Chemical Research in Chinese Universities

Cover and Content of Chemical Research in Chinese Universities Vol.30 No.4(2014)

2014, 30(4): 0-0.

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co-Condensation Synthesis of Salicylaldimine Calcium Complex Containing Mesoporous Silica Nanoparticles as Carriers for Drug Release

TANG Duihai, ZHANG Weiran, WANG Yifan, MIAO Jing, QIAO Zhen'an, HUO Qisheng, ZHANG Lirong

2014, 30(4): 531-537. doi:10.1007/s40242-014-4097-8

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A series of functional mesoporous silica nanoparticles(MSNs) was synthesized by a one-step simple synthesis approach involving co-condensation of tetraethoxysilane(TEOS) and salicylaldimine ligand(Sal-Si) in the presence of cetyltrimethylammonium chloride(CTAC) under basic conditions. The target MSNs with different sizes (50, 100 and 200 nm, respectively) were obtained. Furthermore, the Ca²⁺ cations were also introduced into MSNs. The prepared nanoparticles were characterized by means of infrared(IR) spectra, thermogravimetric analysis(TGA), inductively coupled plasma(ICP), CHN elemental analysis, nitrogen adsorption-desorption, scanning electron microscope(SEM) and transmission electron microscope(TEM). Ibuprofen(IBU) which contains carboxyl groups was selected as a model drug. The results of drug loading and release reveal that the loading capacities and release behaviors of the model drug are highly dependent on the Ca²⁺ cations in MSNs. The release of IBU from the MSNs functionalized by Ca²⁺ cations is found to be effectively controlled when compared to the release from the MSNs without the functionalization of Ca²⁺ cations, which is due to the ionic interaction between carboxyl groups in IBU and Ca²⁺ cations in MSNs.

Rapid Synthesis and Photoluminescence Properties of Eu-doped ZnO Nanoneedles via Facile Hydrothermal Method

LANG Jihui, WANG Jiaying, ZHANG Qi, XU Songsong, HAN Qiang, ZHANG Yan, ZHAI Hongju, CAO Jian, YAN Yongsheng, YANG Jinghai

2014, 30(4): 538-542. doi:10.1007/s40242-014-4028-8

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Eu-doped ZnO nanoneedles with different doping concentrations were prepared via the facile hydrothermal method. The crystal structure, morphology and photoluminescence property of the ZnO nanoneedles were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS), photoluminescence spectroscopy(PL) and Raman spectroscopy. The results show that the europium ions are incorporated into the crystal lattice of ZnO matrix in trivalent ions. The nanoneedles are 2—3 μm in length and 100 nm in the tip diameter. PL and Raman measurements indicate that higher Eu³⁺doping concentration may destroy the crystallization of the nanoneedles and decrease the ratio of I_UV/I_DLE, which is mainly due to the more defects in the doped ZnO nanoneedles. And the characteristic red emissions of Eu³⁺ ions are found by the PL spectroscopy with the Eu³⁺ doping concentration increasing, which are attributed to the ⁵D₀→⁷F₀, ⁵D₀→<⁷F₁and ⁵D₀→⁷F₂ transitions.

Ca-P Conversion Coating on AZ60 Magnesium Alloy for Biomedical Application

CHENG Zhongji, LIAN Jianshe, HU Xiaoli, YANG Xiaohong, LI Guangyu

2014, 30(4): 543-548. doi:10.1007/s40242-014-4082-2

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To improve the anti-corrosion behaviors of magnesium alloy in the inner environment of human body, a bioactive Ca-P coating was deposited on the AZ60 magnesium alloy by a novel simple method. The morphologies of the Ca-P coatings formed under different treatment time were studied by scanning electron microscopy(SEM). The corrosion behaviors of Ca-P coating were investigated by electrochemical polarization test and electrochemical impedance spectroscopy in both 3%(mass fraction) NaCl solution and simulated body fluid(SBF). Immersion test in SBF was performed to evaluate the corrosion rate of Ca-P coated magnesium alloy. X-Ray diffraction(XRD) analysis result shows that the coating mentioned above mainly consists of dicalcium phosphate dehydrate(CaHPO₄·2H₂O, DCPD) and β-tricalcium phosphate dehydrate[β-TCP, Ca₃(PO₄)₂], which exhibits good corrosion resistance. After magnesium alloy was immersed in 1 mol/L NaOH solution at 80℃ for 2 h, hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂, HA] appeared on the magnesium alloy substrate, which can further decrease the corrosion rate of AZ60 magnesium alloy in SBF.

