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01 June 2018, Volume 34 Issue 3

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Contents

2018, 34(3):  0-0. 

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Letter

Chiral Phase-transfer Catalysts Bearing Multiple Hydrogen-bonding Donors Derived from Amino Acids: Efficient Catalysts for Diastereo-and Enantioselective Nitro-Mannich Reaction

LIU Yu, WEI Zhonglin, LIU Yuxin, WANG Jingdong, CAO Jungang, LIANG Dapeng, DUAN Haifeng, LIN Yingjie

2018, 34(3):  333-337.  doi:10.1007/s40242-018-8005-5

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Articles

Porous Organic Frameworks-derived Porous Carbons with Outstanding Gas Adsorption Performance

YAN Tingting, XING Guolong, DAS Saikat, BEN Teng, QIU Shilun

2018, 34(3):  338-343.  doi:10.1007/s40242-018-8014-4

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A series of porous carbon materials was synthesized via high temperature pyrolysis from well-defined and thermally stable precursors, namely porous organic frameworks(POFs), in inert atmosphere. The porous carbon materials showed enhanced gas adsorption capacities together with increased heat of adsorption and stronger affinity between the frameworks and the gases as compared to the precursor materials. To exemplify, sample C-POF-TBBP-1000 with a high BET surface area of 1290 m²/g can adsorb 2.8 mmol/g CH₄(273 K, 101.325 kPa), 5.4 mmol/g CO₂(273 K, 101.325 kPa) and 2.2% H₂(mass fraction, 77 K, 101.325 kPa), thereby surpassing most other porous adsorbent materials reported till date. The study highlights the potential of porous carbons derived from novel porous organic framework structures for gas adsorption applications.



Acetic Acid Assistant Hydrogenation of Graphene Sheets with Ferromagnetism

SUN Qiushi, WANG Xiaofeng, LI Benxian, WU Yunpeng, ZHANG Ziqing, ZHANG Xinyang, ZHAO Xudong, LIU Xiaoyang

2018, 34(3):  344-349.  doi:10.1007/s40242-018-8001-9

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Ferromagnetism of pure carbon-based materials has been widely researched for several years. In therocially and experimentally, semi-hydrogenation graphene sheets exhibit ferromagnitism, which is related to the degree of hydrogenation. Here we reported the controllable hydrogenation of graphene using ball-milling method with acetic acid as hydrogenating agent. The hydrogenation graphene sheets were characterized by means of transmission electron microscopy(TEM), Raman spectroscopy and X-ray photoelectron spectroscopy, and magnetic measurement. The relusts of Raman spectroscopy demonstrate that the relative intensity of D band increases with the hydrogenation degree. The resluts of magnetic meansurement indicate the maximal magnetic moment of 0.274 A·m²/kg at 2 K for semi-hydrogenation graphene.



Sustainable Synthesis of Hierarchically Porous Silicalite-1 Zeolite by Steam-assisted Crystallization of Solid Raw Materials Without Secondary Templates

LIU Xiaofang, ZENG Shangjing, WANG Runwei, ZHANG Zongtao, QIU Shilun

2018, 34(3):  350-357.  doi:10.1007/s40242-018-7400-2

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Hierarchical silicalite-1 zeolites were obtained from the direct conversion of a mixture of ground solid raw materials via a steam-assisted crystallization(SAC) method without involvement of any mesoscale template. Only a trace amount of water was necessary during the crystallization, implying that the amount of water can be dramatically reduced, which still offers easy separation and high yields. The simple procedure involved only grinding and heating, which not only saves resources and energy, but also significantly reduces the discharge of eco-friendly synthesis of zeolites for practical applications. Compared to conventional bulk silicalite-1, the nanosized hierarchical zeolites with MFI structure show enhanced removal capabilities for methylene blue owing to their hierarchical porosity.



Two Coordination Compounds Bearing Bis(2-dimethylaminoethyl) Ether: Syntheses, Crystal Structures and Catalytic Application to the Henry Reaction

LIU Chao, LIU Yijie, ZHANG Lili, JIANG Kun, ZHANG Li

2018, 34(3):  358-362.  doi:10.1007/s40242-018-7343-7

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Two novel coordination compounds, namely [Cu₂(BDMAEE)(CH₃COO)₄]_n(1) and[Ni(BDMAEE)Cl₂](2)[BDMAEE=bis(2-dimethylaminoethyl) ether], have been synthesized and characterized by IR, elemental analysis, PXRD and X-ray single crystal diffraction. In compound 1, the central Cu(Ⅱ) ion is coordinated with four oxygen atoms and one nitrogen atom, forming a distorted square pyramidal geometry. The asymmetric units composed of one Cu(Ⅱ) ion, two acetates and a half of BDMAEE are connected to form an infinite 1D chain structure by the bridging acetate and the BDMAEE. In compound 2, the central Ni(Ⅱ) ion is coordinated with one oxygen atom, two chlorine anions and two nitrogen atoms, forming a distorted square pyramidal geometry. The compounds exhibited excellent catalytic properties in the Henry reaction of nitromethane with some aromatic aldehydes, and the optimized reaction conditions were obtained.



