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10 October 2018, Volume 39 Issue 10

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Cover and Content of Chemical Journal of Chinese Universities Vol.39 No.10(2018)

2018, 39(10):  0-0. 

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Review

Basic Theory and Critical Problems in the Trajectory Surface Hopping Simulations on the Chemiluminescent Reaction of Organic Peroxides^†

YUE Ling,LIU Yajun

2018, 39(10):  2113-2118.  doi:10.7503/cjcu20180516

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Chemiluminescence, which is widely applied in various analysis and daily use, are a specific type of excited chemical reactions. The trajectory surface hopping(TSH) nonadiabatic molecular dynamics is often used to simulate the chemiluminescent and bioluminescent reactions. This review introduced the basic theory and critical techniques of TSH including the initial sampling, calculations of nuclear potential energies and forces, computational scheme of nonadiabatic transition probabilities.



Articles:Inorganic Chemistry

Synthesis and Electroluminescence Characterization of Mixed-C^N Ligand Tris-cyclometalated Ir(Ⅲ) Complexes^†

MA Xiaoyu,LIANG Jie,YE Ling,FAN Yong,XU Jianing,YE Kaiqi

2018, 39(10):  2129-2135.  doi:10.7503/cjcu20180334

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Two novel mixed 4-methyl-2,5-diphenylpyridine(MDP)/5-methyl-2-phenylpyridine(PMP) tris-cyclometalated iridium complexes Ir(MDP)₂(PMP)(complex 1) and Ir(MDP)(PMP)₂(complex 2) have been synthesized and characterized systematically in terms of their photophysical and electrochemical properties, and the effect of the molecular and the stacking structure on the photoelectric performance was investigated through the single crystal structure and theoretical calculation. The phosphorescent organic light-emitting diodes(PhOLEDs) based on both new phosphors showed the rather high maximum external quantum efficiency(EQE) of 22.4% and 20.7%, and maximum power efficiency(PE) values of 86.0 and 77.5 lm/W respectively, with the low efficiency roll-off.



Effect of Crystal Matrix on Energy Transfer Mechanism in Rare-earth Upconversion Nanomaterials^†

TANG Keyun,LI Luoyuan,FU Limin,AI Xicheng,ZHANG Jianping

2018, 39(10):  2136-2142.  doi:10.7503/cjcu20180274

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Yb³⁺, Er³⁺ doped NaREF₄(RE³⁺=Lu³⁺, Y³⁺, Yb³⁺) nanoparticles with uniform size and hexagonal-phase were prepared by the solvothermal method. The steady-state luminescence spectra and the time-resolved luminescence spectra were characterized to explore the luminescence properties for the evaluation of energy transfer mechanisms in three matrix(NaLuF₄, NaYF₄, NaYbF₄) nanomaterials. The experimental data showed that NaLuF₄:20%Yb³⁺, 2%Er³⁺ nanomaterial performed stronger upconversion luminescence(UCL) intensity, relatively higher green/red ratio(I_{540 nm}/I_{654 nm}) and longer luminescence lifetimes, while NaYbF₄:2%Er³⁺ nanomaterial presented relatively weaker properties in these aspects. The difference of energy transfer mechanisms in three matrix(NaLuF₄, NaYF₄, NaYbF₄) nanoparticles was also displayed and analyzed. Comparative results showed why the NaLuF₄ matrix nanoparticles were the best matrix materials from the perspective of the UCL energy transfer mechanisms. This work provides new insights that the energy transfer process can be influenced via changing the matrix nanoparticles, and can give helpful guidance for the future optical UCL applications of rare-earth doped nanomaterials.



Methane Storage Performace of Self-activated Seaweed-based Carbon Materials^†

WANG Yun,BEN Teng

2018, 39(10):  2143-2153.  doi:10.7503/cjcu20180224

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Two types of carbon material were prepared by self-activation using the seaweeds Hizikia fusifarme(Sar) and Laminaria japonica(Lam) as raw materials. The methane storage capacity of SarCW-900-HF and LamCW-900-HF are up to 272 mg/g(mass fraction 21.3%) and 246 mg/g(mass fraction 19.4%) at room temperature and pressure of 3.5 MPa. The specific surface area of the two materials are 812 and 671 m²/g, and pore volume are 0.45 and 0.44 cm³/g, respectively. The peak of pore distribution is at 1.1 nm. After tableting under pressure of 20 MPa, the methane adsorption volume ratio reached 274 and 449 cm³(STP)/cm³, beyond the DOE’s target of 263 cm³(STP)/cm³.



Luminescence Property and Detection Capability Towards Hg²⁺ of LEuH Composites with Mo{\mathrm{S}}_4^{2-} and OS^- Anions^†

LI Jian,XIE Linxia,LIANG Zupei,GUO Rong,LIU Chenyu,MA Shulan

2018, 39(10):  2154-2160.  doi:10.7503/cjcu20180153

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NO₃-LEuH(LEuH=layered europium hydroxide) precursor was synthesized via a developed hydrothermal method, and co-intercalation of Mo$S_{4}^{2-}$ and OS^- into LEuH layers was achieved by an ion-exchange with N$O_{3}^{-}$, thus a series of composites of (MoS₄)_xOS_1-x-LEuH(x=0.02, 0.10, and 0.20) with different molar ratios of Mo$S_{4}^{2-}$ to OS^- was obtained. The structure and property of(MoS₄)_xOS_1-x-LEuH composites were investigated via powder X-ray diffraction(XRD) patterns, Fourier transformed infrared spectra(FTIR) and photoluminescence(PL) spectra. The delaminated (MoS₄)_xOS_1-x-LEuH in formamide presented markedly quenched luminescence of layer Eu³⁺ ions at 614 nm, and higher Mo$S_{4}^{2-}$:OS^- molar ratios(from 0.02:0.98 to 0.20:0.80) resulted in weakened luminescence intensity. The fluorescence recognization ability towards heavy metal ions of Hg²⁺, Cu²⁺, Ag⁺ and Pb²⁺ of the delaminated (MoS₄)_0.02OS_0.98-LEuH composite was investigated. After addition of aqueous solutions of Hg²⁺(0.01—10 μmol/L), the (MoS₄)_0.02OS_0.98-LEuH exhibited enhanced luminescence of layer Eu³⁺.