Synthesis and in vitro Evaluation of Manganese(II)-porphyrin Modified with Chitosan Oligosaccharides as Potential MRI Contrast Agents

LIU Yun, HUANG Yan, BOAMAH Peter Osei, ZHANG Qi, LIU Yuanyuan, HUA Mingqing

2014, 30(4): 549-555. doi:10.1007/s40242-014-4015-0

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Mn-TCPP-CS_n(n=6, 11, 20) as a type of potential magnetic resonance imaging(MRI) contrast agents were synthesized via manganese(II) meso-tetra(4-carboxyphenyl) porphyrin(Mn-TCPP) modified with chitosan oligosaccharides(CS_n). Experimental data of infared(IR), UV-Vis, MS, inductively coupled plasma-atomic emission spectrometer(ICP-AES) and size exclusion chromatography evidenced the formation of Mn-TCPP-CS_n. The stability results show that Mn-TCPP-CS_n in aqueous solution was stable enough to prevent Mn(II) ions from leaking. The magnetic properties in vitro indicate that Mn-TCPP-CS₂₀ possesses higher longitudinal relaxivity(r₁=10.38 L·mmol^-1·s^-1) in aqueous solution than unmodified porphyrin Mn-TCPPNa₄[manganese(II) meso-tetra(4-carboxyphenyl) porphyrin, tetrasodium salt](r₁=5.10 L·mmol^-1·s^-1) and the commercial contrast agent Gd-DTPA(r₁=4.05 L·mmol^-1·s^-1). The preliminary T₁-weighted flash image studies in vitro show that the contrast and the imaging signal of Mn-TCPP-CS_n were superior to those of Mn-TCPPNa₄ and Gd-DTPA under the same conditions. The 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide(MTT) assay shows that Mn-TCPP-CS_n has a good biocompatibility. In addition, the thermodynamical parameters(ΔH<0, ΔS<0, ΔG<0) of Mn-TCPP-CS_n bound to bovine serum albumin(BSA) show that Mn-TCPP-CS_n could bind to BSA spontaneously, where the binding complex was stabilized mainly by van der Waals interactions and hydrogen bonds. These results suggest that Mn-TCPP-CS_n have the advantage of becoming a potential MRI contrast agent.

Selective Growth of GaN on Slope Cone-shaped Patterned Sapphire Substrate

YANG Dechao, LIANG Hongwei, QIU Yu, LI Pengchong, LIU Yang, SHEN Rensheng, XIA Xiaochuan, YU Zhennan, CHANG Yuchun, ZHANG Yuantao, DU Guotong

2014, 30(4): 556-559. doi:10.1007/s40242-014-3556-6

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Cone-shaped patterned sapphire substrate was prepared by inductively coupled plasma etching and GaN nucleation layer was grown on it by metal-organic chemical vapor deposition. A selective growth of GaN nucleation layer was found on the slope of the cone-shaped patterned sapphire substrat, and the distribution morphology of GaN had significantly changed after it was recrystallized. GaN selective growth and redistribution were analyzed by investigating the distribution of crystallographic planes on the cone surface and the atom array of specific planes at atom level.

A Novel Coumarin-based Fluorescence Chemosensor for Fe³⁺

WANG Ruiping, WAN Qihua, FENG Feng, BAI Yunfeng

2014, 30(4): 560-565. doi:10.1007/s40242-014-3192-1

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A novel coumarin derivative[7-diethylamino-2-oxo-2H-chromene-3-carboxylic acid(6-amino-pyridin- 2-yl)-amide, CFe1] has been synthesized and its potential application as a chemosensor for the detection of metal ions has been further investigated. The responses of CFe1 to Fe³⁺ were studied by fluorescence emission spectrometry in the presence of other metal ions such as Al³⁺, Ba²⁺, Ca²⁺, Co³⁺, Cr³⁺, Cu²⁺, Fe²⁺, Hg²⁺, Mg²⁺, Mn²⁺, Na⁺, Ni⁺, Pb²⁺, Zn²⁺, K⁺, and Ag⁺. CFe1 showed a good selectivity for Fe³⁺ with fast response, a wide pH span of 3.3—9.18, and a large Stocks shift. CFe1 in the presence of Fe³⁺ and ethylene diamine tetraacetic acid(EDTA) makes the blue solution fade to colorless, which is due to the formation of CFe1-Fe³⁺ complex instead of any catalytic action of Fe³⁺. Furthermore, the imaging of Fe³⁺ in cultured single mice microglia cells was realized with the aid of CFe1, indicating that CFe1 has a great potential to be used as promising models for the future design of novel and robust chemosensor for metal ion detection in the field of biomedical and environmental analyses.