A Label-free Fluorescent Aptasensor for Turn-on Monitoring Ochratoxin A Based on AIE-active Probe and Graphene Oxide

MA Lian, XU Bin, LIU Leijing, TIAN Wenjing

2018, 34(3):  363-368.  doi:10.1007/s40242-018-8072-7

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A label-free fluorescent aptasensor for specific and ultrasensitive monitoring ochratoxin A(OTA) was developed using the specific aptamer of OTA(OSA) as recognition element, an aggregation-induced emission(AIE) molecule(a 9,10-distyrylanthracene with two ammonium groups, DSAI) as a fluorescent probe, and graphene oxide(GO) as a quencher. In the absence of OTA, the AIE probe DSAI and OSA complex(DSAI/OSA) is adsorbed on the GO surface, and the fluorescence of DSAI will be quenched efficiently via the fluorescence resonance energy transfer(FRET) from DSAI to GO. Upon the OTA addition, a more stable complex(OSA-OTA) is formed and released from GO. Meanwhile, DSAI and OSA-OTA can form a new complex(DSAI/OSA-OTA), then the fluorescent signal of DSAI recovers gradually. Therefore, by introducing GO and DSAI, the fluorescence signal of DSAI can be easily turned from "off" to "on" after the addition of OTA, and the ultrasensitive detection of OTA by monitoring the change of the fluorescence signal of DSAI can be readily realized. The detection limit of the assay can reach 0.324 nmol/L with a linear detection range of 10-200 nmol/L. And the aptasensor exhibits high selectivity for OTA against other analogues. Moreover, it has been successfully applied for the detection of OTA in red wine samples.



Synthesis of Highly Sensitive Fluorescent Probe Based on Tetrasubstituted Imidazole and Its Application for Selective Detection of Ag⁺ Ion in Aqueous Media

MI Zhiming, CHEN Yao, CHEN Xiaodong, YAN Liuqing, GU Qiang, ZHANG Hanqi, CHEN Chunhai, ZHANG Yumin

2018, 34(3):  369-374.  doi:10.1007/s40242-018-7426-5

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A small molecule fluorescent probe, 4-[2-(4-chlorophenyl)-4,5-diphenyl-1H-imidazol-1-yl]aniline(L) for detecting Ag⁺ ion was gently synthesized via one-pot multi-component reaction catalyzed by H₃[PW₁₂O₄₀] under solvent-free microwave irradiation. When the concentration of Ag⁺ ion changed from 0 to 8.0×10⁻⁶ mol/L in the solution of H₂O/CH₃OH(19:1, volume ratio), the fluorescence emission spectrum was blue-shifted and accompanied by a gradual increase in fluorescence intensity with a low detection limit of 3.0×10⁻¹¹ mol/L. Moreover, UV-Vis absorption titration experiment demonstrated a 1:1 stoichiometric ratio and an association constant of (9.95±0.44)×10⁵ L/mol between probe L and Ag⁺ ion, and thus their complexation mechanism was also proposed and verified. More importantly, this fluorescent probe was remarkably specific for Ag⁺ ion under the interference of other metal ions and exhibited a wide pH application range of 4.0-8.0. Additionally, preliminary application of this probe was also carried out and satisfactory results were shown.



Identification and Evaluation of a Panel of Ginsenosides from Different Red Ginseng Extracts with Nootropic Effect

