Chemical Research in Chinese Universities

Chemical Research in Chinese Universities Vol.31 No.4 February 2015

2015, 31(4): 0-0.

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Hydrothermal Synthesis, Structure and Property of Transition Metal(Mn, Zn, Cd or Pb) Coordination Frameworks Using Quinoline-8-oxy-acetate Acid and Dicarboxylic Acid as Ligands

ZHANG Guochun, QIAO Chengfang, LIANG Jiehui, WEI Qing, XIA Zhengqiang, CHEN Sanping

2015, 31(4): 489-497. doi:10.1007/s40242-015-5104-4

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Five transition metal coordination compounds, [Mn₂(8-qoac)₂(bdc)(H₂O)₄](1)(8-qoacH=quinoline-8-oxy- acetate acid, H₂bdc=benzene-1,4-dicarboxylic acid), [Zn₄(8-qoac)₄(bdc)₂]_n(2), {[Cd₂(8-qoac)₂(Hip)₂(H₂O)₂]· (H₂O)₄}_n(3)(H₂ip=benzene-1,3-dicarboxylic acid), [Pb₃(8-qoac)₂(bdc)_1.5(H₂O)Cl]_n(4) and [Zn₂(8-qoac)(8-ql)(bdc)]_n(5)(8-Hql=8-hydroxyquinoline), were synthesized by hydrothermal syntheses of metal salts with benzenedicarboxy- lic acid and 8-qoacH. Compound 1 possesses a discrete dimer bridged by bdc^2- ligand. Compound 2 presents a 2D layer network constructed from bdc^2- linkers and 1D infinite ribbons, in which Zn(II) centers are bridged by 8-qoac^- with a tetradentate binding mode. Compound 3 displays a 1D zigzag chain, with adjacent chains further connected via extensive O—H···O hydrogen bonds to generate a 3D supramolecular structure. Compound 4 shows a 3D framework containing trinuclear lead secondary building units and bdc^2- linkers, in which a new coordination mode of 8-qoac^- ligand is observed. In compound 5, Zn(II) ions are simultaneously bridged by 8-qoac^-, 8-ql^- and bdc^2- ligands to form tetranuclear zinc units, which are further interlinked by bdc^2- linkers to yield a 2D wave-like layer. Based on intraligand(IL)(π-π^*) fluorescent emission, compounds 1―5 possess strong purple fluorescent emissions. In addition, the thermal stabilities of compounds 1―5 were studied.

Hydrothermal Synthesis of a New Zinc Phosphite (C₅H₇N₂)₂·[Zn₃(HPO₃)₄] with Intersecting 8- and 12-Ring Channels

DONG Zhaojun, YAN Yan, ZHANG Wenqing, WANG Yu, LI Jiyang

2015, 31(4): 498-502. doi:10.1007/s40242-015-5021-6

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Using 4-aminopyridine as the structure-directing agent(SDA), a new open-framework zinc phosphite, (C₅H₇N₂)₂·[Zn₃(HPO₃)₄](ZnHPO-CJ70), was synthesized under hydrothermal condition. Single-crystal X-ray diffraction analysis reveals that ZnHPO-CJ70 is constructed by the strictly alternating ZnO₄ tetrahedra and HPO₃ pseudo-pyramids, with their vertexes linked to generate a three-dimensional(3D) open framework with intersecting 8- and 12-ring channels. Further characterizations of ZnHPO-CJ70 were performed by means of X-ray powder diffraction(XRD), elemental analysis(ICP, CHN), infrared spectroscopy(IR) and thermogravimetric(TG) analyses. The results of luminescent test shows that ZnHPO-CJ70 exhibits strong fluorescence emissions in the solid state at room temperature.

Assembly of Two Coordination Polymers Based on 2,2'-Bipyridyl-4,4'-dicarboxylic Acid Ligand

WANG Jing, LUO Xiaolong, YUAN Yang, ZHANG Lirong

2015, 31(4): 503-507. doi:10.1007/s40242-015-5015-4

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Two novel 2D coordination polymers, [Co(BPDC)DMSO]·DMSO(1)(BPDC=2,2'-bipyridyl-4,4'-dicar- boxylic acid) and [Zn(BPDC)DMF]·DMF(2), were synthesized from 2,2'-bipyridyl-4,4'-dicarboxylic acid ligand (H₂BPDC) under solvothermal conditions. Single crystal X-ray diffraction analyses reveal that compound 1 crystallizes in orthorhombic system and Pca2₁ space group with a=1.29628(13) nm, b=1.13721(13) nm, c=1.66457(19) nm, α=90°, β=90°, γ=90°, V=2.4538(5) nm³. Compound 2 crystallizes in monoclinic system and P2₁/c space group with a=0.9429(6) nm, b=1.4757(10) nm, c=1.5980(9) nm, α=90°, β=114°, γ=90°, V=2.030(2) nm³. Compounds 1 and 2 exhibit two different 3-connected hcb and fes topologies, respectively. The structures of the two compounds both contain interesting characters of double-helical chains(left- and right-handed helical chains). Additionally, the magnetic and luminescent properties of the two compounds were studied.

