Table of Content

01 August 2018, Volume 34 Issue 4

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CONTENTS

2018, 34(4):  0-0. 

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Letter

Temperature-dependent Photoluminescence of Silicon Nanocrystals Embedded in SiO₂ Matrix

ZHANG Tianning, ZHANG Kenan, CHEN Xiren, WANG Shuxia, ZHANG Rongjun, SHAO Jun, CHEN Xin, DAI Ning

2018, 34(4):  513-516.  doi:10.1007/s40242-018-7417-6

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Articles

Heterostructure Ag@WO_3-x Composites with High Selectivity for Breaking Azo-bond

FANG Zhenxing, CHEN Yan, WANG Boran, JIAO Shihui, PANG Guangsheng

2018, 34(4):  517-522.  doi:10.1007/s40242-018-8095-0

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The heterostructure Ag@WO_3-x(x=0.1 or 1) composites with high selectivity for breaking azo-bond were obtained by in situ reduction of Ag₂WO₄. The crystal structure and morphology of Ag@WO_3-x were characterized by X-ray powder diffraction(XRD), scanning electron microscope(SEM) and transmission electron microscope(TEM). The residue solution of methyl orange(MO) after degradation was tested by gas chromatograph mass spectrometer (GCMS) to analyze the exact components. The results indicate that the products after degradation are N, N-dimethylaniline, N, N-dimethyl-p-phenylenediamine and sulfanilic acid. This is caused by specific breaking of azo-bond in MO. The azo-bond breaking of MO by Ag@WO_3-x could occur in dark without any light illumination. Therefore, we proposed a possible mechanism for this azo-bond breaking reaction based on the reaction condition and results.



Development of a Two-photon Ratiometric Fluorescent Probe for Glutathione and Its Applications in Living Cells

XU Gaoping, TANG Yonghe, LIN Weiying

2018, 34(4):  523-527.  doi:10.1007/s40242-018-8089-y

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Glutathione(GSH), as the most abundant intracellular biothiol, plays an important role in the redox homeostasis of the organism. Abnormal concentrations of GSH in cells may lead to many malignant diseases, such as cancer, liver damage and neurodegenerative diseases. It is urgent to develop effective methods to detect GSH in living organisms. In this work, a new two-photon ratiometric fluorescent probe Co-GSH based on the coumarin-chalcone dye platform was judiciously developed. Based on the Michael-addition reaction, Co-GSH was able to identify GSH with high selectivity and sensitivity. Furthermore, assisted by laser-scanning confocal microscopy, Co-GSH could specifically response GSH over the other biothiols, including Cys and Hcy, in living HeLa cells by using one-and two-photon modes.



Simple and Sensitive Determination of Aromatic Acids in Coconut Water by g-C₃N₄@SiO₂Based Solid-phase Extraction and HPLC-UV Analysis

QIANGBA Gezhen, ZHU Gangtian, YU Qiongwei, FENG Yuqi

2018, 34(4):  528-535.  doi:10.1007/s40242-018-8041-1

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In this study, graphitic carbon nitride deposited silica(g-C₃N₄@SiO₂) was prepared by simple pyrolysis of melamine on silica and then used as a solid-phase extraction(SPE) sorbent for the extraction of four representative aromatic acids including benzoic acid(BA), salicylic acid(SA), indolyl-3-butyricacid(IBA) and naphthalene acetic acid(NAA) in coconut water(CW) samples. g-C₃N₄@SiO₂ exhibited an excellent adsorption capacity for the four aromatic acids, which are in the concentration range of 500-558.8 μg/g. The four aromatic acids could be directly captured by g-C₃N₄@SiO₂ from CW samples within 5 min. Thus, a rapid, simple and effective method for the analysis of four aromatic acids in CW samples was developed by coupling g-C₃N₄@SiO₂-based SPE with high performance liquid chromatography-ultraviolet(HPLC-UV) detection. The linearity of the developed method was in the range of 20-1000 ng/mL and its limit of detection was in the range of 1.9-5.7 ng/mL, which were signi-ficantly lower than those of the reported similar methods. The intra-day and inter-day precisions(based on the relative standard deviation, n=3) of the four aromatic acids were under 9.5% and 10.4%, respectively. The developed method was applied to determining the four aromatic acids in real CW samples and the spiked recoveries varied from 81.1% to 121.8%.



