Chemical Research in Chinese Universities

Chemical Research in Chinese Universities Vol.31 No.6 December 2015

2015, 31(6): 0-0.

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Ionic Liquid-assisted Formation of Lanthanide Metal-organic Framework Nano/Microrods for Superefficient Removal of Congo Red

XIAO Yi, CHEN Fang, ZHU Xixi, QIN Hongling, HUANG Hongmei, ZHANG Youyu, YIN Dulin, HE Xiaoxiao, WANG Kemin

2015, 31(6): 899-903. doi:10.1007/s40242-015-5237-5

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New lanthanide metal-organic framework(MOF) nano/microrods, [C₄mim]Cl-Eu-MOF, [C₈mim]Cl-Eu- MOF and [C₁₂mim]Cl-Eu-MOF, were conveniently synthesized via an ionic liquid-assisted hydrothermal method and characterized by means of powder X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), thermogravimetric analysis(TG) and transmission electron microscopy(TEM). The obtained nano/microrods with low surface areas were efficient for the removal of Congo red(CR) from aqueous solutions. Under the optimum conditions, [C₄mim]Cl-Eu-MOF with a specific surface area of 5.1 m²/g exhibited an ultrahigh adsorption capacity of 2606 mg/g toward CR. Notably, the adsorption efficiency of [C₄mim]Cl-Eu-MOF for CR via nano/microscale stacking can be directly demonstrated by TEM. In-depth understanding of CR removal by [C₄mim]Cl-Eu-MOF nano/microrods was also supported by FTIR, Raman spectroscopy and zeta potential analyses.

Concentric Circular Approach in Mesoporous Silica Transition Process from Hexagonal to Vesicular Structure

HUANG Jue, XIE Shihang, MU Mingwei, PENG Ce, CAO Mengjing, YAO Youwei, CAI Qiang

2015, 31(6): 904-908. doi:10.1007/s40242-015-5137-8

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We studied the synthesis of mesoporous silica from cetyltrimethyl ammonium bromide(CTAB) and sodium dodecyl sulfate(SDS) at different molar ratios(R). X-ray diffraction(XRD), scanning electron spectroscopy (SEM), transmission electron spectroscopy(TEM) and nitrogen sorption analysis were then used to further investigate the internal relationship among different morphologies and structures, as well as the mechanism of the transition from hexagonal to vesicular structure. The results reveal that as R increased, a consistent and gradual transition occurred via a concentric circular secondary structure formed. The antagonistic effect between the decreasing curvature of surfactant micelle and increasing curvature of secondary structures may be the reason for the complex morphologies synthesized, and the increasing bending energy ΔG_b is the main driving force for the transition.

Quantitative Determination of Cr in Ink by Laser-induced Breakdown Spectroscopy(LIBS) Using ZnO as Adsorbent

WEI Jiao, ZHANG Tianlong, DONG Juan, SHENG Liwen, TANG Hongsheng, YANG Xiaofeng, LI Hua

2015, 31(6): 909-913. doi:10.1007/s40242-015-5210-3

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Laser-induced breakdown spectroscopy(LIBS) technique was applied to detecting chromium in ink with ZnO as adsorbent, and the LIBS spectra were preprocessed by wavelet denoising. The laser energy and delay time were optimized depending on the signal-to-noise ratio(SNR) and intensity of three analysis atomic lines(Cr 425.43 nm, Cr 427.48 nm and Cr 428.97 nm). Compared with other analysis lines, atomic line of Cr 427.48 nm was selected as the analysis line for the quantitative analysis of Cr in ink as the calibration curve of it showed a better linear relationship (correlation coefficient R²=0.9778), and the relative error of Cr in the measured ink was 52.96%. Since the single spectral line used for calibration curve method is often influenced by matrix effect and other factors, partial least squares regression(PLS) as multivariate calibration method has been applied to predicting the concentration of Cr in ink, and the relative error of Cr in the measured ink was 10.48%. The result obtained from the PLS method was better than that from the calibration curve when comparing the relative error, demonstrating that, based on adsorbent, LIBS combined with PLS provides an effective, practical and convenient technique for the determination of trace element in aqueous solution.

Studies on Intestinal Transport of Ginsenoside Compatibility with Veratrum nigrum via Caco-2 Cell Monolayer Model Coupled with UPLC-ESI-MS Method

MA Yinghui, LIU Yuanyuan, WEI Mengying, SONG Fengrui, LIU Zhongying, PI Zifeng

2015, 31(6): 914-918. doi:10.1007/s40242-015-5207-y

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The Caco-2 cells have been recognized as effective tools to be applied to imitating the drug absorption in human intestine for the transport of drug. Herein, Caco-2 cell monolayer model was used to study the transport of the ginsenoside compatibility with Veratrum nigrum in different proportions. A specific high performance liquid chromatography-electrospray ionization-mass spectrometry(HPLC-ESI-MS) method was developed for the semiquantitative determination of ginsenoside in intestinal transport with Dioscin as an internal standard. For the Caco-2 model constructed, two influencing factors were investigated, including time and concentration. The results suggest that the absorption of ginsenoside Re, Rg1, Rb1, Rc, Rb2 and Rd are time- and concentration-dependent and the excretions of Rb1, Rc, Rb2 and Rd have a relatronship with some transport proteins. The bioavailability of the ginsenosides has reduced compared to the single Panax ginseng extract when compatibility with a certain amount of Veratrum nigrum.