DAI Yulin, ZHANG Ying, ZHAO Xu, JEON Youjin, ZHENG Fei, MA Li, YUE Hao

2018, 34(3):  375-381.  doi:10.1007/s40242-018-7422-9

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Red ginseng has been gradually discovered to have pharmacological and physiological effects. It is well known that the most important bioactive components of ginseng are ginsenosides. The nootropic effect of ginsenosides from nine different red ginseng extracts was evaluated here. Nine groups of mice were perfused with different concentrations of nine red ginseng extracts, respectively, and two groups of mice with distilled water. The nootropic effect of ginsenosides on mice was evaluated with behavior tests and a biochemical indicator study. The extracts were identified by rapid resolution liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry(RRLC-Q-TOF-MS). Furthermore, principal component analysis(PCA) was used to analyze the contribution of chemical components from different ginseng groups. The extracts with the most and the weakest effective nootropic were found. It is notable that extract processing is a very important factor to decide pharmacological functions of ginseng extracts. As a conclusion, the most effective extract method for ginsenosides has been found. A panel of 13 ginsenosides has been screened out as chemical markers with nootropic effect, which include high level ginsenosides Ra0, Rb1, Rc, Rb2, Rb3, Re, Rd, and Rg1 and low level ginsenosides mRb1, mRc, mRb2, mRd, and F2. Low level ginsenosides were first time to be discovered as possible nootropic compounds. This method may shed light on fast discovery of bioactive compounds of medicinal plants with low level compounds.



Anti-allergic Effects of Ginsenosides Extracted by High Temperature and High Pressure Method

LIU Ying, LI Xuwen, ZHANG Hanqi, WU Qian, SHI Xiaolei, JIN Yongri

2018, 34(3):  382-388.  doi:10.1007/s40242-018-7329-5

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Ginseng(Panax ginseng C. A. Mey.) is a traditional medicinal herb in Asia. Studies have shown that ginsenosides significantly affect immunoregulation and rare ginsenosides have anti-allergic effects. In this research, a high temperature and high pressure method was utilized to increase the contents of rare ginsenosides in the ginseng extract(GE). The anti-allergic effects of this extract were investigated in vivo. Water was used as the extraction solvent in extracting the rare ginsenosides via the high temperature and high pressure method. Extraction time and temperature were investigated in order to increase the contents of rare ginsenosides. Rare ginsenosides were qualitatively analyzed by HPLC-ESI-MS and quantitatively analyzed by HPLC-UV. Anti-allergic effects of the extracts were assessed using the ovalbumin(OVA)-induced allergic asthma model in vivo. An extraction temperature of 145℃ and extraction time of 2.0 h were chosen as the optimal conditions. Compared with traditional method, the contents of total rare ginsenosides extracted were considerably higher using the new method, that is, 14.74 times that extracted by the traditional method. In our in vivo experiments, treatment with high concentration GE may have anti-allergic effects in decreasing the total amount of IgE in serum and IL-4 in bronchoalveolar lavage fluid(BALF), and in improving the ratio of CD4⁺ to CD8⁺ T cells. The high temperature and high pressure method was an effective method to obtain GE containing more rare ginsenosides, which maybe become anti-allergic agents.



Qualitative and Quantitative Analysis of Flidersiachromones in Three Agarwood Samples by HPLC-MS/MS

YANG Jinling, DONG Wenhua, CHEN Huiqin, KONG Fandong, WANG Jun, MEI Wenli, DAI Haofu

2018, 34(3):  389-396.  doi:10.1007/s40242-018-7273-4

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HPLC/ESI/MS² was used in the qualitative and quantitative analysis of flidersiachromones(FTPECs) in three agarwood samples of Aquilaria sinensis, including an artificial holing agarwood, a wild agarwood, and a high quality agarwood named "Qi Nan". From these three agarwood samples, totally forty-six FTPECs were identified, and twenty-five of which were tentatively identified by the analysis of MS fragmentation ions, the others were indentified via comparing the retention time and MS fragmentation ions of them with those of the reference compounds. Besides, quantitative determination of five characteristic FTPECs(F14, F16 and F18-F20) in the three agarwoods was carried out, and it was found that the absolute content of each compound of these five FTPECs showed positive correlation with the quality of agarwood samples. Due to the wide distribution of four of these FTPECs(F16 and F18-F20) in the chemical constituents of agarwood, it is suggested that the total absolute content of these four FTPECs may be set as one of basis for agarwood quality evaluation.



Interference Adsorption Mechanisms of Dimethoate, Metalaxyl, Atrazine, Malathion and Prometryn in a Sediment System Containing Coexisting Pesticides/Heavy Metals Based on Fractional Factor Design(Resolution V) Assisted by 2D-QSAR

