Chemical Research in Chinese Universities

Chemical Research in Chinese Universities Vol.34 No.6 December 2018

2018, 34(6): 0-0.

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Stereoselective Synthesis of a Common 3-Oxabicyclo[3.2.0]heptan-2-one Core Building Block Toward Illicium Sesquiterpenes via Desymmetrization

LIU Wentan, WANG Bo

2018, 34(6): 867-870. doi:10.1007/s40242-018-8229-4

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Facile Synthesis of Fe₃Pt-Ag Nanocomposites for Catalytic Reduction of Methyl Orange

HAN Donglai, LI Boxun, XING Guoliang, ZHANG Yuanyuan, CHEN Yue, SUN Yantao, ZHANG Yongjun, LIU Yang, YANG Jinghai

2018, 34(6): 871-876. doi:10.1007/s40242-018-8241-8

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The polyethyleneimine dithiocarbamate was employed as polymers to synthesize Fe₃Pt-Ag nanocomposites by using the seed deposition method. Fe₃Pt-Ag nanocomposites were utilized for the catalytic degradation of methyl orange(MO) in the presence of NaBH₄. Fe₃Pt-Ag nanocomposites showed good chemical catalytic activity and stability in pollutants degradation. Furthermore, Fe₃Pt-Ag nanocomposites can keep their efficiency till four cycles. The results suggest that the nanocatalysts with recyclability have broad prospects in environmental conservation applications.

Acylation of Anisole Catalyzed by Hierarchical Porous Hβ Zeolite Modified with Cr

LI Guohua, LI Huipeng, ZHAO Hua, CAI Tianfeng, LI Yange and GUAN Shengnan

2018, 34(6): 877-881. doi:10.1007/s40242-018-8151-9

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Modified hierarchical porous Hβ zeolite was obtained by metal modification of Hβ zeolite, which was treated with alkaline solution, and the catalysts before and after modification were characterized by means of X-ray diffraction(XRD), nitrogen adsorption-desorption, scanning electron microscopy(SEM), X-ray fluorescence(XRF), NH₃ temperature-programmed desorption and Fourier-transform infrared spectroscopy(FTIR). The activities of acylation of anisole with acetic anhydride were also investigated. The results show that the Hβ zeolite, which was treated with alkaline solution has microporous and mesoporous structures that could improve the diffusion performance of chemical reaction. The amount of acid was modulated with metal modification. The Hβ zeolite modified by 5%(mass fraction) metal chromium had the best catalytic performance. The conversion of acetic anhydride acylation was 93.01% under the optimal conditions, which was higher than that of other catalysts. The catalyst not only showed good activity, but also exhibited a stable performance in regeneration tests.

One Step Hydrothermal Synthesis of Flower-shaped Co₃O₄ Nanorods on Nickel Foam as Supercapacitor Materials and Their Excellent Electrochemical Performance

WANG Chen, MENG Yanshuang, WANG Lei, ZHU Fuliang, ZHANG Yue

2018, 34(6): 882-886. doi:10.1007/s40242-018-8073-6

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Flower-shaped Co₃O₄nanorods directly grown on nickel foam(Co₃O₄/NF) were prepared by one step hydrothermal method at low temperature. Co₃O₄nanorods are directly connected with the nickel foam, and no binder is needed as an additive, so the Co₃O₄/NF electrode has good electrical conductivity. This flower-shaped structure makes larger surface area of Co₃O₄nanorods that exposes to the electrolyte, thus promoting the redox reaction. The Co₃O₄/NF electrode shows a high specific capacitance of 2005.34 F/g at the current density of 0.5 A/g and a high capacitance retention of 98.0% after 5000 cycles. The high superior capacitive performance with high specific capaci-tance and the excellent cyclic performance indicate that the one step hydrothermal method has great potential application in supercapacitors.

Determination of Lignans in Schisandra sphenanthera and Schisandra chinensis Using Ionic Liquid-based Ultrasonic-assisted Extraction and High-performance Liquid Chromatography

GUAN Lianyue, LUO Qiang, LIANG Na, YU Wei

2018, 34(6): 887-892. doi:10.1007/s40242-018-8306-8

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A green, rapid and precise sample pretreatment technique, IL-based UAE(ionic liquid-based ultrasonic-assisted extraction), was coupled with high-performance liquid chromatographic separation to identify the main effective components in Schisandra sphenanthera(S. sphenanthera) and Schisandra chinensis(S. chinensis) including schisantherin A, schisandrin A, and deoxyschizandrin. Four different types of ionic liquids have been investigated, finally[C₆MIM] [BF₄] was used as the extraction solvent. A powder form of S. sphenanthera and S. chinensis was mixed with the[C₆MIM] [BF₄] to produce a suspension. This suspension was ultrasonically extracted in a water bath at room temperature. Several of the process parameters were optimized, including the type of ionic liquid used and its volume, the sample amount, the size of the sample particle, the extraction time, etc. HPLC calibration curves were established for all the analytes and proved to be linear(r>0.9999). The lowest detection level for schisandrin A was 0.12 μg/mL, for schisantherin A was 0.08 μg/mL, and for deoxyschizandrin was 0.10 μg/mL. The recoveries of the target compounds were from 74.19% to 109.33%. The standard deviations for detection were generally no more than 6.31%. In contrast to conventional extraction methods, the IL-based UAE did not involve volatile organic volatile solvents, and the analysis time, required sample and solvent volumes were also lower than those of the conventional techniques.

