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10 November 2018, Volume 39 Issue 11

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Cover and Content of Chemical Journal of Chinese Universities Vol.39 No.11(2018)

2018, 39(11):  0-0. 

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Articles:Inorganic Chemistry

Highly Stable Fluorine Containing Hierarchical Porous Covalent Organic Framework^†

CHEN Qidan, TANG Junjie, FANG Qianrong

2018, 39(11):  2357-2362.  doi:10.7503/cjcu20180190

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Covalent organic frameworks(COFs) are an emerging class of crystalline and porous polymers synthesized by condensation reactions of organic building blocks linked through strong covalent bonds. How-ever, constructing dual-pore COFs with applicative building blocks were faced with enormous challenges due to the complicated topological structures formed through the limited strategies. Herein we describe the design and synthesis of a new dual-pore COF with a hexagram-like structure, named ETTA-TFA-COF, synthesized by linking a D_2h symmetric monomer and a C₂ symmetric monomer which leading the formation of dual-pore structure. The structure of the ETTA-TFA-COF was confirmed by theoretical simulation, powder X-ray diffraction(PXRD) investigation, nitrogen adsorption-desorption study, and FTIR spectra analysis. In the meantime, ETTA-TFA-COF material exhibit excellent stability in alkaline solution compared to COF materials of similar structure but without fluorine atoms.



Synthesis, Crystal Structure and Fluorescent Properties of Transition Metal Complexes Constructed with 2-(3'-Carboxyphenoxy)benzoic Acid and N-Donor Ligands^†

LI Zheng, LI Rui, LI Xia

2018, 39(11):  2363-2371.  doi:10.7503/cjcu20180347

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Taking 2-(3'-carboxyphenoxy)benzoic acid(2,3'-H₂oba), 1,3-bis(4-pyridyl)-propane(DPP) and 1,4-bis(1,2,4-triazole-1-)butane(BTB) as ligands, two transition metal complexes Cd(2,3'-oba)(DPP)(1) and Zn(2,3'-oba)(BTB)_0.5(2) were obtained by hydrothermal method. Complex 1 is a two-dimensional network structure, the coordination environment of the central Cd²⁺ is {CdO₄N₂}, the 2,3'-oba ligand and the DPP ligand link Cd²⁺ into Cd²⁺-2,3'-oba-Cd²⁺-DPP helical chains by bidentate chelating and monodentate bridging modes, respectively. Complex 1 is linked by intermolecular hydrogen bonding and self-assembled into a three-dimensional supramolecular structure. Complex 2 is a three-dimensional framework structure, and the central Zn²⁺ adopts a five-coordinated distortion quadrilateral cone configuration {ZnO₄N}. The 2,3'-oba ligand links the adjacent Zn²⁺ as a bidentate chelate and a bidentate bridge to form a two-dimensional network layer. The BTB molecule bridges the Zn²⁺ and connects adjacent network layers to form a three-dimensional structure. Fluorescence spectroscopy indicates that complexes 1 and 2 have maximum emission at 437 nm and 359 nm, respectively, both are derived from the π^*-π transition of the ligand. The broad-spectrum pesticide mesotrione has a significant quenching effect on the fluorescence intensity of complex 2, thus complex 2 can be used as a chemical sensor for detecting mesotrione.



Controllable Synthesis of γ-Al₂O₃ Hexagonal Nanoplates with Ionic Liquids as the Template^†

LEI Xuanxuan, TANG Shaokun, LI Lin, SUN Liwei

2018, 39(11):  2372-2379.  doi:10.7503/cjcu20180300

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γ-Al₂O₃ hexagonal nanoplates with unique crystal orientations were synthesized via an ionic liquid-assisted hydrothermal method using aluminum chloride as the aluminum source, n-butylamine as the precipitant and [Bmim]BF₄ as the template. The synthesized products were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FTIR) and N₂ isothermal adsorption-desorption. The results suggested that the crystalline phase of the precursors could be changed with the addition of ionic liquid. By adjusting the content of [Bmim]BF₄, the precursors could be transformed from γ-AlOOH to the mixture of gibbsite and diopside. The final alumina products were obtained after high temperature calcination and the structural transformation of alumina from rhombohedral nanosheets to hexagonal nanoplates were achieved. The well-defined γ-Al₂O₃ hexagonal nanoplates with average diameter of 600 nm and thickness of 200 nm were finally formed after reaction at 160 ℃ for 24 h when the molar ratio of [Bmim]BF₄ to aluminum source was 0.15, and their exposed facets consisted of {111} planes as basal surfaces and {110} planes as lateral surfaces. Compared with the rhombohedral nanosheets prepared without [Bmim]BF₄ template, the obtained hexagonal nanoplatests possessed relatively larger specific surface area(203 m²/g) and more uniform mesoporous structure(4.2 nm). Meanwhile, the template effect of [Bmim]BF₄ on the controllable synthesis of γ-Al₂O₃ hexagonal nanoplates was investigated in detail.



Influence of Sodium Dodecyl Benzene Sulfonate on Crystallization Behavior of Calcium Carbonate^†

LI Mengwei, ZHAO Changming, CHENG Tiexin, ZHOU Guangdong

2018, 39(11):  2380-2385.  doi:10.7503/cjcu20180020

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CaCO₃ particles were prepared by gas diffusion method with CaCl₂ and (NH₄)₂CO₃ as raw materials and sodium dodecyl benzene sulfonate(SDBS) as the template. The effect of SDBS of different concentrations on the crystallization behavior and morphology of CaCO₃ in solution was studies. The results of scanning electron microscopy(SEM), X-ray diffraction(XRD) and Fourier transform infrared spectroscopy(FTIR) show that the CaCO₃ sample was mainly calcite crystal with regular rhombic hexahedron morphology when SDBS was not added to the solution, and vaterite crystals with spherical morphology when SDBS was added to the solution, indicating that adding SDBS to the solution could change the crystal growth mode of CaCO₃. With the increase of SDBS concentration in the solution, the relative content of vaterite crystals in the CaCO₃ samples increased gradually. When the concentration of SDBS was 1.2 mmol/L, almost all the samples were vaterite crystals. With the further increase of SDBS concentration in the solution, due to the change of micelle morphology and the deterioration of stability, the metastable vaterite crystal in the sample changed to the stable calcite crystal, the relative content of the vaterite crystal gradually decreased, and the crystal presented flower, hexagonal, spindle shapes and other morphological features.



