the range of 1.16×10⁴—1.37×10⁵ a.u. Comparatively, when adsorbing the alkali metal Li atom on the PPV derivatives modified with only donor(—NH₂) or acceptor(—CN) group, the first hyperpolarizabilities of systems can be significantly improved further, where the β₀ values of Li@[NH₂-(PPV)₄] and Li@[(PPV)₄-CN] can be as large as 1.61×10⁵ and 2.85×10⁵ a.u., respectively. This can be attributed to the case that the cooperation effect of lithium salt and Donor-π-Acceptor can result in the more evident decrease of main transition energy of system. Further, this cooperation effect can be strengthened significantly in the Li-adsorbed PPV derivatives decorated with donor/acceptor(—NH₂/—CN) pairs, which can lead to the more effective improvement of β₀ value(up to 3.56×10⁵ a.u. at n=4). This work can provide some new valuable insights for designing the new type of high-performance NLO materials based on the excellent PPV systems.



Molecular Dynamics Study on Binding Strength and Conformation of Dendrimer-based Drug Delivery Systems^†

ZHANG Fada, LIU Yi, XU Jingcheng, LI Shengjuan, WANG Xiunan, SUN Yue, ZHAO Xinluo

2015, 36(6):  1156-1165.  doi:10.7503/cjcu20150050

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We carried out all atomistic molecular dynamics simulations on poly(amidoamine)(PAMAM) dendrimer-based drug-delivery systems where PAMAMs bind non-covalently with four types of anticancer drug molecules including CE6, DOX, MTX, and SN38, respectively. We focus on the study of binding strength, size, and drug diffusion behavior of the complex systems influenced by the number and types of drug molecules as well as the generation(G0—G2) and surface PEGlyation of PAMAM. The simulations show that the deformation of PAMAMs themselves contributes significantly to the strength of drug-PAMAM binding. Multiple drug loading expands PAMAM dendrimers significantly but affects barely the sizes of PEGlyated PAMAM. The surface PEGlyation of PAMAM allows encompassing more drug molecules with stronger binding strength, thus increasing the efficiency of drug loading and retention time. This research provides theoretical evidence for designing novel dendrimer-based drug delivery systems.



Studies on Graphene Suspension and Self-assembled Graphene-based Membranes^†

YANG Li, LI Kongzhai, WANG Hua, WEI Yonggang, ZHU Xing

2015, 36(6):  1166-1173.  doi:10.7503/cjcu20150025

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Two kinds of surfactants, sodium dodecyl sulfate(SDS) and polyvinyl alcohol(PVA), were used to improve the dispersion of graphene in water. It was found that SDS can avoid the reunion between graphene layers, which makes the graphene evenly dispersed in the aqueous solution. Graphene(G) and Graphene flake films(GF) on the surface of ITO electrode were prepared via spin-coating with graphene dispersions. Scanning electron microscopy(SEM) and atomic force microscopy(AFM) results showed that the two types of graphene films represent a yarn shape of transparent flake structure. G/Ru and GF/Ru composite membranes were also prepared by molecular film self-assembly of the graphene films and Ru complex, which were characterized by cyclic voltammetry(CV) and ultraviolet-visible(UV-Vis) spectrometry. The results showed that the prepared composite films own high activity for the absorption of sunlight, indicating excellent photoelectric properties.



Photocatalytic Activity of Tetrabutyl Ammonium Hydroxide Modified TiO₂ Under Visible Light Irradiation^†

KUANG Yuanjiang, GU Yao, GUO Limei, WANG Haitao, WANG Enjun, CAO Yaan

2015, 36(6):  1174-1179.  doi:10.7503/cjcu20140952

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Tetrabutyl ammonium hydroxide modified TiO₂ photocatalyst(TBAH-TiO₂) was prepared by a sol-gel method and surface modification method with tetrabutyl ammonium hydroxide(TBAH). The structure, crystallite size and energy levels of the photocatalysts were studied by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), transmission electron microscopy(TEM), Fourier transform infrared(FTIR) spectroscopy and surface photovoltaic spectroscopy(SPS). The experimental results of 4-chlorophenol photocatalytic degradation showed that TBAH-TiO₂ exhibited a better photocatalytic activity than TiO₂. Its photocatalytic efficiency is 2.6 and 1.7 times as high as that of pure TiO₂ under visible light and ultraviolet light, respectively. The results reveal that NO_x(x=1, 2 and 3) species that exist on the surface of the TBAH-TiO₂ catalyst introduce the energy level of surface states 0.20 eV above the valence band. This energy level not only makes the catalyst responsible to visible light but also promotes the separation of photogenerated carriers. Thus, the activities under ultraiolet light and visible light irradiations are increased.