Synthesis, Structure and Photoelectric Property of A Series of Ni(Ⅱ) Complexes Constructed Through Aromatic Carboxylic Ligands^†

YUN Jixing,HU Zhili,LI Yumeng,JIN Jing,CHEN Chong,YAN Xin,LIU Yonghua,DING Yu,CHI Yuxian,NIU Shuyun

2018, 39(10):  2161-2169.  doi:10.7503/cjcu20180076

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Six Ni(Ⅱ) complexes based on aromatic carboxylic ligands, [Ni(pz)₄(H₂O)₂]·2H₂btc·H₂O(1), {[Ni₂(pz)₈(btec)]·4H₂O}_n(2), {[Ni(H₂btec)(phen)]∙2H₂O}_n(3), [Ni(Hbdc)₂(pz)₄](4), {[Ni₃(bdc)(pz)₁₂]·2H₂O}_n(5) and [Ni(bdc)(pz)₂(H₂O)]_n(6)(pz=pyrazole, H₃btc=1,3,5-benzenetricarbolylic acid, H₄btec=1,2,4,5-benzenetetracarboxylic acid, phen=1,10-phennanthroline, H₂bdc=1,2-benzenedicarboxylic acid), were hydrothermally synthesized. All the complexes were structurally and photophysically characterized by means of single crystal X-ray diffraction, infrared(IR) and UV-Vis-NIR electronic spectra, elemental analysis, X-ray diffraction(XRD) and surface photovoltage spectra(SPS). The Ni(Ⅱ) centers in six complexes have the square-pyramid or octahedral coordination environment. Complexes 1 and 4 have 2D supramolecular structure networked by hydrogen bonds. Complexes 2 and 3 possess 2D coordination framework structure constructed by btec^4- ligands with monodentate and monoatomic bridging modes. Complexes 5 and 6 have 1D coordination chain structure built by bdc^2- anions with monodentate/chelating coordination modes, which are further networked into 2D supramolecules by hydrogen bonds. All the six complexes exhibit certain photo-electric conversion properties under the inducement of UV-Vis lights. When a positive electric field is applied to the six complexes, the intensity change of photoelectric response of the six complexes presents difference which correlates with the bonding mode of the structure and type of the organic ligands.



Synthesis of Amphiphilic Silica Nanoparticles with Double-sphere Morphology^†

LUO Jianhui,YANG Jie,LI Yuanyang,HE Lipeng,JIANG Bo

2018, 39(10):  2170-2177.  doi:10.7503/cjcu20170849

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Amphiphilic silica nanoparticles with double-sphere morphology were fabricated via the assembly of hydrophobic silica nanoparticles and hydrophilic nanoparticles through chemical interaction. Silica nanopartilces prepared by the sol-gel method were modified by hexamethyldisilazane(HMDS) and 3-glycidoxy-propyltrimethoxysilane(KH560) to obtain hydrophobic silica nanoparticles and hydrophilic silica nanoparticles respectively, which were then further linked together by the chemical bond on the surface of nanoparticles. The as-prepared amphiphilic silica nanoparticles with double-sphere morphology can stabilize the cyclohexane in water Pickering emulsion, indicating the good amphiphilic property of amphiphilic silica nanoparticles with double-sphere morphology.



Analytical Chemistry

Rapid Separation of Ginsenosides Based on Multi-walled Carbon Nanotubes^†

MIAO Rui,WU Dongxue,WANG Qiuying,ZHAO Huanxi,LI Xue,XIU Yang,LIU Shuying

2018, 39(10):  2178-2184.  doi:10.7503/cjcu20180280

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Multi-walled carbon nanotubes(MWCNTs) were employed as the selective adsorbent to investigate their performance in the rapid separation of ginsenoside from ginseng extract. Ginseng was ultrasonically extracted in aqueous methanol. The resulting extract mainly consisted of ginsenoside and saccharide. Saccharide in ginseng was similar with ginsenoside in polarity, and was the main interfering component during the extraction and separation of ginsenoside. Therefore, it is essential to separate saccharide from ginsenoside in ginseng extract. MWCNTs could rapidly adsorb and desorb ginsenoside in ginseng extract, but not the saccharide. Based on this selective adsorption, a novel method using MWCNTs for the rapid separation of ginsenoside and saccharide was developed. Under the optimized separation conditions, MWCNTs had high degree of saccharide separation and ginsenoside recovery, both of which were more than 90%, and also had high adsorption capacity of 15.0—24.0 μg/mg to the 8 main ginsenosides, Rb1, Rb2, Rc, Rd, Re, Rg1, 20(S)-Rf and Ro. Further research revealed that the 8 ginsenosides could reach the adsorptive and the desorptive equilibrium within 3 min, and their recovery were significantly affected by the polarity of desorption solvent. The short equilibrium time was the foundation of the rapid separation of ginsenoside. Comparing with conventional material used for the separation of ginsenoside, such as macroporous resin, MWCNTs-based separation method is less time-consuming, more convenient and efficient.