Analytical Chemistry

L-Cystine Sensor Based on Modification of Extended Gate of FET with Polydithiodipropanesulfonic Acid Membrane^†

YANG Jia, ZHANG Yuyang, LIU Chen, LI Jiaxin, XIAO Zhongliang, LI Dan, ZHANG Ling, CAO Zhong

2018, 39(11):  2386-2394.  doi:10.7503/cjcu20180283

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A novel sensing device capable of detecting L-cystine was constructed by designing the gate gold electrode(GGE) of a field effect transistor(FET) to extend a certain distance and self-assembly of polydithiodipropanesulfonic acid(SPS) on the surface of GGE. The topological structure of the modified GGE was characterized by means of scanning electron microscopy. Through electrochemical cyclic voltammetry and impedance analysis together with X-ray photoelectron spectroscopy, the response mechanism of the SPS modified GGE for the L-cystine detection has been well investigated. With electrostatic interaction, the SPS poly-anion membrane with negative charge in aqueous solution could adsorb the L-cystine molecules containing positive charge, which may form a double electric layer resulting in change of membrane potential on the sensing interface by recognition of monovalent organic ammonium ion. The electrode exhibited a nice linear potential performance to L-cystine in the range of 5.0×10^-6~1.0×10^-3 mol/L, with a slope of (58.25±1.5) mV/-pc(25 ℃) and a detection limit of 2.69×10^-6 mol/L. The response time for L-cystine was very fast(30 s). The electrode also had good reproducibility and stability. Almost no interferences from common amino acids such as L-glycine, L-alanine, L-valine, L-aspartate, L-proline, L-threonine, L-histidine, L-leucine, L-tryptophan or L-methionine can be observed. Moreover, the electrode can be applied to the determination of L-cystine in real pig serum samples with recovery rate of 91.2%—107.8%. It shows that the sensing device is expected to become a kind of simple and accurate means for the L-cystine analysis.



Metabolomics Study of Serum and Liver in Type 2 Diabetes Mice Induced by High Fat Diet with Vitamin D Deficiency^†

LI Wenwen, ZHU Airu, LONG Yijing, WANG Chunyan, HAN Yuanping, DUAN Yixiang

2018, 39(11):  2395-2404.  doi:10.7503/cjcu20180272

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This study developed mice with type 2 diabetes mellitus(T2DM) through 24 weeks high fat diet feeding with vitamin D deficiency(VDD), and analyzed metabolites in serum and liver to explore the change mechanism of metabolites and metabolic pathways in the development of T2DM. The serum and liver samples of mice were collected and analyzed through gas chromatography-mass spectrometry(GC-MS) coupled with trimethylsilyl derivatization. Orthogonal partial least squares discriminant analysis(OPLS-DA) and nonparametric tests were used to screen the metabolic biomarkers, which in serum were lactate, alanine, glycerol, threonine and glucose, and in liver were lactic acid, ribose, fructose, glucose, oleic acid and palmitic acid, and these serum and liver metabolic biomarkers were all up-regulated in high fat+VDD mice, when compared with control. Additionally, this work conducted overall comparison of metabolites in serum and liver between high fat+VDD group and control group, and further explored the metabolic pathways related to these metabolites, that TCA(tricarboxylic acid) cycle, gluconeogenesis, amino acid andlipid metabolism pathways were significantly enhanced in high fat+VDD mice. The disturbance of these pathways contributes to the development of T2DM.



Relative Hydrophobicity of Drug Molecules and Retention Behavior in Hydrophobic Interaction Chromatography^†

YANG Tong, PENG Rong, HUANG Xinyu, SUN Yansong, CHEN Xiaonong

2018, 39(11):  2405-2410.  doi:10.7503/cjcu20170854

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Botanical medicine plays a significant role in research and production of new drugs, and attracts special attention due to its unique merits, such as rich source, less side effect. There exists certain difficulties to get target products from plant mixture in isolation and purification process. Reverse phase chromatography based on the difference in the polarity and hydrophobicity of drugs is one of the most important methods for purify active ingredients in plants. It is technical significant to establish a simple method to determine the hydrophobicity(retention time) of a target drug compound so as to design the stationary phase materials in chromatographic separation and collect mobile phase solution at an appropriate eluting period. In this study, a variety of botanical medicines were selected as model compounds, their solubility parameters δ_t were calculated by the group contribution method based on the molecular structure of the model compounds and relative retention times t_RR were determined by HPLC. The mathematical model correlating the solubility parameter and the relative retention time is established, t_RR=-0.032+7.27144$e^{-\delta_{t}/3.53874}$(R=0.97). By the method we established, the relative retention time of a drug compound can be obtained by calculating the solubility parameter, which can be used to predict the hydrophobicity and determine the appropriate elution time of such drug compound from hydrophobic membrane chromatography.