Differential Proteomics Analysis on Fluoride-resistant Streptococcus mutans by Label-free Quantitation

ZHAO Hongyan, ZHANG Zhimin, ZHU Laikuan,LI Zhenling, LI Penglian, LIU Jiabai, ZHANG Zhiying

2014, 30(4): 566-571. doi:10.1007/s40242-014-4035-9

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To figure out the changed biological characteristics of a fluoride-resistant strain compared with those of the parent sensitive strain of Streptococcus mutans(S. mutans) with the help of differential proteomics analysis, sixty- seven proteins with obvious differential expression were identified in fluoride-resistant strain. Among them are the important virulence factors causing caries, including glucosyltransferase-S, glucosyltransferase-I, glucosyltransferase-Si, major cell-surface adhesin Pac, F-ATPase β-subunit, Ffh, molecular chaperone DnaK, chaperonin GroEL, and the lactate dehydrogenase. We obtained the differential proteomics expression profiles of the fluoride-resistant strain(UA159-FR) and its parental strain(UA159) of S. mutans. Several important virulence factors bringing about caries were identified to have differential expressions, among which the expression of lactate dehydrogenase in fluoride-resistant strain was enhanced compared to that in its parent strain. The results could provide the basis for analysing the functions of proteins encoded by caries-related genes from the fluoride-resistant S. mutans strain.

Colorimetric Artificial Nose for Identification of Breath Volatile Organic Compounds of Patients with Lung Cancer

WU Yu, HUO Danqun, HOU Changjun, FA Huanbao, YANG Mei, LUO Xiaogang

2014, 30(4): 572-577. doi:10.1007/s40242-014-4005-2

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A novel and highly sensitive colorimetric sensor array was developed for the detection and identification of breath volatile organic compounds(VOCs) of patients with lung cancer. Employing dimeric metalloporphyrins, metallosalphen complexes, and chemically responsive dyes as the sensing elements, the developed sensor array of artificial nose shows a unique pattern of colorific changes upon its exposure to eight less-reactive VOCs and their mixture gas at a concentration of 735 nmol/L within 3 min. Potential of quantitative analysis of VOCs samples was proved. A good linear relationship of 490—3675 nmol/L was obtained for benzene vapor with a detection limit of 49 nmol/L(S/N=3). Data analysis was carried out by Hierarchical cluster analysis(HCA) and principal component analysis(PCA). Each category of breath VOCs clusters together in the PCA score plot. No errors in classification by HCA were observed in 45 trials. Additionaly, the colorimetric sensor array showed good reproducibility under the cyclic sensing experiments. These results demonstrate that the developed colorimetric artificial nose system is an excellent sensing platform for the identification and quantitative analysis of breath VOCs of patients with lung cancer.

Rapid Determination of Amino Acids in Ginseng by High Performance Liquid Chromatography and Chemometric Resolution

HAN Jing, WU Xi, CAI Wensheng, SHAO Xueguang

2014, 30(4): 578-581. doi:10.1007/s40242-014-3543-y

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Ginseng is one of the most important traditional Chinese medicines and functional foods. A method for the fast determination of amino acids in ginseng samples using high performance liquid chromatography(HPLC) was developed, in which strong isocratic elution was employed for simplifying the separation and speeding up the analysis. All amino acids were eluted within 3 min with the chromatogram composed of overlapped peaks from the interferences. Then, non-negative immune algorithm(NNIA) was adopted to resolve the chromatographic signals of the components from the chromatogram measured. The results show that the signals of the amino acids can be correctly extracted by NNIA and the signal extracted can be used for the quantitative analysis. The method was validated via determining six amino acids of four different samples of ginseng. The recoveries of the spiked samples are in a range of 96.6%―106.3%.

Quantitative Near-infrared Spectroscopic Analysis of Trimethoprim by Artificial Neural Networks Combined with Modified Genetic Algorithm

SHAN Hongyan, FEI Yanqun, HUAN Yanfu, FENG Guodong, FEI Qiang

2014, 30(4): 582-586. doi:10.1007/s40242-014-3410-x

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A novel method for rapid, accurate and nondestructive determination of trimethoprim in complex matrix was presented. Near-infrared spectroscopy coupled with multivariate calibration(partial least-squares and artificial neural networks) was applied in the experiment. The variable selection process based on a modified genetic algorithm with fixed number of selected variables was proceeded, which can reduce the training time and enhance the predictive ability when coupled with artificial neural network model.