A Highly Selective and Sensitive Ratiometric Fluorescent Probe for Hypochlorite and Its Application

XUE Longqi, FENG Yusha, SONG Yan, WANG Rui, LIU Dahai, DU Jianshi, YANG Qingbiao, LI Yaoxian

2018, 34(4):  536-540.  doi:10.1007/s40242-018-8028-y

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A novel water-soluble hybrid fluorescein-coumarin dye(FLNC) fluorescence ratiometric probe to recognize OCl^- was designed and synthesized. The most prominent feature of the probe is that the molecular structure contains two different fluorophores, and the fluorescein moiety was connected to coumarin moiety by diacylhydrazine linker. When OCl^- was added, the two fluorophores in the FLNC probe could have a rapid respond simultaneously, with high selectivity and sensitivity towards OCl^- among other reactive oxygen species/reactive nitrogen species(ROS/RNS) and anions, and the detection limit was measured to be 0.30 μmol/L. In addition, the color changes of the solution could be observed by the naked eye and have a short response time(completed within 1 min), which suggestes that the probe FLNC has the potential to be used for real-time detection.



A Label-free and Functional Fluorescent Oligonucleotide Probe Based on a G-Quadruplex Molecular Beacon for the Detection of Kanamycin

ZHU Yuqing, LI Wei, TAN Suzhen, CHEN Tianxiao

2018, 34(4):  541-545.  doi:10.1007/s40242-018-7366-0

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A label-free and turn-off fluorescent method for the quantitative detection of kanamycin based on a functional molecular beacon was developed. The molecular beacon consists of two hairpin structures with a split G-rich oligonucleotide in the middle. The kanamycin's aptamer formed the loops portion for recognizing kanamycin, and the G-quadruplex bound by Thioflavin T(ThT) was employed as the reporter. In the absence of target, the molecular beacon folded into double stem-loops and the splited G-rich oligonucleotid came close to form a G-quadruplex. When ThT bound to the G-quadruplex, the fluorescence intensity of the solution increased. Upon the addition of kanamycin, the function between kanamycin and aptamer unfolded the hairpin and disassembled the G-quadraplex structure, resulting in a significant decrease in the fluorescence intensity. A good linear relationship ranging from 0.7 nmol/L to 10 nmol/L was achieved and the limit of detection was 0.37 nmol/L. Besides, it could efficiently recognize kanamycin in real samples.



Removal of Chromium(VI) from Groundwater Using Oil Shale Ash Supported Nanoscaled Zero-valent Iron

CUI Jian, WANG Ende, HOU Zhimin, ZHOU Rui, JIAO Xinqian

2018, 34(4):  546-551.  doi:10.1007/s40242-018-8104-3

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Oil shale ash(OSA) supported nanoscaled zero-valent iron(OSA-nZVI) was used as a rapid and efficient reductant for Cr(VI) reduction. The optimal mass ratio of nZVI to OSA and the optimal dosage were explored. The effects of initial pH, reaction temperature, initial Cr(VI) concentration, and common cations and anions in groundwater on Cr(VI) reduction were determined in batch experiments. The results show that the optimum initial pH is 5.0. The reaction temperature has a positive effect on Cr(VI) reduction while the real groundwater has a negative effect. Additionally, 84.22% Cr(VI) was still reduced by 3 g/L OSA-nZVI(1:2)(mass ratio of OSA to Fe⁰ was 1:2) within 120 min for 50 mg/L Cr(VI) under conditions of 10℃ and unadjusted pH.



Copper-catalyzed ortho-Monofluorination of Aniline Derivatives with Selectfluor Directed by Picolinic Acid Amides

ZHANG Yingchao, WEN Chunxia, ZHANG Changjing, LI Jizhen

2018, 34(4):  552-558.  doi:10.1007/s40242-018-8113-2

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A novel and facile method for selective ortho-C-H monofluorination of aniline derivatives was achieved using Selectfluor/Cu(OAc)₂/HOAc system. The reaction proceeded via electrophilic process with diverse substrates in acceptable moderate to high yields. The position selectivity was controlled by bidentate coordination of picolinic acid amides with copper.



Acid-catalyzed Dimerization Reaction of Pyrroles to Synthesize Hexaaryl-4,8-dihydropyrrolo[2,3-f]indoles

ZHANG Shuai, ZHENG Ziqi, ZHANG Tong, FU Xue, SHI Shaojia, JIANG Lin, YIN Hongzong

2018, 34(4):  559-563.  doi:10.1007/s40242-018-8031-3

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Pyrroloindoles, as a kind of promising small-melecular hole injetion materials, have attracted wide attention. Herein, we described a simple metal-free method for the synthesis of 4,8-dihydropyrrolo[2,3-f]indole compounds through the acid-catalyzed dimerization reaction of pyrroles. The structures of target 4,8-dihydropyrrolo-[2,3-f]indoles were confirmed by NMR spectrum and X-ray single crystal diffraction. Notably, pyrrole substrates were synthesized conveniently starting from available biological dipeptides. cis-Configuration was preferred when bulky p-toluene sulfonic acid(TsOH) was employed. Excessive aicds empoyed in dimerization would lead to the formation of quantitative pyrrolium chloride intermediate, restraining further conversion to target compounds. Furthermore, the dimerization process was monitored by ¹H NMR spectrum, proving that it followed a second-order kinetics, providing significant insight to the mechanism of dimerization reaction.



