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01 October 2017, Volume 33 Issue 5

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2017, 33(5):  0-0. 

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Articles

Insight into the Reaction Mechanism of Graphene Oxide with Oxidative Free Radical

ZHOU Xuejiao, XU Liangyou

2017, 33(5):  689-694.  doi:10.1007/s40242-017-7070-5

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Graphene oxide (GO),as an important derivative of graphene,could be considered as a super aromatic molecule decorated with a range of reactive oxygen-containing groups on its surface,which endows graphene high reactivity with other molecules.In our previous work,we demonstrated that GO sheets were cut into small pieces (graphene quantum dots,GQDs) by oxidative free radicals (hydroxyl radical HO · or oxygen radical[O]) under UV irradiation.It is notable that reactions involving free radicals are influenced by reaction conditions pronouncedly. However,researches on details about reactions of GO with free radicals have not been reported thus far.In this work, the effects of different factors on the photo-Fenton reaction of GO were studied.It is demonstrated that the reaction rate is closely related to the concentration of free radicals.It is speculated that through the optimization of reaction conditions,the reaction of graphene with free radicals could carry out efficiently for further applications.



A New Biphenylcarbonitrile Based Fluorescent Sensor for Zn²⁺ Ions and Application in Living Cells

FENG Jia, SHAO Xiuqing, SHANG Zhuobin, CHAO Jianbin, WANG Yu, JIN Weijun

2017, 33(5):  695-701.  doi:10.1007/s40242-017-7084-z

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A new and efficient fluorescent sensor 4'-hydroxy-3'-[(4-antipyrineimino) methyl]-4-biphenylcarbonitrile (L) was prepared for the selective detection of Zn²⁺ in aqueous ethanol medium.When excited at 419 nm,the fluorescent intensity of sensor L at 507 nm was remarkably increased more than 54-fold after adding Zn²⁺ ions.The strong green emission of the solution can be easily identified by naked eye under UV light.Thus,sensor L behaves as a naked eye fluorescent-turn on‖ detector for Zn²⁺ ions.The fluorescence enhancement might be attributed to the inhibition of excited state intramolecular proton transfer (ESIPT) and C=N isomerization as well as the chelation enhanced fluorescence (CHEF) effect.The complex solution of sensor L with Zn²⁺ ions exhibited reversibility with ethylene diamine tetraacetic acid (EDTA) and the probe could be recycled for further use.Notably,sensor L could clearly distinguish Zn²⁺ from Cd²⁺.The interaction of sensor L with zinc ions was investigated by means of FTIR, 1H NMR and HRMS spectroscopy.Furthermore,sensor L has been applied for cell imaging studies.



Phytochemical Analysis of Ziziphus jujuba Leaves in Six Cultivars at the Whole Life Stage by High Performance Liquid Chromatography

CUI Xueqin, MA Zhongxiao, BAI Lu, WU Yong, GUO Sen, LIU Qingchao, ZHANG Li, HO Chi-Tang, BAI Naisheng

2017, 33(5):  702-708.  doi:10.1007/s40242-017-7076-z

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Leaves of Ziziphus jujuba Mill.(Z. jujuba) were used as a folk medicine to treat children suffering from typhoid fever, furuncle and ecthyma in China. The present study was to establish a high performance liquid chromatography-diode array detector(HPLC-DAD) method for quality control of Z. jujuba leaves. The validated method was applied to the simultaneous characterization and quantification of sixteen main constituents in thirty samples, which comprised the whole life stage of Z. jujuba leaves from six cultivars in Yulin, Shannxi Province, China. HPLC fingerprint file of Z. jujuba leaves was set up and the results indicate that the major constituents of Z. jujuba leaves are(-)-catechin(1), quercetin-3-O-robinobioside(3), rutin(4) and quercetin-3-O-α-L-arabinosyl-(1→2)-α-L-rhamnoside(6) with the total contents of the nine flavonoids in respective batch ranging from 18.52 mg/g to 39.51 mg/g. In addition,the contents of compounds depend on both the season and the cultivar. During ripening of Z. jujuba leaves, flavonoids of all the cultivars present a similar trend:initially decrease from 25th, Jun. to 5th, Aug., 2015, and then increase for a period of time, finally slightly fluctuate on 5th Oct. The highest contents of total flavonoids were registered on 25th Jun., 2015. Different cultivars have 50%-90% variation on the content for the three classes of compounds. Taken together, the results demonstrate that Z. jujuba leaves have great potential to be a new health-promoting resource based on flavonoids and the best sampling time of them is in June.