Eco-friendly and Cleaner Process Using Online Microwave-assisted Steam Extraction Coupled with Solid-phase Extraction for Trace Analysis of Sulfonamides in Animal Feed

LI Guijie, LIU Chang, WANG Dawei, DING Lan

2018, 34(6): 893-898. doi:10.1007/s40242-018-8166-2

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An environmentally friendly method for extracting sulfonamides(SAs) residues from animal feed was described and applied. The method used online microwave-assisted steam extraction coupled with solid phase extraction(MASE-SPE), which was followed by the analysis using high performance liquid chromatography-mass spectrometry(HPLC-MS/MS). The SAs residues were extracted successively with water steam under microwave irradiation, and thus directly introduced into an SPE column containing cation-exchange resin. The SAs were then eluted with methanol-ammonia(90:10, volume ratio) from the SPE column and followed by HPLC-MS/MS. The limits of detection(LODs) for the analytes ranged from 0.24 ng/g to 0.49 ng/g. The limits of quantification(LOQs) ranged from 0.82 ng/g to 1.63 ng/g. Average recoveries of SAs were 76.3%-92.1%. The developed method was a reliable and environmentally friendly alternative to previous methods with respect to time, solvent and labor consumption for the analysis of SAs in animal foodstuffs.

Quantitative Determination of Urine Glucose: Combination of Laminar Flow in Microfluidic Chip with SERS Probe Technique

SUN Dan, LIU Xiangyuan, XU Shuping, TIAN Yu, XU Weiqing and TAO Yanchun

2018, 34(6): 899-904. doi:10.1007/s40242-018-8163-5

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A surface-enhanced Raman scattering(SERS) sensing approach for urine glucose was developed based on the laminar flow technology in a cross-type microfluidic chip with SERS probes, 4-mercaptophenylboronic acid (MPBA) functionalized Ag nanoparticles. MPBA as the glucose receptor can identify and bind up with glucose at a molar ratio of 2:1, which can cause the aggregation of SERS probes at a certain position of the chip channel and further enhance the SERS signal of MPBA significantly. Thus, the quantitative SERS detection of glucose was achieved indirectly. No sample pretreatment and separation were needed in this method since the SERS detection was achieved in the gradient diffusion and molecular recognition processes between urine glucose and SERS probe in the laminar flow, which simplified the sample treatment procedures, saved detection time and made it feasible for clinic applications. This method shows a good linear relationship within human body's normal physiological range and has high sensitivity and selectivity. The lowest detection concentration can reach 1.0 mg/dL.

Rapid Determination of Tetrodotoxin in Human Plasma by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

CHEN Weizhu, ZHANG Yiping, SUN Jipeng, XIE Quanling, HONG Zhuan, YI Ruizao

2018, 34(6): 905-911. doi:10.1007/s40242-018-8094-1

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A sensitive analytical method was developed to determine tetrodotoxin(TTX) in human plasma samples using protein precipitation, followed by ultra performance liquid chromatography(UPLC) analysis coupled with tandem mass spectrometry(MS/MS) using 11-deoxytetrodotoxin(11-deoxyTTX) as an internal standard. The plasma samples were prepared using protein precipitation prior to being analyzed by UPLC-MS/MS to identify TTX over a zwitterionic-hydrophilic interaction liquid chromatography column. The retention time values of TTX and 11-deoxyTTX were 4.12 and 3.67 min, respectively. TTX and 11-deoxyTTX were monitored and quantitated on the basis of their ion transitions for their respective precursor ions to their product ions(i.e., m/z 320.0→162.1 for TTX and m/z 304.0→176.0 for 11-deoxyTTX) in the multiple reaction-monitoring mode. The lower limit of quantification of this method was determined to be 0.0199 ng/mL. This method showed good linearity for plasma samples that contained TTX concentrations in the range of 0.0199-1.99 ng/mL. The specificity, precision, accuracy, matrix effect, and stability characteristics of this method were also examined. The intra-assay precision and accuracy ranged from 1.89% to 6.00% and from 92.21% to 100.00%, whereas the inter-assay precision and accuracy ranged from 0.64% to 7.75% and from 99.38% to 101.26%, respectively. This new method therefore represents a rapid, accurate, reliable, and highly sensitive method for the qualitative and quantitative analyses of a trace amount of TTX in human plasma samples.