Synthesis and Activity Evaluation of Novel Prenylated Flavonoids as Antiproliferative Agents

Kingsadingthongkham VONGDETH, RAN Liqiong, YAN Lili, WANG Qiuan

2018, 34(4):  564-570.  doi:10.1007/s40242-018-8013-5

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Twenty prenylated flavonoids 1-20 were synthesized by glycoside hydrolysis, dehydrogenation, selective O-methylation, O-prenylation and Claisen rearrangement reaction, from abundant and inexpensive natural flavonoids naringin, hespiredin, quercetin and myricetin. Among them, 1-7, 10-15 and 17-20 are novel compounds, the natural product 3,3',4',7-tetramethoxy-8-prenyl-5-hydroxy flavonoid(16) was synthesized in a high yield. Their antiprolirative activities were evaluated in vitro on a panel of three human cancer cell lines(HeLa, HCC1954 and SK-OV-3). The results show that most of the target compounds displayed moderate to potent antiprolirative activities against the three cancer cells with half maximal inhibitory concentration(IC₅₀) values from 0.49 μmol/L to 95.07 μmol/L. Among them, 3',4',7-trimethoxyl-5-hydroxyl-8-prenyl flavonoid(12) exhibited the strongest antiprolirative activity against the three cancer cells mentioned above with IC₅₀ values of 0.91-7.08 μmol/L. 3',7-Dimethoxy-5-O-prenyl flavone(6) and 3',4',7-trimethoxy-5-O-prenyl flavone(10) showed selective antiproliferative activity against HCC1954 cells with IC₅₀ value of 0.49 and 5.32 μmol/L, respectively.



Synthesis of 9-Substituted Berberine Derivatives with Microwave Irradiation

HAN Xie, SHAO Kaiyuan, HU Wenxiang

2018, 34(4):  571-577.  doi:10.1007/s40242-018-7425-6

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Hyperglycemia is frequently accompanying with hyperlipidemia. To explore the potent drugs with dual-activity and dual-site effects that could reduce blood glucose and blood lipid at the same time, fibrate group with lipid-lowering effect on the 9th position of berberine(BBR) was introduced using the drug design combination principle and the multi-target collaborative treatment method. Moreover, the molecular structure of BBR was modified, and six 9-substituted derivatives of BBR were designed and synthesized, among which, five compounds have never been reported before. In addition, the molecular structures of these derivatives were identified using liquid chromatography-mass spectrometry(LC-MS), ¹H nuclear magnetic resonance(¹H NMR) and ¹³C NMR, respectively. Furthermore, the microwave irradiation experimental technique was applied in the synthesis reaction using the novel microwave synthesizer, which accelerated the reaction rate, enhanced the reaction yield, reduced the reaction by-products, and simplified the post-processing steps. In the meantime, the 9-position regioselective demethylation of BBR was explored through quantum chemical calculation during the synthesis of berberrubine. The computations were consistent with the experimental results, which contributed to deducing the mechanism of its selective methylation.

Synthesis of Polycarbonate Diols(PCDLs) via Two-step Process Using CH₃COONa as an Effective Catalyst

SONG Menglu, YANG Xiangui, WANG Gongying

2018, 34(4):  578-583.  doi:10.1007/s40242-018-7390-0

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Polycarbonate diols(PCDLs) with a number average molecular weight(M_n) of 2800 and a narrow polydispersity index(PDI=1.33) were synthesized from dimethyl carbonate(DMC) and 1,4-butanediol(BD) via a two-step process. The influences of the molar ratios of DMC to BD in the feedstock, polycondensation temperature and polycondensation time on the PCDLs preparation were studied. CH₃COONa showed the best catalytic performance among the catalysts studied. The highest BD conversion of 73.8% and PCDLs yield of 64.7% were achieved under its optimum reaction conditions. Furthermore, based on the results of ¹H NMR, the relationships between the ratio of end groups (-OCH₃/-OH) of oligomers, the M_n and chain-end constitute of resultant polycarbonates were also investigated. The results indicate that PCDLs can be synthesized when the oligomers mostly bear hydroxyl end groups. In contrast, it was impossible to prepare PCDLs when the oligomers were enriched with methyl carbonate end groups.