Azomethine-H as a Highly Selective Fluorescent Probe for Fe³⁺ Detection in 100% Aqueous Solution and Its Application in Living Cell Imaging

YU Fang, QIN Liyuan, SHANG Zhuobin, DONG Zhenming, WANG Yu, JIN Weijun

2015, 31(6): 919-924. doi:10.1007/s40242-015-5163-6

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A simple assay for the detection of Fe³⁺ in water by means of fluorescence spectroscopy was developed based on a commercially available reagent, Azomethine-H(A-H), allowing sensing trace levels of Fe³⁺ with high selectivity over other cations. A significant fluorescence quenching of A-H at 424 nm was found after its binding with Fe³⁺ in 100% aqueous solution at pH=7.0, while other physiologically relevant metal ions posed little interference. The fluorescence responses can be well described by the modified Stern-Volmer equation. A good linear relationship(R²=0.9904) was observed up to 1.6×10^-5 mol/L Fe³⁺ ions. The detection limit, calculated via the 3σ IUPAC(international union of pure and applied chemistry) criteria, was 1.95×10^-7 mol/L. Moreover, the colorimetric and fluorescent response of A-H to Fe³⁺ can be conveniently detected by the naked eye, providing a facile method for visual detection of Fe³⁺. The proposed method was used to determine Fe³⁺ in water samples. Moreover, inverted fluorescence microscopy imaging using human umbilical vein endothelial cells shows that A-H can be used as an effective fluorescent probe for detecting Fe³⁺ in living cells.

Syntheses and Crystal Structures of Functionalized Tetramethyl Resorcinarenes

MU Huarong, ZHOU Rui, SUN Jing, YAN Chaoguo

2015, 31(6): 925-929. doi:10.1007/s40242-015-5235-7

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Tetramethyl resorcinarene, which was obtained by acidic condensation of resorcinol with paraacetoaldehyde, was chemically modified to the functionalized O-acyl, O-tosyl and O-acetate derivatives by corresponding acylation, p-toluenesulfonylation and alkylation reactions. The single crystal structures of these functionalized resorcinarenes and the complex of tetramethyl resorcinarene with 2,2'-bipyridine were determined by X-ray diffraction method. All these resorcinarenes adopt the all-cis configuration with four methyl groups stretching to the down rim and form 1D or 2D structures through H-bonds.

Synthesis of (thia)Calixarene-based exTTF Derivatives and Their Electron Transfers Towards p-Chloranil and C₆₀

ZHAO Bangtun, CHEN Xiuhua, MA Shuxiu, ZHU Weimin

2015, 31(6): 930-935. doi:10.1007/s40242-015-5220-1

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Two novel (thia)calixarene-based exTTF derivatives(3a and 3b) were prepared by Mitsunobu reactions in toluene using diethyl azodicarboxylate(DEAD) and triphenylphosphine(PPh₃) system. The cyclic voltammograms of compounds 3a and 3b were provided, and two electron-irreversible waves with redox potentials were observed. Meanwhile, the intermolecular electron transfer(ET) properties of both compounds 3a and 3b towards p-chloranil(Q) and C₆₀ were investigated via UV-Vis and fluorescent spectroscopies, respectively. The results indicated that the introduced nonoxidable metal ions(Al³⁺, Pb²⁺, Sc³⁺) might promote the intermolecular ET from compounds 3a and 3b towards Q ensembles, whereas the effects of Sc³⁺ were the most impressive. Furthermore, the effects of the same metal ions(Al³⁺, Pb²⁺, Sc³⁺) added for compound 3b were greater than those for compound 3a. Additionally, the photoinduced intermolecular ET from compounds 3a and 3b towards C₆₀ was observed.

Synthesis, Characterization and Biological Activity of Tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine Derivatives asEpidermal Growth Factor Receptor Inhibitors

SUN Bing, YIN Xiu'e, ZHANG Jin, HUANG Jian, XU Yue, ZHANG Furong, WANG Jinhui, WANG Guoqing, HU Chun

2015, 31(6): 936-941. doi:10.1007/s40242-015-5202-3

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Based on the molecular docking studies, which were performed to position Erlotinib and the target compounds into the active site of the epidermal growth factor receptor(EGFR) to determine the probable binding model, a novel series of 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivatives as the novel potential EGFR kinase inhibitors was designed and synthesized. The antitumor activity of all the target compounds against human pulmonary carcinoma cell line A549 has been screened. Of all the target compounds, 4-[2-(1-piperidyl)carbonylmethoxyl- phenthio]-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine(7j) demonstrated the most potent antitumor activity. Several of the target compounds exhibited moderate antitumor activity. The preliminary structure-activity relationships of some target compounds were summarized.