Preparation of a Targeted Tumor Nanocomposites for Combined Photodynamic-photothermal Therapy Based on Partially Reduced Graphene Oxide^†

WANG Xueli,WANG Zhenxin

2018, 39(10):  2185-2191.  doi:10.7503/cjcu20180181

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Partially reduced grphene oxide(pRGO) is synthesized using a mild reduction method by incubating GO suspension under alkaline condition at room tempeature. Aptamer(AS1411) non-covalent binding with cardiogreen(ICG), a photosensitizer and photothermal effect molecule, to the surface of pRGO, was used to target cancer cells for photodynamic therapy(PDT) and photothermal therapy(PTT). Structure and morphology of the as-synthesized pRGO and pRGO-AS1411-ICG(pRAI) nanocomposites were confirmed by menas of FTIR, Raman, XPS, UV-Vis, transmission electron microscopy(TEM) and energy dispersive spectrometer(EDS). pRAI targets cancer cells with AS1411 to produce singlet oxygen for PDT and photothermal effect for PTT upon near-infrared(NIR) light irradiation. Since pRGO is decorated with several AS1411-ICG molecules, the pRGO-AS1411-ICG conjugate yields enhanced binding and therapeutic effect by the added ability to carry multiple photosensitizers. Consequently, pRAI offers a remarkably improved and synergistic therapeutic effect on cells.



Effects of Ginseng Polysaccharides on the Metabolism of Ginsenoside Re in vivo and Transformation of Ginsenoside Re in vitro^†

LI Ruigang,ZHU Na,ZHAO Huanxi,WANG Nan,SUN Hongmei,YUE Hao,LI Jing

2018, 39(10):  2192-2197.  doi:10.7503/cjcu20180080

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To study the effect of ginseng polysaccharides on the absorption of ginsenoside Re metabolite into the blood and the transformation of ginsenoside Re by intestinal microflora in vitro, rapid resolution liquid chromatography coupled with quadruple-time-of-flight mass spectrometry(RRLC/Q-TOF-MS) was performed to investigate the biotransformation process of ginsenoside Re by intestinal microflora in media with and without ginseng polysaccharides, and the pharmacokinetics of the ginsenoside Re metabolite, ginsenoside Rg1, in rats with or without pretreatment with ginseng polysaccharides. For transformation of Re by rat intestinal microflora, five transformed products including ginsenoside Rg1, Rh1, Rg2, F1 and PPT, as well as three transformation pathways were identified. When the intestinal microbiota of rat feces was cultured in vitro, their ginsenoside Re biotransformation activities were significantly induced by ginseng polysaccharides. When ginsenoside Re was orally administered to rats, the peak time(t_max), the maximum plasma concentration(c_max) and area under the plasma drug concentration-time curve(AUC) for the main metabolite, ginsenoside Rg1, were (11.6±6.1) h, (80.1±44.0) ng/mL and (549.3±209.4) ng·h/mL, respectively. When ginsenoside Re was orally administered to rats fed ginseng polysaccharides, t_max, c_max and AUC for ginsenoside Rg1 were (8.2±5.4) h, (98.2±50.6) ng/mL and (691.9±231.2) ng·h/mL, respectively. The results show that ginseng polysaccharides may promote the metabolic conversion of ginsenoside Re to Rg1 and the subsequent absorption of Rg1 in the gastrointestinal tract and may potentiate the pharmacological effects of ginseng.



Organic Chemistry

Synthesis and Biological Activity of Lipoic Acid Ester Derivatives^†

ZHANG Luyun, XU Qian, XIA Guangqing, CONG Li, WANG Yu, ZHANG Hui, ZHU Junyi, ZANG Hao

2018, 39(10):  2198-2205.  doi:10.7503/cjcu20180270

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A series of lipoic acid derivatives was synthesized via the modification of carboxyl groups of lipoic acid, 23 target compounds were obtained and characterized by nuclear magnetic resonance and high resolution mass spectrometry. Lipoic acid derivatives were employed in order to explore the potential structure-antioxidant activity relationships. The antioxidant activities of these compounds were evaluated and compared by the acrolein assay, 1,1-diphenyl-2-picrylhydrazyl(DPPH) assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium(ABTS) assay and ferric reducing antioxidant power(FRAP) assay. Acrolein scavenging activity test results showed that most compounds exhibited acrolein scavenging activities, compounds 3a, 3b, 3e, 3f, 3k, 3m, 3q, 3v and 3w had good acrolein scavenging activities, especially compound 3a showed the highest acrolein scavenging activity which was stronger than carnosine. The experimental results showed that most compounds exhibited DPPH scavenging activities, compounds 3o, 3p, 3v and 3w had good DPPH scavenging activities, especially compound 3w showed the highest DPPH scavenging activity, which was close to 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid(Trolox) and Vitamin C. The results showed that most compounds exhibited ABTS scavenging activities, compounds 3b, 3e, 3u, 3v and 3w had good ABTS scavenging activities, especially compound 3w showed the highest ABTS scavenging activity, which was very close to trolox and Vitamin C. FRAP experimental results showed that most compounds exhibited reduction activities to ferric ion-2,4,6-tri(2-pyridyl)-s-triazine(Fe³⁺-TPTZ) complex, compounds 3b, 3v and 3w had good reduction activities to Fe³⁺-TPTZ complex, especially compound 3w showed the highest reduction activity to Fe³⁺-TPTZ complex, which was stronger than Vitamin C and trolox. The results showed that most compounds exhibited hydroxyl radical scavenging activities, compounds 3j and 3w had good hydroxyl radical scavenging activities, especially compound 3w showed the highest hydroxyl radical scavenging activity which was stronger than trolox. Plasma stability assay results showed that compared with lipoic acid, twenty-three compounds had good plasma stability.