CXCR4 Peptide Conjugated Au-Fe₂O₃Nanoparticles for Tumor-targeting Magnetic Resonance Imaging

LIU Guifeng, CHEN Hongda, YU Shaonan, LI Xiaodong, WANG Zhenxin

2018, 34(4):  584-589.  doi:10.1007/s40242-018-8010-8

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Peptide-functionalized Au-Fe₂O₃ nanoparticles(termed as anti-CXCR4-Au-Fe₂O₃NPs) have been constructed through conjugation of dumbbell-like Au-Fe₂O₃NPs with C-X-C motif chemokine receptor 4(CXCR4) binding cyclic peptide. One dumbbell-like Au-Fe₂O₃NP composes an Au NP[(3.3±0.3) nm in diameter] for conjuga-ting CXCR4 binding cyclic peptide through Au-S covalent bond and a Fe₂O₃NP[(8.7±0.8) nm in diameter] for using as T₂-weighted magnetic resonance imaging(MRI) contrast agent. The anti-CXCR4-Au-Fe₂O₃NPs have reasonable biocompatibility and integration of T₂-weighted MRI contrast and tumor-targeting functionalities. The anti-CXCR4-Au-Fe₂O₃NPs exhibit strong interactions with two kinds of breast tumor cells, MCF-7 cells and MDA-MB-231 cells, and high negative contrast in MRI of MDA-MB-231 tumor bearing mouse with 62% decreasing of MRI signal, indicating that the anti-CXCR4-Au-Fe₂O₃NPs can recognize tumor with high efficacy and specificity.



Metabonomics and Molecular Biology-based Effects of Sugemule-3 in an Isoproterenol-induced Cardiovascular Disease Rat Model

WANG Xiye, WANG Yu, WEI Chengxi, YU Lijun

2018, 34(4):  590-597.  doi:10.1007/s40242-018-7307-y

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Cardiovascular disease(CVD) is a common and serious disease in the elderly, which has characteristically high prevalence, disability, and mortality rates. However, the etiology of CVD is still not very clear. The traditional Mongolian medicine Sugemule-3(SM) is usually used for the treatment of CVD and exhibits a good curative effect. In this study, a serum metabolite profile analysis was used to identify potential biomarkers associated with isoproterenol(ISO)-induced CVD and investigate the mechanism of the action of SM. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was used for the metabono-mics analysis. Principal component analysis(PCA) was used to process the acquired data to differentiate the results of the control, CVD, and SM treatment groups. Orthogonal partial least squares discriminant analysis(OPLS-DA) enabled the identification of 21 metabolites as potential biomarkers that were relevant to phospholipid and energy metabolism. The results indicate that SM played a protective role against ISO-induced CVD in rats by regulating phospholipid and energy metabolic pathways. Further, we verified the apoptotic metabolic pathway using molecular biology methods, such as terminal deoxynucleotidyl transferase(TdT) deoxyuridine 5'-triphosphate(dUTP) nick-end labeling(TUNEL) assay and Western blot analysis. Furthermore, this study identified early biomarkers of CVD and elucidated the underlying mechanism of the therapeutic actions of SM, which is worth further to be investigated for development as a clinical therapy.



Structure of a Mixture of Graphene Plates and Ionic Liquid 1-Octyl-3-methylimidazolium Hexafluoroborate

CHEN Siyan, GAO Zhenhai

2018, 34(4):  598-603.  doi:10.1007/s40242-018-8109-y

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We reported a molecular dynamics simulation study of a mixture of 1-octyl-3-methylimidazolium hexa-fluoroborate([C₈MIN]⁺[PF₆]^-), an ionic liquid, and pristine graphene. Our simulations were performed under various conditions, including several temperatures and distances between graphene plates. By studying the liquid structure of the ionic-liquid graphene mixture, we found that the transition for the ionic liquids entering the middle of two graphene plates should occur within 1.00 and 1.50 nm in the temperature range studied(300-600 K). We also studied the pair correlations between the graphene plates and the head and tail of the cation and the anion. Our study at the molecular level can aid in understanding the detailed molecular structure of the mixture.



Effects of Annealing Temperature on Microstructure and Electrochemical Properties of Perovskite-type Oxide LaFeO₃ as Negative Electrode for Metal Hydride/Nickel(MH/Ni) Batteries

