查找使用阿拉丁产品的科研文献

Excellent humidity sensor based on ultrathin HKUST-1 nanosheets

Qiaoe Wang,Meiling Lian,Xiaowen Zhu,Xu Chen

The copper-based MOF, HKUST-1 has been applied for humidity sensing owing to hydrophilic ligands and open metal sites which are suitable for sensitively detecting moisture. However, most of the research on the sensor HKUST-1 focuses on the role of the central metal. There are few reports on the morphology–activity relationship of HKUST-1. In this work, we synthesized two kinds of HKUST-1 including octahedral structures and ultrathin nanosheets, and systematically studied the performance of moisture sensing. Compared to HKUST-1 octahedra, HKUST-1 nanosheets showed lower and wider detectable humidity range, achieving a fast response. Starting from the exposed hydrophilic functional groups of HKUST-1 nanosheets, we have revealed that hydrophilic ligands play an important role in improving the adsorption capacity during the adsorption process. In addition, ultra-thin HKUST-1 nanosheets act as an excellent mass transfer medium, accelerating proton transfer and water molecule movement. To further improve the performance of the HKUST-1 humidity sensor, black phosphorus quantum dots (BPQDs) with a high surface reactivity were used to build a composite sensing platform. The excellent proton transfer capability of BPQDs leads to one order of magnitude improvement in the sensitivity of the BPQDs/HKUST-1 systems compared to HKUST-1 only.

Dimer conformation of soluble PECAM-1, an endothelial marker

Longguang Jiang,Lin Lin,Rui Li,Cai Yuan,Mingming Xu,Joy H. Huang,Mingdong Huang

Platelet endothelial cell adhesion molecule 1 (PECAM-1) is a cell surface receptor widely distributed on endothelium and hematopoietic-derived cells, and maintain the integrity of the blood vessels. PECAM-1 is widely recognized as an endothelial cell marker. The homophilic interaction through its extracellular domain of PECAM-1 (soluble PECAM-1, or sPECAM-1) is important to its functions. However, structural details for such dimerization are not fully understood. Here we report the production of recombinant sPECAM-1 in large quantity by Drosophila expression system and the small-angle X-ray diffraction (SAXS) study. The recombinant sPECAM-1 was found to form one population of dimer, but not oligomer, and was able to bind to heparin immobilized on a chip in surface plasmon resonance imaging (SPRi) binding experiments. The results of SAXS demonstrated that sPECAM-1 formed a symmetric homodimer of Ω-shape in solution, and each protomer adopted an extended conformation. The dimer is mediated through the intermolecular interactions through the first N-terminal domain (D1) of sPECAM-1. This model provides new structural information for its homophilic interaction mechanism.

1-Naphthylamine thioxanthone-based one-component visible-light photoinitiators

Le Ma,Yang Hou,Jun Nie,Xiaoqun Zhu

The introduction of substituents affects the planarity of the molecule, resulting in different physical and chemical properties. This study synthesized four one-component visible light photoinitiators with different substituents derived from 1-naphthylamine. They were amine-free (BTX), primary amine (BTX-A), secondary amine (BTX-MA), and tertiary amine (BTX-DMA). The photophysical and photochemical properties were explored using UV–visible absorption spectroscopy combined with DFT theory computational simulations. They had excellent absorption properties in the visible light range ( ε : 3200–6300 L mol −1  cm −1 ). The structure of amine substitutions in the initiators showed different redshift phenomena. The maximum absorption wavelength of BTX in the visible region is 388 nm; only a 7 nm red shift occurred for the maximum absorption wavelength of BTX-DMA. While BTX-A had a maximum absorption wavelength of red shifting by 41 nm， the red shift for BTX-MA was about 53 nm, and its UV absorption tail extended to 520 nm. This phenomenon was known to be the result of the combined effect of electronic donor and molecular planarity according to the DFT theoretical calculations. The photopolymerization kinetics of four initiators used for double bond monomers was investigated by real-time FT-IR. The results indicated that polymerization could occur for all the designed systems; the highest double bond conversion could reach 92 % when BTX-DMA was used as a visible-light photoinitiator for the monomer of 2-hydroxyethyl acrylate (HEA).