Construction of Pyrenyl Pairs in dsDNA: Fluorescent Properties of Multiple Pyrenyl-attached dsDNAs Through 7-Substituted 8-Aza-7-deaza-2'-deoxyadenosine Analogues^†

LI Yang, LI Zhiwen, ZHU Junfei, LIU Shihui, HE Junlin

2018, 39(10):  2206-2213.  doi:10.7503/cjcu20180182

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Pyrenyl excimer is well characterized to be a fluorescent tag suitable for the construction of nucleic acids-based biosensors. dsDNA was used as one of the major motifs for the construction of the pyrenyl pairs in the biosensors. Here, 7-pyrenylethynyl-8-aza-7-deaza-2'-deoxyadenosine(2) and 7-pyrenylethyl-8-aza-7-deaza-2'-deoxyadenosine(3) were used to introduce pyrenyl group to duplex DNA, by which the specific base pairing of 2'-deoxyadenosine was kept, and the pyrenyl group was located at the major groove of the duplex. In the B-duplex DNA formed by 5'-d(TAGGTCAATACT)-3' and 3'-d(ATCCAGTTATGA)-5', the canonical residue 2'-deoxyadenosine(dA) was replaced by residue 2 or 3 at several positions, respectively. All the DNA sequences were synthesized on an ABI 392 DNA/RNA synthesizer and characterized by mass spectrum. The thermal stability of the modified duplexes was significantly affected. It was observed that T_m was dramaticly decreased by residue 2 and dramaticly increased by residue 3. It was supposed that the large hydrophobic pyrenyl group was protruded to the hydrophilic major groove by the rigid ethynyl linkage in residue 2, while the flexible linkage in residue 3 permitted the pyrenyl group to stack into the neighboring basepair. The diffe-rent location of the pyrenyl group from residues 2 and 3 was also confirmed by the circular dichroism(CD), the spectra from 300 nm to 450 nm indicated that more pyrenyl stacking formed in the duplexes with residue 2. Especially, the fluorescence switch-on was observed in the formation of the duplex PY03+PY05 and switch-off in the formation of the duplex PY02+D02, respectively. These results demonstrated that the residue 2 was more sensitive to the conformational changes of duplex DNA, and these two pyrenyl group combinations were worthwhile to be further studied in the context of functional nucleic acids for the construction of the pyrenyl-based sensors.



Physical Chemistry

Investigation into the Thermodynamic Properties of Nano-silver Halides Based on the Principle of Dissolution Thermodynamics^†

QIN Fanghong,QIU Jiangyuan,XIAO Biyuan,MI Yan,HUANG Zaiyin

2018, 39(10):  2214-2220.  doi:10.7503/cjcu20180509

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A series of nano-silver halide(AgX, X=Cl, Br, I) materials was prepared at room temperature. Their composition, morphology and structure were characterized. The surface thermodynamics, partial molar surface thermodynamics and specified thermodynamic functions of nano-silver halide were derived based on the essential difference between bulk-silver halide and nano-silver halide combined with Debye-Hückel formula of dissolution thermodynamics. A new effective and universal method for the determination of surface thermodynamics and thermodynamic function of insoluble salt nanomaterials is provided.



Theoretical Studies on the Second-order Nonlinear Optical Properties of Ru^Ⅱ/Ⅲ Complexes of Bipyridyl^†

LI Xiang,WANG Huiying,WANG Hongqiang,YE Jinting,QIU Yongqing

2018, 39(10):  2221-2229.  doi:10.7503/cjcu20180465

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The geometry structures, redox properties, UV-Vis electronic absorption spectra and second-order nonlinear optical(NLO) properties of Ru^Ⅱ/Ⅲ-bipyridyl complexes were investigated by density functional theory(DFT). The results present that the introduction of anthraquinone ligands can effectively increase the first hyperpolarizabilities(β_tot) values, but the position of anthraquinone ligands on the nitrogen phenyl group has little effect on the β_tot values. The analysis of molecular orbital and spin density distributions illustrates that both of the metal Ru^Ⅱ and ancillary ligands can serve as the oxidation center of eigenstates. The difference in the oxidation center has a influence on the charge transfer mode, thus affect the β_tot values of oxidized forms. The β_tot values of oxidation states complexes 1b and 2b were decreased whereas the β_tot values of the complexes 3b and 4b enhance dremarkably. The first hyperpolarizabilities(β_HRS) calculated by the Hyper-Rayleigh Scattering method also comply with this phenomenon. Time-dependent density functional(TD-DFT) results indicate that the eigenstates are mainly performed metal-to-ligand charge transfer(MLCT/ML'CT) mode, while the oxidation states complexes are ligand-to-metal charge transfer(LMCT/L'MCT). This is resulting from the inverse changes in donors and acceptors. Therefore, for such Ru^Ⅱ/Ⅲ-bipyridyl complexes, second-order NLO properties can be effectively regulated by the change of ancillary ligands and redox reactions.