Structure-based Design, Synthesis and Anti-influenza A Virus Activities of Substituted Phenyl-coupled Heterocyclic Ethylamide Derivatives

WANG Yang, LEI Fan, LI Xiaolong, HE Yi, LI Jue, QIU Rui, WU Xueying, HAI Li, WU Yong

2015, 31(6): 942-951. doi:10.1007/s40242-015-5197-9

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A series of new substituted phenyl-coupled heterocyclic ethylamide derivatives was designed and synthesized as anti-influenza agents. In vitro anti-influenza A(A/PR/8/34 H1N1 strain) activities of these compounds were investigated and compared to those of the commercial antiviral drugs(Arbidol and Ribavirin) against the influenza. Specifically, among these twelve compounds exhibiting moderate levels of antiviral activity against influenza A, compounds 30c and 30d are the most effective ones, and as efficacious as the positive control Ribavirin and much more effective than Ingavirin and Arbidol, indicating that they are prospective candidates for further exploration. These results are also consistent with the docking study results in terms of the design of compounds targeting influenza A via viral nucleoprotein.

Design and Synthesis of 1-Glycosyl-4-{N-[(2'-morpholinethoxy)-phenyl]aminomethyl}-1H-1,2,3-triazoles as Calcium Activators

LI Yuxin, DI Fengjuan, WANG Duoyi, CHEN Wei, WAN Yingying, LI Zhengming

2015, 31(6): 952-957. doi:10.1007/s40242-015-5134-y

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A series of novel 1-glycosyl-4-{N-[(2'-morpholinethoxy)phenyl]aminomethyl}-1H-1,2,3-triazoles was designed and synthesized through a simple and efficient multistep synthetic method in good yields. The 1,2,3-triazole moiety acted as a single disubstituted ring and a linker between carbohydrates(D-glucose, D-galactose, maltose and lactose) and morpholine. The compounds were characterized by ¹H NMR, ¹³C NMR and mass spectra(MS). Two different deprotection methods were discussed. The effects of compounds 5a, 5c and 6e on the intracellular calcium ion concentration([Ca²⁺]_i) in the central neurons of S. exigua were well investigated by calcium imaging technique. The results demonstrated that compound 6e could elevate the calcium concentration in the glial cells, not in the neurons.

Design, Synthesis and Biological Evaluation of Novel Benzothiazole Derivatives Bearing Semicarbazone Moiety as Antitumor Agents

MA Junjie, HU Gang, XIE Lijun, CHEN Lei, XU Boxuan, GONG Ping

2015, 31(6): 958-963. doi:10.1007/s40242-015-5034-1

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A series of novel benzothiazole derivatives bearing semicarbazone as a linker was designed and synthesized, and their in vitro antitumor activities were evaluated against four cancer cell lines(HT29, H460, A549 and MDA-MB-231). Most of them showed moderate to excellent activity against all the tested cell lines. Among them, compounds 12a―12i with fluoro-substituted benzyl-1H-indole moiety displayed more potent activity than those with phenyl moiety. The most promising compound 12d exhibited excellent antitumor activity with IC₅₀ values of 0.015, 0.28, 1.53 and 0.68 μmol/L against the four tested cell lines respectively.

Design, Synthesis and Antitubulin Activity of Novel Podophyllotoxin Derivatives as Potent Anticancer Agent

BAI Lifei, WANG Renlei, ZOU Ye, XU Guohua

2015, 31(6): 964-969. doi:10.1007/s40242-015-5325-6

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Twenty novel podophyllotoxin derivatives(1―20) were designed and synthesized. The anti-proliferation activities of these compounds were evaluated against three human cancer cell lines(HepG2, Calu-1 and MCF-7) using podophyllotoxin and Combretastatin A4(CA-4) as positive controls. Among all the compounds, compound 2 displayed more significant anti-proliferation activities against MCF-7 and Calu-1 cell lines and showed lower toxicity towards non-cancer cells. Furthermore, the cell cycle and apoptosis analysis results revealed that compound 2 can cause cell arrest at G2/M phase, leading to cancer cell apoptosis. Meanwhile, it can also reduce the adhesive ability of Calu-1 cells to fibronectin and laminin. The docking simulation results demonstrated that compound 10 can nicely bind to the colchicine site of tubulin. The podophyllotoxin derivatives are worthy to be further investigated to obtain more potent anti-cancer drugs.