YANG Shuqin, LI Yuan, YUAN Yongjie, DONG Zhentao, REN Kailiang, ZHAO Yumeng

2018, 34(4):  604-608.  doi:10.1007/s40242-018-8079-0

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We reported the effects of annealing temperatures on microstructure and electrochemical properties of perovskite-type oxide LaFeO₃ prepared by stearic acid combustion method. X-Ray diffraction(XRD) patterns show that the annealed LaFeO₃ powder has orthorhombic structure. Scanning electron microscopy(SEM) and transmission electron microscopy(TEM) images show the presence of homogeneously dispersed, less aggregated, and small crystals(30-40 nm) at annealing temperatures of 500 and 600℃. However, as the annealing temperature was increased to 700 and 800℃, the crystals began to combine with each other and grew into further larger crystals(90-100 nm). The electrochemical performance of the annealed oxides was measured at 60℃ using chronopotentiometry, poten-tiodynamic polarization, and cyclic voltammetry. As the annealing temperature increased, the discharge capacity and anti-corrosion ability of the oxide electrode first increased and then decreased, reaching the optimum values at 600℃, with a maximum discharge capacity of 563 mA·h/g. The better electrochemical performance of LaFeO₃ annealed at 600℃ could be ascribed to their smaller and more homogeneous crystals.



Oxidative Dehydrogenation of 1-Butene to 1,3-Butadiene Using CO₂ over Cr-SiO₂ Catalysts Prepared by Sol-gel Method

GAO Biao, LUO Yajun, MIAO Changxi, YUE Yinghong, YANG Weimin, HUA Weiming, GAO Zi

2018, 34(4):  609-615.  doi:10.1007/s40242-018-8063-8

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A series of Cr-SiO₂ catalysts with a Cr content(mass fraction) ranging from 0.5% to 9% was prepared by a sol-gel method. The catalysts were characterized by XRD, N₂ adsorption, EDX elemental mapping, Raman spectroscopy, UV-Vis spectroscopy, XPS and H₂-TPR, and their catalytic behavior in the dehydrogenation of 1-butene to 1,3-butadiene(BD) using CO₂ as a soft oxidant was studied. The initial BD yield is well correlated with the amount of Cr⁶⁺ in the fresh catalysts. The highest BD yield of ca. 34% is achieved on the catalysts with 5%-9% Cr at 600℃ and weight hourly space velocity(WHSV) of 4.5 g·g_cat^-1·h^-1. The promoting effect of CO₂ on the BD yield was observed, which can be attributed to the reaction coupling between a simple dehydrogenation of 1-butene and the reverse water-gas shift reaction as well as regaining the oxidation state(lattice oxygen) of reduced Cr³⁺ species due to the mild oxidation ability of CO₂. The Cr-SiO₂ catalyst exhibits higher BD yield than the Cr catalyst supported on SBA-15, which is attributed to the higher amount of Cr⁶⁺ present on the former catalyst.



A Simple, Low-cost Method to Fabricate Drag-reducing Coatings on a Macroscopic Model Ship

WANG Zhipeng, ZHANG Songsong, GAO Shan, OUYANG Xiao, LI Jie, LI Rui, WEI Hao, SHUAI Zhijun, LI Wanyou, LYU Shanshan

2018, 34(4):  616-621.  doi:10.1007/s40242-018-8032-2

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A low-cost method was used to fabricate superhydrophobic coatings on a macroscopic model ship and the drag-reducing effect was investigated at both low and high speed. Hierarchical structures of the superhydrophobic copper coatings were characterized by means of scanning electron microscopy(SEM) and X-ray diffraction(XRD). Drag coefficient tests on surfaces with different wettability(superhydrophilic, hydrophilic, hydrophobic and superhydrophobic surfaces) showed that the as-prepared superhydrophobic surface exhibited a high remarkable drag reduction of 81% at a low speed of 1 mm/s. In the drag-reducing tests with model ship, the superhydrophobic coatings also exhibited around 16% drag reduction at a velocity of 0.3 m/s.



Adsorption of Basic Dyes Using Walnut Shell-based Biochar Produced by Hydrothermal Carbonization

KANG Chunli, ZHU Ling, WANG Yixue, WANG Yuhan, XIAO Kunkun, TIAN Tao

2018, 34(4):  622-627.  doi:10.1007/s40242-018-8018-0

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Hydrothermal carbon(HC) was prepared from walnut shells, which are abundant in Northeastern China. The prepared HC was used as a precursor to produce nitric acid modified carbon(MC). The hydrothermal carbonization included dehydration and decarboxylation processes wherein the hemicellulose was completely decomposed and the cellulose was partly decomposed, with some oxygen-containing functional groups being produced. The aromati-city, specific surface area and pore content of the HC increased, but its polarity decreased. With 6 mol/L nitric acid and a modification time of 15 min, the specific surface area and pore content decreased, but the proportion of oxygen-containing functional groups on the surface increased significantly, thereby improving the dye adsorption performance. The adsorption of methylene blue and malachite green was best described by the pseudo-second-order kinetic and Langmuir isotherm models. The adsorption capacity of MC was determined to be much larger than that of HC.