Organic Chemistry

One-pot Synthesis of β-Carboline Derivatives Catalyzed by CuO Nanoparticles^†

ZHANG Jin, SHI Tiancai, LUO Liwen, LIU Jia, LIU Rong, LIU Le, LIANG Ming, MA Yangmin

2018, 39(11):  2411-2418.  doi:10.7503/cjcu20180326

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Compounds containing β-carboline moiety have a variety of special biochemical and pharmacological activities. In order to explore the method for efficient synthesize β-carbolines, a novel method applied Pictet-Spengler cyclization and coupling oxidation in one-step was studied. Tryptophan esters and aromatic aldehydes were heated in N,N-Dimethylformamide via the promotion of nano CuO. Twenty-five compounds of 1,3-disubstituted-β-carbolines were obtained in moderate to excellent yield with subsequent isolation and purification. Attractive features of this method included simple operation, high efficiency and mild condition. Especially, nano CuO as catalyst and oxidant promoted cyclization and oxidation processes in creating β-carbolines motif.



Preparation of 20(S/R)-Ginsenoside Rg₃ and Their Effects on Regulation of Th1/Th2 Imbalance^†

LIU Ying, CHEN Yanxin, WU Qian, LI Peng, LI Xuwen, SHI Xiaolei, JIN Yongri

2018, 39(11):  2419-2424.  doi:10.7503/cjcu20180372

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20(S)-Ginsenoside Rg₃ and 20(R)-ginsenoside Rg₃ were prepared by degradation and extraction methods from leaves of Panax quinquefolium L. The regulation effects of 20(S)-Rg₃ and 20(R)-Rg₃ on imbalance of Th1/Th2 cell were studied in vivo. As the orthogonal array optimization results shown, when the concentration of acetic acid was 50%, temperature of 80 ℃ and extraction time of 1 h, the conversion rates of 20(S)-Rg₃ and 20(R)-Rg₃ were highest at 12.30% and 14.80%, respectively. Then the 20(S/R)-Rg₃ were purified by chromatographic method. According to the experimental results of activity, 20(S/R)-Rg₃ inhibited the Th2 cells development by down-regulation of IL-4 production. It was associated with the CD40 and TIM-4 expression of LDCs. This work reports a new method to prepare ginsenoside Rg₃ and draw a novel biological mechanism of ginsenoside Rg₃, effects on imbalance of Th1/Th2.



Host-guest Interaction Between Cucurbit[8]uril and Baicalin and Its Effect on the Properties of Baicalin^†

HUANG Jingjing, XU Zhiling, LIAN Xiaowei, ZHANG Xiaodong, TAO Zhu, ZHOU Qingdi, ZHANG Qianjun, WEI Gang

2018, 39(11):  2425-2432.  doi:10.7503/cjcu20180337

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The interaction between cucurbit[8]uril(Q[8]) and baicalin(BAL) was investigated by ultraviolet-visible absorption spectrometry and nuclear magnetic resonance spectroscopy. The results showed that Q[8] and BAL formed an inclusion complex with molar ratio of 1:1. The inclusion stability constant was 2.8×10⁴ L/mol. The phase solubility experiments revealed that the solubility of BAL in water increased 4.5 fold by interacting with Q[8] at 100 μmol/L. The effect of Q[8] on antioxidant activity of BAL was investigated by 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonate acid)(ABTS) method. Both the BAL-Q[8] inclusion complex and BAL had the scavenging ability for ABTS free radicals, and the IC₅₀ values were 5.48 and 5.07 μmol/L, respectively. BAL and BAL-Q[8] were stable in artificial intestinal juice. BAL was degraded rapidly in 6 h, but BAL-Q[8] was not degraded basically in artificial gastric juice, which indicated that Q[8] significantly improved the stability of BAL in artificial gastric juice. In vitro cumulative release results showed that Q[8] increased the cumulative release of BAL in artificial gastric juice by 2 times. The cumulative release rate of BAL-Q[8] was significantly slower than the cumulative release rate of BAL in artificial intestinal juice, which indicated that Q[8] had sustained release effect on BAL.



Synthesis and Biological Activity of 3-Alkylphosphonate Substituted Isoindolinone Derivatives^†

LIU Xiaoyu, XU Yi, TANG Liangfu

2018, 39(11):  2433-2437.  doi:10.7503/cjcu20180215

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A simple and convenient one-pot synthesis of 3-alkylphosphonate substituted isoindolinone derivatives via the reaction of o-lithiated aromatic imines with carbon monoxide under one atmospheric pressure followed with bromoalkyl phosphonate was developed. These newly synthesized 3-alkylphosphonate isoindolinones were characterized by ¹H NMR, ¹³C NMR and ³¹P NMR as well as HRMS. Preliminary in vitro tests for fungicidal activity of these isoindolinone derivatives indicated that most of them exhibit good fungicidal activity.



Highly Stereoselective Reduction of Bulky Carbonyl Compounds by Carbonyl Reductase Variant^†

LIANG Chen, NIE Yao, XU Yan

2018, 39(11):  2438-2444.  doi:10.7503/cjcu20180214

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RCR-F285A/W286A, the variant of the (R)-specific carbonyl reductase(RCR), was used as the biocatalyst for asymmetric reduction of carbonyl compounds with bulky groups. In this study, ketoesters and heterocyclic ketone, including ethyl 2-oxo-4-phenylbutyrate(OPBE), ethyl benzoylacetate(EBA) and 1-benzyl-3-pyrrolidone, were employed. Catalytic property(including enzyme activity and kinetic parameters) and enantioselectivity of RCR-F285A/W286A towards tested bulky substrates were measured. RCR-F285A/W286A exhibited enzymatic activity towards all of the tested substrates. The corresponding chiral alcohols of the tested substrates acting as important pharmaceutical intermediates were prepared with high optical purity(e.e.>99%). Moreover, the effects of reaction conditions, including pH, temperature, substrate concentration, cosolvents and ratio of the optimum cosolvent, on the asymmetric reduction of OPBE with the highest yield were investigated. The results showed that the yield of 80.3% was obtained at pH=7.0, 30 ℃, 1 g/L substrate and isopropanol with volume fraction of 3.5%. Furthermore, fed-batch strategy was adopted to weaken substrate inhibition with the space-time yield 0.062 g·L^-1·h^-1 at 10 g/L OPBE. This result would provide the experimental basis for the industrial application of the enzyme-mediated asymmetric synthesis of ethyl (R)-2-hydroxy-4-phenylbutanoate.