Development of a Novel Kilowatt Microwave Plasma Torch Source for Atomic Emission Spectrometry

ZHU Dan, JIN Wei, YU Bingwen, YING Yangwei, YU Haixiang, SHAN Jin, YAN Yuwei, XU Chen, WANG Baolai, JIN Qinhan

2017, 33(5):  709-713.  doi:10.1007/s40242-017-7072-3

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Traditional low power-microwave plasma torch (MPT) excitation source of atomic emission spectrometry was shown to be good for the introduction of dry aerosols,but poor for wet sample aerosols.In this work,some significant modifications have been made to traditional MPT.A new MPT excitation source working at kilowatt microwave power has been developed.The kilowatt MPT source can sustain stable plasmas with double or even more filaments,presenting a "bell" form,where the region around the converging point is the optimum region for analysis. The tolerance to aqueous aerosol of the torch is enhanced significantly compared to the traditional one.Therefore,the desolvation system that the low power MPT source has to be relied on can be gotten rid of.A set of favorable detection results have been obtained with direct wet sample aerosol introduction.The kilowatt MPT source is expected to become a practical excitation source for atomic emission spectrometry that will be widely used.



An Aptamer-based Colorimetric Sensor for Streptomycin and Its Application in Food Inspection

LIU Zhongcheng, ZHANG Yanfen, XIE Yao, SUN Ying, BI Kewei, CUI Zhe, ZHAO Lijian, FAN Wufang

2017, 33(5):  714-720.  doi:10.1007/s40242-017-7029-6

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An aptamer-based colorimetric biosensor was developed,which could be used to detect residual streptomycin from food quickly and cost-effectively.The ssDNA aptamer target for streptomycin was obtained using systemic evolution of ligands by exponential enrichment through affinity chromatography.A total of 19 candidates were obtained after 10 rounds of selection and were grouped into 3 families according to their similarity of sequence and structure.Among them,aptamer A15 showed the highest affinity for streptomycin tested by fluorescence intensity analysis with a dissociation constant of 6.07 nmol/L.Aptamer A15 also exhibited a higher streptomycin specificity with the lowest detectable limit of 25 nmol/L according to the value of A₆₂₀/A₅₂₀ ratio with AuNP-based colorimetric assay.The method was specific and sensitive for the detection of streptomycin from simply-treated milk and honey at 100 and 125 nmol/L,respectively,and is a promising approach to monitor antibiotics or other small molecules analogues in food inspection.



Analysis and Identification of Chemical Constituents of Fenugreek by UPLC-IT-MSⁿ and UPLC-Q-TOF-MS

WANG Jiaqi, JIANG Wenyue, LIU Zhongying, WANG Junhua, FU Tianyue, WANG Yongsheng

2017, 33(5):  721-730.  doi:10.1007/s40242-017-7136-4

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Fenugreek, a traditional Chinese medical plant, has been widely used as food ingredients because of its outstanding medicinal qualities. The hypoglycemic activity of fenugreek is one of its important pharmacological properties. Both of saponin and flavonoid components have the hypoglycemic activity and their contents in fenugreek are 4%-8% and 1%-2%, respectively. This paper focused on these two types of components to carry out purification research and chemical analysis. The heating reflux extraction method and macroporous resin purification method were designed to prepare the saponins and the flavonoids components from defatted fenugreek seeds. Petroleum ether ultrasonic skim and 70% ethanol refluxing were used for the extraction of saponins and flavonoid from fenugreek. The column of DM130 macroporous resin and D101 macroporous resin were respectively used to prepare fenugreek saponin and flavonoid components, and the total contents of them were 78.56% and 62.28%, respectively. The saponin and flavonoids were subsequently analyzed by an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) along with an ultra-performance liquid chromatography and ion-trap tandem mass spectrometry(UPLC-IT-Mⁿ). As a result, 57 saponins and 19 flavonoid compounds were characterized. The obtained results will provide a theory basis for further research on fenugreek, as well as research and development of hypoglycemic new drugs.