Synthesis and Electrochemical Performance of LiTi₂(PO₄)₃/C Anode for Aqueous Lithium-ion Batteries^†

ZHAO Ping, WEN Yuehua, CHENG Jie, SHEN Yaju, CAO Gaoping, YANG Yusheng

2015, 36(6):  1180-1186.  doi:10.7503/cjcu20140940

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Nano-lithium titanium phosphate(LTP) was synthesized by a Pechini type method. Using polyvinyl alcohol(PVA) as a carbon source, carbon coated LTP(LTP/C) was prepared with different dispersing methods of carbon source. Factors that influence the electrochemical performance of LTP/C anode were discussed. The results indicate that the electrochemical performance of LTP/C anode is mainly dependent on the purity of crystalline phase and degree of crystallinity of LTP and the degree of uniformity for coating carbon on the surface of LTP particles. Nano LTP/C prepared by rotating evaporation dispersing method of carbon source has high purity of crystalline phase and excellent degree of crystallinity, and the coating carbon layer on the surface of nano LTP is very uniform, as a result, excellent electrochemical performance for this LTP/C anode was obtained. An initial discharge capacity of 123 mA·h/g and a capacity retention of over 85% after 200 cycles with a coulombic efficiency above 95% were observed at a 4C rate in pH-neutral 5 mol/L LiNO₃.



Facile Preparation of Amino-modified Pd/TiO₂/C Nanocatalyst and Its Electrocatalytic Performance for Ethanol Oxidation in Alkaline Solution^†

CAO Xiaolu, WANG Longlong, WANG Yajun, XU Qunjie, LI Qiaoxia

2015, 36(6):  1187-1193.  doi:10.7503/cjcu20140931

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A hybrid material consisting of Vulcan XC-72 carbon and TiO₂ nanosheet was fabricated as the support of Pd nanocatalysts. TiO₂ nanosheets were prepared by hydrothermal method with tetrabutyl titanate as a precursor, and then modified by 3-aminopropyltrimethoxysilane(APTMS) solution, which serves as a rivet to anchor Pd²⁺. Pd/TiO₂/C nanocatalyst was obtained by the reduction of NaBH₄. The morphology, composition and structure of the as-prepared Pd/TiO₂/C-APTMS were investigated by transmission electron microscopy(TEM), energy dispersive X-ray spectroscopy(EDS), inductively coupled plasma-atomic emission spectroscopy(ICP-AES), X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS). The electrochemical measurement revealed that Pd/TiO₂/C-APTMS catalyst exhibited higher electrocatalytic activity and stability for ethanol electrooxidation(EOR) in alkaline media as compared to Pd/C and Pd/TiO₂/C catalysts prepared by traditional liquid phase reducing method without APTMS modification. The enhanced activity and durability of Pd/TiO₂/C-APTMs catalyst could be ascribed to the improved dispersion and stabilization of Pd nanoparticles on TiO₂ nanosheet, as well as the electronic structure modificaiton induced by APTMS.



Photocatalytic Performance of Hierarchical TiO₂/Ag₃PO₄ Composite Under Visible-light Illumination^†

LI Weibing, FENG Chang, YUE Jiguang, HUA Fangxia, BU Yuyu

2015, 36(6):  1194-1201.  doi:10.7503/cjcu20140870

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Urchin-like TiO₂ nanomaterial with hierarchical structure(PTHSs) was prepared, then Ag₃PO₄ nanomaterial with visible-light response was deposited on the hierarchical TiO₂ by simple deposition precipitation method, thus a series of PTHSs/Ag₃PO₄ composites with efficient visible-light photocatalytic performance and stability was synthesized. The photocatalytic performance of the PTHSs/Ag₃PO₄ composites for degrading Rhodamine B(RhB) was analyzed. The results show that the photocatalytic performance of PTHSs/Ag₃PO₄ composite is significantly superior to that of pure Ag₃PO₄ and that of TiO₂(P25)/Ag₃PO₄ composite. The composite with a PTHSs/Ag₃PO₄ molar ratio of 1∶1 showed the best photocatalytic performance and it could decolorize the RhB completely in 6 min under visible light illumination. This is because that the urchin-like TiO₂ nanomaterial can provide more load sites than TiO₂ nanoparticle for loading Ag₃PO₄. And the hierarchical TiO₂ can also improve the contact between the surfaces of TiO₂ and Ag₃PO₄ so that the separated efficiency of photo-generated electrons-holes by Ag₃PO₄ is improved. Meanwhile during the photodegradation process, a little Ag⁺ on the surface of Ag₃PO₄ are gradually reduced to Ag⁰, by the plasma resonace effect of which, the absorption and conversion capability of the composite for photon are enhanced and the photocataly-tic performance of the composite material for degrading dyes is further enhanced.