Modification of Aptamer TBA with Extra Functional Groups and the Biological Activities^†

DU Shanshan, LI Yang, GUO Lei, LI Pengyu, CHAI Zhilong, WANG Tao, QUAN Dongqin, HE Junlin

2018, 39(11):  2445-2450.  doi:10.7503/cjcu20180168

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Thrombin binding aptamer(TBA) is a small aptamer for human α-thrombin. Detailed structural analysis has demonstrated that the two-layer G-quartet acts as the structural backbone and three loops have different contributions for the intramolecular stability and the interaction with thrombin. Here, the chemical modification with 5-[(2-aminoethyl)amino-2-oxoethyl]-2'-deoxythymidine(1) on the two loops of TBA(T3T12 and T4T13) were reported. The 5-substituent induced different effect for each residue in the loops. The intramolecular stacking of T4 and T13 were negatively affected for the thermal stability and the inhibitory activity. In the case of the loop T3 and T12 extruding outward, the extra functional groups of the compound 1 were helpful for the interaction with thrombin, the 5-positioned extra amino and amido groups were probably located at the right positions for the hydrogen bonding interaction with the residues from thrombin. These results further confirmed the loop residues for their folding positions, and their contributions could be enhanced by 5-substituted functional groups of 2'-deoxythymidine at specific positions.



Construction of Ginsenoside-β-glucosidase Gene Vector and Biotransformation in Pichia Pastoris^†

LIU Xinru, LIU Chunying, XU Longquan, SONG Jianguo, YU Hongshan

2018, 39(11):  2451-2457.  doi:10.7503/cjcu20180149

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The ginsenoside-β-glucosidase(GluGF) gene was ligated with the expression vector pPIC9K to construct a recombinant plasmid. The recombinant plasmid was transformed into pichia pastoris to expresse and accomplish the biotransformate of ginsenoside Rb₁. The results showed that the recombinant plasmid pPIC9K-GluGF was successfully constructed and transformed into pichia pastoris GS115 competent cells. The optimal volume of methanol for recombinant strain was 0.5%, and the induction time was 168 h. The crude enzyme solution prepared by induction culture could hydrolyze ginsenoside Rb₁. The content of C-K in the product reached 0.09 mg/mL. The enzyme activity of GluGF in the crude enzyme solution was 0.67 U/mg.



Study on Sulfated Glycosylated Fe₃O₄@SiO₂ Nanoparticles Inducing Tumor Cells Apoptosis^†

YUAN Jiayi, YE Baotong, WU Jing, LI Ying, CHEN Jinghua, CHEN Jingxiao

2018, 39(11):  2458-2467.  doi:10.7503/cjcu20180142

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Magnetic Fe₃O₄@SiO₂ nanoparticles(NPs) were first prepared through a solvothermal strategy, after that, selectively protected N-acetylglucosamine was modified on the surface of these NPs by “Click” chemistry, followed by sulfation to obtain a series of sulfated glycosylated Fe₃O₄@SiO₂ NPs with core/shell structure and various sulfation patterns. The components and morphology of these nanoparticles were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM), respectively, before and after the modification. The effects of sulfated glycosyl groups on NPs-induced tumor cell apoptosis and protein signal regulation were studied. The results showed the prepared Fe₃O₄@SiO₂ NPs were uniform and well-dispersed. After the sulfated glycosylation, the average size of NPs increased from 110—130 nm to about 160—180 nm. These NPs could efficiently internalize into tumor cells, regulate the protein expression level of the Bcl-2/Bax pathway, and then induce cell apoptosis in a concentration-dependent manner. The activity was highly related to different sulfation patterns of glycosyl groups on the surface of NPs.



Physical Chemistry

Study on the Interactions Between Na⁺ and N-Methylacetamide and Water by the ABEEM/MM^†

PAN Yiming, ZHANG Jing, TIAN Bo, YAO Jingjing, GONG Lidong, LIU Cui, YANG Zhongzhi

2018, 39(11):  2468-2476.  doi:10.7503/cjcu20180546

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The geometries, binding energies of [Na(H₂O)_n]⁺(n=3—8), [Na(NMA)_n]⁺(n=3—8), [Na(NMA)_n(H₂O)_m]⁺(n+m=4,6)(NMA=N-methylacetamide) were studied with the quantum chemical MP2/6-311++G(d,p)//B3LYP/6-31+G(d,p) level of theory and atom-bond electronegativity equalization method fused into molecular mechanics(ABEEM/MM) fluctuating charge force field. Based on the quantum chemical results, the polarizable ABEEM/MM potential energy functions of the above system were constructed, and the relative parameters were optimized and determined. The results show that the structures, binding energies, charge distributions obtained by ABEEM/MM are in good agreement with those from quantum chemical method(QM). The average absolute deviations(AAD) of distances of Na⁺-ligand, angles, and binding energies are less than 0.007 nm, 2.4°, 8.9 kJ/mol, respectively. The relative root mean square deviations(RRMSD) of distances of Na⁺-ligand, angles, and binding energies are less than 3.5%, 2.0%, 12.4%, respectively. The linear correlation coefficients of the charge distributions from ABEEM/MM and QM are above 0.97.