Synthesis, Biological Evaluation and Molecular Docking of Novel Phenylpyrimidine Derivatives as Potential Anticancer Agents

JIN Bo, TAO Ye, YANG Hongliang

2018, 34(6): 912-917. doi:10.1007/s40242-018-8149-3

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Based on our previous researches, a novel phenylpyrimidine pharmacophore model was proposed and fifteen derivatives were synthesized and characterized by means of spectroscopy methods. The inhibitory effects of them were screened against HeLa cell line by virtue of MTT assay in vitro. The results indicate some of the phenylpyrimidine derivatives exhibit potent biological activities. Among them, compounds 6g and 6h exhibit the best activity at half maximal inhibitory concentrations of 1.5 and 2.8 μmol/L, respectively. These compounds also exhibit good activities against HepG2 cell line and MCF-7 cell line. FLT-3 kinase was screened as the most potent molecular target. Computational docking between compound 6g and FLT-3 was carried out to interpret the binding mode. The results show phenylpyrimidine derivatives have effective antitumor activities, which provides a base for further research of them as antitumor agents.

One-step Construction of Xanthone Scaffold Assisted by Microwave Irradiation to Optimize the Synthesis of DMXAA

JIANG Zhenlei, LIU Jie, ZHOU Fan, ZHANG Jianrun, LIU Zhijun, ZHANG Chao, CHEN Heru

2018, 34(6): 918-922. doi:10.1007/s40242-018-8148-4

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An efficient and concise synthesis of 5,6-dimethylxanthenone-4-acetic acid(DMXAA) was developed. The overall yield of this 3-step procedure was 82%. The key reaction is the one-step construction of xanthone scaffold between 2,5-dibromo-3,4-dimethylbenzoic acid and 2-hydroxyphenyl-acetic acid assisted by microwave irradiation.

Facile Synthesis of 1,5-Diaryl-4-pyridyl-1,2,3-triaozle Derivatives

WANG Yingnan, WEI Chiyu, SONG Zhiguang

2018, 34(6): 923-928. doi:10.1007/s40242-018-8129-7

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A feasible approach to synthesize 1,5-diaryl-4-pyridyl-1,2,3-triaozle via a sequential route from 2-alkynyl pyridine was developed. In this work, KOH was identified as a crucial base to promote the Pd-catalyzed arylation step. Compared to the reported methods, this protocol largely improved the reaction efficiency with overall excellent yield and good functional group tolerance.

Expression of Phytoestrogens in pGL2/AQP1 Promoter Reporter System

WEI Wei, ZHAO Chaoyue, LIU Sitong, JIAO Xiaofei, LIU Xintong, LAN Chuanjian, LI Jiang

2018, 34(6): 929-933. doi:10.1007/s40242-018-8139-5

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In this study, we amplified aquaporin 1(AQP1) promoter sequence with polymerase chain reaction(PCR), then AQP1 promoter fragment and pGL2 basic vector were linked to create an artificial pGL2/AQP1 promoter reporter system. A certain concentration of 17β-estradiol(E2) activated pGL2/AQP1p, which demonstrated the pGL2/AQP1p transcriptional system effective. The pGL2/AQP1 promoter reporter system was applied to evaluate the activate effect on AQP1 of different kinds of phytoestrogens. Dual luciferase reporter gene activity assay showed that a certain concentration phytoestrogens including daidzein and genistein can increase AQP1 promoter transcription activity. In addition, E2, daidzein and genistein can make AQP1 protein endogenous expression level increase and promote the function of water scretion. The result can guide the clinical application to treat the Sjogren's syndrome and provide a necessary molecular tool for the subsequent drug screening.

Screen, Design and Enzymatic Activity Determination of Artificial Microperoxidases

XU Jia, ZHAO Xiaoming, YUAN Ye, SONG Yanhui, WANG Jiaqi, WANG Chonghan, CHEN Yujia, WANG Jianing, YAN Zhijun, GUAN Shuwen, WANG Liping

2018, 34(6): 934-938. doi:10.1007/s40242-018-8053-x

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Peroxidase activity greatly impacts the maintenance of free radical homeostasis, and can prevent or treat diseases related to free radicals. Microperoxidase-11(MP-11) is created via hydrolysis of cytochrome c iron-porphyrin complexes. In these complexes, the heme iron is penta-coordinate with histidine and exhibits excellent antioxidant activity when decomposing hydrogen peroxide. In this study, we screened the Ph.D.-7 and Ph.D.-12 phage display peptide libraries and obtained ten small peptide ligands of deuterohemin(the vinyl groups of oxidized heme). Among these polypeptides, DhHP-7P1, 12P1, 12P2 and 12P6 have good enzymatic activity compared with MP-11, and exhibit activities up to 50% of MP-11. Based on the screened sequences, we designed a series of artificial microperoxidases and determined that a higher peroxidase activity could be achieved with an enzymatic active site containing a second site of histidine residue spaced between two arginine residues with an interval of two amino acids(Dh-XHRXXR).

Molecular Dynamics Simulation: Influence of External Electric Field on Bubble Interface in Air Flotation Process

WU Leichao, HAN Yong, ZHANG Qianrui, ZHU Lin, ZHANG Chuanxin and ZHAO Ruikuan

2018, 34(6): 939-944. doi:10.1007/s40242-018-8195-x

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Molecular dynamics(MD) simulation was performed to investigate the influence of external electric field on the vapour-liquid interface of the bubble during the process of toluene separation by air flotation. The physicochemical properties of vapour-liquid interface, surface tension, probability of a hydrogen bonding near the vapour-liquid interface and the viscosity of liquid phase caused by external electric field were analyzed. The results show that the angle between the water molecule dipole moment and the normal z axis in the vapour phase changes smaller when the external electric field is applied. The surface tension and the probability of hydrogen bonding near the vapour-liquid interface increase with the increase of electric field strength. And the viscosity also increases under an external electric field. The results confirm that the external electric field has a positive effect on the performance of bubbles in air flotation, which may provide useful guidance for the combination of electric field and air flotation technology.