WANG Xiaolei, LI Qing, LI Minghao, LI Yu

2018, 34(3):  397-407.  doi:10.1007/s40242-018-7253-8

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The mechanisms of adsorption of pesticides(dimethoate, metalaxyl, atrazine, malathion and prometryn) and heavy metals(Cu, Cd, Pb, Zn and Ni) coexisting in sediments, with pesticides as target pollutants, and the influence of their main effects and double-order interaction effects were studied using the experimental design module in the Minitab software package with a 2^10?3 fractional factorial design method at resolution V. The main, double-order interaction, synergistic and antagonistic effect values of pollutant concentrations influencing the adsorption of pesticides were set as dependent variables, while various quantum chemical parameters of pesticides were set as independent variables, and two-dimensional quantitative structure activity relationship(2D-QSAR) models were established by stepwise regression to reveal the adsorption mechanisms of pesticides in a composite contamination system. The main effects of pollutants concentration played the primary role in the adsorption of dimethoate and malathion(the rates of contributions were 53.54% and 56.46%, respectively), while double-order interaction effects were primarily responsible for metalaxyl, atrazine and prometryn adsorption(the rates of contributions were 79.05%, 60.21% and 57.89%, respectively) in the pesticide/heavy metals coexisting sediment system. The synergistic effects of the main effects and double-order interaction effects of pollutants concentration(synergistic effects) played a leading role in adsorption of malathion and prometryn(the rates of contributions were 70.61% and 69.61%, respectively), while antagonistic effects of the main effects and double-order interaction effects of pollutants(antagonistic effects) played a dominant role in the adsorption of dimethoate, metalaxyl and atrazine(the rates of contributions were 58.82%, 56.89% and 58.24%, respectively). Moreover, the correlation coefficient value(R²) ranged from 0.986 to 0.999(>0.8783) in the 2D-QSAR model, while the standard deviation(SD) ranged from 0.006 to 0.066 and the F test values were 22.684-199.544, indicating the model has good predictive ability and fit. The 2D-QSAR model revealed a significant correlation(P=0.05) between the main effects of pollutants concentrations on pesticides adsorption(main effect values) and the most positive hydrogen atomic charge(q_H+), the highest occupied molecular orbital energy(E_HOMO) and the dipole moment(μ). Furthermore, double-order interaction effect values of pollutant concentrations influenced the adsorption of pesticides(double-order interaction effect values), and the most positive atomic charge(q⁺), q_H+, and the lowest unoccupied molecular orbital energy(E_LUMO) were significantly correlated. The q_H+, E_HOMO and μ of pesticides were found to be significant factors promoting pesticides adsorption, while the q⁺ and E_LUMO of pesticides were significant inhibiting factors(P=0.05). Overall, this study provides a theoretical basis for further realization of combined pollution control of pesticide pollutants in complex environmental systems.



Design, Synthesis and Biological Activity of Novel Furocoumarin Derivatives as Stimulators of Melanogenesis and Tyrosinase in B16 Cells

NIU Chao, ZANG Deng, Haji Akber AISA

2018, 34(3):  408-414.  doi:10.1007/s40242-018-7338-4

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Sixteen novel and four known(4a, 4d, 4e, 4h) amine derivatives of furocoumarin were synthesized, then submitted to evaluation as stimulators of melanogenesis and tyrosinase in B16 murine cells. Among them, five compounds(4g, 4j-4m) showed potent activating effect on both melanogenesis and tyrosinase in vitro compared with positive control(8-MOP), the most widely used drugs for vitiligo in clinic. Noticeably, compounds 4h and 4j, which contain morpholine and piperazine, were recognized as the most effective stimulator of melanogenesis and tyrosianse in B16 cells separately. These derivatives may serve as lead compounds for further drug discovery for the treatment of vitiligo.



Synthesis of Bisboronic Acids and Their Selective Recognition of Sialyl Lewis X Antigen

WANG Yan'en, LI Xueyan, CHEN Hua, ZHU Mengyuan, LI Xiaoliu

2018, 34(3):  415-422.  doi:10.1007/s40242-018-7328-6

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The development of sensors that recognize Lewis oligosaccharides can help the diagnosis and early detection of cancer. Herein, we reported the design and synthesis of a series of anthracene-based bisboronic acids (9a-9e) with different N-substituents near the boronic acid unit. Among them, compound 9a could recognize sialyl Lewis X(sLe^x) with selectivity over other Lewis sugars, and could significantly stain sLe^x-expressing HEPG2 cells with selectivity over the range of 0.1-10 μmol/L. Compound 9a possibly has two properly positioned boronic acids caused by the steric hindrance by the near N-benzyl substituent group, which empower its sLe^x selectivity and higher binding affinity.