Cytotoxicities, Telomerase and Topoisomerases I Inhibitory Activities and Interactions of Terpyridine Derivatives with DNAs

WEI Chunying, GAO Ning

2015, 31(6): 970-975. doi:10.1007/s40242-015-5256-2

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A novel compound 4-methyl-7-{[4-(2,2':6',2''-terpyridin-4'-yl)benzyl]amino}-2H-chromen-2-one(1) was synthesized, and its DNA-binding properties, cytotoxicity, and telomerase and Topo I inhibitory activities were evaluated. For comparison, the anti-proliferative and Topo I inhibitory activities of another two analogues 2 and 3 were also investigated. Compound 1 is able to stabilize the structures of human telomere(h-tert) and promoter(c-myc and c-kit2) G-quadruplexes and h-tert i-motif. The association constants(K_b) are about 10⁶ L/mol for h-tert G-quadruplex and i-motif, while the values are about 10⁵ L/mol for both promoter G-qaudruplexes and calf thymus DNA(ct-DNA). The binding of compound 1 induces the change of h-tert G-quadruplex from hybrid to antiparallel structure and exhibits 88.7% inhibition of telomerase activity at 8 mmol/L. Both compounds 1 and 3 inhibit significantly Topo I-mediated relaxation of pBR322 DNA. Compounds 1 and 2 show a high inhibitory efficacy on HepG2 and MCF-7 cancer cell lines with IC₅₀ values of about 10^-6 mol/L. The three compounds also induce a delay of cell cycle progression. The coumarin group is vital for improving the biological activity of terpyridine derivatives.

Silica Nanoparticles-mediated Stable Genetic Transformation in Nicotiana tabacum

FU Yuqin, LI Luhua, WANG Hui, JIANG Yuan, LIU Huijing, CUI Xiyan, WANG Piwu, LÜ Changli

2015, 31(6): 976-981. doi:10.1007/s40242-015-5088-0

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Nanoparticles as gene carriers become popular in the mammalian cells, whereas the application of them in plant cells is still very limited. Herein lies a report on silica nanoparticles(SiNPs) modified with positively charged poly-L-lysine(PLL) successfully delivering plasmid-encoded β-glucuronidase(GUS) gene into tobacco with the help of gene gun. The stable transgenic tobacco plants mediated by SiNPs can be obtained. Furthermore, we revealed the quantity of gene and types of receptor materials could affect the expression efficiency. In comparison to conventional gold particles-mediated transformation, the silica nanoparticles-mediated stable genetic transformation enhances transformation efficiency, potentially overcoming transgenic silencing. Our results demonstrate the great potential of SiNPs as gene carrier in plant genetic transformation and prove a novel approach for plant genetic decoration.

New Investigation of Potential Acting on an Electron in a Molecule to Draw Molecular Faces

DU Xia, ZHU Yijing, LIU Shuang, ZHAO Dongxia

2015, 31(6): 982-986. doi:10.1007/s40242-015-5283-z

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A new approach to calculate the potential acting on an electron in a molecule(PAEM) has been established for drawing the molecular face(MF) of a macromolecule, according to the classic point charge model and the atom-bond electronegativity equalization method(ABEEMσπ) for one electron in a molecule. We introduced a dynamic charge distribution from the view of a local electron movement in a molecule based on the new approach, and as further direct evidence, we calculated some physical quantities using the original ab initio method and the new method to verify the accuracy of the method, such as the boundary distance(BD), molecular face surface area(MFSA) and molecular reactivities indicated by the MFs for a variety of organic molecules. All the results by the new method are in agreement with the results by ab initio method.

Low-temperature Heat Capacity and Standard Thermodynamic Functions of D-Galactose and Galactitol

CHENG Ze, XUE Bin, TAN Zhicheng, SHI Quan

2015, 31(6): 987-991. doi:10.1007/s40242-015-5263-3

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The heat capacities of D-galactose and galactitol were measured on a quantum design physical property measurement system(PPMS) over a temperature range of 1.9―300 K, and the experimental data were fitted to a function of T using a series of theoretical and empirical models in appropriate temperature ranges. The fit results were used to calculate thermodynamic function values,C_p,m^θ,Δ₀^TS_m^θ, and Δ₀^TH_m^θfrom 0 K to 300 K. The standard molar heat capacity, entropy and enthalpy values of D-galactose and galactitol at 298.15 K and 0.1 MPa were determined to be C_p,m^θ =(227.96±2.28) and (239.50±2.40) J·K^-1·mol^-1,S_m^θ= (211.22±2.11) and (230.82±2.30) J·K^-1·mol^-1 and = H_m^θ (33.95±0.34) and (36.57± 0.37) kJ/mol, respectively.