Nickel Complexes Based on Salicylaldehyde-imine Ligands: Synthesis, Characterization and Catalytic Oligomerization of Ethylene

CHEN Liduo, HUO Hongliang, WANG Libo, MA Lili, JIANG Yan, XIE Junyi, WANG Jun

2018, 34(6): 945-951. doi:10.1007/s40242-018-8186-y

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A series of nickel complexes {NOON^R}Ni(A:R=Me; B:R=t-Bu; C:R=OMe) based on salicylaldehyde-imine ligands was synthesized through Schiff base condensation and metal complexation reaction. Upon activation with methylaluminoxane(MAO), nickel complexes A-C all exhibited good catalytic activity[turnover frequency=5.2×10⁵-16.3×10⁵ g/(mol Ni·h)] and oligomer selectivity(above 85%, mass fraction) in ethylene oligomerization. In addition, C₈-C₁₂ olefins occupied an important proportion in the products of oligomers. Under the conditions of 4.0 MPa, 25℃ and Al/Ni molar ratio of 275, the catalytic selectivity of A/MAO system toward C₈-C₁₂ was about 30.1%(mass fraction), and the content of C₈-C₁₂ α-olefins was consistently above 70%. Furthermore, besides the ligand environment, the catalytic properties of A-C were substantially affected by experimental parameters, such as the reaction pressure, reaction temperature and Al/Ni ratio.

Graphene-Gold Nanoparticle-modified Electrochemical Sensor for Detection of Kanamycin Based on Target-induced Aptamer Displacement

ZHENG Jingyi, FENG Rongrong, HE Caimei and LI Xiaoxia

2018, 34(6): 952-958. doi:10.1007/s40242-018-8185-z

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A highly sensitive and selective label-free electrochemical sensor was developed for the determination of kanamycin. To improve the sensitivity of the electrochemical sensor, graphene-gold nanoparticles were prepared by a one-step electrochemical coreduction process and were modified on the surface of a glassy carbon electrode. The double-stranded DNA(ds-DNA) duplex probe was immobilized onto the graphene-gold nanoparticle-modified electrode. The introduction of target kanamycin induced the displacement of aptamer from the ds-DNA duplex into the solution. Methylene blue(MB) as a redox indicator monitored the current change using differential pulse voltammetry. Under optimal conditions, the designed electrochemical aptasensor exhibited a wide linear range from 0.1 pmol/L to 10 pmol/L with a detection limit of 0.03 pmol/L for kanamycin. The experimental strategy enabled the direct analysis of milk samples, and the results showed high sensitivity and good selectivity.

Crystal Structures, Thermal Behavior Analysis and Thermal Safety of Two Energetic Salts of Hydrazinyl-1,2,4,5-tetrazine with 3,5-Dinitrosalicylic Acid

CHEN Xiang, ZENG Tian, ZHANG Cong, GUO Zhaoqi, LI Shuailei, MAI Tao, GAO Rong, MA Haixia

2018, 34(6): 959-964. doi:10.1007/s40242-018-8169-z

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Two energetic salts, DPHT·DNS·H₂O(1) and DHT·2DNS·2H₂O(2)[DPHT=3-(3,5-dimethyl-1H-pyrazol-1-yl)-6-hydrazinyl-1,2,4,5-tetrazine; DHT=3,6-dihydrazinyl-1,2,4,5-tetrazine], were synthesized from S-tetrazine with 3,5-dinitrosalicylic acid(DNS). Compounds 1 and 2 were structurally characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction. The thermal behavior of the title compounds was studied by differential scanning calorimetry(DSC) and thermogravimetry(TG). The non-isothermal decomposition kinetics of compound 2 were investigated. The self-accelerating decomposition temperature, thermal ignition temperature, and critical temperatures of thermal explosion were obtained to evaluate the thermal safety of compound 2. The results show compounds 1 and 2 decompose at 150.8 and 179.2℃, respectively. The T_SADT and T_b of compound 2 are higher than those of DHT, which indicates compound 2 is a potential candidate for energetic materials that have good thermal stability.