Theoretical Investigations on the Structure-activity Relationship to the Dielectric Strength of the Insulation Gases^†

HOU Hua, YU Xiaojuan, ZHOU Wenjun, LUO Yunbai, WANG Baoshan

2018, 39(11):  2477-2484.  doi:10.7503/cjcu20180530

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A new structure-activity relationship was obtained on the basis of the electrostatic potential surface of the neutral molecules, including the total surface area, the balanced positive and negative potential separation, the local polarity, molecular density, and the reduced positive surface area. The physical dilemma and computational difficulties in the use of ionic or anionic structures were both removed in the present models. The absolute mean deviation of the theoretical dielectric strengths from the experimental data is as low as 0.06 and the correlation coefficient is 0.993. The effects of electronic structures on the dielectric strength were analyzed to gain insights on the molecular design on the novel insulation gases superior to SF₆.



Theoretical Studies on Enhancing the Stability of the Planar CAl₄ by Al-S Bridge^†

ZHANG Xingxing, WANG Yiqiao, GENG Yun, ZHANG Min, SU Zhongmin

2018, 39(11):  2485-2491.  doi:10.7503/cjcu20180480

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Two planar tetracoordinate carbon(pTC) derivatives, planar CAl₄S^- and quasi-planar CAl₄S₄, were investigated to stabilize the planar CAl₄ core. It was indicated that through structural searches at the B3LYP/def2-TZVP level both of the proposed clusters by the Al-S bridge were global minima of potential energy surface with double aromaticity(σ+π). The planar CAl₄S^- was likely to be captured in the experiment due to its thermodynamic stability. The adaptive natural density partitioning(AdNDP) analysis of quasi-planar CAl₄S₄ suggests that its stability was mainly contributed by partial delocalization of electrons. Four 3-center 2-electron σ-bonds maintain the stability of the Al-S framework; three 5-center 2-electron σ-bonds maintain the stability of the C-Al core; one 5-center 2-electron π-bond facilitates the integral stability of the entire quasiplane.



Preparation and Oxygen Reduction Reaction Catalytic Performance of Fe, N Co-doped Carbon Nanofibers with Encapsulated Iron Nitride^†

LIU Pei, CHENG Qingqing, CHEN Chi, ZOU Liangliang, ZOU Zhiqing, YANG Hui

2018, 39(11):  2492-2499.  doi:10.7503/cjcu20180459

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Fe, N co-doped porous carbon nanofibers with iron nitride(Fe_xN) nanoparticles encapsulated in Fe, N co-doped carbon shell(Fe_xN@Fe-N-C) were preparated through electrospinning, carbonization and NH₃-etching. The Fe_xN@Fe-N-C catalyst exhibits excellent catalytic activity for oxygen reduction reaction(ORR) in both acid and alkaline media. The half-wave potential(E_1/2) in acidic medium can reach to 0.81 V(vs. RHE), while the E_1/2 in alkaline medium is 0.897 V(vs. RHE), which is even higher than that of commercial Pt/C catalyst. After 10000 cycles of accelerated durability test in acid media, the E_1/2 only decreases by 26 mV, demonstrating the excellent durability of Fe_xN@Fe-N-C. Ion probing and acid-etching experiments indicate that both Fe-N_x sites and Fe_xN nanoparticles contribute to the ORR activity.



One-step Preparation and UV-Fenton Properties of Fe₃O₄/TiO₂@Bio-carbon Composities^†

YU Xiaodan, LIN Xinchen, FENG Wei, LI Weiguang

2018, 39(11):  2500-2506.  doi:10.7503/cjcu20180450

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A novel maize straw carbon(MSC) skeleton layered mesoporous material, Fe₃O₄/TiO₂@MSC, was synthesized by using maize straw as raw material and calcination with iron salt and titanium salt solution. The degradation of tetracycline hydrochloride(TCH) in UV-Fenton system was studied. The as-synthesized catalysts were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), N₂ adsorption-desorption, scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The results showed that the prepared Fe₃O₄/TiO₂@MSC retained the original pore morphology of maize straw. The nano-Fe₃O₄ and TiO₂ grew on the surface of MSC. The straw carbon as a framework improved the dispersion of nano-Fe₃O₄, prevented its agglomeration, increased the stability of catalyst, and increased the specific surface area and active site of the material, thereby enhancing the UV-Fenton’s reactivity. The synergistic effect of TiO₂ photocatalysis and UV-Fenton system can promote the conversion of Fe(Ⅲ) to Fe(Ⅱ). Therefore, under the same conditions, TCH degradation efficiency in Fe₃O₄/TiO₂@MSC catalyzed UV-Fenton system reached 99. 8% after 40 min reaction, much higher than those in Fe₃O₄@MSC+H₂O₂(30%), UV+H₂O₂(73%), UV+Fe₃O₄@MSC+H₂O₂(89.1%) and UV+Fe₃O₄/TiO₂+H₂O₂(89.2%) systems. And the system can achieve satisfactory removal effect under neutral or even alkaline conditions.



Spectral Characterization of the Interaction Between Methamphetamine and Serum Albumin^†

WANG Yan, CHEN Ping, WANG Yunfei, LIU Guiying, YANG Xi, SU Ying, LI Junyang, LIU Weiwei, LIN Lie

2018, 39(11):  2507-2512.  doi:10.7503/cjcu20180447

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The fluorescence spectroscopy technique and molecular docking method were used to research the interaction between methamphetamine and bovine serum albumin (BSA). Firstly, the fluorescence spectra of BSA and BSA containing methamphetamine were studied, and experimental results show that methamphetamine leads to the fluorescence quenching of BSA. On this basis, the molecular dynamics between methamphetamine and BSA was simulated by the molecular docking method, and the results indicate that the methamphetamine probably interact with BSA in tryptophan and phenylalanine residues through electrostatic forces. Therefore, the interactions between methamphetamine and tryptophan, phenylalanine were studied, respectively. Results from the fluorescence spectroscopy indicate that methamphetamine leads to the fluorescence quenching of tryptophan, phenylalanine, respectively. Given the above, we can conclude that the methamphetamine bind with BSA through electrostatic forces, and the binding sites are tryptophan and phenylalanine residues.