Effects of Donor and Acceptor on Optoelectronic Performance for Porphyrin Derivatives: Nonlinear Optical Properties and Dye-sensitized Solar Cells

MI Yongsheng, LIANG Pengxia, YANG Zhou, WANG Dong, CAO Hui, HE Wanliand YANG Huai

2015, 31(6): 992-996. doi:10.1007/s40242-015-5241-9

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Typical asymmetric donor-π-bridge-acceptor(D-π-A) zinc porphyrin dyes have been synthesized, and further modified by reacting the ethynyl groups of them with click reagent through a formal [2+2] click reaction. The electronic interaction between the push and pull electronic groups and the click reaction process were investigated by UV-Vis absorption spectroscopy. The nonlinear optical(NLO) properties of the dyes were studied by the Z-scan technique and clearly reverse saturable absorption to saturable absorption(RSA-SA) transition could be observed through click reaction of the dyes with TCNE. Furthermore, the photovoltaic properties of these porphyrin dyes were reaso- nably explained by the J-V curve fitting based on the equivalent-circuit model as well as the comparison between the absorption and incident-photon-to-current-conversion efficiency(IPCE) spectra. Besides, these dyes with different donors or acceptors could self-assembly into different microstructures by phase transfer methodology.

Facial Preparation of Magnetic Lipase as Efficient Biocatalyst to Resolute Esters Enantioselectively

ZHANG Yanmei, QUAN Chunshan, LIU Baoquan, FAN Shengdi

2015, 31(6): 997-1002. doi:10.1007/s40242-015-5209-9

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Magnetic lipase was prepared by a facial and cost-effective method. Lipase from Pseudomonase cepacia was covalently linked to Fe₃O₄ nanoparticles, which were produced by co-precipitating Fe²⁺ and Fe³⁺ ions in ammonia solution and subsequent coating with 3,4-dihydroxylaldehyde. Magnetic Fe₃O₄ nanoparticles modified with 3,4-dihydroxylaldehyde bonded lipase efficiently(47 mg/g). The resulting magnetic-lipase is active(0.68 μmol·min^-1·mg^-1) and enantioselective(e.e. of the product >98%) in the hydrolysis of racemic 1-phenylethyl acetate. Furthermore, as a heterogeneous catalyst, the magnetic-lipase can be magnetically recycled, and a retained activity of 48% was obtained even after 6 cycles.

Pd/AlF₃ Catalysts for Catalytic Dehydrofluorination of 1,1,1,3,3-Pentafluoropropane

WANG Fang, ZHANG Wenxia, LIANG Yan, WANG Yuejuan, LU Jiqing, LUO Mengfei

2015, 31(6): 1003-1006. doi:10.1007/s40242-015-5190-3

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A series of Pd/AlF₃ catalysts was prepared by an impregnation method and tested for vapor-phase dehydrofluorination of 1,1,1,3,3-pentafluoropropane(HFC-245fa) to synthesize 1,3,3,3-tetrafluoropropene(HFO-1234ze). The highest activity was obtained over Pd/AlF₃ catalyst containing 1.0%(mass fraction) of Pd, with an HFC-245fa conversion of 79.5% and an HFO-1234ze selectivity of 99.4% after the reaction at 300 ℃ for 100 h. The reactivity was related to the surface acidity, as AlF₃ provided active sites for the reaction. With the addition of Pd, the catalyst stability could be significantly improved. Raman spectroscopic and thermal-gravimetric analysis results reveal that there was less carbon deposit on spent Pd/AlF₃ catalyst surface because Pd could effectively pyrolyse it. Thus, Pd/AlF₃ catalysts were bi-functional for dehydrofluorination of HFC-245fa.

Graphene Supported Platinum Nanoparticles as Catalyst for Oxygen Reduction Reaction

ZHANG Wenyu, WANG Zhixin, SHEN Yan, XI Muyao, CHU Xuebin, XI Chunyu

2015, 31(6): 1007-1011. doi:10.1007/s40242-015-5171-6

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Graphene supported Pt nanoparticles were fabricated via electrochemical reduction method and the application of them in oxygen reduction reaction was also investigated. The results of field emission scanning electron microscope(SEM), X-ray photoelectron spectroscopy(XPS) and Raman spectroscopy reveal that the interaction between Pt nanoparticles and graphene sheets can prevent graphene from agglomeration and improve the electronic conductivity of the composite. And the graphene supported Pt nanoparticles exhibit excellent electrocatalytic activity toward oxygen reduction reaction.

A Synergistic Strategy for Nanoparticle/Nanofiber Composites Towards p-Nitrophenol Catalytic Hydrogenation

WANG Wei, WANG Ke, HE Jiaojie, ZHANG Xintong, WANG Ce, ZHAO Zhiwei, CUI Fuyi

2015, 31(6): 1012-1017. doi:10.1007/s40242-015-5155-6

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Nanoparticle(NP)/nanofiber(NF) composites based on Ag/hydrostable-polyvinyl alcohol were fabricated by a green synergistic strategy via electrospinning. The electrospun NFs served as an in situ reducing agent for the metal salt precursors and a protecting agent for the resulting NPs. Additionallly, during the fomation of the NPs, the water-soluble NFs were in situ oxidized and catalyzed by the metal ions to achieve chemical crosslinking. This two-in-one process achieves polymer curing and metal nanoparticles reducing/protecting synergistically. It eliminates the usage of organic electrospinning solvents, conventional chemical reducing agents and stabilizers, as well as harmful chemical crosslinking agents during the whole process. By the absolutely green synergistic electrospinning, nanoparticle/nanofiber composites with super-hydrophilicity, good hydrostability, as well as uniform and thin particle sizes were obtained. They exhibited enhanced activities when used for catalytic hydrogenation of p-nitrophenol in water.