Design and Synthesis of Macrocyclic Polyoxazoles

QI Fuling, GAO Lianxun, HAN Fushe

2014, 30(4): 587-592. doi:10.1007/s40242-014-4069-z

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Two macrocyclic polyoxazoles with different sizes and numbers of side chains were designed and synthesized from the linear-type precursors obtained by the iterative application of oxazole formation reaction via effective trimerization or dimerization respectively under highly diluted conditions in one pot.

Nucleophilic Polymer-supported Tertiaryphosphine Organocatalysis: [3+2] Annulation Reaction of Alkyl 2-Butynoates withActivated Alkenes

LIU Hailing

2014, 30(4): 593-595. doi:10.1007/s40242-014-4063-5

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JandaJel resin-supported triphenylphosphine(JJ-TPP), was used as an effective organocatalyst for the [3+2] annulation reaction of alkyl 2-butynoates with electron-deficient alkenes to afford the corresponding cyclopentenes in 40%―68% isolated yields. JJ-TPP was reused after simple filtration and vacuum drying.

Stereoselective Synthesis of Sulfonyl-substituted trans-2,3-Dihydrofuran Derivatives via Reaction of Arsonium Ylides with α,β-Unsaturated Ketones

CAO Long, ZHOU Xiaohong, CHEN Jie, ZHANG Hui, DENG Hongmei, SHAO Min, McMILLS Mark C., CAO Weiguo

2014, 30(4): 596-600. doi:10.1007/s40242-014-4061-7

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Trans-2,3-dihydrofuran derivatives 3 or 4 substituted with a sulfonyl group were prepared with high chemoselectivity and good yields by [1+4]-addition reaction of α,β-unsaturated ketones 1 with arsonium bromide 2 in CH₂Cl₂ in the presence of potassium carbonate at room temperature. The structures of the products were characterized by IR, MS, ¹H NMR, elemental analysis and single crystal X-ray diffraction analysis. A mechanism for the formation of products was also proposed.

One Pot, Multi-component Synthesis of 3-[(4-Aryl-thiazol-2-yl)-hydrazono]-1,3-dihydro-indole-2-one

AYCHILUHIM Tewodros Birhanu, VEDULA Rajeswar Rao

2014, 30(4): 601-604. doi:10.1007/s40242-014-4036-8

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A series of 3-[(4-phenyl-thiazol-2-yl)-hydrazono]-1,3-dihydro-indole-2-one(4a―4g) and 3-{[4-(2-oxo- 2H-chromen-3-yl)-thiazol-2-yl]-hydrazono}-1,3-dihydro-indol-2-one(6a―6d) has been prepared in a one-step procedure from condensation reaction of isatin(1), thiosemicarbazide(2) and bromoacetophenones(3)/or 3-(2-bromoacetyl)coumarins(4). The method provides a simple and efficient route to prepare the compounds in good yields and in a short experimental time as compared to its stepwise procedure.

Syntheses of Lactam Derivatives of Chenodeoxycholic Acid and in vitro Antiproliferative Activity

HUANG Yanmin, YAO Qiucui, CUI Jianguo, GAN Chunfang, HUANG Qianyang, SU Bing, ZHOU Aimin

2014, 30(4): 605-613. doi:10.1007/s40242-014-4003-4

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With chenodeoxycholic acid as starting material, a series of lactam derivatives of chenodeoxycholic acid was synthesized and their antiproliferative activities against some cancer cells were determined. Among the synthesized derivatives, compounds 6 and 18 displayed distinct antiproliferative activity against PC-3, H-292, SKBR3 and Hey-1B cancer cells, and compounds 10, 17 and 18 showed significant antiproliferative activity against SKBR3 cells. Our results reveal that the position of hydroximino on ring A or B of the parental scaffold dramatically affects the antiproliferative activity of these compounds. The conversion of 7-hydroximino to other substituent or 7-hydroximino to 3-hydroximino in the compounds resulted in a dramatic decrease of the antiproliferative activity, suggesting the importance of 7-hydroximino group for the biological activity of the compounds. The structure/activity correlation generated from the studies provides valuable information for the further design of novel chemotherapeutic drugs.