Li₄Ti₅O₁₂ Modification by Bifunctional Bionic Membrane as Anode Materials for Lithium-ion Batteries^†

YANG Shuting, LI Qianhui, FAN Yuchang, WANG Qiuxian, DU Ting, YUE Hongyun

2018, 39(11):  2513-2519.  doi:10.7503/cjcu20180328

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Anode material with excellent electrochemical properties was obtained by coating the polydopamine(PDA)/Super P(SP) layer with the dual effect of both ionic conduction and electronic conduction on the surface of Li₄Ti₅O₁₂ particles. The morphology, structure and electrochemical properties of the composites were characterized by X-ray diffraction(XRD), field emission scanning electron microscopy(SEM), transmission electron microscopy(TEM), charge-discharge cycle curves, and cyclic voltammetry(CV). The results showed that when the thickness of the coating layer was controlled at about 10 nm and the content of Super P was 3%(mass fraction), the sample displayed an outstanding electrochemical performance: the initial discharge capacity is 175 mA·h/g at 0.2C and the reversible discharge capacity is still above 160 mA·h/g after 150 cycles.



Effect of Derivatives of Glycerol Sulfite as Electrolyte Additive on Electrochemical Performance of Lithium Ion Battery^†

AI Shujuan, ZONG Chengxing, WU Wei, FENG Jingjing, JIN Can, FU Fengzhi, LIU Jing, SUN Donglan, ZHENG Qin, GUO Yeping

2018, 39(11):  2520-2528.  doi:10.7503/cjcu20180321

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Three compounds, bis-[(2-oxido-1,3,2-dioxathiolan-4-yl)methyl]terephthalate(BMTP), tris[(2-oxido-1,3,2-dioxathiolan-4-yl)methyl]benzene-1,3,5-tricarboxylate(TMBT1) and tetrakis[(2-oxido-1,3,2-dioxathiolan-4-yl)methyl]benzene-1,2,4,5-tetracarboxylate(TMBT2), were designed and synthesized. Those compounds were added in lithium ion battery and their effect was thoroughly investigated by rate of charge and discharge test, galvanostatic charge and discharge test, electrochemical impedance spectroscopy(EIS) and scanning electron microscopy(SEM). The results showed that a dense and stable solid electrolyte interface(SEI) layer could be formed on the surface of the spheroidized graphite electrode with TMBT1, improving the electrode-electrolyte interface. And the increase of impedance with TMBT1 as electrolyte additive after 80 cycles was small. The performance test of battery show that the addition of TMBT1 can improve the rate performance and cycle stability of the battery, while the addition of BMTP and TMBT2 did not make the battery performance better. The results also suggest that number of cycle sulfite group on benzene ring has a huge influence on the performance of the lithium ion battery.



Influences of Ionic Additive Tetrabutylammonium-bis(fluorosulfonyl)imide on Performance of Lithium Metal Batteries^†

WANG Fengchun, ZHOU Wanli

2018, 39(11):  2529-2533.  doi:10.7503/cjcu20180316

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An ionic compound, tetrabutylammonium-bis(fluorosulfonyl)imide(TBA-FSI) was employed as an additive to lithium metal batteries. The 1 mol/L lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)-based 1,3-dioxolane(DOL)/dimethoxyethane(DME) electrolyte showed high compatibility toward lithium metal anode when 5%(mass fraction) TBA-FSI was added owing to the formation of a LiF-, Li₃N- riched solid electrolyte interpase(SEI) film on lithium metal anode. As a result, the lithium dendrite growth was significantly restricted and coulombic efficiency of Li|Cu cells was markedly enhanced.



Effects of EGCG on Amyloid β-Protein Fibrillogenesis and Cytotoxicity at Different pH Values^†

ZHANG Huan, DONG Xiaoyan

2018, 39(11):  2534-2543.  doi:10.7503/cjcu20180260

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The inhibitory effects of (-)-epigallocatechin-3-gallate(EGCG) on amyloid β-protein(Aβ₄₂) aggregation were investigated under different conditions of pH=5.0, 6.0 and 7.4. The results showed that EGCG could significantly inhibit Aβ₄₂ aggregation and cytotoxicity at different pH values, but the interactions between EGCG and Aβ₄₂ were remarkably affected by the pH values. When incubating at pH=5.0, EGCG could not effectively inhibit Aβ₄₂ fibrillization at the early stage, as evidenced by the fact that 35.1% β-sheet structure and 50% thioflavin T(ThT) fluorescence remained after 24 h incubation. The reason was attributed to the rapid accumulation of Aβ₄₂ and the weakened interactions between EGCG and Aβ₄₂. At the specific condition(pH=5.0), EGCG prevented Aβ₄₂ fibrillization by reducing the hydrophobicity of Aβ₄₂, thereby remodeling amyloid aggregates. At pH=6.0, the interactions between EGCG and Aβ₄₂ increased. Therefore, EGCG displayed an enhanced inhibitory activity on Aβ₄₂ fibrillization, leading to the decrease of Aβ₄₂ aggregation rate and almost complete suppression of the conversion of Aβ₄₂ into β-sheet conformation and ThT fluorescence. By contrast, under the physiological condition(pH=7.4), slower Aβ₄₂ aggregation was observed than the aggregations at acidic conditions. The decrease in Aβ₄₂ self-assembly propensity made more stable binding of EGCG to Aβ₄₂, leading to stabilization of Aβ₄₂ structure and increased lag phase of Aβ₄₂ aggregation. As a result, EGCG significantly inhibited Aβ₄₂ aggregation and the corresponding cytotoxicity at the physiological condition.