Insights into the Interactions Between Corrinoid Iron-sulfur Protein and Methyl Transferase from Human Pathogen Clostridium difficile

WEI Yaozhu, TAN Xiangshi

2017, 33(5):  731-735.  doi:10.1007/s40242-017-7142-6

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The human pathogen Clostridium difficile infection(CDI) is one of the most important healthcareassociated infections. Methyltransferase(MeTr_Cd) and corrinoid iron-sulfur protein(CoFeSP_Cd) are two key proteins in the acetyl-coenzyme A synthesis pathway of Clostridium difficile, which is essential for the survival of the pathogen and is absent in humans. Hence, the interaction between MeTr_Cd and CoFeSP_Cd can become innovative targets for the treatment of human CDI. In this study, the interaction between MeTr_Cd and CoFeSP_Cd was verified by fluorescence resonance energy transfer measurements. The influence of the interaction on the tertiary structure of MeTr_Cd and CoFeSP_Cd was studied by ANS-labeled fluorescence measurements. Molecular docking was also performed tounderstand the mechanism of the protein interactions. These results provide a molecular basis for innovative drug design and development to treat human CDI.



Effects of Inclusion of Chrysin in Cucurbit[8]uril on Its Stability, Solubility and Antioxidant Potential

XU Zhiling, LIAN Xiaowei, LI Mengjie, ZHANG Xiaodong, WANG Yi, TAO Zhu, ZHANG Qianjun

2017, 33(5):  736-741.  doi:10.1007/s40242-017-7096-8

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The host-guest interaction between cucurbit[8]uril(Q[8]) and chrysin(CHR) has been studied by means of 1H NMR, mass spectrometry(MS), differential thermal analysis(DTA), and UV-Vis spectrophotometry. The results show that CHR forms a 1:1 inclusion complex with Q[8], with a binding constant of CHR with Q[8] by UV absorption being 5.4×10⁶. Phase solubility experiments show a 5.13-fold increase in the solubility of CHR through interaction with Q[8]{c(Q[8])=10^-4 mol/L}. A study of the evolution of UV absorption spectra with time shows that Q[8]significantly increases the stability of CHR. The antioxidant activity of CHR-Q[8] has been tested by the ABTS method. The CHR-Q[8] inclusion complex shows a better scavenging effect towards the ABTS radical than CHR, with respective IC₅₀ values of 1.05×10^-6 and 3.07×10^-6 mol/L. In vitro release studies have shown that CHR-Q[8] has a sustained release effect.



Synthesis of a Newly Modified Poly-H₈-BINOL Ligand and Its Applications in the Asymmetric Addition of Triethylaluminium to Aromatic Aldehydes

LIU Can, OUYANG Kunbing, YANG Nianfa

2017, 33(5):  742-745.  doi:10.1007/s40242-017-7093-y

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A new H₈-BINOL polymer was synthesized by radical polymerization and proved to be an effective catalyst in enantioselective addition of triethylaluminium to aromatic aldehydes in the presence of titanium isopropoxide. The polymer can be prepared with simple steps and reused without losing its enantioselectivity and catalytic activity.



FeCl₃·6H₂O-Catalyzed Synthesis of β-Ketothioesters from Chain α-Oxo Ketene Dithioactals

ZHAO Hui, DIAO Quanping, YU Haifeng, LI Tiechun, LIAO Peiqiu, HOU Dongyan

2017, 33(5):  746-752.  doi:10.1007/s40242-017-7082-1

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A FeCl₃·6H₂O-catalyzed synthesis of β-ketothioesters from the hydrolysis reaction of chain α-oxoketene dithioacetals was carried out. Subsequently, we explored the FeCl₃·6H₂O-catalyzed Friedel-Crafts alkylation of the synthesized β-ketothioesters with alcohols in CH₃CN at 25℃, affording the desired α-alkylated β-ketothioesters in excellent yields. Wide scope of the substrates, use of inexpensive reagents, high yields under mild reaction conditions are notable features of these reactions.