Polymer Chemistry

Chitosan-assisted WO₃ Ultrathin Film and Electrochromic Performance^†

LIU Shuping, LIU Yichun, WANG Wei

2015, 36(6):  1202-1207.  doi:10.7503/cjcu20150176

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A nanocomposite material consisting of WO₃ and chitosan(CS) was fabricated by layer-by-layer(LbL) method in which CS was used as the additional component. The morphology and electrochemical behavior of the composite film were investigated by UV-Vis spectra, scanning electron microscopy(SEM) and cyclic voltammograms(CV). The electrochromic properties of the film were performed by in situ UV-Vis spectroscopy and electrochemical station. The results showed that the composite film was found to switch from colorless to deep blue, with the optical contrast of 48.0% and coloration efficiency of 58.5 cm²/C. Furthermore, the switching times were 9.5 s for coloration and 1.8 s for bleaching. Obviously, chitosan plays an important role in enhancing electrochromic performance of WO₃-based material.



Preparation, Characterization and Stability of Avermectin Nano Aqueous Dispersion^†

ZHANG Wenxiang, MEI Hao, GUAN Wenxun, TANG Liming

2015, 36(6):  1208-1212.  doi:10.7503/cjcu20150095

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Two reactive hydroxyl groups made avermectin a component to prepare anionic polyurethane dispersant containing avermectin structure units. The structure of the resulting dispersant was characterized by ¹H nuclear magnetic resonance spectrometer and infrared spectrometer. Based on the structural similarity between the dispersant and avermectin, avermectin nano aqueous dispersion was fabricated via addition the solution of dispersant and avermectin into water. The influences of carboxyl content and the molecular weight of the dispersant on the particle size of the dispersion were investigated. The results indicated that smaller particles were obtained at higher carboxyl content and the dispersing ability was affected by the molecular weight of the dispersant. The transmission electron microscopic image of the dispersion revealed that almost spherical particles with most of the size in the range of 20—40 nm were formed. Moreover, the dispersion displayed high centrifugal stability and dilution stability.



Adjusting the Oxygen Content of the Cured Polyaluminocarbosilane Fibers^†

YUAN Qin, SONG Yongcai, WANG Guodong

2015, 36(6):  1213-1220.  doi:10.7503/cjcu20150014

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The oxygen content of the SiAlCO fibers was a key for the transformation from SiAlCO fibers to dense stoichiometric SiC fibers after sintering at >1700 ℃, which was mainly introduced during curing process. The novel preoxidation-thermal curing method was applied to the conversion of polyaluminocarbosilane(PACS) fibers and the oxygen content of the SiAlCO fibers as-pyrolyzed was adjustable in 10%—13%(mass fraction). A minimal degree of preoxidation of the PACS green fibers, which performed at 190 ℃ for 4 h leading to 7.87%(mass fraction) oxygen pick-up, is necessary for their further thermal-curing. Then, the preoxidation fibers formed crosslinking structure after thermal-curing at 450 ℃ under N₂ flow. The curing process was investigated by gel permeation chromatography(GPC), infrared spectrum(IR) and thermogravi-metric analysis-mass spectra(TG-MS). The results show that the Si—OH bonds are formed after the Si—H bonds in the structure of PACS fibers reacting with oxygen molecular during preoxidation. Additionally, partial Si—OH bonds could react with each other continuously to form Si—O—Si structure, resulting in molecular increase. During the thermal-curing process, the residue of Si—OH further react with each other at lower than 300 ℃. The formation of Si—CH₂—Si structure resulted from the reaction between Si—H bond and Si—CH₃ bond happened in the range of 300—450 ℃.