One-pot Hydrothermal Synthesis of rGO-Fe₃O₄ Hybrid Nanocomposite for Removal of Pb(II) via Magnetic Separation

CAO Wei, MA Yiran, ZHOU Wei, GUO Lin

2015, 31(4): 508-513. doi:10.1007/s40242-015-4487-6

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The reduced graphene oxide-Fe₃O₄(rGO-Fe₃O₄) hybrid nanocomposite was prepared via a one-pot facile hydrothermal method for adsorption of heavy metal ions. The results of compositional and morphological characterizations show that the Fe₃O₄ NPs with an average diameter of 20 nm have been uniformly dispersed in rGO sheets. Due to the higher specific surface area of rGO and the magnetic properties of Fe₃O₄ nanoparticles, the prepared rGO-Fe₃O₄ hybrid nanosheets showed good adsorption capacity for the removal of Pb(II) from wastewater by simple magnetic separation. The result of control tests show that the adsorption capacity of rGO-Fe₃O₄can be influenced by the ratio of ferric chloride(FeCl₃) to graphene oxide(GO) during the process of sample preparation and the initial concentration of Pb(II). A better adsorption capacity was 30.68 mg/g at n(FeCl₃)/m(GO) ratio of 1:5(mmol:mg) at pH=7.0 with the initial concentration of Pb(II) ions of 80 mg/L, and the experimental data were well fitted with the Langmuir adsorption model. The composite with absorbed Pb(II) can be easily collected by magnetic separation from wastewater because of the excellent magnetism of Fe₃O₄ NPs. The rGO-Fe₃O₄ hybrid nanocomposite provides an effective and environment-friendly absorbent with great application potential in water purification.

Investigation on Ligand Exchange Kinetics on CdSe/ZnS Quantum Dot Surface Utilizing Pyrene as Flourescent Probe

CHANG Yulei, LIU Nian, LIU Huan, YANG Yanming, ZHAO Yili, LI Yapeng, YUAN Hang

2015, 31(4): 514-518. doi:10.1007/s40242-015-5110-6

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Direct ligand exchange kinetics between hydrophilic molecules and quantum dots(QDs) was investigated. Meanwhile, pyrene was exploited as probe to detect the efficiency of the ligand exchange reaction between octadecylamine-coated QDs(ODA-QDs) and different ligands[ligand 1: NH₂G3-OH, ligand 2: G4.5-PEG5-FA5, ligand 3: (COOH)₂G3-OH or ligand 4: G4.5-PEG1-FA1]. It was indicated that water-soluble QDs exhibit the same fluorescence and absorption spectra as ODA-QDs when they were dissolved in chloroform. Furthermore, the cellular experiments demonstrated that the folic acid(FA) targeting poly(amidoamine)(PAMAM) modified QD conjugates could be used as molecular targeting sensing systems for nanoparticle probes.

Rapid Absolute Determination Platform of Nucleic Acid for Point-of-care Testing

SONG Bofan, JIN Wei, SONG Qi, JIN Qinhan, MU Ying

2015, 31(4): 519-525. doi:10.1007/s40242-015-4503-x

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Nowadays nucleic acid tests are promising to be considered as point-of-care testing(POCT). However, no such devices are currently available that can perform all the functions, including absolute nucleic acid determination, worldwide on-site detection, rapid analysis and real-time results reporting via ubiquitous mobile networks simultaneously with full package and automated means of measurement. In this study, we presented a compact low-cost portable POC automated testing platform with all attributes mentioned above. A disposable self-priming compartmentalization(SPC) microfluidic chip is used to conduct isothermal amplification. The platform also includes a micro-computer controlled heating unit, an inexpensive optical imaging setup, and a mobile device with customized software. It may become a useful tool for the rapid on-site detection of infectious diseases as well as other pathogens.

Design and Synthesis of 3-Triazolo-coumarins and Their Applications in Scavenging Radicals and Protecting DNA

LIU Zhihui, WANG Yingnan, SUN Jingbo, YANG Yang, LIU Qingwen, LIU Zaiqun, SONG Zhiguang

2015, 31(4): 526-533. doi:10.1007/s40242-015-5191-2

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In this study, we synthesized a series of 3-triazolo-coumarins and evaluated their antioxidant activities respectively by two methods: trapping 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical(ABTS^+·) and oxidation of DNA which was induced by Cu²⁺/glutathione(GSH), ·OH and 2,2'-azobis(2-amidinopropane hydrochloride)(AAPH). Among the nine 3-triazolo-coumarins, compounds 6c and 6f―6i were synthesized for the first time, which exhibited the capability of terminating radical propagation-chains in oxidation of DNA induced by AAPH. In this study, we found that phenethylamine moiety, hydroxyl and ortho-methoxy are the key groups to enhance the antioxidant activities of compounds.

Synthesis of Long Chain Fatty Acids Acylated Coumarin Glycoside Esters with Lipase as Catalyst

LIU Duo, CAI Shuanglian, LUAN Fangjian, WANG Qiu'an

2015, 31(4): 534-538. doi:10.1007/s40242-015-5048-8

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A series of novel coumarin glycoside esters(1―9) was synthesized through the acylation reaction of 4-methylcoumarin-7-O-β-D-glucoside(11) with different long chain fatty acids catalyzed by lipase in organic medium. The acylation occurred regioselectively at the 6'-OH of glycosyl moiety. The enzymatic synthesis was optimized to achieve 54%―70% yield using immobilized lipase(Novozym 435, 10 mg/mL) as catalyst and acetone and pyridine(9:1, volume ratio, water content<1%) as solvent with an acyl donor/coumarin glycoside molar ratio of 10:1 at a temperature of 40―50 ℃ for 96 h. All the synthesized compounds were confirmed.