Two New Baccharane Glycosides from Seeds of Impatientis balsamina L. with in vitro Growth Inhibitory Activity in Human Cancer A375 Cells

WU Qian, JIN Yongri, YAO Hua, LIU Ying, LI Peng, LI Xuwen

2017, 33(5):  753-757.  doi:10.1007/s40242-017-7061-6

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Two new baccharane-type glycosides(1 and 2), together with seven known baccharane-type glycosides(3-9) hosenkoside A, hosenkoside B, hosenkoside C, hosenkoside F, hosenkoside M, hosenkoside K and hosenkoside G were isolated from the dried seeds of Impatientis balsamina L. The new baccharane-type glycosides were identified as honsenkol A-3-O-β-D-glucopyranosyl-26-O-β-D-glucopyranosyl-28-O-β-D-glucopyranosyl-O-β-Dglucopyranosyl(1) and (3S,4R,17R,20S)-17-hydroxy-3-O-β-D-xylopyranose(12)-β-D-glucopyranosyl-26-O-β-Dglucopyranosyl-28-O-β-D-glucopyranosyl-21,24-epoxybaccharane(2), respectively, by spectroscopic methods, including NMR(1D and 2D), IR and HR-ESI-MS. Compounds 1 and 2 were evaluated for in vitro inhibitory activity against the cell lines. Compound 2 with a new baccharane skeleton had anti-hepatic fibrosis activity against A375 cells in bioassay results, which means the new compounds have potential value in antitumor applications.



Design, Synthesis and Biological Activities of Novel 4,5-Disubstituted-3-S-(β-D-acetylglycosyl)-1,2,4-triazole Derivatives

CHENG Dandan, WEI Wei, LI Yuxin, HUA Xuewen, ZHOU Yunyun, LIU Jingbo, LI Yonghong, YU Shujing, XIONG Lixia, LI Zhengming

2017, 33(5):  758-764.  doi:10.1007/s40242-017-7053-6

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A series of novel 4,5-disubstituted-3-S-(β-D-acetylglycosyl)-1,2,4-triazole derivatives was designed and synthesized via the strategy of introducing S-β-D-acetylglycosyl fragments into 1,2,4-triazole ring. The structures of 17 target compounds were characterized by means of 1H NMR, ¹³C NMR and high-resolution mass spectrometer (HRMS). The results of insecticidal activity indicated that compound 5a displayed 60% lethality rate at 100 mg/L concentration. More importantly, the introduction of the carbohydrate fragment to the 1,2,4-triazole core could improve the insecticidal activities since the insecticidal activities of compounds 5 were better than those of compounds 4 and this result was also supported by calcium imaging technique. The antifungal activity of the target compounds showed that some novel compounds displayed moderate to good inhibition rate against Sclerotinia sclerotiorum andBotrytis cinerea, in which compound 5p exhibited 78.8% inhibition rate against Sclerotinia sclerotiorum and 68.6% inhibition rate against Botrytis cinerea. The herbicidal activities of compounds 5 against Brassica campestris indicated that most of the target compounds showed moderate to good activities, especially compound 5g which showed 52.9% herbicidal activity at the concentration of 200 mg/L.



Theoretical and Experimental Study of the Reaction of 2-Guanidinobenzimidazole on a Series of meta-Substituted Benzaldehydes

MONIA Chebbi, HAMMOUDA Chebbi, HEDI M'rabet, YOUSSEF Arfaoui

2017, 33(5):  765-772.  doi:10.1007/s40242-017-6476-4

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The syntheses of a variety of 1,3,5-triazinebenzimidazoles obtained by the cyclocondensation reaction of 2-guanidinobenzimidazole with a series of meta-substituted benzaldehydes were reported. The prepared compounds were fully characterized by IR and NMR spectroscopies. Based on the density functional theory(DFT) calculations method, quantum chemical calculations were performed by Gaussian 09 set of programs. All possible transition states, reactants and products were fully optimized at the hybrid density functional B3LYP level using the 6-311+G(d,p). The geometries of five possible tautomers of 2-amino-4-aryl[1,3,5]triazino[1,2-a]benzimidazoles were optimized in ethanol, using conductor like polarizable continuum(CPCM) in the gas phase. The energetic diagrams of tautomeric equilibrium showed that form A is the most stable tautomer which proved to be in accordance with the X-ray diffraction structure analysis. In order to interpret the reaction mechanism, the chemical reactivity was studied using local and global reactivity indexes.