Promoting Effects of Iron on CO Oxidation over Au/TiO₂ Supported Au Nanoparticles

ZHONG Siyuan, HAN Qiuwan, ZHU Baolin, HUANG Weiping and ZHANG Shoumin

2018, 34(6): 965-970. doi:10.1007/s40242-018-8141-y

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Fe-doped TiO₂ supported gold nanoparticles as high-performance CO oxidation catalysts were prepared. XRD data revealed that TiO₂ support was in an anatase phase. After calcination at 300℃, the sample showed nanotube structure, and the size of gold nanoparticles was 3.1 nm. When calcined at 500℃, most nanotubes broke, and gold nanoparticles grew up to 5.9 nm. XPS spectrum indicated the presence of Fe in the +3 oxidation state. Au/Fe-TiO₂(Au:1.44%, Fe:1.35%) calcined at 300℃ possessed the best catalytic activity, and it could completely convert CO at 25℃. The temperature of 100% CO conversion(T_100%) of Fe-free catalyst was 40℃. After the catalysts were stored at room temperature for 7 d, T_100% of Au/Fe-TiO₂ increased from 25℃ to 30℃, while T_100% of Fe-free catalyst increased from 40℃ to 80℃. The catalytic activity and storage stability of Au/TiO₂ could be improved by Fe-doping. The increase of specific surface area, generation of oxygen vacancies and new adsorption sites, depression of the growth of gold nanoparticles, and strong metal-support interaction were responsible for the promoting effect of iron on the catalytic performance of Au/TiO₂ for CO oxidation.

Stripping Voltammetric Analysis of Mercury at Base-treated Graphene Oxide Electrodes

QIU Yaru, DONG Lini, XIANG Dong, LI Li and ZHU Liande

2018, 34(6): 971-977. doi:10.1007/s40242-018-8134-x

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According to the Rourke's model, graphene oxide(GO) synthesized from the oxidation of graphite actually consisted of partly oxidized graphene sheets and highly oxidized debris(OD). The OD was strongly adhered to the surface of graphene sheets, while they could be facilely removed by a base-washing procedure. The existence and removal by base-washing of OD were characterized by means of thermogravimetric analysis(TGA), FTIR spectroscopy, X-ray photoelectron spectroscopy(XPS), transmission electron microscopy(TEM) and Raman spectroscopy. The adsorption of OD not only made a great difference to the physical and chemical properties of GO, but also affected its electrochemical behavior when it was employed as an electrode material. In this article, we demonstrated that the electrochemical deposition and the subsequent voltammetric stripping analysis of mercury were significantly influenced by the presence of OD. The consequence suggests that the presence of OD on the sheets of GO restricts the electrochemical deposition behavior of mercury and further lowers the sensitivity of the voltammetric stripping responses. The sensitivity was observed as 0.78 A·L·mol^-1 at base-washed(bw)-GO/GC(glassy carbon) better than that at as-prepared GO(a-GO)/GC for 0.28 A·L·mol^-1. The limit of detection was calculated as 2.95 and 0.83 μmol/L before and after removing the OD, respectively. The availability of both electrodes was evaluated by detecting Hg²⁺ in lake water specimens using standard samples recovery.

Transient Optical Characteristics of Broad Absorption Band Excitons Modulated by Micro-cavity

LI Kaijiao, ZHANG Zhenyu, CUI Haining, WANG Haiyu

2018, 34(6): 978-982. doi:10.1007/s40242-018-8133-y

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The understanding of light-matter interaction within micro-cavity lays the basic groundwork for many future photon-related technologies and applications. We prepared low quality metal-insulator-metal(MIM) micro-cavity consisting massive two-level broad absorption band dye(Nile Red) excitons, which randomly dispersed in SU-8 polymer negative resist matrix and measured their optical characteristics. New binate transmission peaks with large energy separation(so-called Rabi-splitting phenomenon) and their angular anti-crossing behavior in consequence of the interaction between dye excitons and confined photons were observed. It was also confirmed that the separated energy can be tuned by changing the doped exciton concentrations. Time-resolved transient absorption measurements showed that such an interaction is indeed a coherent one but rather a strong coupling one and one can modulate such a coherent mechanism by easily adjusting the detuning between dye excitons and confined cavity photons. This work may provide a comprehensive and deep understanding for such massive broad absoprtion band excitons-doped MIM micro-cavities and represent a further step to realize optical cavity-modulated devices in future.

Facile Self-templating Melting Route Preparation of Biomass-derived Hierarchical Porous Carbon for Advanced Supercapacitors

WANG Can, WANG Dianyu, ZHENG Shuang, FANG Xueqing, ZHANG Wenli, TIAN Ye, LIN Haibo, LU Haiyan, JIANG Lei

2018, 34(6): 983-988. doi:10.1007/s40242-018-8127-9

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Biomass-derived porous carbons show great potential as electrode materials for supercapacitors due to the environmental friendliness. However, most of the carbonaceous electrode materials suffer from low specific capaci-tance and rate capacity because of the poor porosity. Here, we reported a simple and effective approach to prepare micro/nano-hierarchical structured carbon materials derived from rice husk by NaOH-KOH molten salt co-activation. The as-prepared activated carbons exhibit high porosity and suitable pore size distributions for more electrolyte ion adsorption, which are all beneficial for achieving remarkable electrochemical performances, such as high specific capacitance(194.6 F/g), excellent rate capability(retention of 85.9%) and outstanding cycling stability. Thus, the above biomass-derived carbon materials with high porosity and micro/nano structures obtained by co-activation method offered a new insight into novel electrode material for the use in energy storage systems with high energy density and excellent rate performance.

