TETRAHEDRON
·
2017
·
IF 2.651
Bing Lin,Wen-Hui Zhang,Dan-Dan Wang,Yi Gong,Qi-Di Wei,Xiong-Li Liu,Ting-Ting Feng,Ying Zhou,Wei-Cheng Yuan
Developed herein is a diversity-oriented one-pot multicomponent synthesis of polycyclic 3,3′- pyrrolidinyl-dispirooxindoles 3 via a multicomponent 1,3-dipolar cycloaddition event of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles 2 with azomethine ylides (thermally generated in situ from isatins and proline or thioproline). Products bearing four consecutive stereocenters consist of two oxindole moieties and a polycyclic pyrrolidinyl core, including vicinal spiroquaternary stereocenters fused in one ring structure were smoothly obtained in high yields (up to 85% yield) with good diastereoselectivity (up to >20:1). Valuable features of this method were application of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles as 1,3-dipolarophiles and the design of new hybrid architectures for biological screenings through the adequate fusion of these sub-units of isoxazole and 3,3′-pyrrolidinyl-dispirooxindole, generating drug-like molecules.
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高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2017
·
IF 3.615
Bo Xu,Xuejiao Li,Zhiming Chen,Tao Zhang,Cuncheng Li
Pd@MIL-100(Fe) composite nanoparticles were synthesized and characterized by high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction analysis, nitrogen adsorption-desorption analysis, X-ray photoelectron spectroscopic (XPS) analysis, energy-dispersive X-ray spectroscopy (EDS) and element mapping. Due to the local restriction or confinement effect of the unique pore/surface structure within the MIL-100(Fe) nanospheres , small Pd nanoparticle (4–6 nm) were obtained with high stability without using any surfactant as stabilizer . The as-synthesized Pd@MIL-100(Fe) composite nanoparticles were then employed for the catalytic reduction of 2/3/4-nitrophenol, which exhibiting high catalytic activity and recyclability attributed to the synergistic effect between Pd nanoparticles and MIL-100(Fe) nanospheres.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 18
·10245-10250
·
IF 3.269
X. X. Wu,H. Zhou
Recently, porous carbon materials have attracted attention due to their versatile properties. In this study, a hierarchical porous N-doped carbon (NHPC) was successfully synthesized as a catalyst support using a facile method. A large amount of Pd nanoparticles were uniformly loaded on the NHPC with an average diameter of about 4.45 nm. The synthesized Pd/NHPC nanocatalyst exhibited excellent stability and reusability toward the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) at room temperature. The uniformity and high reusability of Pd/NHPC was mainly attributed to the abundant doped nitrogen as a coordinated site to largely stable Pd nanoparticles. Herein, the excellent properties of NHPC provided ideas for the fabrication of other NHPC supported noble nanoparticles, which can be applied in various catalytic reductive reactions.
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高影响因子
Energy & Environmental Science
·
2017
·Vol. 10
·期 11
·2401-2410
·
IF 29.518
Ya-Fang Qi,Dong-Xing Kou,Wen-Hui Zhou,Zheng-Ji Zhou,Qing-Wen Tian,Yue-Na Meng,Xin-Sheng Liu,Zu-Liang Du,Si-Xin Wu
Although the substitution of Cu by Ag to suppress CuZn defects offers several advantages in overcoming the large open-circuit voltage (Voc) deficit for Cu2ZnSn(S,Se)4 (CZTSSe) solar cells, an excellent performance has not been achieved to date primarily due to the Fermi level pinning at the CdS/absorber interface and large recombination at the absorber/Mo interface. Herein, we developed a composition grading strategy to achieve a V-shaped Ag-graded structure with a higher Ag content on both the back and front surfaces of the (Cu,Ag)2ZnSn(S,Se)4 (CAZTSSe) layer. The key advantages of this Ag-graded structure are as follows: the higher content towards the CdS/absorber interface can create weak n-type donor defects and retard Fermi level pinning, whereas the lower content at the interlayer maintains the conductivity and light absorption; moreover, the other higher content towards Mo back contact can effectively suppress the recombination and improve the utilization of long-wave incident light. By appropriately adjusting the Ag gradient, we demonstrated a significant increase in Voc, and an unexpected conversion efficiency of 11.2% was achieved. This is the highest efficiency achieved to date for Ag-substituted CZTSSe solar cells, and the result supports a new aspect that synthesis of a composition-graded CAZTSSe absorber has great potential for future research.
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高影响因子
Arabian Journal of Chemistry
·
2017
·
IF 4.553
Waqar Uddin,Gang Hu,Xuanxuan Sun,Hui Zhang,Yegui Wang,Lin Hu
A novel method for identification of two aromatic isomers of mono hydroxy benzoic acid (HBA) was reported by using their different perturbation effects on the potential oscillations of a Belousov-Zhabotinsky (BZ) system. In such a system, a macrocyclic complex of Cu [CuL](ClO 4 ) 2 was used as catalyst in which ligand L is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. To the BZ system, 3-hydroxy benzoic acid (3-HBA) could temporarily quench and regenerate potential oscillations with damping characters after inhibition time (t in ) while 4-hydroxy benzoic acid (4-HBA) could only change the oscillation amplitude (ΔA) to give damping oscillations with no inhibition time. Thus, these two isomers of HBA were identified. Reaction mechanisms of BZ have been proposed by FKN model. An explanation of perturbation mechanism is that, although 3-HBA reacted with BrO 2 while 4-HBA reacted with BrO 3 − , they all produced 1,4-quinone.