Synthesis of 5-(Sulfamoylmethyl)indoles by Mild Negishi Coupling and Their Application in Almotriptan

LI Xiaolong, QIU Rui, WAN Weili, CHENG Xu, HE Yi, HAI Li, WU Yong

2015, 31(4): 539-542. doi:10.1007/s40242-015-5030-5

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A new synthetic route of almotriptan was described. The application of Negishi coupling reaction simplified the process and significantly improved the yield. The synthetic route was also expected to be general for the synthesis of other tryptamines like sumatriptan and avitriptan.

Solvent-free 1,3-Dipolar Cycloaddition of Azomethine Imines with Terminal Alkynes Promoted by Calcium Fluoride Under the Ball Milling Condition

CHEN Xianglong, JIA Chunman, CAO Li, ZHANG Dela, LIU Shuixiang, ZHANG Qi

2015, 31(4): 543-548. doi:10.1007/s40242-015-4480-0

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A convenient and efficient procedure for the synthesis of N,N-bicyclic pyrazolidinone derivatives has been developed via the reaction of azomethine imines with terminal alkynes under the ball milling condition without solvent, which was promoted by calcium fluoride with a catalyst of copper(I) salt. The cyclization reactions exhibited moderate to high yields.

Bifunctional Salen-Cu(II) Complex as Efficient Catalyst for N-Arylation of Imidazoles and Suzuki-Miyaura Coupling Reactions

WANG Yi, GAO Jingyi, ZHAO Mengdan, LI Jiamei

2015, 31(4): 549-552. doi:10.1007/s40242-015-4437-3

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Bifunctional Salen-Cu(II) complex catalyzed cross-coupling reactions of aryl halids with imidazoles or phenylboronic acid reagents have been developed as practical methods for C―N and C―C bond formation. The procedure tolerates aryl halides with various functional groups(such as methoxy, acetyl, nitrile, fluoro and nitro groups) and gives the corresponding coupling products in moderate to high yields. The catalyst remained active after five successive catalytic runs without loss in performance.

Detection and Comparison of Structure and Function of Wild-type Pneumolysin and Its Novel Mutant PlyM2

SUN Tianxu, HOU Hongjia, LU Jingcai, XU Man, GU Tiejun, WANG Dandan, DONG Yunliang, JIANG Chunlai, KONG Wei, WU Yongge

2015, 31(4): 553-557. doi:10.1007/s40242-015-5105-3

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Here is reported a novel pneumolysin(Ply) mutant(PlyM2) that addresses a long-standing problem for vaccine development in this field: detoxification of Ply in the premise of retaining antigenic integrity. Structure and function of wild-type Ply(PlyWT) and PlyM2 mutants were detected and compared. Their structures were not signi- ficantly different according to the analysis by thermal-dependent fluorescence spectroscopy and circular dichroism spectroscopy. PlyM2 was confirmed to have lost hemolytic activity and yet could induce neutralizing antibodies to prevent in vitro hemolysis by PlyWT and Streptococcus pneumoniae(S. pneumoniae). These results give support to PlyM2 to be a new protein antigen for inclusion in the development of an effective pneumococcal multiprotein vaccine.

14-3-3 Proteins Interact with FRMD6 and Regulate Its Subcellular Localization in Breast Cancer Cells

MENG Fanbo, FENG Wei, XIN Hua, TIAN Zhuang, ZHANG Yu, ZHANG Liping

2015, 31(4): 558-563. doi:10.1007/s40242-015-5097-z

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The Hippo pathway is evolutionarily conserved from Drosophila to mammals. FRMD6 is one crucial upstream component of the Hippo pathway while its function and regulatory mechanism are largely elusive. We decided to purify the protein complex of FRMD6 to further explore its regulatory mechanism. We established the MCF7 breast cancer cells that stably expressed FRMD6 by retroviruses infection. And we purified the FRMD6-interacting protein complex for further analysis by high performance liquid chromatography-mass spectrometry/mass spectrometry(HPLC- MS/MS). Interestingly, we observed that the major binding partner of FRMD6 is 14-3-3 family of proteins. The interaction between FRMD6 and 14-3-3 proteins was detected by co-immunoprecipitation(CO-IP). The disruption of their interaction resulted in the nuclear localization of FRMD6. Importantly, the T28A mutant of FRMD6 showed stronger tumor suppressor function than wild type(WT) FRMD6. Our results indicate that 14-3-3 proteins tightly regulate the subcellular localization of FRMD6 so as to endow FRMD6 with the tumor suppressor function on breast cancer.