Preparation and Characterization of Cellulose Propionate-g-diethylene Glycol Hexadecyl Ether Solid-solid Phase Change Material^†

WANG Dong, HAN Na, ZHANG Xingxiang, WANG Lejun, WANG Ning, LI Wei, YU Wanyong, LI Zhinan

2015, 36(6):  1221-1227.  doi:10.7503/cjcu20141027

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A series of cellulose propionate-g-diethylene glycol hexadecyl ether(CP-g-E₂C₁₆) solid-solid phase change materials was prepared by chemical grafting method with dibutyl tin dilaurate(DBTDL) as the catalyst, cellulose as the matrix material, diethylene glycol hexadecyl ether as the functional substance. The structure, phase change properties and thermal stability were characterized using Fourier transform infrared spectroscopy(FTIR), hydrogen nuclear magnetic resonance spectrum(¹H NMR), differential scanning calorimetry(DSC), thermogravimetric analysis(TG) and wide-angle X-ray diffraction(XRD). The results showed that CP-g-E₂C₁₆ solid-solid phase change materials were prepared. CP-g-E₂C₁₆ copolymers with different feeding ratios, substitute degree and grating percents of E₂C₁₆ are in the range of 0.12—0.37 and 17.1%―33.4%, respectively. The onset melting temperatures of CP-g-E₂C₁₆ are in the range of 25—34 ℃, the melting enthalpy increases from 40 to 62 J/g. The thermal resistant temperatures of CP-g-E₂C₁₆ are all higher than 237 ℃, which are 21—40 ℃ higher than E₂C₁₆. All the products show good temperature-adjusting performance for solid-solid phase transition, which is expected to be used in cellulose-based thermo-regulating fiber field.



Hydrophobic Modification of Ammonium Polyphosphate and Its Application in Flame Retardant Polypropylene Composites^†

LIU Jianchao, XU Miaojun, LI Bin

2015, 36(6):  1228-1235.  doi:10.7503/cjcu20140998

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Ammonium polyphosphate(APP) surface was modified with (3-aminopropyl)triethoxysilane(KH550), then microencapsulated by silicone in situ polymerization of tetraethyl orthosilicate(TEOS), finally surface-modified with (heptadecafluoro-1,1,2,2-tetradecyl)trimethoxysilane to prepare the hydrophobic APP(M-APP). The structure and surface elemental composition of M-APP were characterized by Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS), and the results indicated that M-APP was the target product. The wettability of the modified APP was measured by water contact angle(CA) test and the CA reached 134°, which demonstrate the modified APP possessed obviously hydrophobic property. The modified APP mixed with triazine char foaming agent(CFA) with the mass ratio of 4∶1 to prepare intumescent flame retardant(IFR) and afterwards IFR was incorporated into polypropylene(PP) to prepare flame retardant PP composites. The flame retardancy and thermal degradation behavior of PP composites were evaluated by limiting oxygen index(LOI), vertical burning(UL-94) and thermal gravimetric analysis(TGA) tests. The water resistant property of the flame retarded PP materials were evaluated by water resistant test, and the mechanical properties were measured by the tensile, flexural and impact strength test, the compatibility between the flame retardant and polymer was investigated by scanning electron microscopy(SEM). The results indicated that the modified APP/CFA/PP composite reached UL-94 V-0 flammability rating when the loading amount of IFR was 23%, the PP composite after water resistance test still successfully passed UL-94 V-0 rating and the mass loss was only 0.92%. Under the same experimental conditions, the APP/CFA/PP composite after water resistance test was no rating in vertical burning test and the mass loss was 2.45%. It can be deduced that hydrophobic modification of APP can greatly improve the water resistance of the flame retardant PP material. The TGA results indicated that the incorporation of IFR into PP matrix improved the thermal stability and char-forming ability of PP composite, the formed intumescent char layer during combustion protect the underlying matrix from further combustion and degradation, consequently enhanced the flame retardancy of PP materials. The results of SEM and mechanical test revealed that the modification of APP improved the compatibility between the flame retardant and PP matrix, which resulting in the increase of the mechanical properties of the flame retarded PP composites.



Preparation and Characterization of Biodegradable Adhesive Based on Catechol^†

ZHANG Dongliang, HUANG Yubin, LI Xiaoyuan

2015, 36(6):  1236-1242.  doi:10.7503/cjcu20140812

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Macromolecular initiator aminated monomethoxy poly(ethylene glycol)(abbreviated as mPEG-NH₂) was synthesized to get mimic bioadhesives mPEG-b-P(LL-g-DHPPA) and mPEG-b-P(LG-g-Dopamine). The structures of target products were confirmed by nuclear magnetic resonance(NMR), Fourier transform infrared spectroscopy(FTIR) and gel permeation chromatography(GPC), and the degree of the catechol moiety grafting density of these two polymers were tested to be 30% and 28.6%, respectively. The results of tensile stripping experiments demonstrated that the mimic bioadhesive that bearing amino groups on its side chain[i.e., mPEG-b-P(LL-g-DHPPA)] exhibited higher adhesive strength and faster curing speed.