Mechanisms and Kinetics of Reaction CHClBr^·+NO₂

YANG Lei, LIU Yuyu, DUAN Xuemei

2015, 31(6): 1018-1022. doi:10.1007/s40242-015-5144-9

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The reaction CHClBr^·+NO₂ was investigated via quantum chemical methods and kinetic calculations. The reaction mechanism on the singlet potential energy surface(PES) was considered by B3LYP method, and the energies were calculated at the CCSD(T) and CASPT2 levels of theory. The rate constants and the ratios of products were obtained by utilizing VTST and RRKM methods over wide temperature and pressure ranges. Our results indicate that carbon-to-nitrogen approach via a barrierless process is preferred in the initial association of CHClBr^· and NO₂. The dominant product is BrNO+CHClO(P1), which agrees well with the experimental observation. P2(ClNO+CHBrO) and P3(HNO+CBrClO) may also have minor contributions to the reaction. The calculated overall rate constants are independent of pressure and consistent with the experimental data, which can be fitted with the following equation over the temperature range of 200—1500 K: k(T)=2.31×10^-15T^0.99 exp(771/T). Compared with reaction CH₂Br^·+NO₂, reaction CHClBr^·+NO₂ has decreased the overall rate constants.

Theoretical Investigation on Binding Process of Allophanate to Allophanate Hydrolase

ZHANG Zidong, ZHANG Jilong, ZHENG Qingchuan, KONG Chuipeng, LI Zhengqiang, ZHANG Hongxing, MA Jianzhang

2015, 31(6): 1023-1028. doi:10.1007/s40242-015-5108-0

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Several molecular simulation methods were integrated to investigate the detailed binding process of allophanate to allophanate hydrolase and predict their stable complex structure. The optimal enzyme-substrate complex conformation demonstrates that along with Arg307 and Tyr299, Gly124 is also one of the key anchor residues in the stable complex. The energetic calculation suggests the existence of an intermediate state in the enzyme-substrate binding process. The further atomic-level investigation illuminates that Tyr299, Arg307 and Ser172 can stabilize the substrate in the intermediate state. By this token, the residues Arg307 and Tyr299 function in both binding process and getting stable state.

How Mutations Affecting the Ligand-receptor Interactions: a Combined MD and QM/MM Calculation on CYP2E1 and Its Two Mutants

WANG Yan, ZHENG Qingchuan, ZHANG Jilong, XIE Mo, ZHAN Jiuyu, ZHANG Hongxing

2015, 31(6): 1029-1038. doi:10.1007/s40242-015-5071-9

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Cytochrome P450(CYP) 2E1 is a dual function monoxygenase with a crucial role in the metabolism of 6% of drugs on the market at present. The enzyme is of tremendous interest for its association with alcohol consumption, diabetes, obesity and fasting. Despite the abundant experimental mutagenesis data, the molecular origin and the structural motifs for the enzymatic activity deficiencies have not been rationalized at the atomic level. In this regard, we have investigated the effects of mutation on the structural and energetic characteristics upon single point mutations in CYP2E1, N219D and S366C. The molecular dynamics(MD) simulation combined with quantum mechanics/molecular mechanics(QM/MM) and noncovalent interaction(NCI) analysis was carried out on CYP2E1 and its two mutants. The results highlight the critical role of Phe207, which is responsible for both structural flexibility and energetic variation, shortening the gap between the theory and the experimentally observed results of enzymatic activity decrease. The underlying molecular mechanism of the enzymatic activity deficiencies for mutants may be attributed to the changes of spatial position of Phe207 in the two mutants. This work provides particular explanations to how mutations affect ligand-receptor interactions based on combined MD and QM/MM calculations. Furthermore, the mutational effects on the activity of CYP2E1 obtained in the present study are beneficial to both the experimental and the computational works of CYPs and may allow researchers to achieve desirable changes in enzymatic activity.