Preparation of Furfural Converted from Xylose via Fixed Bed Catalyzation and Gas Phase Neutralization^†

SUI Guanghui, CHENG Yanyan, LIU Huan, DUAN Yajun, WANG Xiaofeng, YANG Xiaomin, WANG Zichen

2018, 39(11):  2544-2549.  doi:10.7503/cjcu20180246

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Furfural was produced via fixed bed catalyzation and gas phase neutralization, in order to optimize the clean production process and solve the problem of the low resource utilization and environmental pollution in furfural industry. In the fixed bed catalytic process, the effects of acid concentration of catalyst sulfuric acid, the original concentration of xylose solution and added cocatalysts on the yield of furfural were investigated. In the gas phase neutralization process, the effects of metal cation and anion on the yield and the acidity of furfural were investigated. The results show that the yield of furfural can achieve 74.12% in the suitable conditions, which are 2 mol/L sulfuric acid, 10% xylose solution(mass fraction), 80 g NaCl. In the gas phase neutralization process, the influence of anion on the furfural yield is S$O^{2-}_{4}$>Cl^->C$O^{2-}_{3}$>OH^-, however, the metal cation had little effect. The acidity of furfural prepared by gas phase neutralization all conforms to the national standard GB/T 1926.1-2009.



Polymer Chemistry

Facile Synthesis of Hollow Silica Particles and Fine Tuning Their Structures^†

MENG Qingnan, WANG Kai, TANG Yufei, ZHAO Kang

2018, 39(11):  2550-2555.  doi:10.7503/cjcu20180433

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First, by adjusting the dosages of citric acid, resorcinol formaldehyde resin(RF) particles with different sizes were prepared. Then, hollow silica particles(h-SiO₂) with raspberry-like morphologies were synthesized using the RF particles as acid-dissolvable templates. If the citric acid concentration was fixed, smaller h-SiO₂ with smoother surface were produced as more FeCl₃ was added. In addition, the Fe ions also facilitated the removal of the RF templates, leading to formation of the h-SiO₂ with larger surface areas. Along this way, Au nanoparticles loaded h-SiO₂(Au@h-SiO₂) had also been produced, which showed good catalytic performance in MB reduction. Therefore, a facile and flexible method was provided here to construct the h-SiO₂ with different structures, which may find potential applications in many fields.



Molecular Dynamics Investigation of Adhesion Between CL-20/TNT Co-crystal Surfaces and Adhesives of PLA, PCL, P(LA-co-CL)^†

LIU Bei, GAO Pei, LI Shenshen, XIAO Yunqin, XIAO Jijun

2018, 39(11):  2556-2564.  doi:10.7503/cjcu20180331

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Molecular dynamics simulations were performed to study the adhesion properties of green adhesives onto four different co-crystal surfaces of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexazisowurtziane/2,4,6-trinitrotoluene(CL-20/TNT). The green adhesives studied in this article include polyactic acid(PLA), polycaprolactone(PCL) and their copolymer[P(LA-co-CL)]. Simulations of the bulk polymers were employed over a wide range of temperatures including the volumetric glass transition temperature, so as to validate the force field used. The computed glass transition temperatures and densities compare well with experiment and calculation based on group additive method. Simulations of the interfaces show that the wettability are obviously greater for the crystal surfaces and adhesive molecules both having much polarity. The pair correlation function computations illustrate that in this case, there are apparently a number of H-O atom pairs in 0.5 nm ranges among these interfaces. The wettability for PCL with lowest polarity among the three adhesive molecules on all crystal surfaces studied here are all significantly smaller.



Nanomechanics of Polyphenylacetylene Derivatives by AFM-based SMFS^†

LI Xun, WANG Xiao, YAO Ruixiang, SUN Jingzhi, ZHANG Wenke

2018, 39(11):  2565-2571.  doi:10.7503/cjcu20180261

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We quantitatively investigated the effect of iodine and pH on the stability of the helical structure formed by polyphenylacetylene derivatives using atomic force microscopy(AFM) based single-molecule force spectroscopy(SMFS) and circular dichroism(CD). The AFM measurement results showed that the addition of iodine into the system caused the decrease of the plateau heights in the stretching curves recorded during the SMFS experiments. In addition, the pH value increase can weaken the intra-polymer hydrogen bond and interrupt the integrity of the helical structure. However, the CD result did not show any detectable changes upon the addition of iodine and the change of pH value, which indicate that SMFS is a very sensitive and powerful method for subtle structure study.



Research on Self-healing Insulating Material Based on Host-guest Cooperation^†

LIN Musong, PENG Lei, FU Qiang, QIAN Yihua, CHEN Tiansheng, ZHANG Sheng, MA Xiaoqian

2018, 39(11):  2572-2580.  doi:10.7503/cjcu20180236

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In order to solve the damage and crack of the insulating material during the installation and operation of the power cable, we prepared a self-healing cable insulating material PVP/p(HEMA-co-BA). This self-healing material was synthesized by the radical polymerization using HEMA, BA, PVP and a host-guest assembly, which is assembled through the interaction between the host(CD-Al₂O₃ NPs) and guest molecule(HEMA-Ad). The material was characterized by infrared spectroscopy, 2D infrared spectroscopy, ¹H NMR spectroscopy, ¹³C NMR spectroscopy, dynamic thermomechanical analyzer, universal tensile tester, and 3D ultra-depth of focus microscopy. The results show that there are two kinds of supramolecular interactions(the host-guest interaction and the hydrogen bond) in the material. The self-healing material PVP/p(HEMA-co-BA) has good thermal stability(the heat-resisting temperature can reach 200 ℃) and good insulation property. It also has property of self-healing and can self-heal for many times. The storage modulus of the material increases(up to 432 MPa) with the increase of the cross-linking agent at 20 ℃. The self-healing efficiency decreases with the cross-linking agent increases.