Studies on the Activities of Electrophilic Sites on Benzene Ring of 4-Substituted Anilines and Their Acyl Compounds with Multiphilicity Descriptor

SHEN Xizhou, HE Huajun, YANG Bowen, ZHAO Zhigang, SHAO Kaiyuan, HU Wenxiang

2017, 33(5):  773-778.  doi:10.1007/s40242-017-7112-z

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In this paper, the activities of electrophilic sites on benzene ring of 4-substituted anilines and their acyl compounds were studied with the quantitative indicator of multiphilicity descriptor. Four substituents were synthesized with microwave irradiation in good yields to verify the quantitative analysis data. Friedel-Crafts acylation was carried out by the microwave method for the first time.



Fluorine-free Ionic Liquid Based on Thiocyanate Anion with Propylene Carbonate as Electrolytes for Supercapacitors:Effects of Concentration and Temperature

ZHANG Lifeng, DU Suqing, SONG Qiaolan, LIU Yi, GUO Shouwu

2017, 33(5):  779-784.  doi:10.1007/s40242-017-7100-3

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High performance supercapacitors were constructed using ionic liquid 1-ethyl-3-methylimidazolium thiocyanate(EmimSCN)-based electrolyte with chemically reduced graphene oxide(CRGO) as electrodes. Propylene carbonate(PC) was selected as the solvent due to its stable physical and electrochemical properties. Then, in -depth study of the concentration and temperature effects on the electrochemical properties of the EmimSCN/PC electrolyte was carried out. Electrochemical measurements revealed that 2.0 mol/L EmimSCN/PC electrolyte delivered good electrochemical performance(131 F/g of the specific capacity after 3000 cycles at room temperature). Moreover, the assembled supercapacitors exhibited good capacitive behavior at an extending temperature(397 F/g of the specific capacity after 3000 cycles at 50℃), demonstrating that the EmimSCN/PC electrolyte is a promising candidate for safe high-power supercapacitors.



Density Functional Theoretical Studies on Effect of Intramolecular Hydrogen Bonds on Reduction of Nitrophenols

ZHANG Hongmei, LIU Yan, MA Fangping, QIU Wei, LEI Bo, SHEN Jinyou, SUN Xiuyun, HAN Weiqing, LI Jiansheng, WANG Lianjun

2017, 33(5):  785-793.  doi:10.1007/s40242-017-7066-1

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Intramolecular hydrogen bonds(IMHBs) can lead to different physicochemical characteristics of nitrophenols(NPs) that determine their environmental behavior. In the present work, to reveal the relationship between IMHB and nitrophenol reduction, the effects of IMHB on the molecular geometries and properties of a series of n itrophenols were investigated with density functional theory(DFT) calculations. The results of the geometry optimization and atoms-in-molecules(AIM) analysis indicate relatively strong IMHBs in ortho-substituted nitrophenols, whose stability could be significantly improved. In comparing the E_LUMO and adiabatic electron affinities(AEA) of the nitrophenol isomers, the presence of IMHBs benefited the reductive degradation of NPs, consistent with a previous study. To gain an insight into the effect mechanism of IMHBs on the reductive degradation behavior of these molecules, the condensed electrophilicity Fukui index(f^-), natural charges and Wiberg bond orders of these nitrophenol isomers were calculated. The calculations indicate that the electrophilic reactivity activity of the O atom on the nitro group could be significantly improved due to the formation of IMHBs, which results in the enhanced reductive degradation of ortho-substituted NPs.