Surfactant Effects on the Permeability of Photosynthetic Membrane from Rhodobacter sphaeroides 2.4.1 Probed by Electrochromic Shift of Endogenous Carotenoids

ZHOU Xuan, YU Jie, WANG Peng, ZHANG Jianping

2018, 34(6): 989-994. doi:10.1007/s40242-018-8105-2

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Four surfactants, sodium cholate(SC), n-dodecyl-β-D-maltopyranoside(DDM), lauryldimethylamine oxide(LDAO) and Triton X-100(TX), which are generally used in photosynthetic pigment-protein complexes preparation, were studied on their interaction with photosynthetic membrane from Rhodobacter sphaeroides 2.4.1 by electrochromic absorption band-shift of endogenous carotenoids and by vesicle size measurements as well. The surfactant critical micelle concentration(cmc) was found to be negatively correlated with the capability of enhancing the permeability of photosynthetic membranes to proton, and more elaborated model of surfactants interacting with membranes was obtained. The electrochromic absorption band-shift measurement might develop into a useful tool to evaluate the effects of surfactants on various membranes.

Molecular Dynamics Simulations and Steered Molecular Dynamics Simulations of Glabridin Bound to Wild Type and V30A Mutant Transthyretin: Ligand-linked Perturbation of Tertiary Conformation

YU Zhengfei, HAN Jiarui, LIU Ye, ZHU Jingxuan, TIAN Xiaopian and HAN Weiwei

2018, 34(6): 995-1003. doi:10.1007/s40242-018-8085-2

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Transthyretin(TTR), as a tetrameric protein, functions as a neuroprotector. The native TTR homotetramer dissociates into dimers and monomers. Dimers and monomers self-assemble into amyloid fibrils, and this process can lead to some diseases. Native TTR homotetramer is a widely accepted model for TTR amyloid formation. In this study, simulations using molecular dynamics(MD) and steered MD(SMD) were performed to explore the mechanisms for glabridin(Glab), a specific inhibitor for TTR binding, for V30A mutant and wild-type(WT) TTR. MD simulation results indicate that, compared with Glab binding to WT and V30A mutant, the WT TTR could lead to the collapse of β-strands from Ser52 to His56 at chain A. This phenomenon facilitated the easy dissociation of chains A and C. Calculations of the binding free energy between the two chains showed that the V30A-Glab TTR complex displayed a lower binding energy than other systems(WT TTR and WT-Glab TTR). Then, SMD simulation was performed to explore the unbinding pathway for Glab through the WT and V30A mutant TTR. The results show that Lys15(chain A) produced a hydrogen bond with Glab at the force peak via the WT TTR tunnel. Meanwhile, in the V30A TTR mutant, the hydrogen bond between Lys15(chain A) and Glab was broken at the force peak. This condition was beneficial for Glab to be taken off from the protein. Our theoretical results will be useful in designing a new specific inhibitor of TTR protein to control the TTR homotetramer dissociation.

One-step Synthesis of N-Doped Mesoporous Carbon as Highly Efficient Support of Pd Catalyst for Hydrodechlorination of 2,4-Dichlorophenol

TANG Haodong, XIANG Meng, XU Bin, LI Ying, HAN Wenfeng and LIU Zongjian

2018, 34(6): 1004-1008. doi:10.1007/s40242-018-8052-y

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Although the hard template method is often employed to prepare N-doped mesoporous carbon(N-MC), the removal of the silica template commonly involves theuse of highly toxic HF or repeated treatment with NaOH solution. Herein, we reported a polyvinylidene fluoride-assisted one-step method for synthesis of N-MC, namely the silica-free N-MC can be prepared via temperature-programmed thermal treatment of a slurry obtained by dispersing nano-silica into a solution containing sucrose, urea, oxalic acid, polyvinylidene fluoride and dimethylacetamide. The resulting N-MC, which owns 3.47%(mass fraction) nitrogen and a surface area of 929 m²/g, is a highly suitable support of Pd catalyst used in hydrodechlorination of 2,4-dichlorophenol, with its performance being much better than those of MC and activated carbon. The excellent catalytic hydrodechlorination activity of the Pd/N-MC catalyst can be attributed to its strong metal-support interaction, which results in a good Pd dispersion and high resistance to the growth of nanosized Pd under reaction conditions.

Synthesis, Structure Characteristic and Thermal Behavior of Two New Metal-organic Azo-triazole Compounds: [Zn(phen)₃]·ZTO·6H₂O and[Cu(phen)₃]·ZTO·6H₂O

DING Zimei, CAO Wenli, ZHENG Hui, HUANG Jie, XU Kangzhen, SONG Jirong

2018, 34(6): 1009-1013. doi:10.1007/s40242-018-8051-z

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[Zn(phen)₃]·ZTO·6H₂O(1) and[Cu(phen)₃]·ZTO·6H₂O(2) were synthesized by the reaction of Zn(NO₃)₂·6H₂O/Cu(NO₃)₂·3H₂O with 4,4-azo-1H-1,2,4-triazol-5-one(ZTO) and 1,10-phenanthroline(phen). The two compounds were characterized by elemental analysis and IR spectrum analysis, respectively. Compound 1 was also characterized by single crystal X-ray diffraction analysis. For compound 1, the coordination geometry around the Zn²⁺ is a distorted octahedron, with the bite angles of 76.7(3)°-77.6(4)° for all three phen ligands. Moreover, the thermal behaviors and thermal decomposition kinetics were studied and analyzed. Besides, thermal stability and safety parameters(T_SADT, T_b) are 164.7 and 166.4℃ for compound 1, and 149.6 and 150.8℃ for compound 2, respectively.