Gene Clone and Characterization of a Novel Thermostable β-Galactosidase with Transglycosylation Activity from Thermotoga naphthophila RUK-10

YANG Jingwen, DI Xiangjun, WANG Man, GAO Renjun

2015, 31(4): 564-568. doi:10.1007/s40242-015-5032-3

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We cloned and expressed a new recombinant β-galactosidase(TN0949) from Thermotoga naphthophila RKU-10 with the pET28a(+) vector system in Escherichia coli BL21(DE3), and determined its catalytic capability to synthesize alkyl glucosides. The recombinant enzyme was purified to a single band via heat treatment and Ni²⁺-NTA affinity chromatography. The molecular mass of the recombinant enzyme was estimated to be 79 kDa with sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE). TN0949 can hydrolyze o-nitrophenyl β-D- galactopyranoside at the optimum pH and temperature of 6.5 and 80 ℃, respectively. TN0949 can also hydrolyze lactose at the optimum pH and temperature of 5.2 and 80 ℃, respectively. The K_m values for the hydrolyses of o-nitrophenyl β-D-galactopyranoside and lactose were 0.82 and 83.65 mmol/L, respectively. TN0949 was stable over a wide range of pH(3.0 to 7.0) after 24 h of incubation. The half-lives of TN0949 at 75, 80 and 85 ℃ were 22, 6 and 1.33 h, respectively. The enzyme displayed the capability to use lactose as the transglycosylation substrate to synthesize butyl galactopyranoside and hexyl galactopyranoside, indicating its suitability as a candidate industrial biocatalyst.

Efficient and Low-voltage Phosphorescent Organic Light-emitting Devices Based on Blue Iridium Complex Host

YU Jing, YIN Yongming, XIE Wenfa, ZHANG Letian

2015, 31(4): 569-572. doi:10.1007/s40242-015-5243-7

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By adopting a phosphorescent host/guest system consisting of blue iridium complex as host and a series of phosphorescent dyes as guest, efficient and low-voltage monochromic organic light-emitting devices(OLEDs) were fabricated. The devices with blue iridium host have higher power efficiency than the device with the conventional host 4,4'-N,N'-dicarbazole-biphenyl. The enhancement of the maximum power efficiency in green phosphorescent device can reach 37.2%. Dichromatic white OLED could be achieved by simply adjusting the concentration of the orange dyes. At a brightness of 1000 cd/m², the power efficiency of the white device is 8.4 lm/W with a color rendering index of 76.

Enhanced Anticorrosion Properties of Epoxy Coatings from Al and Zn Based Pigments

WAN Kai, LI Changcheng, XING Cuijuan, ZHAO Haizhou, YU Liangmin

2015, 31(4): 573-580. doi:10.1007/s40242-015-5050-1

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Anticorrosion epoxy coatings from Al and Zn based pigments were synthesized by adjusting their volume ratios, aiming at their increasing anticorrosion performances. The anticorrosion properties were examined via electrochemical impedance spectroscopy, Tafel polarization curve analysis and salt spray test. The coating morphologies before and after the salt spray tests were studied via scanning electron microscopy(SEM). The elemental and chemical compositions of the corroded surfaces of the coatings were analyzed by means of X-ray photoelectron spectroscopy(XPS). The results indicate that the coating composed of Al/Zn at 10:1(volume ratio) displays the maximum anticorrosion performances, which are superior to those of pristine Al or Zn based pigment.

Preparation of Sulfur-doped PANI/TiO₂ Nanowires and Its Sensing Properties to Mercury

WANG Dong, LIU Xiaomeng, FANG Zhenxing, LI Jian, SUN Mojie

2015, 31(4): 581-584. doi:10.1007/s40242-015-5017-2

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TiO₂ nanowires were successfully prepared via a simple hydrothermal method and a layer of sulfurized polyaniline(PANI) was loaded onto their surface to prepare a sensor of elemental mercury at room temperature. The sulfurized PANI/TiO₂ composite sensor has a high sensitivity to mercury in a range of density from 5.57 mg/m³ to 126.18 mg/m³ at room temperature. The response time and recovery time are relatively short. We also investigated the sensitivity and response time to other interfering gases, such as NO₂, SO₂ and NH₃. And the sulfurized PANI/TiO₂ composite material shows a good selectivity for element mercury. The microscopic structure of the sensor was investigated via X-ray diffraction(XRD), scanning electron microscopy(SEM) and energy dispersive X-ray analysis (EDAX). The sulfurized PANI/TiO₂ composite material shows a high sensitive response, and good selectivity to element mercury, which is promising for the application in the detection of element mercury.

Novel One-component Positive-tone Chemically Amplified I-Line Molecular Glass Photoresist Based on Tannic Acid

WEI Qi, WANG Liyuan

2015, 31(4): 585-589. doi:10.1007/s40242-015-5016-3

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Molecular glass resist has been considered as one of the best choices for a new generation of lithography. In this work, a new type of photoactive compound was obtained by the esterification of tannic acid with 2-diazo-1- naphthoquinone-4-sulfonyl chloride(2,1,4-DNQ-Cl) and ditertbutyl dicarbonate. The new obtained compound possessed both a photosensitive group of diazonaphthoquinone sulfonate(2,1,4-DNQ) and a group of acidolytic protection. Upon the irradiation of the compound under 365 nm light, the former group was photolyzed and converted into indene carboxylic acid along with a small amount of sulfonic acid, which could lead to the deprotection of the latter group. As a result, a novel i-line molecular glass photoresist was formed with the chemical modification of tannic acid. The experimental results show that the modificated compound had a fair solubility in many organic solvents. The lithographic performance of the resist was evaluated on an i-line exposure system with high photosensitivity and resolution as well.