Thermodynamic Description of the MCl₂-ThCl₄ (M:Mg, Ca, Sr, Ba) Systems

XIE Mengya, LI Xiang, DING Yaping, ZHANG Guoxin

2017, 33(5):  794-798.  doi:10.1007/s40242-017-7033-x

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The phase equilibria for the MCl₂-ThCl₄(M:Mg, Ca, Sr, Ba) binary systems were critically evaluated and optimized based upon the CALPHAD approach. The substitutional solution model(SSM) was used to describe the liquid phase. All the intermediate compounds were treated as stoichiometric compounds of which Gibbs energies comply with the Neumann-Kopp rule. Thermodynamic model parameters optimization for respective phases was conducted by the least squares minimization procedure with required input data available from experimental measurements. Satisfactory agreements between all calculated results and experimental data were achieved which demonstrates that thermodynamic databases for the MCl₂-ThCl₄(M:Mg, Ca, Sr, Ba) binary systems were ultimately derived in the present work allowing safe extrapolation into multi-component system for guiding relative industrial applications.



A New and Facile Strategy for Determination of Lead and Cadmium Using Silver Electrodes Manufactured from Digital Versatile Discs

CUI Wenyu, FAN Lishuang, GENG Lin, AN Maozhong, ZHANG Fujun

2017, 33(5):  799-803.  doi:10.1007/s40242-017-7010-4

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The use of a digital versatile disc(DVD)-based Ag electrode for the square-wave anodic stripping voltammetric determination of Pb²⁺ and Cd²⁺ was described. The effect of I^- on the stripping analysis of Pb²⁺ and Cd²⁺ at Ag electrodes was first studied. I^- significantly improved the stripping peaks of both Pb²⁺ and Cd²⁺. The square-wave voltammetric stripping response was linear over 5-50 μg/L for Pb²⁺ and Cd²⁺ with a deposition time of 118 s. The detection limits were 0.2 and 2.6 μg/L for Pb²⁺ and Cd²⁺, respectively. The high sensitivity, selectivity, and stability of this DVD-based Ag electrode enabled its practical application for simple, rapid and economical determination of trace levels of Cd²⁺ and Pb²⁺ in tap water samples. In addition, detection can be achieved without sample deoxygenation and the electrode can be easily manufactured.



High Selectivity to Diphenyl Carbonate Synthesized via Transesterification Between Dimethyl Carbonate and Phenol with C₆₀-doped TiO₂

QU Yingmin, YANG Hao, WANG Songlin, CHEN Tong, WANG Gongying

2017, 33(5):  804-810.  doi:10.1007/s40242-017-6500-8

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An environmentally friendly heterogeneous catalyst, C₆₀-doped TiO₂(denoted as C₆₀-TiO₂), was prepared and firstly used to catalyze the synthesis of diphenyl carbonate(DPC) via the transesterification of phenol and dimethyl carbonate(DMC). The characterization results of FTIR, XRD, XPS, SEM, TEM and digital optical microscope(MIC) show that C₆₀ promotes the dispersion of TiO₂ and the prepared conditions affect the dispersion and the electron density of Ti species. The C₆₀-TiO₂-8[n(Ti):n(C₆₀)=8:1] prepared with toluene and calcined at 200℃ exhibits the best catalytic performance. The DPC selectivity of 86.5% attained over C₆₀-TiO₂-8 was much higher than that(about 50%) attained over Ti-based catalysts reported, which was originated from the electronic effect of C₆₀ and the efficient dispersion of Ti species by C₆₀. The phenol conversion slowly decreased from 34.4% to 26.7% after four consecutive runs due to the leach of Ti species. It also suggested that the C₆₀ could relieve the leach of Ti species compared with other Ti-based catalysts reported. Moreover, C₆₀-TiO₂-8 exhibited excellent catalytic behavior for disproportionation of methyl phenyl carbonate(MPC) with high DPC selectivity.



Heterogeneous h-BN@Cyclodextrin@Pd(Ⅱ) Nanomaterial:Fabrication, Characterization and Application as a Highly Efficient and Recyclable Catalyst for C-C Coupling Reactions

SANG Rui, CHENG Xu, LI Weijian, LUO Pengfei, ZHANG Yong, NIE Ruifang, HAI Li, WU Yong

2017, 33(5):  811-815.  doi:10.1007/s40242-017-6455-9

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An efficient and ligand-free method for the Suzuki and Heck cross-coupling reactions has been successfully developed using h-BN-supported palladium as the catalyst. This green methodology represents a cost-effective and operationally convenient process for the synthesis of biaryls, stilbenes and acrylates. Wide scope of substrates, good to excellent yields, low reaction time, water as solvent, ligand-free, non-toxicity and recyclability of the catalyst are the main merits of these protocols. In addition, the h-BN@γ-CD@Pd(Ⅱ) nanomaterial has been fully characterized by TG, SEM, IR, XRD, XPS and ICP-AES analysis. And it could be easily recovered and reused for at least nine times without any considerable loss of catalytic activity. Above all, this work demonstrates the possibility of using cyclodextrin-modified h-BN as an efficient support for the hydrophilic heterogeneous catalysts.