Synthesis of Camptothecin-10-O-glucoside Using an Engineered Oleandomycin Glucosyltransferase

ZHU Xuelin, YE Qinmei, WEN Chao, CHEN Liping, LIANG Guangping, ZENG Ting, ZHANG Dongmei, JIANG Renwang

2018, 34(3):  423-427.  doi:10.1007/s40242-018-7309-9

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Oleandomycin glycosyltransferase variant P67T/S132F/A242V(ASP) was used to convert 10-hydroxy-camptothecin into camptothecin-10-O-glucoside, which was confirmed by spectral analysis. Compared to the previously reported results, the present study reached the conversion rate up to 80% through the optimization of reaction conditions. In addition, compared with 10-hydroxycamptothecin(HCPT), camptothecin-10-O-glucoside inhibited the proliferation of Huh7 cells in a concentration-dependent manner and showed stronger antineoplastic effect but lower toxicity. Furthermore, camptothecin-10-O-glucoside induced more apoptotic cells as compared with the parent compound.



Site-specific PEGylation of Human Growth Hormone by Mutated Sortase A

SHI Hui, SHI Qingyang, James T. OSWALD, GAO Ying, LI Leijiao, LI Yunhui

2018, 34(3):  428-433.  doi:10.1007/s40242-018-8023-3

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Human growth hormone(hGH), a classic therapeutic protein, which promotes growth and wound healing, is released from the pituitary gland. As a protein drug, its short half-life is its main barrier to therapeutic efficacy. Various strategies have been designed to prolong its serum half-life, the most common of which is the conjugation with polyethylene glycol(PEG), as this has been shown to significantly extend protein's serum half-life. However, PEGylation often results in random conjugation, which can lead to impaired protein function and hinder purification, characterization and evaluation of the PEGylated protein. Therefore, site specific PEGylation is a promising direction for PEG-protein conjugation. Here we took advantages of the mutated sortase A(7M) enzyme, which can enzymatically ligate the universal α-amino acids to a C-terminal tagged protein. This then allows specific modification of the C-terminal of hGH with PEG. This site-specific bound PEG-hGH has similar efficacy, receptor binding and cell proliferation as wild-type hGH; however, pharmacokinetic analysis demonstrates that its serum half-life is almost 24 times that of wild-type hGH. Herein, we provided a promising advancement in the development of site specific PEGylated therapeutic proteins.



3D-Graphene/Boron Nitride-stacking Material: a Fundamental van der Waals Heterostructure

FU Peng, JIA Ran, WANG Jian, Roberts I. EGLITIS, ZHANG Hongxing

2018, 34(3):  434-439.  doi:10.1007/s40242-018-8075-4

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The 3D periodic graphene/h-BN(G/BN) heterostuctures were studied. The stacking forms between the graphene and h-BN layers were discussed. The varieties of the geometric and electronic configurations at the interface between graphene and h-BN layers were also reported. The metal-semiconductor transform of the G/BN material can be achieved by adjusting the stacking form of the h-BN layers or changing the proportion of graphene layers in the unit cell. An electrostatic potential well was found at the interface. Due to the potential well and the only dispersion correlation at the interface, the dielectric constant ε_zz in vertical direction was independent on the variety of the thickness or the proportion of the compositions in an unit cell.



Surface Properties and Etherification in Microemulsion Systems of Novel Brönsted Acid Surfactants

YANG Mingqing, WEI Zhonglin, DUAN Haifeng, LIN Yingjie

2018, 34(3):  440-443.  doi:10.1007/s40242-018-8046-9

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Novel Brönsted acid-surfactants with different alkyl chains were synthesized via a two-step process, and their surface properties were studied. The critical micelle concentration(cmc), surface tension at the cmc(γ_cmc), and ability of these compounds to lower the surface tension by 0.02 N/m(C₂₀ and pC₂₀) were investigated at 25 and 40℃. The molecular architecture of the compounds strongly influenced these physicochemical parameters. The ability of these compounds to lower surface tension was found to be good. Etherification in microemulsions formed by these surfactants as well as dodecylbenzenesulfonic acid(DBSA) was performed; surfactants 3a and 3b were found to be much more efficient than dodecylbenzenesulfonic acid(DBSA).



Effect of VO₄^3- Substitution on the Electrochemical Properties of a LiSn₂(PO₄)₃ Anode Material