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Environmental Science-Nano
·
2016
·Vol. 4
·期 2
·493-502
·
IF 5.896
Jialuo Yu,Xiaoyan Wang,Qi Kang,Jinhua Li,Dazhong Shen,Lingxin Chen
A novel molecular imprinting fluorescence nanosensor was constructed via a facile surface imprinting polymerization one-pot synthesis strategy for highly selective and sensitive recognition and detection of 4-nitrophenol (4-NP) based on an electron-transfer induced fluorescence quenching mechanism. 2-Aminoethyl methacrylate hydrochloride (AMA) was first used as a surfactant to interact with aqueous carboxyl-CdTe quantum dots (QDs) and the resultant AMA-modified QDs were used as a core support and a fluorescent signal source. Then, an ultrathin 4-NP imprinted shell (ca. 4 nm) was formed on the QD surface (i.e., QD@MIPs) by a simple facile free radical polymerization step. The one-pot synthesis simplified the imprinting process and shortened the experimental period. The imprinted sites bound the template of 4-NP efficiently through the hydrogen bonding interactions and showed excellent recognition selectivity for 4-NP over its analogues with a high imprinting factor of 9.1. The electron transfer process between QDs and 4-NP led to significant fluorescence quenching of the QD@MIPs nanosensor, by which 4-NP could be sensed, and high detection sensitivity up to 0.051 μM was attained. Furthermore, the sensor was successfully applied to determine 4-NP in seawater and lake water samples, presenting high recoveries in the range of 92.7–109.2% at three spiking levels with the relative standard deviation within 3.1–4.8%. The simple, rapid, reliable QD@MIPs-based method proved to be potentially applicable for the highly selective and sensitive fluorescence determination of trace 4-NP in complicated environmental water samples.
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Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 38
·19525-19538
·
IF 7.443
Shaojun Chen,Funian Mo,Shiguo Chen,Zaochuan Ge,Haipeng Yang,Jiandong Zuo,Xinke Liu,Haitao Zhuo
Both liquid crystalline polymers and shape memory polymers are attractive to researchers. This paper describes the development of a supramolecular liquid crystalline complex exhibiting a multi-shape memory effect and liquid crystalline properties. 4-n-Octyldecyloxybenzoic acid (OOBA) is connected to a pyridine-containing polyurethane (PySMPU), forming a new PySMPU/OOBA complex. The results of this study demonstrate that the complex maintains the intrinsic crystallization and liquid-crystalline properties of OOBA and combines the shape memory effects of PySMPUs. Shape memory investigations demonstrate that the PySMPU/OOBA complexes have a good multi-shape memory effect, exhibiting triple- and quadruple-shape memory behaviours. For the triple-shape memory behaviours, the strain fixity at the first stage is lower than that at the second stage, while the strain recovery at the first stage is higher than that at the second stage. Overall, increasing the OOBA content improves the strain fixity but reduces the strain recovery due to the lubrication of the OOBA long chains. The successful combination of the liquid crystalline properties and multi-shape memory effect makes the PySMPU/OOBA complexes potentially applicable in smart optical devices, smart electronic devices and smart sensors.
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高影响因子
Materials Science & Engineering C-Materials for Biological Applications
·
2014
·
IF 2.736
Wencai Zhu,Hui Huang,Xiaochun Gao,Houyi Ma
Poly(4-aminobenzoic acid)/electrochemically reduced graphene oxide composite film modified glassy carbon electrodes (4-ABA/ERGO/GCEs) were fabricated by a two-step electrochemical method. The electrochemical behavior of acetaminophen at the modified electrode was investigated by means of cyclic voltammetry. The results indicated that 4-ABA/ERGO composite films possessed excellent electrocatalytic activity towards the oxidation of acetaminophen. The electrochemical reaction of acetaminophen at 4-ABA/ERGO/GCE is proved to be a surface-controlled process involving the same number of protons and electrons. The voltammetric determination of acetaminophen performed with the 4-ABA/ERGO modified electrode presents a good linearity in the range of 0.1–65 μM with a low detection limit of 0.01 μM (S/N = 3). In the case of using the 4-ABA/ERGO/GCE, acetaminophen and dopamine can be simultaneously determined without mutual interference. Furthermore, the 4-ABA/ERGO/GCE has good reproducibility and stability, and can be used to determine acetaminophen in tablets.