Simultaneous Reduction of Aldehyde Group to Hydroxymethyl Group in Palladium-catalyzed Suzuki Cross-coupling Reaction

WANG Yingchun, LI Xiuying, LI Yajun, PAN Yingming, CHENG Keguang, WANG Hengshan

2014, 30(4): 614-618. doi:10.1007/s40242-014-3562-8

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The authors presented an efficient method for the palladium-catalyzed Suzuki cross-coupling reaction with the simultaneous reduction of the aldehyde to a hydroxymethyl group. This method allows halide substituted aryl aldehydes to readily react with arylboronic acids, producing polycyclic aromatic alcohols in moderate to good yields. The reaction was catalyzed by Pd(OAc)₂(3%, molar fraction) at 150℃ in the presence of 6%(molar fraction) 1,4-diazabicyclo[2.2.2]octane(DABCO) and 3 times the molecular weight of K₂CO₃ in the mixture solvent of N,N-dimethylformamide(DMF)/H₂O[V(DMF):V(H₂O)=5:1].

DDQ/TFA: an Efficient Nonmetallic Reagent System for the Oxidative Coupling to Construct Phenanthrene Rings

LI Ling, HU Yanna, WANG Kailiang, WANG Qingmin

2014, 30(4): 619-623. doi:10.1007/s40242-014-3561-9

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A mild synthetic method of a series of phenanthrenes with different substituents on the phenanthrene ring is described. The method involves intramolecular oxidative coupling with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ)/trifluoroacetic acid(TFA) as oxidant to produce phenanthrenes in high yields and is fit for large-scale preparation. Furthermore, DDQ can be regenerated by a simple oxidation. The present approach solves a key step for the synthesis of polycyclic structures related to an alkaloid tylophorine.

Design, Synthesis and Antitumor Activity of Pyrrolopyrazinone-chalcone Hybrids

MENG Ying, ZHANG Hongwei, LIU Zehua, ZENG Shanchao, ZHANG Hongwei, SUN Chiyu, ZHANG Lijuan, ZHAO Mingming, WANG Guan, JIANG Mengying, SHI Wei, SONG Hongrui

2014, 30(4): 624-631. doi:10.1007/s40242-014-3542-z

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A series of pyrrolopyrazinone-chalcone hybrids(12a―12q) was designed, synthesized and screened for their antitumor activity against SKOV-3, A549 and HeLa cell lines in vitro. Compared with the pyrrolopyrazinone(10a) and 5-fluorouracil(5-FU), nearly all the tested compounds showed significantly-improved antitumor acti- vities. The most promising compounds 12e and 12k(IC₅₀=0.25 and 0.88 μmol/L) respectively show activities of 123 and 35 times that of compound 10a(IC₅₀=30.74 μmol/L) against HeLa cell line. The result reveals that the presence of chalcone moiety is beneficial to their activity and selectivity.

One-pot Copper Nanoparticle-catalyzed Synthesis of Imidazo[1,2-a]pyridines Under Solvent-free Conditions

ZONG Chenglong, ZENG Runsheng, ZOU Jianping

2014, 30(4): 632-638. doi:10.1007/s40242-014-3520-5

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A direct and efficient approach to synthesize imidazo[1,2-a]pyridines through three-component one-pot reaction of 2-aminopyridine, aldehyde and terminal alkyne catalyzed by Cu-nanoparticles under solvent-free conditions has been developed. This method provides a rapid access to substituted imidazo[1,2-a]pyridines with good yields(up to 85%).

Synthesis and Tumor Cytotoxicity of Novel N-Substituted Glucosamine-bearing Oleanolic Acid Derivatives

REN Li, LIU Yang, YU Guihua, GAO Yuan, LIU Xin, WANG Bo, DENG Xiaonan, CHENG Maosheng

2014, 30(4): 639-643. doi:10.1007/s40242-014-3522-3

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Eleven novel triterpenoid saponins, N-substituted-β-D-glucosaminide derivatives of oleanolic acid, were designed and synthesized via a stepwise glycosylation strategy. These compounds were evaluated for in vitro cytotoxic activity against six different tumor cell lines. Most of the compounds inhibited the growth of, at least, one tumor cell line effectively at micromolar concentrations. Preliminary structure-activity relationships(SARs) indicate that acylation of the nitrogen of the glucosamine-bearing triterpenoid saponins affords the compounds that are highly cytotoxic towards specific tumor cell lines.