Graphene/γ-AlOOH Hybrids as an Enhanced Sensing Platform for Ultrasensitive Stripping Voltammetric Detection of Pb(II)

FAN Wei, MIAO Yue'e, LIU Tianxi

2015, 31(4): 590-596. doi:10.1007/s40242-015-5006-5

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The reduced graphene oxide(RGO)/γ-AlOOH hybrids with different γ-AlOOH contents were successfully prepared via a facile one-pot hydrothermal method. In these hybrids, RGO acts as a conductive linker for improving electron transport, and γ-AlOOH nanoplatelets help to adsorb the target metal ions on the electrode surface, thus facilitating the electrochemical behavior of the hybrids. The sensitivity of as-prepared RGO/γ-AlOOH hybrids toward Pb(II) was tested by square wave anodic stripping voltammograms(SWASV) and the mass ratio of graphene to γ-AlOOH was optimized to improve the sensing performance of RGO/γ-AlOOH hybrids. Owing to the superior absorbability of γ-AlOOH for heavy metal ions and excellent electrical conductivity of graphene, the detection limit of the hybrids for heavy metal ions was found to be as low as 1.5×10^-11 mol/L with optimized γ-AlOOH content in the hybrids. The experimental conditions, such as pH value, mass of electrode material, and deposition time were also investigated and optimized. The as-prepared RGO/γ-AlOOH hybrids demonstrate high electrochemical activity and good sensing performance, which offers an alternative platform for the electrochemical sensors.

DFT Studies on Second-order Nonlinear Optical Properties of a Series of Axially Substituted Bis(salicylaldiminato) Zinc(II) Schiff-base Complexes

LIU Chunguang, ZHANG Dingfan, GAO Mingli, LIU Shuang

2015, 31(4): 597-602. doi:10.1007/s40242-015-5004-7

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Coordination of an axial ligand to metal center to enhance the second-order nonlinear optical(NLO) response of a two-dimensional bis(salicylaldiminato) zinc(II) Schiff-base complex is an unprecedented model. The second-order NLO responses of a series of axially substituted bis(salicylaldiminato) zinc(II) Schiff-base complexes were explored according to the finite field(FF) method at CAM-B3LYP/6-31+G(d) level(LANL2DZ basis set for metal atoms). The results show that the second-order NLO properties can be effectively tuned by exchanging the donor and accepter of the axial ligand and extending the length of the conjugated bridge along the axial direction. A system involving the electron acceptor along the appropriate direction has a large three-dimensional second-order NLO response. Meanwhile, time dependent density functional theory(TD-DFT) method was employed to calculate the physical parameters of excited states. The results show that the Y- and Z-polarized transitions of the zinc(II) Schiff-base complex are the first and second excited states, respectively, and have a low-lying excited energy. Although the X-polarized transition has a high excited energy, the large oscillator strength indicates that it will significantly contribute to the second-order NLO response.

Influence of Cr on the Electronic Properties of Passive Film on B30 Alloy in NaOH Solution

SHANG Yongbin, XIAO Shuqin, QIU Xiaolin, WEI Yaming

2015, 31(4): 603-610. doi:10.1007/s40242-015-4469-8

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The influence of Cr on the electronic properties of the passive film on B30 alloy in NaOH solution was studied via electrochemical impedance spectra(EIS), potentiodynamic curve and Mott-Schottky plot. The Cr doped in the passive film on B30 alloy was detected by X-ray photoelectron spectroscopy(XPS). XPS results show that Cr₂O₃ appeared on the passive film, which implied the enhanced anti-corrosion of B30 alloy. The passive film showed a p-type semi-conductive character. The acceptor density(N_A) was in an order of magnitude of 10²² cm^-3, and N_A decreased with the increment of Cr. EIS results show that the film resistance(R_f) increased with increasing the amount of Cr. The diffusion coefficient(D₀) was calculated to be in a range of 10^-16—10^-17 cm^-2/s on the basement of point defect model(PDM).

Experimental Binary Phase Diagram of Bilayer Compounds [n-C_nH_2n+1N(CH₃)₃]₂CoCl₄

WU Kezhong, SUN Xiaolong, RUAN Bei, XIONG Yuanyuan, CHEN Jing

2015, 31(4): 611-614. doi:10.1007/s40242-015-4418-6

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Compounds [n-C_nH_2n+1N(CH₃)₃]₂CoCl₄(n=16, C₁₆C₃Co; n=18, C₁₈C₃Co) containing lipid-like bilayers embedded in a crystalline matrix exist in solid-solid phase transition. The low-temperature bilayer structures of the two compounds were organized by neutralizing CoCl₄^2- with alkylammonium ions. Alkyl chains lay parallel to each other and slightly tilted with respect to the normal of the inorganic layers. The adjacent alkyl chains interacted with each other by van der Waals interaction. When the temperature increased, the two compounds underwent a reversible solid-solid phase transformation within 310―330 K. In such a case, the chains showed a large motional freedom, and a disordered phase appeared. The structures can alternatively be viewed as a double layer of alkylammonium ions between CoCl₄^2- sheets and be considered as crystalline models of lipid bilayers. The experimental subsolidus binary phase diagram of [n-C₁₆H₃₃N(CH₃)₃]₂CoCl₄-[n-C₁₈H₃₇N(CH₃)₃]₂CoCl₄ was constructed over the entire composition range by differential scanning calorimetry and X-ray diffraction technique. Experimental phase diagram indicates one stable intermediate phase [n-C₁₆H₃₃N(CH₃)₃][n-C₁₈H₃₇N(CH₃)₃]CoCl₄ at w_{C₁₆C₃Co}= 39.89% and two invariant three- phase equilibria, which shows two eutectoid temperatures: T_e1 at (316±1) K for w_{C₁₆C₃Co}= 27.35% and T_e2 at (313±1) K for w_{C₁₆C₃Co}=59.76%. These three noticeable solid-solution ranges are α-phase at the left, β-phase at the right, and γ-phase in the middle of the phase diagram.