Preparation of Monodispersed Carbon Spheres via Hydrothermal Carbonization of Ascorbic Acid and Their Application in Lithium Ion Batteries

ZHOU Xuejiao, XU Liangyou, LIU Xiyao, ZHANG Junjun, DIAO Hongchao, MA Xiaohua

2018, 34(4):  628-634.  doi:10.1007/s40242-018-7382-0

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Hydrothermal carbonization is one of the most appealing strategies to prepare carbon spheres(CSs). Nevertheless, the precursors of hydrothermal carbonization are limited to several saccharides currently and the obtained CSs are easily interconnected among each other, giving rise to difficulties in further treatment and applications. In this work, ascorbic acid was used as precursor in the hydrothermal procedure and monodispersed CSs could be fabricated without any catalysts. In addition, the composites of CSs and chemical reduced graphene oxide(CRG) possessing three dimensional network structures were fabricated, which exhibited excellent electrochemical performance used as anode in lithium ion battery(LIB). Meanwhile, the effects of size distributions of CSs on the electrochemical performances were evaluated.



Preparation and Characterization of SiO₂/Co and C/Co Nanocomposites as Fisher-Tropsch Catalysts for CO₂ Hydrogenation

HAN Fuqin, ZHANG Zhe, NIU Na, LI Jian

2018, 34(4):  635-642.  doi:10.1007/s40242-018-7381-1

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To fabricate high-density cobalt-based catalysts, we first synthesized SiO₂/C composites via a hydrothermal method and removed C and SiO₂ by two different methods, respectively. The as-prepared SiO₂ and C supports then reacted with cobalt acetylacetonate and N,N-dimethylformamide(DMF) under hydrothermal conditions to prepare SiO₂/Co and C/Co nanocomposite catalysts. The catalysts were characterized by X-ray diffraction(XRD), scanning electron microscope(SEM), transmission electron microscopy(TEM), inductively coupled plasma mass spectrometry(ICP), energy dispersive X-ray fluoresence spectrometer(EDX), and nitrogen adsorption. It was found that hexagonal cobalt nanocrystals were successfully integrated with the mesoporous silica or carbon nanotube supports. SEM and TEM results show that SiO₂/Co composites with a hollow/mesoporous sphere structure and C/Co composites with a tubular structure have been successfully synthesized. Both composite samples show superparamagnetism exhibiting an S-type hysteresis loop, which originated from the cobalt nanoparticles in the samples. Nitrogen adsorption/desorption curves suggest that the SiO₂ and C supports have well-developed pore structures and large specific surface areas, and the loading and good dispersity of cobalt nanoparticles on the supports were proven by ICP and EDX. Moreover, the samples exhibited good and stable catalytic activity, demonstrating that the two composites are suitable catalysts for Fischer-Tropsch CO₂ hydrogenation.



Structure and Excitation Dynamics of β-Carotene Aggregates in Cetyltrimethylammonium Bromide Micelle

ZHANG Di, TAN Liming, DONG Jia, YI Jiaqiang, WANG Peng, ZHANG Jianping

2018, 34(4):  643-648.  doi:10.1007/s40242-018-7379-8

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The β-carotene(β-Car) aggregate was prepared by self-assembly in cetyltrimethylammonium bromide (CTAB) micelle. The ground state absorption measurement showed that the aggregate has J-type characteristics and resonance Raman spectra gave the intrinsic explanation of molecular interaction in aggregate. Upon excitation at the optical allowed S₂ state of aggregate, direct generation of triplet state via singlet fission(SF) mechanism was observed. Excitation dynamics was elucidated by fs-transient absorption spectroscopy and ns-flash photolysis, respectively. The triplet state life time of aggregate was found to be independent of the ambient oxygen molecules.



Preparation of Ag₃PO₄/AgBr Hybrids Using a Facile Grinding Method and Their Applications as Photocatalysts

ZHANG Xiaojun, YAN Keqiang, SONG Yu, WANG Zhe, WU Jialong, YU Dayu

2018, 34(4):  649-654.  doi:10.1007/s40242-018-7363-3

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Highly efficient visible-light-induced Ag₃PO₄/AgBr hybrids were prepared via a facile and effective grinding method. The synthetic route was simply achieved through the grinding of Ag₃PO₄ with NaBr in an agate mortar at room temperature. During the grinding process, the mechanochemical effect induced the solid-state reaction of Ag₃PO₄ and NaBr to form AgBr nanoparticles on the surface of the Ag₃PO₄ particles. After calcination and wa-shing, Ag₃PO₄/AgBr hybrids were obtained. The AgBr shells prevented photocorrosion and improved the structural stability in water. Interestingly, the compositions, morphologies and optical absorption properties of the Ag₃PO₄/AgBr hybrids could be finely controlled by adjusting the NaBr content and grinding time. The photocatalytic activities of the as-prepared samples were investigated in terms of the degradation of rhodamine B(RhB) under visible light irradiation. The photocatalytic activities of the Ag₃PO₄/AgBr hybrids were much improved compared to those of of Ag₃PO₄ or AgBr individually. Under visible light irradiation for 1 h, the Ag₃PO₄/AgBr hybrids exhibited a 66.8%-76.8% increase in photocatalytic efficiency compared to pure Ag₃PO₄.