Effects of Three New Modified Molecules on the Structural Stability of Different Aβ42 Fibers^†

LI Jinxing,XING Xiaofeng,QI Zhongnan,AI Hongqi

2018, 39(10):  2230-2237.  doi:10.7503/cjcu20180434

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The misfolding and aggregation of amyloid-β(Aβ) peptides, which result from Aβ self-aggregation and aggregation induced by metal ion, are the key factors in the pathogenesis of Alzheimer’s diseases(AD). It has experimentally been verified that erythrosine B(ER), Tanshinone(TS) and clioquinol(CQ) can inhibit the aggregation of amyloid peptides in different degree. However, the exact interaction mechanisms of these molecules are different. Through breaking and reorganizing the structure of these drug molecules in combination with their qualities, we designed three new modified molecules for AD treatment in silico and expected that they could possess the composite advantages of metal chelation, rotating bonds and NR binding preference. The results showed that modified molecules have different effects on distinct conformer of Aβ42 fibers. Some of them can disassemble the aggregated fibers, while others increase the fibrous stability. In particular, some small molecules disassemble amyloid fiber in a specific mode but play an inverse stability role in another. It was found for the first time that although some small negative-charged molecules have strong repulsive effect on the like charged fiber, their interaction still has an ability to disassemble certain fibrous conformers. This discovery provides a new pathway to disassemble or stabilize amyloid fiber and even to design new drugs by modification of modified small molecules.



Electrochemical Studies on the Working Mechanism of Lithium-rich Manganese Based Material Coated by MnO₂ ^†

QIU Jiaxin,JIANG Qi,GAO Yike,PENG Junqi,DUAN Zhihong,LU Xiaoying

2018, 39(10):  2238-2244.  doi:10.7503/cjcu20180343

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In order to investigate the characteristic reactions and structural changes of lithium-rich manganese based material coated by MnO₂, the lithium-rich manganese based material was prepared by solid state reaction, and then modified with MnO₂ by chemical precipitation and heat treatment. The electrochemical performances of the obtained materials were characterized by constant current charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy. The working mechanism of lithium-rich manganese based materials coated by MnO₂ was studied by discussing the changes of the electrochemical reactions before and after the modification. The results show that the coating MnO₂ can work as the container of lithium. During the heat treatment process, lithium and nickel elements of the lithium-rich manganese based material migrate and diffuse into the MnO₂ coating to form a new spinel composite phase, which reversibly participates in the subsequent cyclic reactions and makes its contribution to enhance the battery electrochemical performances.



Self-assembled Monolayers for Controllable Adhesion of DOPA^†

MENG Xiufeng,ZHAI Zhiwei,GUO Aijun

2018, 39(10):  2245-2252.  doi:10.7503/cjcu20180291

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11-Mercapto-1-undecanol and 1-dodecyl mercaptan with —OH or —CH₃ as capping groups respectively were self-assembled onto gold surfaces at molar ratios of 1:0, 3:1, 1:1, 1:3 and 0:1, prepa-ring binary monolayers with various hydrophilic-hydrophobic properties and chemical compositions. The monolayers were characterized by X-ray photoelectron spectroscopy(XPS), contact angle(CA) and atomic force microscope(AFM) methods. The adhesion properties of dopa and liquid phase environment-related water droplets against self-assembled monolayers(SAMs) were also investigated. It can be found that the OH-terminated SAMs had the most superior anti-dopa adhesion ability. With the molar ratio decrease of —OH groups and the introduction of the —CH₃ groups on the surface, the adhesion ability of dopa to the surface is increased. Furthermore, the pure OH-terminated SAMs showed a strongest droplet adhesion performance, and with the molar ratio of —OH groups decreasing, the droplet adhesion to the surface become weak. The introduction of the —CH₃ groups significantly reduced the surface water adhesion. The experimental results showed that the OH- or CH₃-terminated SAMs is difficult to possess anti-dopa and droplet-adhesion properties at the same time and the adhesion ability of the binary mixed SAMs can be adapted to a specific environment, which proposed a new concept for the design and preparation of anti-adhesion materials.



Preparation and Selective Adsorption Performance of Polyaniline Silicon Magnetic Composite by Multilayer Assembly for Sulfonic Dye^†

ZHOU Yanfen,MENG Zhe,WANG Zelan,LI Jiguang,MEN Xiuqin,LIU Wanyi

2018, 39(10):  2253-2264.  doi:10.7503/cjcu20180259

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A multi-layer core-shell polyaniline silicon magnetic composite(Fe₃O₄@SiO₂@PANI) via in situ oxidation polymerization-coprecipitation of silicon magnetic particles(Fe₃O₄@SiO₂) as core at low temperature was prepared. The structure, surface morphology and properties of Fe₃O₄@SiO₂@PANI composites were characterized by means of X-ray means of diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). Using sulfonic azo dyes-methyl orange(MO), congo red(CR), and anthraquinone dye-alizarin red(AR) in aqueous solution, respectively, as an example for dyes in wastewaters, the effects of dyes adsorption pH, adsorption time, dyes concentration and amount of Fe₃O₄@SiO₂@PANI on the adsorption process were studied. The sulfonic dyes was more effective with weakly acidic(pH<6.0). The maximum adsorption capacity of MO, AR and CR on Fe₃O₄@SiO₂@PANI were 26.05, 69.58 and 34.0 mg/g, respectively, under optimized conditions. Analysis of the adsorption results demonstrated that the adsorption was better fit by Langmuir adsorption equation compared to Freundlich adsorption. The results suggested that the shell PANI of Fe₃O₄@SiO₂@PANI composite had good affinity for sulfonic dyes, and the removal efficiency of composites on dye wastewater reached up to 96.5%. In addition, the magnetic composite could be effectively and simply separated by using an external magnetic field and had good repeatability as sorbent of the sulfonic dye wastewater treatment.