Effect of Lanthanum on Catalytic Performance of Ru/Al₂O₃ Catalyst for Hydrogenation of Esters to Corresponding Alcohols

ZHANG Lei, ZHENG Xiaojuan, LI Ruixiang

2015, 31(4): 615-620. doi:10.1007/s40242-015-4382-1

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Ru-La/γ-Al₂O₃ catalyst was prepared by impregnation method and characterized by temperature programmed reduction(TPR), transmission electron microscopy(TEM), X-ray photoelectron spectra(XPS), Brunauer- Emmett-Teller(BET), X-ray diffraction(XRD), and NH₃-temperature programmed desorption(NH₃-TPD). NH₃-TPD revealed that the strong acidic centers in γ-Al₂O₃ are not the major factor to cause the hydrolysis of esters to acids in the hydrogenation of esters. The results of TPR and TEM indicate that the appropriately added lanthanum results in the good dispersion of ruthenium and the easy reduction of ruthenium oxide on Ru-La/γ-Al₂O₃, which could promote the catalytic activity of Ru-La/γ-Al₂O₃ for the hydrogenation of methyl propionate to propanol. When the amount of lanthanum added in the catalyst was up to 9%(mass fraction), 4%Ru-9%La/γ-Al₂O₃ catalyst gave a conversion of methyl propionate of 98.1% and a selectivity of 94.8% to propanol at a reaction temperature of 180 ℃ and a hydrogen pressure of 5.0 MPa.

Extraction of Lithium from Salt Lake Brine with Triisobutyl Phosphate in Ionic Liquid and Kerosene

GAO Daolin, YU Xiaoping, GUO Yafei, WANG Shiqiang, LIU Mingming, DENG Tianlong, CHEN Yuwei, BELZILE Nelson

2015, 31(4): 621-626. doi:10.1007/s40242-015-4376-z

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Three ionic liquids(ILs), namely, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-me- thylimidazolium bis[(trifluoromethyl)sulfonyl]imide and 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sul- fonyl]imide with the triisobutyl phosphate(TIBP) and kerosene system were respectively used to extract lithium ion from salt lake brine with a high concentration ratio of magnesium and lithium experimentally. Results indicate that the highest extraction selectivity for lithium was obtained with IL 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)- sulfonyl]imide. The effects of solution pH and phase ratio R(O/A) on the extractive step and the influence of acid concentration of the stripping solution and R(O/A) on the back extraction step were also investigated systematically. The single-step extraction efficiency of lithium ion was 83.71% under the optimal extraction conditions, and the single-step back extraction efficiency was 85.61% with a 1.0 mol/L HCl in 1.0 mol/L NaCl medium as stripping agent at R(O/A)=2. The liquid-liquid extraction mechanism and the complex of the ligand with lithium were proposed.

Modeling and Thermodynamics of Methylene Blue and Acid Blue 80 Adsorption onto Potato Residue Based Activated Carbon

LIU Yani, LUO Xinsheng, ZHANG Zhe, ZHOU Pengxin, YANG Zhiwang

2015, 31(4): 627-632. doi:10.1007/s40242-015-4327-8

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A study was made on the adsorption kinetics and thermodynamics of methylene blue(MB) and acid blue 80(AB80) onto powder of activated carbon(PAC) prepared by chemical method from dry potato residue(DPR). The PAC was characterized by N₂ adsorption-desorption isotherms analysis and scanning electron microscopy. The ma- ximum adsorption capacities of PAC for MB and AB80 at 303 K are 532.19 and 156.22 mg/g, respectively. The results indicate that the adsorption kinetics of the selected dyes on PAC is well-described by the pseudo-second order model. And their thermodynamic data were analyzed via the isotherms of Langmuir, Freundlich, Redlich-Peterson, Toth and Sips, and the thermodynamic parameters were calculated. The results show that PAC is a fast and effective adsorbent for removing the cationic dyes from aqueous solutions.

Mechanical Properties and Network Structure of Hydrophobic Association Hydrogels Prepared from Octylphenol Polyoxyethylene(7) Acrylate and Sodium Dodecyl Sulfate

LIANG Zi, GAO Tingting, XU Jianan, LI Zhiying, LIU Xiaoli, LIU Fengqi

2015, 31(4): 633-639. doi:10.1007/s40242-015-5122-2

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Hydrophobic association hydrogels(HA-gels) with high mechanical strength were prepared by free radical micellar copolymerization in aqueous solutions of acrylamide(AM), anion surfactant sodium dodecyl sulfate(SDS) and a small amount of hydrophobic monomer octylphenol polyoxyethylene(7) acrylate(OP-7-AC). We found that the molar ratio of SDS to OP-7-AC has a great effect on the tensile strength and other mechanical property parameters. The best ratio point R' was determined. On the basis of Mooney theory and statistical theory, the critical tensile ratios and critical tensile strengths of the hydrogels were obtained, elastic parameters C₁and C₂were calculated via uniaxial tensile equation and structural parameters, such as the effective network chain density and the averaged molecular weight of the chain between cross-linking points of all the hydrogels were evaluated. The results indicate that the variation of mechanical property parameters depends on the number of effective cross-linking points and the match degree of long and short chains.