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PubMed
高影响因子
CRYSTENGCOMM
·
2014
·Vol. 16
·期 28
·6450-6458
·
IF 3.858
Song Li,Jia-Mei Chen,Tong-Bu Lu
Although polymorphism is a common phenomenon, the polymorphism of co-crystals is not studied extensively as compared to single-component molecules. Herein we report polymorphism in a co-crystal system comprising 5-fluorouracil, and 4-hydroxybenzoic acid with a 1 : 1 stoichiometry. The polymorphs were characterized by single-crystal and powder X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis. Crystal structure analysis revealed different synthons of 5-fluorouracil and 4-hydroxybenzoic acid in two forms. The solvent-drop grinding experiments show a high degree of solvent polarity specificity. The theoretical and experimental methods suggest an enantiotropic relationship between the polymorphs.
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高影响因子
BIORESOURCE TECHNOLOGY
·
2014
·
IF 5.039
Yu-Cai He,Zhi-Cheng Tao,Xian Zhang,Zhen-Xing Yang,Jian-He Xu
An NADH-dependent reductase (CmCR) from Candida magnoliae was discovered by genome mining for carbonyl reductases. After CmCR was overexpressed in Escherichia coli BL21, a robust reductase-producing strain, recombinant E. coli CCZU-K14, was employed for the efficient synthesis of ethyl ( S )-4-chloro-3-hydroxybutanoate (( S )-CHBE) from the reduction of ethyl 4-chloro-3-oxobutanoate (COBE). After the optimization, the optimum reaction conditions were obtained. Notably, E. coli CCZU-K14 had broad substrate specificity in reducing both aliphatic and aromatic substrates, and excellent enantioselectivity of CCZU-K14 was observed for most of the tested substrates, resulting in chiral alcohols of over 99.9% ee . Moreover, COBE at a high concentration of (3000 mM) could be asymmetrically reduced to ( S )-CHBE in the high yield (>99.0%) and high enantiometric excess value (>99.9% ee ) after 14 h. Significantly, E. coli CCZU-K14 shows high potential in the industrial production of ( S )-CHBE and its derivatives (>99.9% ee ).
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PubMed
高影响因子
Nanoscale
·
2013
·Vol. 5
·期 13
·5905-5911
·
IF 6.233
Lingxin Chen,Xiuli Fu,Jinhua Li
In this work, a simple and sensitive surface-enhanced Raman scattering (SERS) strategy was developed for recognition and detection of trypsin, by using anti-aggregation of 4-mercaptopyridine (4-MPY)-functionalized silver nanoparticles (AgNPs) based on the interaction between protamine and trypsin. The polycationic protamine not only served as a substrate for enzyme hydrolysis but also worked as a medium for SERS enhancement, which could bind negatively charged 4-MPY-functionalized AgNPs and induce their aggregation. The hydrolysis catalyzed with trypsin in sample solution decreased the concentration of free protamine, resulting in the dispersion of AgNPs and thus decreasing the Raman intensity of 4-MPY, by which the trypsin could be sensed optically. A detection level down to 0.1 ng mL−1 for trypsin was obtained. The induced accumulation of AgNPs modified with Raman reporter 4-MPY largely enhanced the SERS responses. A good linearity was found within the wide range over five orders of magnitude and reasonable relative standard deviations (between 2.4 and 11.6%) were attained. By using trypsin as a model, the new concept can provide an excellent platform for ultrasensitive SERS measurements of various proteases/enzymes which can lead to nanoparticles stability change through catalyzed hydrolysis toward substrate.
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PubMed
高影响因子
APPLIED GEOCHEMISTRY
·
2017
·
IF 2.581
Wei Zhang,Li Zhou,Hongfeng Tang,Heping Li,Wenlei Song,Gang Xie
The solubility of fluorite in hydrothermal conditions is important in ore forming and geothermal processes and groundwater utilization. However, a quantitative description of the geochemical behavior of fluorite under hydrothermal conditions has not been previously reported. In this work, the solubility of fluorite in Na-K-Cl solutions at temperatures up to 260 °C and ionic strengths up to 4 M was determined by experiments and modeling. The solubility products obtained in this work at 30 and 50 °C under ambient pressure and those from literature were used to regress the density model parameters for fluorite solubility product calculation at high temperature. The Pitzer interaction model was adopted to calculate the activity coefficient . The fluorite solubility determined in KCl solution at 250 °C under vapor saturated pressure and that from the literature were combined with the low-temperature thermodynamic properties of heat capacity and osmotic coefficient to obtain the binary parameters of NaF and KF at temperatures up to 260 °C. A thermodynamic model was then developed for calculating the fluorite solubility in Na-K-Cl solution at temperatures up to 260 °C, under vapor saturated pressure and ionic strengths up to 4 M. As calculated from this model, fluorite solubility measured at 200 °C and 0.1 M NaCl was well predicted. Both temperature and ionic strength had significant effects on fluorite solubility, and fluorite exhibited a similar dissolution pattern in both NaCl and KCl solution. When the concentration was lower than 2 M, the solubility of fluorite first increased with temperature, reached a maximum at approximately 100 °C, and then decreased. When the concentration was higher than 2 M, the solubility of fluorite increased monotonically with temperature.
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