Probe Staurosporine Drug Binding Site on Protein Kinase by PFSC

ZHENG Kun, YANG Hong, ZHAO Xiaofei, JIANG Yang, SUN Chuantao, YANG Jia'an

2014, 30(4): 644-649. doi:10.1007/s40242-014-3550-z

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We used a new approach, protein folding shape code(PFSC), to predict the potential staurosporine binding sites in protein kinases. Firstly, all available three dimensioned(3D) structures of protein kinases in protein databank(PDB) were converted into one-dimensional PFSC description, based on which a PFSC-kinome library was constructed. Secondly, a set of protein kinase-staurosporine complexes were analyzed to define the common structural features of the binding sites. Thirdly, the structural features of the staurosporine binding sites were used to virtually screen the PFSC-kinome library to predict multiple protein receptors that have potential binding capacity for staurosporine. Collectively, the development of the similar method for predicting drug binding site demonstrates that virtual screening protein database can provide valuable information on drug discovery and understanding of pharmacological pathways.

Synthesis and Electrochemical Performance of Co₃O₄/Graphene

WANG Hongzhi, SHI Yulei, LI Zixuan, ZHANG Weiguo, YAO Suwei

2014, 30(4): 650-655. doi:10.1007/s40242-014-4109-8

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Co₃O₄/reduced graphene oxide composites were synthesized via a simple electrochemical method from graphene oxide and Co(NO₃)₂·6H₂O as raw materials. Co₃O₄ nanoparticles with sizes of around 30—50 nm were distributed on the surface of graphene nanosheets confirmed by scanning electron microscopy and transmission electron microscopy. Electrochemical properties of Co₃O₄/graphene composite were tested by cyclic voltammetry, galvano- static charge-discharge, and electrochemical impedance spectroscopy. The Co₃O₄/reduced graphene oxide composite was used as the pseudocapacitor electrode in the 2 mol/L NaOH aqueous electrolyte solution. The Co₃O₄/reduced graphene oxide composite electrode exhibited a specific capacitance of 357 F/g at a current density of 0.5 A/g in a three-electrode system. 72% of capacitance was retained when the current density increased to 3 A/g. The Co₃O₄/reduced graphene oxide composite prepared electrodes show a high rate capability and excellent long-term stability. After 1000 cycles of charge and discharge, the capacitance is still maintained 87% at a current density of 1 A/g, indicating that the composite is a promising alternative electrode material used for supercapacitors.

Theoretical Exploration of Stereochemical Nonrigidity for R_fCo(PF₃)_x(CO)_4-x(R_f=CF₃, C₂F₅, C₃F₇, x=0-4)

LIU Tingting, LU Xi, ZHANG Mingtao

2014, 30(4): 656-660. doi:10.1007/s40242-014-4075-1

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The stereochemical nonrigidity of R_fCo(PF₃)_x(CO)_4-x(R_f=CF₃, C₂F₅, C₃F₇, x=0―4) was studied at the theoretical level of B3LYP/6-311+G^* via Gaussian 09. The intramolecular rearrangements in these penta-coordinated compounds are mainly caused by the vibrations of perfluoroalkyl groups. All the barriers along the reaction coordinate are less than 66.9 kJ/mol, which indicates that the rearrangements are kinetically favorable and hard to elucidate by experiment. Besides, ligand PF₃ is a ligand similar to CO, the energy difference between the reactant and product is small.

Highly Efficiency p-Type Dye Sensitized Solar Cells Based on Polygonal Star-morphology Cu₂O Material of Photocathodes

DU Sisi, CHENG Pengfei, SUN Peng, WANG Biao, CAI Yaxin, LIU Fengmin, ZHENG Jie, LU Geyu

2014, 30(4): 661-665. doi:10.1007/s40242-014-4020-3

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Cuprous oxide(Cu₂O), as an important p-type semiconductor, has been widely investigated due to its high electron transmission and facile preparation. However, the electrode made of only Cu₂O has been rarely investigated. In order to demonstrate the possibility that material Cu₂O can be applied to the electrode of p-type dye sensitized solar cells(DSSCs), the photo-electrodes made of prepared Cu₂O powder and commercial Cu₂O particles have been fabricated. The results show that the electrode based on as-prepared Cu₂O(Cu₂O-2) powder exhibits higher performance than that based on commercial Cu₂O(Cu₂O-1) particle. The device based on Cu₂O-2 electrode reaches into an open-circuit voltage of 0.71 V, a short-circuit current density of 1.3 mA/cm², a fill factor(FF) of 46%, and a conversion efficiency of 0.42% measured under AM 1.5G(100 mW/cm²) illumination. The enhancement performance of Cu₂O-2 is attributed to the high dye adsorption of Cu₂O-2 compared with that of Cu₂O-1. To the best of our knowledge, this is the highest conversion efficiency value reported for solar cells based on Cu₂O-DSSC. This work provides that Cu₂O is also a candidate for constructing the electrode of p-type dye sensitized solar cells.