Synthesis and Characterization of Poly(ω-pentadecalactone) for Its Industrial-scale Production

CHANG Qing, LI Li, YANG Dalei, ZHANG Mingyao, TON-THAT Minh-Tan, HU Wei, LÜ Shuai

2015, 31(4): 640-644. doi:10.1007/s40242-015-5092-4

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The synthesis of biomaterial poly(ω-pentadecalactone)(PPDL) with yttrium isopropoxide as initiator in bulk was explored for its industrial-scale production. The weight-average molecular weight(M_w) of PPDL could be controlled by the molar ratio of monomer to initiator(M/I), polymerization temperature(T_p) and period(t_p). The syn- thesis conditions were optimized, and a high M_w of 9.2×10⁴ of PPDL could be obtained by the reaction at an M/I molar ratio of 1000/1 and 100 ℃ for only 30 min, which presented tough properties with a tensile strength of about 20 MPa and an elongation at break of about 300%. This mechanical property was comparable to that of high density polyethylene(HDPE). The melting point was about 96 ℃, and 5% of mass loss temperature(T_5%) was as high as 340 ℃. Thus, the PPDL with good mechanical properties and high thermal stability can be synthesized without solvent at low expenses.

Novel Porous Polyethersulfone Beads as Matrix to Immobilize Comamonas testosteroni sp. bdq06 in Quinoline Biodegradation

GENG Zhi, ZHU Suiyi, YU Yang, LU Ying, LIN Rao, GUO Shujun, BIAN Dejun, YANG Xia, HUO Mingxin, HUO Hongliang

2015, 31(4): 645-650. doi:10.1007/s40242-015-5047-9

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Novel matrix beads for the immobilization of strain Comamonas testosteroni sp. bdq06 to degrade quinoline were fabricated from polyethersulfone(PES). The beads have an average size of 3 mm and a surface dense layer of 20 microns. To help adhesion and proliferation of bacterial cells, the surfaces of the PES beads were etched, and numerous holes about 1.5 micrometers in diameter were generated as tunnels for cell colonizing in the larger internal cavities of about 5 micrometers in diameter. The quinoline degradation was remarkably enhanced by the cells immobilized in PES beads compared with that by the free cells at pH 5.0 or 10.0 and a temperature of 40 ℃. The enhanced degradation of quinoline was contributed to the biofilm on the surface of PES beads, resulting in the significant reduction of retention time from 9 h to 2 h. Furthermore, the beads remain intact after the ultrasonic treatment of them for 30 min or recycling 50 times, indicating that they have excellent mechanical strength, flexibility and swelling capacity. Thus, PES beads have great potential to be matrix for the cell immobilization in bioaugmentation.

Surface Modification of 316L Stainless Steel by Grafting Methoxy Poly(ethylene glycol) to Improve the Biocompatibility

XIAO Yanlong, ZHAO Lei, SHI Yongfeng, LIU Ning, LIU Yongli, LIU Bin, XU Qinghua, HE Chaoliang, CHEN Xuesi

2015, 31(4): 651-657. doi:10.1007/s40242-015-5027-0

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Percutaneous coronary intervention(PCI) has become an important method for the treatment of the patients with coronary heart disease; however, problems, such as vascular endothelial inflammation, late thrombosis, and stent restenosis still exist as a result of poor biocompatibility of the materials. To enhance the biocompatibility, methoxy poly(ethylene glycol)(mPEG) was immobilized on the surface of AISI 316 grade stainless steel(SS)(AISI: American Iron and Steel Institute). First, silanized mPEG was synthesized by the direct coupling of mPEG with 3-isocyanatopropyltriethoxysilane(IPTS) via urethane bonds, and the silanized mPEG was then grafted on the surface of SS that was hydroxylated with piranha solution. The results obtained from contact angle goniometry, X-ray photoelectron spectroscopy(XPS), and atomic force microscopy(AFM) confirm that the mPEG modified steel contained more C and Si and less Fe and Cr on its surface, exhibiting a morphological change and decrease in the contact angle. The biocompatibility of the mPEG modified SS was evaluated with fibrinogen adsorption, platelet activation and adhesion, and human umbilical vein endothelial cell(HUVEC) adhesion. Fibrinogen adsorption, platelet activation, and adhesion were clearly suppressed on the surface-modified steel. In addition, human umbilical vein endothelial cell(HUVEC) could adhere and proliferate on the surface of the mPEG-modified SS. This study indicates that the modification of 316L SS with mPEG could enhance the biocompatibility and provide a primary experimental foundation for the development of next-generation coronary stent materials for clinical application.