Preparation of Cu Doped SnO₂ Cathode Material for Electroreduction of Carbon Dioxide at Low Overpotential^†

HU Xueyan,WANG Na,HAO Yuting,XU Zhiqing,WANG Minghui,SHI Gaiqin,YANG Huimin,LIANG Zhenhai

2018, 39(10):  2265-2271.  doi:10.7503/cjcu20180226

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Cu doped SnO₂ was prepared through one-step hydrothermal method with SnCl₄·5H₂O as precursor material and CuCl₂ as dopant. The surface morphology, crystal structure and element composition as well as valence state were characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS). The properties of the material and the reduction of CO₂ were investigated by cyclic voltammetry, Tafel plot and electrochemical impedance spectroscopy under normal temperature and pressure in 0.5 mol/L NaHCO₃ solution. The results show that SnO₂ has rutile structure and Cu²⁺ ions replace some Sn⁴⁺ ions of SnO₂. Besides, the particles size decreases slightly after doping Cu⁺. Through electrochemical performance evaluation, the best catalytic performance was achieved as the Cu doping content was 1.5%. The current density reached 3.5 mA/cm², the Tafel slope was 55.1 mV/dec and the maximum Faradic efficiency reached 23% when the catalyst loading amount was 0.8 mg. The Faradic efficiency is 12 times that of pure SnO₂. Therefore, the Cu doped SnO₂ can be used as cathode material for electrocatalytic reduction of CO₂.



In-situ High Temperature Raman Spectroscopic and Decomposition Thermodynamic Study of the Structure of Potassium Hydrogen Sulfate and Its Melt^†

YANG Yejin,YOU Jinglin,WANG Jian,WANG Min,HE Yingxia,WU Zhidong

2018, 39(10):  2272-2279.  doi:10.7503/cjcu20180170

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In-situ high temperature Raman spectroscopic technology was used to study the phase transitions of KHSO₄ from ambient temperature to 550 ℃. Raman vibrational wavenumber and scattering activity of KHSO₄ crystal and K₂S₂O₇ melt were calculated based on Density functional theory(DFT) and ab initio quantum chemical studies, respectively. The major vibrational modes were assigned, Raman scattering cross sections were also obtained, which led to establish the relationship between the area of the characteristic peak and species concentrations. And thermodynamic enthalpy were also calculated through the Factsage database as a comparison in the process of decomposition to confirm the experimental calculated thermodynamic enthalpy. Results show that the structure of KHSO₄ transforms from chain to dimer at 210 ℃, along with the crystal symmetry changing from monoclinic to orthogonal one. It decomposes during 220—550 ℃, which results in the formation of K₂S₂O₇. The reaction enthalpy(ΔH) of (72.59±2.40) kJ/mol was calculated from the equilibrium constant.



Functionalization of Carbon Electrode and Subsequent Electrochemical Deposition of Nanostructured Manganese Oxide^†

FENG Dongyang,GUO Di,LIU Xiaoxia

2018, 39(10):  2280-2288.  doi:10.7503/cjcu20180111

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Carbon cloth(CC) was treated by cyclic voltammetry in designed potential range to afford partially reduced functionalized carbon cloth(RFCC). Electrochemical deposition of nanostructured MnO₂ was conducted on RFCC. The influence of electrodeposition solution on MnO₂ deposition was investigated and N-MnO₂/RFCC was prepared in the solution containing (NH₄)₂SO₄. The results show that the functionalization of CC is helpful to improve its wettability, while the introduced oxygen containing functional groups can facilitate the uniform distribution of Mn²⁺ in the deposition solution to promote the uniform growth of MnO₂ nanoparticles. The adding of (NH₄)₂SO₄ is helpful to increase the specific surface area of MnO₂, leading to improved charge storage behaviors.



Polymer Chemistry

Performance of Phosphorus Sorption on Thermosensitive Zirconium Alginate Hydrogel Beads with Full-interpenetrating Network^†

LUO Huayong,RONG Hongwei,ZENG Xueyang,WANG Randeng,CHU Zhaorui

2018, 39(10):  2289-2297.  doi:10.7503/cjcu20180064

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Thermosensitive poly(N-isopropylacrylamide)/zirconium alginate hydrogel beads with full-interpenetrating network(PNIPAM/Alg-Zr) were prepared and explored as a sorbent for phosphorus(P) recovery from aqueous solutions. The sorption of P onto PNIPAM/Alg-Zr was affected by pH, temperature and co-existing anions. A maximum uptake capacity of 30.42 mg/L was observed at pH=2. A low temperature was favourable for the sorption process. The presence of S$O_{4}^{2-}$ had a certain interference on P sorption while a slight effect of S$O_{4}^{2-}$ under higher ionic strength was observed. The sorption kinetics followed the pseudo-second-order model and was regulated by surface and intraparticle diffusion. The isotherm data were well fitted to the Freundlich model. The P-loaded PNIPAM/Alg-Zr achieved a faster desorption rate under a high temperature stimulus, and the uptake capacity of P remained stable after five times regeneration. The inferred sorption mechanisms were electrostatic interaction and ligand exchange verified by the analysis of pH value at zero point charge(pH_pzc) and XPS. PNIPAM/Alg-Zr exhibited good column-sorption characteristic, and the Thomas model could fit well the experimental data.