Preparation of Hollow/Porous Crosslinkable Hyperbranched Polyaryletherketone Microspheres^†

QIN Shi, JING Liwei, ZHANG Chunfeng, WANG Guibin, ZHANG Shuling

2018, 39(11):  2581-2585.  doi:10.7503/cjcu20180232

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Amino-terminated hyperbranched polyaryletherketone(NH₂-HPAEK) was synthesized. Then the hollow/porous microspheres with NH₂-HPAEK as core and polyvinyl alcohol(PVA) as shell were prepared by the solvent-volatilization method, in which PVA aqueous solution was used as the continuous phase, and NH₂-HPAEK tetrahydrofuran solution was used as disperse phase. Finally, the structure of the hollow/porous microspheres was fixed by the crosslinking reaction between the amino groups of NH₂-HPAEK and aldehyde groups of glyoxal. The crosslinked hollow/porous microspheres have structural stability and are suitable for use in harsh environments.



Synthesis of Oxygen-bridged Binuclear Titanium and Nickel Complexes and Application in Catalysis of Bimodal Polyethylene^†

WANG Tieshi, CHEN Jianjun, YE Lin, ZHANG Aiying, FENG Zengguo

2018, 39(11):  2586-2593.  doi:10.7503/cjcu20180216

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To explore the potential of oxygen-bridged bisphosphinimine titanium and nickel complexes possessing bimetallic centers as catalysts for olefin polymerization, two oxygen-bridged diphosphorus compounds, named bis-(2-diphenylphosphino) phenylether(1a) and 9,9-dimethyl-4,6-bis(diphenylphosphino)xanthene(1b), were synthesized. After Staudinger reaction with Me₃SiN₃ in toluene under reflux, compound 1a with a flexible diphenyl ether bridge was converted into the bisphosphinimine precusor, while compound 1b with a rigid xanthene bridge was transformed into the monophosphinimine one. Subsequently, the dehalosilylation with CpTiCl₃ afforded the corresponding phosphinimine titanium complexes 3a and 3b, respectively. Single titanium center complex 3b further reacts with NiBr₂(DME) to translate into titaniumnickel heteronuclear bimetallic complex 4b. The structures of the complexes were characterized by ¹H, ¹³C, ³¹P NMR and elemental analyses. And the molecular structures of complexes 3a and 4b were further determined by single-crystal X-ray diffraction analysis. When activated by the methylaluminoxane(MAO), complexes 3a and 4b displayed high catalytic activity for ethylene polymerization. The bimetallic titanium complex 3a produced a wide molecular weight distribution polyethylene product, while the titanium-nickel heteronuclear bimetallic complex 4b gave rise to the bimodal polyethylene product.



Synthesis, Characterization and Cell Imaging of Water Soluble Polythiophene Derivative^†

WANG Fengyan, YAN Ni, WEI Junji, XIA Huiyun, SONG Lifang, SONG Jiale, GAO Lining, YAN Luke

2018, 39(11):  2594-2600.  doi:10.7503/cjcu20180204

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A new polythiophene derivative, random copolymer of N,N,N-trimethyl-2-(2-{2-[2-(thiophen-3-yl)ethoxy]ethoxy}ethoxy)ethanaminium bromide and(4-{[2-(2-{2-[2-(thiophen-3-yl)ethoxy]ethoxy}ethoxy)ethyl]carbamoyl}phenyl)boronic acid, abbreviated as PT-2, was synthesized through FeCl₃ oxidative polymerization reaction. Its optical properties and applications in cellular imaging were investigated. The UV-Vis absorption and fluorescence emission spectra were measured in water solution, the absorption maximum is 419 nm, emission maximum is 579 nm, molar absorption coefficient is 4.6×10³ L/(mol·cm), fluorescence quantum yield is 12%. Dynamic light scattering test showed that the average particle size of its aggregates formed in water was about 234 nm. Under the irradiation of mercury lamp(100 W), PT-2 exhibits a satisfactory photostability. Moreover, after co-culture with human lung cancer(A549) cells for 24 h, PT-2 shows low cytotoxicity and could be enriched in the cytoplasm. It’s fluorescence image could superposed well with lysosome-specific dye(Lyso Tracker Blue DND-22). Thus, PT-2 has potential application value in lysosomal-specific cell imaging.



Preparation of Flexible and Conductive Lignosulfonate-polypyrrole Paper by Self-assembly Polymerization^†

HUANG Wenjing, DING Zixian, QIU Xueqing, YANG Dongjie

2018, 39(11):  2601-2610.  doi:10.7503/cjcu20180122

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Flexible and load-controllable lignosulfonate-polypyrrole conductive paper with high-stability was prepared by self-assembly polymerization method using lignin derived from the pulping liquor as dispersant and dopant. The infrared spectroscopy(IR), scanning electron microscope(SEM), conductivity, tensile strength and electrochemical tests were used to characterize the properties of the conductive paper. The effects of dopants and assembled layers on electrical and mechanical properties of the conductive paper were also investigated. The results showed that the loading amount, conductivity and stability of lignosulfonate-polypyrrole paper were improved with the increase of layers, and the load was linearly correlated with the number of layers. Compared with in-situ polymerization, the conductive paper prepared by self-assembly polymerization had better properties. Lignosulfonate not only played a role as dispersant and dopant but also better improved the comprehensive performance of the conductive paper than hydrochloric and polystyrene sulfonic. More importantly, since lignosulfonate had a three-dimensional network structure and strong interaction with the fibres, the conductive stability under various bending states and the tensile strength of conductive paper were remarkably improved. The oxidation resistance and waterproof of lignosulfonate could also increase the conductive stability of conductive paper in air and moisture.