Effect of Hydrodynamic Interaction on Flow-induced Polymer Translocation Through a Nanotube

DING Mingming, DUAN Xiaozheng, LU Yuyuan, SHI Tongfei

2015, 31(4): 658-663. doi:10.1007/s40242-015-5001-x

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We investigated the effect of hydrodynamic interaction(HI) on flow-induced polymer translocation through a nanotube by Brownian dynamics simulations. Whether there is HI in the simulation system is separately controlled by using different diffusion tensors. It is found that HI has no effect on critical velocity flux for long polymer chains due to the competition between more drag force and the hindrance of chain stretching from HI, however, HI broadens the transition interval. In addition, for flow-induced polymer translocation with HI, the critical velocity flux firstly slowly decreases with the increase of chain length and then becomes identical to that of it without HI, that is, the critical velocity flux is independent of chain length. At the same time, HI also accelerates the translocation process and makes the relative variation amplitude of single bead translocation time smaller. In fact, HI can enhance the intrachain cooperativity to make the whole chain obtain more drag force from fluid field and hinder chain stretching, both of which play an important role in translocation process.

Preparation and Chiral Recognition of Thermosensitive Poly(N-isopropylacrylamide) Microgels Containing Modified L-Phenylalanine Groups

CHEN Jiaojiao, YIN Yue, FU Hongjun, LI Qifeng, ZOU Jiwei

2015, 31(4): 664-668. doi:10.1007/s40242-015-4461-3

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Thermosensitive poly[N-isopropylacrylamide(NIPAM)-co-N-acryloyl-L-phenylalanine ethyl ester (NALPE)] microgels were prepared by the free radical polymerization of NIPAM and chiral monomer, NALPE. Such microgels exhibited spherical shape and favorable monodispersity. Increasing the content of NALPE units would enhance the average diameter, but decrease the thermosensitivity and volume-phase transition temperatures of the microgels. Compared with PNIPAM microgels, the microgels containing NALPE units performed chiral recognozable capacities for D-phenylalanine and D-tartaric acid, and the enantioselectivity and adsorption capacity of the microgels improved with increasing the temperature and/or the content of NALPE units.

Graft of Chiral Amino Alcohol onto Poly(menthyl vinyl ketone) and the Grafted Polymer's Inducement to the Asymmetric Addition of Phenylacetylene to Aromatic Ketone

LIU Can, ZHOU Ya, YANG Liwen, YANG Nianfa, ZHANG Anlin

2015, 31(4): 669-673. doi:10.1007/s40242-015-4440-8

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A new kind of optically active polymer bearing chiral amino alcohol was prepared by means of graft. The resulting grafted polymer was obtained as follows. First, the carbonyl of optically active helical poly(menthyl vinyl ketone)(poly-MVK) was reduced to hydroxyl group with lithium aluminum hydride as a reductant to yield poly(1-menthyl-2-propen-1-ol)(poly-MPO). Second, the hydroxyl group of poly-MPO reacted with epichlorohydrin to yield methyloxirane-loading poly-MPO[(poly-MPO)-MO]. Third, the(poly-MPO)-MO reacted with amine to produce optically active polymer bearing chiral amino alcohol[(poly-MPO)-APO]. The (poly-MPO)-APO was applied to the asymmetric addition of phenylacetylene to aromatic ketone. Good enantioselectivities were achieved and the catalyst could be recovered and reused 5 times with unchanged enantioselectivity and slightly decreased activity.

Smoothing of Fast Assembled Layer-by-layer Films by Adjusting Assembly Conditions

DUAN Yang, AN Qi, ZHANG Qian, ZHANG Yihe

2015, 31(4): 674-679. doi:10.1007/s40242-015-4414-x

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To prepare layer-by-layer(LbL) multilayers in time-efficient manners by the dipping method is highly appealing. However, the fast LbL assembly produces multilayers with high surface roughness. In our attempt to smooth the surface morphologies of LbL multilayers obtained by fast assembly(5 s dipping), we studied the influence of the assembly conditions on the surface morphologies. The study shows that by properly adjusting the assembly conditions, such as washing duration, water annealing period, and drying with nitrogen flow, LbL multilayers with enhanced surface smoothness could be obtained through fast LbL assembly.

Electrical Responses and Stable Behavior of Polyaniline-polyurethane Concave Lens Array Film in Electrolyte

MENG Xiaomin, YANG Xiaohang, WANG Hongjuan, JIA Ruokun

2015, 31(4): 680-684. doi:10.1007/s40242-015-4398-6

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We present a synthetic methodology of polyaniline-polyurethane(PANI-PU) copolymer using interfacial in situ polymerization. PANI-PU copolymer was obtained through in situ polymerization of aniline precursor and the concave lens array film was molded by water drops. The fabrication of unique structured film was obtained through a solvent evaporation self-formed system. The detailed nanostructures of the film were illustrated by scanning electron microscopy(SEM) images, which showed homogeneous structure in a close-packed hexagonal arrangement. The dimension of well-structured hexagon ranged from 10.8 μm to 12.9 μm. Sensitive electrical responses of the concave lens array film resulted in the changes of swelling/shrinkage ratio in electrolyte under various conditions. Dimensional control of the film was achieved via adjusting a series of parameters including time, voltage, concentration and type of electrolyte. The electrical responses resulted rearranged molecular chain caused by redox reaction via powered PANI. Most importantly, the film maintained its response characteristics after 16 cycles. The high stability of film could be directly attributed to PU doping, which could help the PANI enhancing the mechanical strength and chemical solubility in solution.

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