FENG Xiaojing, HE Jun, WANG Xiaoran, WANG Gongkai, WANG Xin, PENG Huifen

2018, 34(3):  444-450.  doi:10.1007/s40242-018-8003-7

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VO₄^3- anion was used to partially substitute for PO₄^3- in the Nasicon compound of LiSn₂(PO₄)₃ via a sol-gel method. XRD analysis revealed that the VO₄^3--substituted samples did not have a single LiSn₂(PO₄)₃ phase, and some secondary phases like SnO₂ and SnP₂O₇ appeared. Introduction of the VO₄^3- anion did not prevent the LiSn₂(PO₄)₃ compound from decomposing during the initial lithiation; however the VO₄^3- anion substitution remar-kably enhanced the rate capability and cycling performance of the products because they reduced the charge transfer impedance, increased the lithium ion diffusion, and strengthened the role of the Li₃PO₄ matrix due to the precipitation of the Li₃VO₄phase. Of the substituted samples, the sample with a nominal composition of LiSn₂(PO₄)_2.5(VO₄)_0.5 delivered a capacity of 449.2 mA·h/g at a rate of 0.25 C after 25 cycles and 373.8 mA·h/g at 2 C rate. Those values surpassed some previous reports on LiSn₂(PO₄)₃ and the LiSn₂(PO₄)₃/C composites. Accordingly, the partial substitution of phosphorus by vanadium in LiSn₂(PO₄)₃ is a feasible technique to remarkably improve its electrochemical properties.



Effect of Thermal Cycles on the Thermal Expansion Behavior of T700 Carbon Fiber Bundles

GENG Guoliang, MA Xiaofei, GENG Hongbin, WU Yiyong

2018, 34(3):  451-456.  doi:10.1007/s40242-018-7430-9

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The relationships between the coefficient of thermal expansion(CTE) of T700 carbon fiber bundles(CFBs) and the thermal cycles were investigated. The microstructure of T700 CFBs was analyzed with Raman spectra and XRD before and after the thermomechanical test. The results indicated that the T700 CFBs exhibited negative expansion in the direction of parallel fibers in the temperature range of -150-150℃. The thermal strain that occurred during the heating and the cooling thermal cycle had an unclosed curve that served as the loop. When the experimental load was the same, the position of strain loop tended to move upward, and the length of the specimen increased continuously with the thermal cycles increasing. The microstructural analysis suggested that the degree of structural order and the degree of orientation along the fiber axis were improved with the increase of thermal cycles. The change of microstructure parameters could be the primary cause of the negative CTE's variation within the T700 CFBs.



Thermodynamic Evaluation of NaF-MF_n(M=Be, U, Th) Systems for Molten Salt Reactor

WU Shuang, LI Xiang, ZHANG Peng, AN Xuehui, XIE Leidong

2018, 34(3):  457-463.  doi:10.1007/s40242-018-7398-5

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The phase diagrams of NaF-BeF₂, NaF-ThF₄and NaF-UF₄systems were assessed based on thermodynamic principles, and diverse thermodynamic models were adapted to different systems. Associate solution model (ASM) was used to describe the Gibbs energies of liquid phase of the NaF-BeF₂system, whereas other systems(NaF-ThF₄and NaF-UF₄) were treated with the substitutional solution model(SSM) and intermediate compounds were described as stoichiometric compounds according to the Neumann-Kopp rule. All the thermodynamic model parameters were optimized by the least squares procedure until good coincidence was achieved between the calculated results and the experimental data. The derived thermodynamic parameters will be merged into the NaF-BeF₂-ThF₄-UF₄ database to develop the thorium molten salt reactor(TMSR) project.<



Visible-light Photochromism of Phosphomolybdic Acid/ZnO Composite

SUN Wentian, SI Yunheng, JING Haitao, DONG Zhaojun, WANG Chunxu, ZHANG Yupeng, ZHAO Lichen, FENG Wei, YAN Yan

2018, 34(3):  464-469.  doi:10.1007/s40242-018-7377-x

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A novel photochromic hybrid ZnO was synthesized by doping with phosphomolybdic acid(PMoA). It could respond to visible light and fade in color when treated with hydrogen peroxide(H₂O₂). The microstructure and photochromic properties were investigated via X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), transmission electron microscopy(TEM), ultraviolet-visible spectroscopy(UV-Vis) and X-ray photoelectron spectroscopy(XPS). The XRD patterns show that the prepared ZnO is pure and has a hexagonal wurtzite structure. The FTIR results demonstrate the existence of a strong interaction between PMoA and ZnO. Due to PMoA doping, the rough surface morphology of ZnO became smooth, as verified by the SEM images. The TEM images illustrate that pure ZnO exhibits a polycrystalline structure with irregular morphology. PMoA was wrapped on the surface of ZnO. After visible-light irradiation, the composite changed from slight yellow to blue and returned to the original color in the presence of H₂O₂. The composite had good photosensitivity and photochromic reversibility. The photochromic process was in accord with photoinduced electrons transfer mechanism.