Effect of Synthetic Method and Reductant on the Morphology and Photocatalytic Hydrogen Evolution Performance of Ru Nanoparticles

KONG Chao, HAN Yanxia, HOU Lijie, CHEN Dongping, WU Bowan

2017, 33(5):  816-821.  doi:10.1007/s40242-017-6452-z

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Ru nanoparticles were synthesized using the photoreduction and chemical reduction methods. Ru nanoparticles were used as a cocatalyst to develop a photocatalytic hydrogen evolution system sensitized by Eosin Y(EY), and the effects of the synthetic method and reductant on the morphology and photocatalytic hydrogen evolution performance of Ru nanoparticles were studied. The results indicated that Ru nanoparticles prepared by photoreduction and thermochemical reduction by ethanediol had a relatively uniform size, and the photoreduced Ru showed higher photocatalytic performance than Ru reduced by ethanediol and methanal. The amount of H₂ evolution in 60 min over Ru(photoreduction)-EY was 1247.7μmol, which was 13.6 and 14.3 times that over Ru prepared by chemical reduction methods under the same photoreaction conditions. The calculation of binding energies showed that a higher binding energy of Ru nanoparticles and glycol was one of the main reasons for the uniform size and low photocatalytic performance of Ru reduced by glycol. The results indicated that different preparation methods and reductants had a significant influence on the catalytic activity of Ru catalyst.



Comparison of the Catalytic Performances of Different Commercial Cobalt Oxides for Peroxymonosulfate Activation During Dye Degradation

ZHANG Botao, ZHANG Yang, XIANG Weixu, TENG Yanguo, WANG Ying

2017, 33(5):  822-827.  doi:10.1007/s40242-017-6413-6

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The catalytic performances of different commercial cobalt oxides(Co_xO_y, i.e., Co₂O₃, Co₃O₄, and CoO) for peroxymonosulfate(PMS) activation in dye degradation were compared in this study. The CoO/PMS system exhibited the highest catalytic oxidation performances with more than 96% methylene blue(MB) removal at 90 min. The concentration of dissolved cobalt ions from CoO was 1.474 mg/L at neutral pH and 5.231 mg/L at acidic pH at 90 min which accounted for the high MB removal and CoO activated PMS homogeneously compared to the associated CoSO₄/PMS. Co₃O₄ and Co₂O₃ exhibited similar catalytic performances and characteristics. The MB removal in Co₃O₄/PMS and Co₂O₃/PMS system were more than 88% at neutral pH and over 64% at acidic pH, respectively, in 90 min. The concentration of dissolved cobalt ions from Co₃O₄ and Co₂O₃ was less than 0.018 mg/L at neutral pH and 0.036 mg/L at acidic pH at 90 min. The MB removal achieved by Co₃O₄/PMS and Co₂O₃/PMS were approximately three times higher than that achieved by their associated CoSO₄/PMS systems and the heterogeneous catalysis played a principal role in the processes. According to scavenger experiments, the contributions of the hydroxyl radicals in the MB degradation were negligible compared to sulfate radicals in the CoO/PMS system. Hydroxyl radicals contributed one-third or more and sulfate radicals were the dominant oxidizing species in the Co₃O₄/PMS and Co₂O₃/PMS systems. Co_xO_y could also effectively activate PMS to generate free radicals for degradation of other dyes. The dyedegradation processes in Co₃O₄/PMS, Co₂O₃/PMS and CoSO₄/PMS systems followed pseudo-first-order kinetic model and dye degradation rates in different systems were also compared.