Synthesis, Spectroscopic, Thermochemical Properties of Lanthanide Complexes with 3,4-Diethoxybenzoic Acid and 1,10-Phenanthroline

QI Xiaoxia, REN Ning, ZHANG Dahai, ZHANG Jianjun

2015, 31(6): 1039-1045. doi:10.1007/s40242-015-5052-z

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Three novel lanthanide complexes [Ln(3,4-DEOBA)₃phen]₂[Ln=Eu(1), Tb(2), Dy(3); 3,4-DEOBA=3,4- diethoxybenzoate; phen=1,10-phenanthroline] were synthesized and characterized by elemental analysis, molar conductance, X-ray diffraction and infrared spectrometry. The luminescence spectra of complexes 1 and 2 show the characteristic emission of Eu³⁺ ion(⁵D₀→⁷F_0—3) and Tb³⁺ ion(⁵D₄→⁷F_6—3). The thermal decomposition mechanism of the title complexes and the analysis of the evolved gases were investigated by thermogravimetry/differential scanning calorimetry-Fourier transform infrared(TG/DSC-FTIR) technology. The results indicate the complexes are thermally stable. In the thermal decomposition of the complexes, phen molecules lost firstly, and then 3,4-DEOBA ligand decomposed into H₂O, CO₂ and other gaseous molecules. Besides, several gaseous organic fragments were also detected. The heat capacities of complexes 1―3 were measured by DSC in a temperature range of 263.15―340.15 K. Based on the fitted polynomial and thermodynamic equations, the smoothed heat capacities and thermodynamic functions of the three complexes were calculated. The study on biological activity showed that the complexes exhibited good antibacterial activity against Candida albicans, Staphylococcus aureus and Escherichia coli.

Characterization of UV-curable Poly(ethylene glycol) Diacrylate Based Hydrogels

QIN Xuzhen, HU Qianqian, GAO Guanghui, GUAN Shuang

2015, 31(6): 1046-1050. doi:10.1007/s40242-015-5341-6

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Poly(ethylene glycol) diacrylate/polyvinyl alcohol(PEGDA/PVA) hydrogels were prepared from PEGDA and PVA as precurors by means of single UV radiation(UV ra.), UV radiation followed by high energy electron beam irradiation(Irra.), UV radiation followed by freeze-thawing(FT) or UV ra. and Irra. followed by FT, respectively. 2-Hydroxy-1-[4-(hydroxyethoxy)phenyl]-2-methyl-1-propanone(Irgacure 2959) was used as a photoinitiator. The effects of the various methods on the swelling and mechanical properties of the hydrogels were investigated. The results show that hydrogels made by UV ra. plus high energy electron beam irradiation followed by FT showed a higher crosslinking density and a larger tensile strength than those made by the other methods.

Synthesis and Dyes Adsorption Properties of Calix[4]crown-grafted Chitosan Chelating Polymer

FANG Xiaoting, GUO Hongyu, YANG Fafu, BAI Xiaoyan

2015, 31(6): 1051-1055. doi:10.1007/s40242-015-5242-8

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By the Schiff-base condensation of formacyl calix[4]crown(2) with raw chitosan, a novel calix[4]crown- grafted chitosan chelating polymer(3) was conveniently prepared in good yield. The structure of polymer 3 was confirmed by elemental analysis, infrared(IR) spectrometry and X-ray diffraction(XRD) analysis. The elemental analysis suggests that the grafting degree of calixcrown unit was 22% on the amino groups of chitosan. The morphological characteristic of polymer 3 was studied by scanning electron microscopy(SEM). Polymer 3 possessed loose porous and smooth morphology of surface. The dyes adsorption abilities of polymer 3 for a series of organic dyes[Orange I(OI), Neutral red(NR), Victoria blue B(VB) and Brilliant green(BG)] were studied by solid-liquid adsorption experiments. The adsorption percentages increased from 45%―60%(raw chitosan for dyes) to 75%―90%(polymer 3 for dyes). The highest adsorption percentage reached 89% for VB. The saturated adsorption capacities for OI, NR, VB and BG were as high as 622, 564, 854 and 781 mg/g, respectively. The adsorption abilities kept stable at 70%―90% in the scope of pH=5―9. The adsorption abilities for anionic dye(OI) decreased gradually with the increase of pH and the opposite trend was observed for cationic dyes(NR, BG, VB). The adsorption percentages were 70%―90% after five times' cycles for adsorption.

Anion Exchange Membranes Based on Chloromethylation of Fluorinated Poly(arylene ether)s

MEI Wenhai, WANG Zhen

2015, 31(6): 1056-1061. doi:10.1007/s40242-015-5236-6

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This report details the properties of fluorine-containing anion exchange membranes(AEMs) synthesized by chloromethylation and quaternization of fluorinated poly(arylene ether)s(FPAEs) based on decafluorobiphenyl and bisphenol A. Meanwhile, we compared their properties with those of their non-fluorinated counterparts, Udel-based AEMs. The reactivity of the chloromethylation of fluorinated poly(arylene ether)s was lowered by the strong electron-withdrawing group, per-fluorinated biphenyl residue. Therefore higher temperature, more chloromethylation reagent, and longer reaction time were needed in the chloromethylation of FPAEs. Because of the hydrophobicity of fluorine, the swelling of FPAEs was depressed. In the FPAE-based AEMs, the water uptake of FPAE-1 membrane(F-1) was just 30%. There is a strong correlation between water uptake and conductivity for both Udel- and FPAE-based AEMs. Among all the membranes, the water uptake and the conductivity of FPAE-3 membrane(F-3) could reach up to 100% and 13.47 mS/cm respectively at 30 ℃. The mechanical properties of FPAE-based AEMs at room temperature were worse than those of Udel-based ones because of the weak intermolecular interaction caused by the low polarizability of fluorine. However, their high temperature mechanical properties are better, which can be explained in terms of low swelling.