Theoretical Studies on Aromaticity of Spiro Metallaaromatics of (C₁₀H₁₀M)^2-(M=Ni, Pd, Pt)

LIU Nannan, WANG Jian

2018, 34(3):  470-474.  doi:10.1007/s40242-018-7354-4

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Aiming to identify the spiro metallaaromatic systems with potential application value, (C₁₀H₁₀M)^2?(M=Ni, Pd, Pt) derivatives were theoretically investigated. (C₁₀H₁₀M)^2?-Iso1, which has two 6-membered rings(6MRs) connected by the M spiro atom, is a 14π-aromatic as a whole plane. (C₁₀H₁₀M)^2?-Iso2 has one 6π-aromatic 5MR and one 10π-aromatic 7MR connected by the spiro atom. The free (C₁₀H₁₀M)^2? dianions could not exist due to their rather high frontier orbital energies, while the neutral (C₁₀H₁₀M)Li₂ compounds are extremely stable against dissociation. Since (C₁₀H₁₀M)Li₂ coumponds are not fully coordinated, they trend to form (C₁₀H₁₀M)Li₄²⁺ dications, or even[(C₁₀H₁₀M)Li₂]_n polymers. Arguably, (C₁₀H₁₀M)^2? planes are not the only examples for spiro metallaaromaticity, their derivatives are also potential material building blocks.



Experimental Investigation and Thermodynamic Modeling of the NaCl-NaNO₃-Na₂SO₄ Ternary System

LI Xiang, FEI Zejie, WANG Yang, XIE Leidong

2018, 34(3):  475-479.  doi:10.1007/s40242-018-7339-3

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Molten salts as heat transfer and storage materials have been used to nuclear energy and concentrated solar power(CSP) applications. In this work, the system of molten salt mixture based on thermodynamic principles was designed as thermal energy storage(TES) materials. The substitutional solution model can be employed to describe the Gibbs energies of all liquid phase. Thermodynamic model parameters for the NaCl-NaNO₃-Na₂SO₄ subsystems were conducted by thermodynamic evaluation and optimization based on experimental phase-equilibria data. Thus, a set of self-consistent thermodynamic database was eventually obtained to reliably calculate the whole phase diagram and thermodynamic properties for the NaCl-NaNO₃-Na₂SO₄ternary system. The results manifest that the eutectic point of theternary system located at T=280℃ and x_NaCl=8.4%, x_NaNO3=86.3% and x_Na2SO4=5.3%. Moreover, the results predicted were verified experimentally using differential scanning calorimetry(DSC) and the agreement between the measured value[T=(287±2)℃] and predicted value(T=280℃) was satisfactory. Thus, the thermodynamic calculation method will be used to design and develop novel molten salt mixture as thermal energy storage materials.



Removal of Low-concentration Ammonia from Ambient Air by Aluminophosphates

LI Chunyang, WU Shujie, YU Guiyang, YANG Xuwei, LIU Gang, ZHANG Wenxiang

2018, 34(3):  480-484.  doi:10.1007/s40242-018-7281-4

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A series of aluminumphosphate materials was prepared and used as adsorbents for the removal of ammonia at low concentrations. The influence of various preparation parameters, including the pH value of sol, calcination temperature and molar ratio of P/Al, on the structure and surface properties as well as adsorption capacity was investigated. The results showed that large amount of P-OH present on the surface of aluminophosphates was suitable for the removal of ammonia. They were the major source of weak Brönsted acid sites and acted as the main active centers for capturing ammonia.



Effect of Phosphoric Acid on HZSM-5 Catalysts for Prins Condensation to Isoprene from Isobutylene and Formaldehyde

YU Xue, ZHANG Yuewei, LIU Bing, MA Huiyong, WANG Yan, BAO Qiang, WANG Zhenlü

2018, 34(3):  485-489.  doi:10.1007/s40242-018-7236-9

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A series of HZSM-5 zeolites modified with different amounts of phosphoric acid(P/HZSM-5) was prepared. The physicochemical features of the P/HZSM-5 catalysts were characterized via X-ray diffraction(XRD), N₂ adsorption-desorption, NH₃-temperature programmed desorption(NH₃-TPD) and Fourier tranform infrared(FTIR) spectra of the adsorbed pyridine, and the performances of the catalysts for Prins condensation to isoprene from isobutylene and formaldehyde were investigated. The maximum isobutene conversion and isoprene selectivity were 10.3% and 94.6% on the HZSM-5 catalyst with a Si/Al molar ratio of 600 using 5%(mass fraction) phosphoric acid. The phosphoric acid modification not only modulated the amount of acidic sites but also regulated the acid type. An appropriate amount of weak Lewis and Brönsted acid sites served as the active sites for the condensation of isobutene with formaldehyde, and the strong acid sites could cause side reactions and coke deposition.