Molar Surface Gibbs Energy of the Aqueous Solution of Ionic Liquid[C₄mim] [OAc]

TONG Jing, ZHENG Xu, TONG Jian, QU Ye, LIU Lu, LI Hui

2017, 33(5):  828-832.  doi:10.1007/s40242-017-6386-5

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The values of density and surface tension for aqueous solution of ionic liquid(IL) 1-butyl-3-methylimidazolium acetate([C₄mim] [OAc]) with various molalities were measured in the range of 288.15-318.15 K at intervals of 5 K. On the basis of thermodynamics, a semi-empirical model-molar surface Gibbs energy model of the ionic liquid solution that could be used to predict the surface tension or molar volume of solutions was put forward. The predicted values of the surface tension for aqueous[C₄mim] [OAc] and the corresponding experimental ones were highly correlated and extremely similar. In terms of the concept of the molar Gibbs energy, a new Eötvös equation was obtained and each parameter of the new equation has a clear physical meaning.



Swelling Process of Thin Polymer Film Studied via in situ Spectroscopic Ellipsometry

XU Lin, ZOU Zhiming, ZHANG Huanhuan, SHI Tongfei

2017, 33(5):  833-838.  doi:10.1007/s40242-017-7075-0

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The swelling process of thin polystyrene films in quantity was studied in this paper using the in situ spectroscopic ellipsometry. We systematically investigated the influence of film thickness on the swelling process of thin polystyrene films. The results show that in the case of high M_w polystyrene(M_w=400000), the curve of the swelling degree as a function of time discloses that the relaxation of the long polymer chains accompanies the diffusion of acetone molecules. The swelling process is via the Fickian relaxation mechanism. Both the values of the equilibrium swelling degree and the diffusion coefficient of acetone molecules in the polystyrene film decrease as the film thickness reduces under confinement. However, in the case of low M_w PS(M_w=4100), the dewetting process is so fast before the equilibrium of swelling that the whole swelling process cannot be observed.



Photo Responsive Silver Nanoparticles Incorporated Liquid Crystalline Elastomer Nanocomposites Based on Surface Plasmon Resonance

ZHANG Jindi, WANG Jun, ZHAO Lina, YANG Wenlong, BI Meng, WANG Yuchang, NIU Hongyan, LI Yuxin, WANG Binsong, GAO Yachen, LI Chensha, HUANG Xuezhen

2017, 33(5):  839-846.  doi:10.1007/s40242-017-7067-0

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We reported a nano-Ag/liquid crystalline elastomer(LCE) nanocomposite by incorporating silver nanoparticles into a monodomain polysiloxane-based LCE matrix via a novel experimental protocol. The photo-thermomechanical actuation of the LCE matrix was realized via the surface plasmon resonance of silver nanoparticles while converting light into heat. The photoresponsive properties of nano-Ag/LCE nanocomposites were investigated with varying illumination intensities and silver nanoparticle doping concentrations(0.04% to 0.2%, mass fraction). The nano-Ag/LCE nanocomposites show sensitive deformation under irradiation due to their excellent photothermal conversion efficiency, and this photostimulated muscle-like actuation is fully reversible via the on-off behavior of light. Incorporating silver nanoparticles into the LCE matrix also improves the mechanical properties and enhances the load-actuation capability of the material.



Preparation and Biocompatibility of Polyester Films Grafted with Functional mPEG Copolymers

MA Yanhong, JIANG Yan, LIANG Yuan, ZHANG Weiwei, ZHANG Hongwen, ZHANG Rong

2017, 33(5):  847-852.  doi:10.1007/s40242-017-7032-y

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The surface of poly(ethylene terephthalate)(PET) films is inert, hydrophobic, and incompatible with blood, which has limited its practical bioapplication. In this case, better biocompatibility could be achieved by surface modification. In this study, the grafted copolymer of functional methoxypolyethylene glycol(mPEG) derivatives and styrene from the PET surfaces was prepared via surface-initiated atom transfer radical polymerization(SI-ATRP). The structures, composition, properties and surface morphology of the grafted PET films were characterized by Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), contact angle measurements and scanning electronic microscopy(SEM). The results indicate that the surface of the PET films has been covered by a thick targeted copolymer layer that converted the hydrophobic surface of PET to an amphiphilic surface. The bacterial adhesion and cell culture results indicate the copolymer-grafted PET film may possess good biocompatibility.