Preparation, Structure and Properties of Strong, Transparent Cellulose Materials^†

LIU Yu,CHEN Gang,ZHU Jiatian,CHEN Wenjin,HU Wen,LIU Yingyao,FANG Zhiqiang

2018, 39(10):  2298-2303.  doi:10.7503/cjcu20180177

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A strong, transparent cellulose material was prepared by a two-step method(delignification and pressure drying). The obtained cellulose material not only exhibited a highest transmittance of 68%(600 nm) and a transmission haze of 95%, but also has a maximum tensile strength of 362 MPa and an elastic modulus of 9.5 GPa. Scanning electron microscope(SEM), X-ray diffraction(XRD), thermal gravimetric analyzer(TGA), ultraviolet-visible(UV-Vis) spectrophotometer, and tensile tester were applied to analyze the structure, mechanical and optical properties, thermal stability, and crystallinity of cellulose material. and the underlying principles for the optical transparency and strong tensile strength of the cellulose material was confirmed based on above characterizations.



Effect of Side Groups on Conformational Characteristics of Containing Phosphor, Fluoride, Oxygen and Silane Polymers^†

MA Haizhu,HAN Wentao,TAO Fei

2018, 39(10):  2304-2311.  doi:10.7503/cjcu20180155

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Formulas of mean-square radius of gyration and mean-square dipole moment were deduced by the improved rotational-isomeric-state model and the generator matrix method. The configuration-conformation dependent properties of inorganic and semi-inorganic polymers were investigated by these basic quantities. From comparing the calculated results, it is found that the flexibility and polarity of chain are related to the heteroatom constituents, the size of side group, the conformation energies and tacticity of chain. The polarity of asymmetric polymers is greater than that of symmetric polymers. Duo to existence the crowd side groups, poly(methylphenylsilylene)(PMPS) and poly(dimethylsilylene)(PDMS) have greater chain dimensions than those of poly(methlphenysiloxanc), poly(silastyrene) and polyphosphate. Especially, the dimensions of PMPS chain with and without considering side group have a difference of 4.68%. The intrinsic viscosity changes obviously as configuration parameters and degree of polymerization increase. Similarly, the temperature coefficients of PDMS also change uniquely as degree of polymerization increase. Therefore, it suggests that the size, distribution and polar of side groups cannot be neglected in estimating the dimension and polarity of polymers.



Fractionation and Fraction Characterization of trans-Polyisoprene Rubber Alloys within Reactor^†

NIU Qingtao,ZOU Chen,WANG Riguo,LI Lange,HE Aihua

2018, 39(10):  2312-2319.  doi:10.7503/cjcu20180151

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Trans-1,4-polyisoprene rubber alloys(TPIR) with different butadiene incorporation catalyzed by supported titanium Ziegler-Natta catalyst within pilot plant reactor were effectively fractionated by the stepwise isothermal crystallization fractionation method. The microstructure, molecular weight(M_w) and molecular weight distribution(M_w/M_n), butadiene unit content($\bar{F}_{Bd}$), crystallization behavior and crystal form of main fractions were analyzed by ¹³C NMR, GPC, DSC and XRD. The results showed that trans-1,4-polyisoprene rubber alloys were mainly composed of 7 fractions(A—G). TPIR-05 with low butadiene incorporation was mainly composed of fraction C, D, G; TPIR-10 with high butadiene incorporation was mainly composed of fraction A, B, C, D, G. Fraction A having high butadiene unit content($\bar{F}_{Bd}$=22.4%, molar fraction) was gradient multi-block trans-1,4-poly(isoprene-co-butadiene) copolymers containing trans-1,4-polyisoprene(TPI) blocks and trans-1,4-polybutadiene(TPB) blocks; Fractions B, D were gradient trans-1,4-poly-(isoprene-co-butadiene) copolymers with low butadiene unit content($\bar{F}_{Bd}$=2.7%—6.5%) and long TPI blocks; fractions C were trans-1,4-polyisoprene homopolymers; fraction G were random trans-1,4-poly-(isoprene-co-butadiene) copolymers with high butadiene unit content($\bar{F}_{Bd}$=15.6%—20.4%) and weak crystallizability. The possible chain structure models for these fractions were proposed.



High-frequency Specific Dielectric Properties of Carbon Black Filled Rubber Composites^†

WANG Wenqi,LIN Yu,WU Guozhang

2018, 39(10):  2320-2326.  doi:10.7503/cjcu20180141

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In order to develop high-performance microwave human tissue-equivalent materials,it is a great challenge to endow polymer composites with tunable high-frequency specific dielectric properties. The effects of carbon black(CB) particle size, specific surface area, structure and the CB-matrix interaction on electrical conductivity and high-frequency specific dielectric properties of rubber composites were systematically investigated in this paper. The results show that the percolation threshold is high in CB-filled strong polar acrylic rubber(AR) composites, and the addition of CB can enhance the low-frequency dielectric constant due to strong CB-AR interfacial interactions. However, the dielectric properties decay quickly with increasing frequency, resulting from the strong interfacial polarization. While in the case of weak polar(nonpolar) silicone rubber composites, the dielectric properties at high frequencies decay relatively slowly with increasing frequency. Although CB particles with big size, small specific surface area and low structure are not conducive to form the percolation network, the high-frequency dielectric properties attenuate slowly with an increase of frequency. The results reveal that it is possible to simulate the broadband dielectric properties of human muscle and fat with CB-filled silicone rubber composites.