Preparation of Cu(II)-imprinted Nanofibers from co-Electrospinning PVA and Imprinting Complex

LIU Xuan, YANG Jiali, TONG Lanyan, ZHANG Qian, LI Xiaowei, CHEN Jida

2015, 31(6): 1062-1065. doi:10.1007/s40242-015-5208-x

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A novel method to prepare ion-imprinted nanofibers(IINFs), i.e., the electrospinning and ion imprinting technique is presented. The electrospinning solution was composed of the matrix polymer and the imprinting complex. The model fibrous ion-imprinted adsorbent[Cu(II)-IINF] was synthesized from poly(vinyl alcohol) as the matrix polymer and the complex of Cu(II) and L-histidine as the imprinting complex. The product was characterized by Fourier transform infrared spectrometry(FTIR) and the scanning electron microscopy(SEM), respectively. The adsorption of Cu(II)-IINF for Cu(II) was conducted by a batch of experiments. The adsorption capacity reached 114.75 mg/g at 45 ℃ and the selectivity coefficients of Cu(II)-IINF for Cu(II) relative to Pb(II), Ni(II) and Zn(II) were 51.6, 54.4 and 66.3, respectively. In addition, Cu(II)-IINF also has good regeneration performance and the efficiency of adsor- bing Cu²⁺ is about 88.3% of the initial adsorption capacity after five cycles. All these results demonstrate that the reported method for preparing fibrous ion-imprinted adsorbents is feasible, and Cu(II)-IINF is a promising adsorbent for the efficient removal and recovery of copper ions from the aqueous solution.

Synthesis and Electrochemical Properties of a Novel Poly(ether sulfone) with Oligoaniline Pendants

LI Fangfei, WANG Jiayu, ZHOU Mingjuan, LIU Xincai, WANG Ce, CHAO Danming

2015, 31(6): 1066-1071. doi:10.1007/s40242-015-5149-4

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A novel poly(ether sulfone) with oligoaniline pendants(PESOP) was prepared by K₂CO₃-mediated nucleophilic polycondensation and characterized with Fourier-transform infrared spectrometry(FTIR), ¹H nuclear magnetic resonance(¹H NMR) and gel permeation chromatography(GPC). The cyclic voltammetry(CV) curve of PESOP reveals the reversible electroactivity. In the electrochromism study, PESOP film exhibited good electrochromic properties with a high contrast value, moderate switching time and acceptable coloration efficiency. After running 1000 cycles, the PESOP/indium-tin oxide(ITO) electrochromic device remained unchanged except for the drifting of base line, which certified its good electro-photo stability of the fabricated electrochromic device. Moreover, the polarization technique and electrochemical impedance spectroscopy(EIS) were used to study the anticorrosion performance of PESOP coatings on the cold rolled steel(CRS) in a 5%(mass fraction) NaCl solution. All the results indicate that the obtained PESOP is a competitive candidate as anticorrosion material.

Highly Porous Amidoximed Carbon Nanofibers Supported Palladium(0) Nanoparticle Catalyzed Heck Reaction

MENG Qingrun, BAI Jie, GUO Shoujun, LI Chunping

2015, 31(6): 1072-1077. doi:10.1007/s40242-015-5093-3

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Highly porous amidoximed carbon nanofibers(AOCNFs), which were fabricated via a conventional electrospinning technique followed by chemically modification, impregnation-reduction and carbonization process, had been used for the immobilization of palladium nanoparticles(Pd NPs) catalyst. During the carbonization process, polystyrene(PS) was selectively decomposed from bicomponent fibers, generating porous fibers. Fourier transform infrared spectroscopy(FTIR) result revealed the functional groups on PAN-PS fibers(PAN=polyacrylonitrile), AOPAN-PS fibers and AOCNFs; scanning electron microscopy(SEM) was used to observe the morphology of all stages of nanofibers; transmission electron microscopy(TEM) result gave the structure of through-hole morphology clearly visible and the dispersion of Pd NPs on the surface of nanofibers; and X-ray photoelectron spectra(XPS) confirmed that Pd nanoparticles on the surface of AOCNFs was of the metallic state. Moreover, the as-prepared catalyst exhibited high catalytic activity and efficient recycle for Heck coupling reactions between iodobenzene and acrylates.

Retraction Note

FENG Deri, LIU Jiaan, LIANG Shuang, WANG Yanyan, XU Youjun

2015, 31(6): 1078-1078. doi:10.1007/s40242-015-5000-1

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