Facile Route to Enzyme Immobilization: Gloucose Oxidase Entrapped in Titania Under Mild Environmental Conditions and Consequent Electrochemical Sensor Response

YU Zhihui, LIU Dandan, LI Yunqiao

2018, 34(3):  490-494.  doi:10.1007/s40242-018-7231-1

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A facile one-step method to the immobilization of the combination of glucose oxidase(GOD) and catalase(CAT) in mesostructured TiO₂ was proposed. The results obtained by transmission electron microspectroscopy and nitrogen adsorption-desorption analysis clearly show that the TiO₂ mediated by the combination of GOD and CAT(CGC) has a large surface area and a narrow pore-size distribution. The CGC immobilized on mesostructured TiO₂ exhibits direct electrochemistry and good electrocatalytic performance without any electron mediator.



Silver Chloride Loaded Hollow Mesoporous Silica Particles and Their Application in the Antibacterial Coatings on Denture Base

LI Xianliang, SHI Zuosen, CUI Zhanchen, ZHU Song

2018, 34(3):  495-499.  doi:10.1007/s40242-018-7376-y

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Hollow mesoporous silica particles(HMSPs) were prepared by using polystyrene microspheres as a template and loaded with silver chloride(AgCl) to act as antibacterial agents. The HMSPs possess radially oriented pore channels and a high loading amount of AgCl. The AgCl loaded HMSPs were then dispersed in hybrid coatings with different mass ratios to fabricate antibacterial coatings. The antibacterial activities of the coatings were tested against Candida albicans(ATCC 10231) and Streptococcus mutants(ATCC 25175). The resulting antibacterial coatings exhibited high antibacterial activities, high hardness, and acceptable adhesion to the substrate.



Hybrid Hydrogels Toughened by Chemical Covalent Bonding and Physical Electrostatic Interactions

LIU Li, PAN Ge, WANG Licheng, REN Xiuyan, ZHANG Xinyue, WU Guangfeng

2018, 34(3):  500-505.  doi:10.1007/s40242-018-7375-z

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Polystyrene nanoparticles with negative charges(n-PSs) were synthesized using styrene(St) and sodium styrene sulfonate(NaSS) as initial materials by surfactant-free emulsion polymerization. Subsequently, a hybrid hydrogel was prepared using acrylamide(AAm) and methacryloyloxyethyltrimethyl ammonium chloride(DMC) as co-monomers with N,N'-methylenebisacrylamide(MBA) as a chemical crosslinker and n-PSs as a physical electro-static interaction agent. The resulting hybrid hydrogels exhibited excellent tensile strength and elongation at break. The tensile stress of hybrid hydrogels was seven times greater than that of hydrogels without n-PSs. The elongation at break of hydrogels reached 700%, which was much higher compared to those of the hydrogels without n-PSs. Furthermore, swelling measurements of the hydrogels indicate that there is an overshoot in the swelling process and the extent of overshoot decreases with the increasing n-PSs. Therefore, the work presented here provides a method for improving the mechanical properties of hydrogels via the introduction of polymeric nanoparticles.



Bipolar Blue Light-emitting Polyfluorenes Containing Dibenzothiophene-S,S-dioxide/Carbazole Units

LIANG Li, LIU Jie, ZHANG Yuhao, HU Liwen, GUO Ting, YANG Wei, CAO Yong

2018, 34(3):  506-512.  doi:10.1007/s40242-018-7311-2

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Bipolar blue light-emitting polyfluorenes(PFSO-Cz) containing electron-deficient dibenzothiophene-S,S-dioxide(SO) and electron-rich carbazole(Cz) unit were synthesized. All the polymers show a high thermal stability with the decomposition temperatures over 400℃ and higher photoluminescence quantum yields. The highest occupied molecular orbital energy levels(E_HOMO's) slightly enhance and the lowest unoccupied molecular orbital energy levels(E_LUMO's) gently depress with the increase of Cz content in the polymers. PL spectra of the polymers display remarkable red shift and broadening with the increase of solvent polarities, indicating significant intramolecular charge transfer(ICT) effect in the polymers. Electroluminescence(EL) spectra of the polymers exhibit a broadening tendency with increasing the content of Cz unit in the polymers. The superior device performances were obtained with the maximum luminous efficiency(LE­_max) of 5.2 cd/A, the maximum external quantum efficiency(EQE_max) of 4.8% and the Internationale de l'Eclairage(CIE)(x,y) coordinates of (0.16, 0.17) for PFSO15-Cz10 based on the single-layer device of ITO/PEDOT:PSS/EL/CsF/Al. The results indicate that the efficient bipolar blue light-emitting polyfluorenes are also constructed by Suzuki copolymerization using the monomers in common use.