Assembly and Post-modification of Fe₃O₄@MIL-100(Fe) for Knoevenagel Condensation

ZHANG Yanmei, ZHANG Fan, ZHANG Xiang, XU Yingmei, QI Xiaohui, QUAN Chunshan

2018, 34(4):  655-660.  doi:10.1007/s40242-018-7361-5

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Many efforts have been devoted to the integration of magnetic nanoparticles and metal organic frameworks, which makes it easy and simple to separate the nano-sized metal organic frameworks from liquid phase. Amino-functionalized magnetic metal organic frameworks[Fe₃O₄@MIL-100(Fe)-NH₂]were prepared by a stepwise assembly method followed by post-modification with electron-rich reagent. This magnetic catalyst was characterized by means of X-ray diffraction(XRD), transmission electron microscopy(TEM), scanning electron microscopy(SEM) and nitrogen adsorption, and tested in Knoevenagel condensation as a base catalyst. The magnetic catalyst exhibits a core-shell structure and can afford a high activity for the Knoevenagel condensation due to its bifunctional property and reduced diffusion limitation. Furthermore, it could be recovered magnetically and recycled three times. Although activity loss was observed in the recycle experiments, it could be reactivated by dispersing in a fresh modifier solution.

A Novel Nano-sized Catalyst CeO₂-CuO/Hollow ZSM-5 for NO_x Reduction with NH₃

YI Ting, LI Jingwei, ZHANG Yibo, YANG Xiangguang

2018, 34(4):  661-664.  doi:10.1007/s40242-018-7333-9

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Hollow-ZSM-5 was synthesized by a traditional hydrothermal method without alcohol, and a novel nano-sized Ce-Cu/hollow ZSM-5 sample was prepared by conventional incipient wetness impreganation. The catalysts were characterized by TEM, SEM, XRD, NMR and N₂ adsorption-desorption. The results indicate that the hollow-ZSM-5 has a good MFI structure with large surface area. The synthesized CeO₂-CuO/hollow ZSM-5 showed an excellent catalytic activity for NO_x conversion(90% NO_x conversion were obtained) in the temperature range of 340-550℃ under GHSV=480000 mL·g^-1·h^-1 due to its appropriate redox ability and acidity.



Study on the Preparation of Mercaptoacetic Acid-modified Heterophylla Shell and Its Application in Separation and Enrichment of Pb²⁺ in Environmental Samples

LYU Linlin, JIANG Xiaojun, JIA Lian, AI Tian, WU Hang

2018, 34(4):  665-669.  doi:10.1007/s40242-018-7331-y

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To increase the adsorption capacity of the Corylus heterophylla Fisch(HS) for Pb²⁺, HS was chemically modified using NaOH aqueous solution and 95% ethanol and was labeled as SHS; then SHS was chemically modified using mercaptoacetic acid. The SHS modified with mercaptoacetic acid(MHS) was characterized using FTIR, SEM, and XPS. The results indicated that the -SH group was present on MHS, and after Pb²⁺ adsorption, the absorption value of the characteristic peak of the -SH group decreased. The adsorption and desorption properties of this functionalized material were investigated as well as the influences of parameters, such as pH value, type of desorption reagent, dosage, flow rate and maximum sample volume. The Pb²⁺ adsorption of MHS reached a maximum with pH>5. The experimental data of Pb²⁺ adsorption using MHS were fitted using the Langmuir isothermal adsorption model, and a maximum adsorption capacity of 61.54 mg/g was obtained. This was much higher than the adsorption capacity of SHS before modification with the thiol group. After adsorption, MHS was desorbed using a 0.2 mol/L HCl solution, and the percent of desorption was higher than 99%. MHS was used as a solid-phase extractant in the analysis and determination of Pb²⁺ content in food and water samples, and the enrichment times achieved 150-fold.