Foams of Supramolecular Network Constructed by Poly(calixarene-piperazine) Amide and 2,2'-Bipyridine^†

MIAO Ruixiang,LIU Dongqing,REN Shun,ZHU Zexian,CHEN Yingbo,ZHANG Yufeng

2018, 39(10):  2327-2334.  doi:10.7503/cjcu20180131

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Calixarene derivative, 5,11,17,23-tetra-tert-butyl-25,27-di(chloroacetyloxy)-26,28-dihydroxycalix[4]arene(DC), was used as organic phase monomer to prepare poly(calixarene-piperazine)amide(D) through interfacial polymerization with piperazine aqueous solution. Compound D showed induced self-assembly actions under different factors. It could self-associate into double distribution vesicles of average diameter of 28 and 164 nm, respectively. 2,2'-bipyridine(bpy) crosslinked D into supermolecular network. H₂O turned network into foams at the interface of water-ethyl acetate. Foams are large-scale structure constructed by D and bpy and H₂O droven by weak intermolecular interaction including π-π staking, hydrophobic-hydrophobic interaction and interfacial effect. This work provide a new material for large scale supermolecular building and stimuli-responsive function.



Preparation of Lignin/ZnO Composite Nanoparticles and Its Application in Waterborne Polyurethane^†

FU Fangbao,WANG Huan,ZHONG Ruisheng,QIU Xueqing,YANG Dongjie

2018, 39(10):  2335-2342.  doi:10.7503/cjcu20180128

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A series of lignin/zinc oxide(LQAs/ZnO) composites with different lignin content was prepared through a precipitation method using quaternized alkali lignin(LQAs), zinc acetate and sodium hydroxide as raw materials. The results of X-ray diffraction(XRD), scanning electron microscope(SEM), transmission electron microscope(TEM) and ultraviolet-visible spectroscopy(UV-Vis) demonstrated that the as-prepared LQAs/ZnO composites exhibited a hybrid structure and the microstructure was significantly influenced by the dosage of NaOH. The UV-absorption performance of LQAs/ZnO composites enhanced remarkably compared with pure ZnO. In addition, the optical and mechanical properties of waterborne polyurethane(WPU) films doped with LQAs/ZnO composites were investigated. The tensile strength and the elongation at break of WPU films blended with LQAs/ZnO composites were 81.5% and 10.9%, respectively, higher than those of pure WPU films. The tensile strength and the elongation at break of the WPU composite films were maintained above 25 MPa and 360% by a 192 h of UV-aging test. LQAs/ZnO composites could effectively enhance the UV shielding performance and the anti-ultraviolet aging ability of WPU.



Synthesis and Performance of PEEK/Nap-PAEK Modified WMCNTs Composites^†

LIN Li,CHEN Zheng,SHANG Yingshuang,WANG Zhaoyang,GAO Yanwei,JIANG Zhenhua,ZHANG Haibo

2018, 39(10):  2343-2349.  doi:10.7503/cjcu20180123

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A kind of poly(aryl ether ketone) containing naphthalene(Nap-PAEK) was prepared and coated on the surface of multi walled carbon nanotube(MWCNTs) fillers as surface modifier. A series of PEEK/MWCNTs composites was prepared by physical blending of the MWCNTs coated with Nap-PAEK and poly(ether ether ketone)(PEEK) resin, and the thermal and mechanical properties of the composites were also investigated. The results show that Nap-PAEK can improve the dispersion of MWCNTs in N-methyl-2-pyrrolidone(NMP) solution and PEEK matrix effectively due to the strong π-π interaction between Nap-PAEK and MWCNTs. After surface modified by Nap-PAEK, the dispersion capacity of MWCNTs in NMP increased about 10 times. With the addition of only 2%(mass fraction) WMCNTs, PEEK/Nap-PAEK-MWCNTs composite shows the tensile strength increased by 14.5% and the elongation increased by 116.7% compared to those of pure PEEK, realizing the simultaneous reinforcing and toughening of PEEK resin. After the addition of modified MWCNTs, the thermal stability of PEEK was also improved.



β-Cyclodextrin Based Star-like Polymer for Loading Chlorambucil^†

CHEN Tao,HUANG Chan

2018, 39(10):  2350-2356.  doi:10.7503/cjcu20180124

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Star-like polymer with β-cyclodextrin core(β-CD) and poly(N,N-dimethylaminoethyl methacrylate) arms(PDMAEMA), β-CD-PDMAEMA, was synthesized by atom transfer radical polymerization using brominated β-CD as initiator. The structure of the polymer was determined by Fourier transform infrared spectrophotometer(FTIR) and ¹H nuclear magnetie resonance(NMR). The polymer was used to load hydrophobic anticancer drug chlorambucil(CLB) in both ethanol and water. The loading efficiency of CLB and in vitro release performance and mechanism at 37 ℃ in buffer solutions with various pH values were investigated by UV absorption spectroscopy. The results show that, compared to that in ethanol, the hydrophobic internal cavity of β-CD in the core of the star-like polymer includes more CLB in water, which leads to higher drug loading ratio, shorter and less burst release. The release of CLB from the star-like polymer follows the diffusion mechanism. The release rate and cumulative release amount of CLB are affected by the protonation degree of PDMAEMA arms, which results to pH responsive release behavior. The acidic condition is beneficial to more efficient and sustained release of CLB.