Effects of Aluminum on Thermal Decomposition of Hexogen/Ammonium Perchlorate

ZHU Yanli, XIAO Zhixia, JIAO Qingjie, REN Hui, HUANG Hao

2014, 30(4): 666-671. doi:10.1007/s40242-014-4016-z

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Thermogravimetry-differential scanning calorimetry-mass spectrometry-Fourier transform infrared spectrometry(TG-DSC-MS-FTIR) simultaneous analysis was used to study the effects of 10.7 μm and 40 nm Al on the thermal decomposition of the Hexogen/ammonium perchlorate(RDX/AP, 1/2, mass ratio) mixture. TG-DSC results show that there are two mass loss processes for the thermal decomposition of RDX/AP/Al. The first one is mainly ascribed to the thermal decomposition of RDX. The reaction rate of RDX/AP/10.7 μm Al is so fast that the apparent activation energy, calculated by model-free Friedman method, is negative, which is the same as that of RDX/AP. 30%(mass fraction) 40 nm Al added in RDX/AP change the activation energy from negative to positive value. The second mass loss process of the RDX/AP/Al mixture is ascribed to the thermal decomposition of AP. This process can be divided into three stages for RDX/AP with and without Al. The kinetics model is not changed in the presence of micro-sized Al, while it is changed from CnB/D1/D1 to CnB/D1/D4 after the addition of 40 nm Al to RDX/AP. The reaction rate constant of the first stage and the end temperature of the second stage decrease, while the end temperatures of the third stage increase in the presence of 40 nm Al. The MS-FTIR results show there is a competition between the formation reactions of HNCO, N₂O and NO₂ during the second mass loss process.

Non-isothermal Decomposition Kinetics of [Cu(en)₂H₂O](FOX-7)₂·H₂O

ZHANG Yu, DONG Kaiyue, QIU Qianqian, XU Kangzhen, HE Fei, SONG Jirong, ZHAO Fengqi

2014, 30(4): 672-675. doi:10.1007/s40242-014-3549-5

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The thermal behavior and non-isothermal decomposition kinetics of [Cu(en)₂H₂O](FOX-7)₂·H₂O (en=ethylenediamine) were studied with DSC and TG-DTG methods. The kinetic equation of the exothermal process is dα/dt=(10^17.92/β)4α^3/4exp(-1.688×10⁵/RT). The self-accelerating decomposition temperature and critical temperature of the thermal explosion are 163.3 and 174.8℃, respectively. The specific heat capacity of [Cu(en)₂H₂O](FOX-7)₂·H₂O was determined with a micro-DSC method, with a molar heat capacity of 661.6 J·mol^-1·K^-1at 25℃. Adiabatic time-to-explosion was also estimated as 23.2 s. [Cu(en)₂H₂O](FOX-7)₂·H₂O is less sensitive.

Isothermal Evaporation of Quaternary System Li⁺, K⁺, Mg²⁺//Cl^--H₂O at 348 K

LI Jiajia, ZENG Ying, WANG Chun, YU Xudong

2014, 30(4): 676-680. doi:10.1007/s40242-014-3506-3

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The solubilities of the quaternary system Li⁺, K⁺, Mg²⁺//Cl^--H₂O were investigated at 348 K via isothermal evaporation. The densities and refractive indices of its equilibrated solution were also determined experimentally. On the basis of the obtained data, the metastable phase diagram, the water content diagram, the diagrams of the density and refractive index against the composition of this quaternary system were constructed. The quaternary system Li⁺, K⁺, Mg²⁺//Cl^--H₂O at 348 K belongs to a complex type with the formation of two carnallite double salts, which are potassium carnallite(K-carnallite) and lithium carnallite(Li-carnallite). There are five salts like potassium chloride (KCl), lithium chloride monohydrate(LiCl·H₂O), bischofite(MgCl₂·6H₂O), K-carnallite(KCl·MgCl₂·6H₂O) and Li-carnallite(LiCl·MgCl₂·7H₂O), seven unvariant curves named AH₃, BH₂, CH₃, DH₁, EH₁, H₁H₂ and H₂H₃, and three invariant points, namely H₁, H₂ and H₃, included in this metastable phase diagram. Comparisons between the stable phase diagram at 298 K and metastable phase diagram at 348 K of this quaternary system show that all the crystalline forms of the salts are not changed, whereas the crystallization areas of salts are changed significantly with temperature. The scope of KCl crystallization increases from 82% to 95% and that of K-carnallite decreases from 15.80% to 0.32% along with the temperature increasing from 298 K to 348 K, respectively.