Synthesis and Properties of PGS-Li Scaffold

LIU Zhihui, LU Yadong, FENG Wei, YANG Junxing, GAO Shang, SONG Lijie, WANG Yao, WANG Bowei

2018, 34(4):  670-675.  doi:10.1007/s40242-018-8164-4

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Lithium ion-doped polyglycerol sebacate scaffold(PGS)-Li was synthesized by adding lithium ions to polyglycerol sebacate(PGS) during its crosslinking process due to the specific effects of lithium ions on periodontal ligament cells, cementoblasts and the eminent performance of PGS. The molecular mass, composition, structure, porosity, thermal properties, and hydrophilicity of the composite were characterized by gel permeation chromatography(GPC), Fourier transform infrared spectroscopy(FTIR), inductively coupled plasma optical emission spectrometer(ICP-OES), scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS), thermogravimetric analyzer(TGA) and contact angle measurments, and the degradation of the material was evaluated by in vitro degradation experiments. The biological activity of PGS-Li scaffold was detected by calcein-AM staining and cytotoxicity test. The results indicate that PGS-Li scaffold has been successfully synthesized, which has similar composition and structure to PGS, but slightly larger molecular weight. In addition, the porosity and pore size of PGS-Li scaffold ba-sically meet the requirements of engineering scaffold materials and the seaffold shows better performance in terms of hydrophilicity and thermal stability than PGS. In vitro degradation experimental results show that the degradation rate of PGS-Li scaffold is higher than that of PGS. What's more, the results of cytotoxicity test and cell staining show that there is no significant difference in the proliferation and cell morphology of cementoblasts.



Light-stimulus Dual-drug Responsive Nanoparticles for Photoactivated Therapy Using Mesoporous Silica Nanospheres

WU Peng, ZHOU Dongfang, HUANG Yubin, LI Jizhen

2018, 34(4):  676-683.  doi:10.1007/s40242-018-8077-2

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Photoactivated therapy is an exciting new method of cancer treatment. A new light-stimulus dual-drug responsive nanoparticles based on mesoporous silica nanoparticles(MSN) were developed to control cellular anticancer drug release. The prepared Curcumin(Cur)-loaded nanoparticles MSN-Pt-PEG@Cur[PEG=poly(ethylene glycol)] could be activated by photostimulation to generate reactive oxygen species(ROS) from Cur and Pt(Ⅱ) from Pt(IV), respectively. Compared with free anti-cancer drugs' chemotherapy and single photoactivated therapy, the prepared MSN-Pt-PEG@Cur displayed increased cytotoxicity. Therefore, the strategy of light-stimulus dual-drug responsive nanoparticles is a promising approach to photoactivated therapy.



Preparation and Properties of Magnetic-fluorescent Microporous Polymer Microspheres

ZOU Xiaohu, WEI Zhizhi, DU Jing, WANG Xiaotao, ZHANG Gaowen

2018, 34(4):  684-690.  doi:10.1007/s40242-018-7413-x

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Microporous microspheres can be used as functional nanomaterial carriers for their microporous structure and higher specific surface area. In this study, magnetic fluorescent polymer microspheres were prepared by incorporating Fe₃O₄ nanoparticles and CdSe/ZnS quantum dots(QDs) into hyper-crosslinked microporous polymer microspheres(HCMPs) via the in situ coprecipitation method and swelling-diffusion. The HCMPs predominantly have micropores, and their specific surface area is as high as 703.4 m²/g. The magnetic-fluorescent microspheres maintain the superparamagnetic behavior of Fe₃O₄, and the saturation magnetization reaches 38.6 A·m²/kg. Moreover, the composite microspheres exhibit an intense emission peak at 530 nm and achieve good fluorescence.



Analysis of Protein Moiety of Polysaccharide Conjugates Water-extracted from Low Grade Green Tea

CHEN Xiaoqiang, SHAO Shengrong, XIE Jianchun, YUAN Hao, LI Qian, WU Long, WU Zhengqi, YUAN Haibo, JIANG Yongwen

2018, 34(4):  691-696.  doi:10.1007/s40242-018-7335-7

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Tea polysaccharide conjugates(TPCs) were water-extracted and purified from low-grade green tea. Although TPC contains 1.97% covalent binding proteins, Coomassie brilliant blue G250 and R250 could not detect this protein. The "should-shape" absorption peak observed at 250-280 nm in the UV-Vis spectrum was caused by quinone compounds derived from polyphenol oxidation during TPC extraction. The UV-Vis spectrum could be used to detect the decolorizing degree of TPC. TPC aqueous solution merely presented the negative charge properties of its polysaccharides instead of the acid-base property of its protein section, and exhibited higher stability at pH greater than 5.0. No precipitation or haze occurred in three TPC/epigallocatechin gallate(EGCG) aqueous mixtures during 12 h storage. TPC had emulsifying activity, which indicated that its protein moiety formed hydrophobic groups. It is proposed that some of the physicochemical properties of the TPC protein moiety are shielded by its polysaccharide chain.