Preparation of Corn Stalk-Walnut Shell Mix-based Activated Carbon and Its Adsorption of Malachite Green

KANG Chunli, SHANG Dan, YANG Ting, ZHU Ling, LIU Fang, WANG Nan and TIAN Tao

2018, 34(6): 1014-1019. doi:10.1007/s40242-018-8045-x

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The mix-based activated carbon derived from corn stalk and walnut shell was prepared by chemical activation method using phosphoric acid as the activator. The optimized conditions for preparation were obtained by the orthogonal experiment, the characterizations of the activated carbon were performed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy(FTIR), Boehm's titration method and nitrogen adsorption. For the prepared mix-based activated carbon, the highest iodine number, methylene blue number and BET surface area are 720.5 mg/g, 195.0 mg/g and 1187 m²/g, respectively, and the pores are mainly mesopores. The mix-based activated carbon shows the higher adsorption capacity for malachite green than the raw materials, the activated carbons prepared only from corn stalk or walnut shell and the commercial activated carbon. The kinetics and thermodynamics of the adsorption can be satisfactorily described by the pseudo-second-order kinetic model and the Langmuir isotherm model, separately.

Efficient Removal of Lead from Washing Effluent of Lead-contaminated Soil with Garlic Peel

CHEN Xing, YIN Lipu, ZHOU Hongyu, LIU Junyou, LI Xiaohui, AI Xianbin, HUANG Kai

2018, 34(6): 1020-1027. doi:10.1007/s40242-018-8019-z

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Wastewater produced from the soil washing process contains heavy metals, which limits its reuse for washing. So it is necessary to develop an efficient and economical way to recycle it, and this study presented a biosorption method to realize this goal. A typical soil sample contaminated by lead was taken from the real field near a lead smelting factory, used for the toxic metals extraction with dilute citric acid. A leach liquor was obtained with lead ions at the level of 12.35 mg/L, Cd 1.2 mg/L, Cu 1.5 mg/L, Zn 2.6 mg/L, as well as the coexisting anions, such as sulphate, silicate, chloride at the concentration of several hundred miligram per liter. The garlic peel was modified by a simple chemical saponification process and used as the biosorbent for toxic metal removal. Firstly, the adsorption behavior of lead ions on the saponified garlic peel was systematically investigated using the synthetic solutions, and then the adsorption mechanisms were explored by detailed experiments combining with the thermodynamic calculation reuslts of the aqueous system of Pb(Ⅱ)-citrate-H₂O. It was found that in artificial solution containing 0.01 mol/L citrate, the maximum adsorption capacity of 261.0 mg/g was reached at pH near 3.0, and also at this very pH value the Pb²⁺ and Pb(H₂Cit)⁺ were the dominant lead species, which are favorable for adsorption due to its easier approaching to the -COO^- ligands in the saponified garlic peel partilces via charge attraction, and the appearance of Pb(HCit)⁰ and Pb(Cit)^- at pH above 3.0 inhibits the adsorption. Secondly, the real leach liquor was used for adsorption tests, and twice adsorption under the optimal conditons would decrease the residual concentrations of Pb, Cd, Cu and Zn to zero. After elution by using 0.1 mol/L nitric acid, the adsorbed metals can be recovered and garlic peel can be reused for at least 10 cycles effectively. This study presents a prospective biosorption method for economical and efficient removal of the lead ions from soil washing wastewater with citric acid as the leaching reagent.

Bentonite Reinforced Tough Composite Hydrogels as Potential Artificial Articular Cartilage

LU Xueting, FENG Wei, WANG Honglei, HU Qianqian, GUAN Shuang, GUO Peipei

2018, 34(6): 1028-1034. doi:10.1007/s40242-018-8219-6

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Novel tough composite hydrogels were prepared from inorganic bentonite(IB), polyvinyl alcohol(PVA) and polyethylene glycol(PEG) by means of a freeze-thaw technique, during which IB acted as multifunctional physically crosslinking junction and a filler to bridge the 3D network hydrogel; while the physical adsorption between IB and the polymer chains served as sacrificial bonds and increased the energy dissipation efficiency. The effects of different content of IB(w_IB) on the morphological, thermal, swelling, and mechanical properties of the hydrogels were investigated. It was found that the added IB promoted the material crosslinking and stability, and the mechanical properties of the hydrogels were significantly improved with increasing w_IB. The highest tensile stress of the hydrogel was achieved(1.1 MPa) when w_IBwas 5%. The synthesized hydrogels with high mechanical strength and low friction coefficient are potential candidate materials for artificial cartilage.