An Improved Prediction Equation of Refrigerants Surface Tension Based on the Principle of Corresponding States

LI Wenzhe, BI Shengshan, ZHAO Guanjia, WU Jiangtao

2014, 30(4): 681-684. doi:10.1007/s40242-014-3487-2

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The surface tensions of 21 pure refrigerants have been predicted by a new improved equation based on the principle of corresponding states with double referenced fluids. The average absolute deviation between the calculated surface tensions from the equation and the experimental result is -0.015 mN/m. The surface tensions of 9 binary mixtures were calculated in consideration of certain mixing rules. And the average absolute deviation between the calculated surface tensions from the equation and the experimental result is -0.251 mN/m. The new improved prediction equation can be used for calculating the surface tension of environmental friendly refrigerants.

Acyl Thioacetamide-group Chelated Nanofiber to Adsorb Silver Ions from Aqueous Systems

ZHANG Chengcheng, LI Xiang, ZHENG Tian, ZHAO Rui, WANG Ce

2014, 30(4): 685-689. doi:10.1007/s40242-014-4190-z

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The acyl thioacetamide-group chelated nanofiber was prepared from polyacrylonitrile(PAN) fiber with thioacetamide as vulcanization agent by an electrospinning process combined with chemical modification. It was found that the chelated nanofiber displays a high adsorption capacity and adsorption selectivity for Ag(I) ions from aqueous systems. The adsorption capacity of Ag(I) ions on chelated nanofiber increases with the increase of adsorption time. Kinetics of the Ag(I) ions adsorption was found to follow pseudo-second-order rate equation. Based on the characterization results, a possible mechanism of Ag(I) ions adsorbed on the acyl thioacetamide-group chelated nanofiber was proposed. The chelated nanofiber could not only chelate to Ag(I) ions but also reduce them. This study provides a promising nanofiber material for removing heavy metal ions.

Effects of Various Factors on the Modification of Carbon Nanotubes with Polyvinyl Alcohol in Supercritical CO₂ and Their Application in Electrospun Fibers

CHEN Zhimin, ZHANG Jianan, GUO Yuanlong, ZHANG Hao, CAO Jingjing, XU Qun, WANG Shuxia, WANG Bo, LIU Zhaotie

2014, 30(4): 690-697. doi:10.1007/s40242-014-3535-y

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Supercritical(SC) CO₂ anti-solvent induced polymer epitaxy(SAIPE) method was used to help prepare nanohybrid carbon nanotubes(CNTs) wrapped with polyvinyl alcohol(PVA) nanocrystals. With the variation of a series of experimental conditions or peripheral effects, such as PVA concentration, CNTs concentration, and SC CO₂ pressure, the optimal experimental variables for PVA-nanocrystals growing on CNTs have been found. The adsorption of polymer on CNTs via multiple weak molecular interactions has been studied by Fourier transform infrared(FTIR) spectroscopy and Raman spectroscopy. The mechanism about the formation of PVA nanocrystals on CNTs can be suggested through the experimental phenomena. These CNTs wrapped with PVA nanocrystals can be directly used as nanofillers to fabricate PVA composite fibers reinforced with CNTs by electrospinning.

Mechanical Properties of PPV Film in Thermal Elimination Process

LI Qingsong, YANG Qingxiang, ZHANG Haiquan

2014, 30(4): 698-701. doi:10.1007/s40242-014-3527-y

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This paper deals with the relationships between the structure of poly(p-phenylene vinylene)(PPV) film and treatment temperature and their mechanical properties. The chemical structures and aggregated structures of PPV precursor(PPV_pre) and PPV treated at three node temperatures(125, 155 and 230℃) were investigated by FTIR spectrometry and X-ray diffraction. The results show that the content of trans-conformation and the size of the crystalline domains increased with the increase of treatment temperature. The mechanical performances of the corresponding polymers were studied by nanoindentation. The elastic modulus and hardness of PPV films decreased with the increases of the content of trans-conformation and the size of the crystalline domains. These results suggest that the conformation and the size of the crystalline domains are able to induce the elastic modulus and hardness variation of PPV films.

Erratum to: One-pot Synthesis of 1,5-Diaza-2,6-cyclooctadiene-3,7-dicarboxylates Through a Multiple-component Reaction

LI Yufeng, WANG Xinglong, LI Wei, WU Zhengguang, SHI Jie, MA Hongfei

2014, 30(4): 702-702. doi:10.1007/s40242-014-4000-1

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