Porous Organic Polymer Nanoparticles for Sensing of Unsaturated Hydrocarbons

LIU Zhi, XU Feifan, ZHAO Zhijie, HE Yuhua, ZHANG Hongxing, ZOU Guangtian, LI Yangxue

2018, 34(6): 1035-1040. doi:10.1007/s40242-018-8161-7

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The design and synthesis of porous organic polymers for the potential application in chemical sensors remains a huge challenge nowadays. Herein, a porous organic polymer possessing tetrazole groups(TTZ-3) was synthesized via simple Schiff base chemical reaction. Thermogravimetric analysis(TGA), Fourier transform infrared spectrometer(FTIR), solid-state¹³C cross polarization/magic angle spinning nuclear magnetic resonance(CP/MAS NMR), transmission electron microscopies(TEM) and field-scanning electron microscopies(FE-SEM) were adopted to cha-racterize the structure and morphology in detail. Significantly, the formed polymers exhibited special detection of unsaturated hydrocarbons through fluorescence enhancement based on photoactivatable 1,3-dipolar cycloaddition reactions. Furthermore, the reaction activity of different unsaturated hydrocarbons towards the polymers was investigated. This work highlights the great potential of porous organic polymers as chemical sensors in realizing environmental pollution monitoring and reducing the incidence of disease, such as chronic obstructive pulmonary disease.

pH-Responsive Polycarbonate Copolymer-based Nanoparticles for Targeted Anticancer Drug Delivery

LI Yunxia, DU Wenjuan, FU Zhiguang, WANG Huanhuan, WANG Jiexin, LE Yuan, ZHANG Jianjun, WEN Ning

2018, 34(6): 1041-1050. doi:10.1007/s40242-018-8147-5

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A smart polycarbonate(PCA) copolymer-based nanoparticle(NanoPCA) with pH-responsive, long-term stability, and tumor targeting ability was successfully developed by synthesizing and assembling a series of functional PCA-based copolymers including poly(2-amino-1,3-propanediol carbonate-co-L-lactide)[P(CA-co-LA)], poly(2-amino-1,3-propanediol carbonate-co-L-lactide)-g-methoxy-poly(ethylene glycol)[P(CA-co-LA)-g-MPEG], and poly(2-amino-1,3-propanediol carbonate-co-L-lactide)-g-poly(ethylene glycol)-cyclic(Arg-Gly-Asp-D-Phe-Lys)[P(CA-co-LA)-g-PEG-cRGD] for targeted anticancer drug delivery. pH-Responsive studies demonstrated that the loading doxorubicin(DOX) released faster from NanoPCA at acidic conditions due to protonation effects of P(CA-co-LA) copolymers. Furthermore, the in vitro and in vivo investigations demonstrate that the DOX-loaded NanoPCA exhibited significant tumor targeting ability, outstanding antitumor effect and excellent biological safety in the treatment of oral squamous cell carcinoma(OSCC). Therefore, this work provides a promising drug delivery platform for cancer therapy and other applications.

Grafting of MIPs from PVDF Membranes via Reversible Addition-fragmentation Chain Transfer Polymerization for Selective Removal of p-Hydroxybenzoic Acid

DONG Yanying, YU Ping, SUN Qilong, LU Yang, TAN Zhenjiang, YU Xiaopeng

2018, 34(6): 1051-1057. doi:10.1007/s40242-018-8146-6

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Effective molecularly imprinted membranes(MIMs) were developed as an efficient adsorbent for the selective removal of p-hydroxybenzoic acid(p-HB) from acetylsalicylic acid(ASA, aspirin). The MIMs were grafted successfully from poly(vinylidene fluoride) microfiltration membranes via reversible addition-fragmentation chain transfer(RAFT) polymerization. The graft copolymerization of acrylic acid(AA) in the presence of template p-hydroxybenzoic acid led to molecularly imprinted polymer(MIP) film coated membranes. The obtained MIMs were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectrophotometer(FTIR) and Raman spectra, and batch mode adsorption studies were carried out to investigate the specific adsorption equilibrium, kinetics and selective recognition properties of different MIMs. The kinetic properties of the MIMs could be well described by the pseudo-second-order rate equation. Selective permeation experiments were performed to evaluate the permeation selectivity of the p-HB imprinted membranes. The observed performances of the MIMs are applicable to the further purification of aspirin.

Bio-template Synthesis of Spirulina/α-Fe₂O₃ Composite with Improved Surface Wettability

MENG Qingling, XIE Chenchen, DING Ran, CAO Liang, MA Ke, LI Li, WENG Zhankun and WANG Zuobin

2018, 34(6): 1058-1062. doi:10.1007/s40242-018-8080-7

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Bio-template method has recently attracted much attention because of its prominent advantages in obtai-ning morphology controlled materials with structural specificity, complexity and their unique functions. The bio-template method combining with electrochemical deposition was employed to synthesize spirulina/hematite composite microstructures using native spirulina as template. A great amount of hematite(α-Fe₂O₃) nanoparticles can be formed and deposited onto the spirulina, resulting in a robust and pseudo-homogeneous surface. And the spirulina/α-Fe₂O₃ composite exhibits an improved surface wettability due to its helical morphology. This facile strategy may open new horizons in the field of replicating specific biological structures for functional materials in other potential applications.

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