Chemistry of catalytic cracking of cyclohexene and 1-methylcyclopentene

Xueqian Zhang,Jiasong Yan,Shuai Yuan,Shanqing Yu,Qingyu Liu,Xikai Wang,Rui Li

Whether cycloalkanes undergo six- or five-membered ring-opening reaction pathways remains controversial. In this work, the catalytic cracking reactions of cyclohexene and 1-methylcyclopentene, as model compounds, were investigated in a pulse microreactor. The characteristics of the reactions of the two model compounds were compared in terms of isomerization, cracking, and hydrogen transfer reaction, and the reasons for the differences in their catalytic reactions were analyzed in combination with thermodynamic and molecular simulation calculations. The results have shown that the catalytic cracking product distributions of cyclohexene and 1-methylcyclopentene were similar owing to their easy mutual isomerization; the five-membered ring-opening cracking pathway was more thermodynamically advantageous than that of six-membered ring-opening cracking, and therefore, the yield of the ring-opening cracking product of 1-methylcyclopentene was comparatively higher; the main products of the hydrogen transfer reaction of the two compounds were alkanes and aromatic hydrocarbons. By comparing the product distributions and reaction activation energies, the ring-opening reaction pathways were clarified, and the catalytic cracking reaction networks of cyclohexene and 1-methylcyclopentene were established.

Synthesis of 2-Amino-1-indanone from DL-Phenylalanine

Rong Zhao,Peijiang Guo,Junyu Dong,Xiaoping Zhang,Xiaofei Sun,Yun Tian,Qingle Zeng

Kinetics of atmospheric reactions of 4-chloro-1-butene

Zhu Jianqiang,Tsona Narcisse T.,Du Lin

Chloroalkenes are among the important anthropogenic organic compounds emitted in the atmosphere as a result of their wide use in synthetic processes in industry. Despite their well-known adverse effects on human health and air quality, the chemistry of these chloroalkenes remains poorly explored. In this work, reactions of 4-chloro-1-butene (CBE), a representative example of chloroalkenes, with O 3 , OH, NO 3 , and Cl are investigated in a 100-L Teflon reaction chamber equipped with gas chromatography-flame ionization detector (GC-FID). The absolute rate method was used for the reaction with O 3 while the relative rate method was used for reactions with OH, NO 3 , and Cl. The following rate constants were obtained at room temperature (298 ± 2) K and atmospheric pressure: (3.96 ± 0.43) × 10 −18 , (2.63 ± 0.96) × 10 −11 , (4.48 ± 1.23) × 10 −15 , and (2.35 ± 0.90) × 10 −10  cm 3 molecule −1  s −1 , for reactions with O 3 , OH, NO 3 , and Cl, respectively. Atmospheric lifetimes of CBE calculated from rate constants of the different reactions obtained in this work showed that reaction with OH is the main loss process for CBE, while in coastal areas and in the marine boundary layer, the CBE loss by Cl reaction becomes important. Estimation of the value of the photochemical ozone creation potential (POCP) indicated that CBE has a large ozone formation potential. The present work underlines the need for further studies on the atmospheric chemistry of chlorinated VOCs.

Phenolic compound SG-1 from Balanophora harlandii and its derivatives exert anti-influenza A virus activity via activation of the Nrf2/HO-1 pathway

Runhong Zhou,Jianan Hu,Jingnan Qiu,Shengsheng Lu,Haixing Lin,Ruifeng Huang,Shaofen Zhou,Guoqing Huang,Jian He

Influenza A virus (IAV) is one of the leading causes of respiratory illness and continues to cause pandemics around the world. Against this backdrop, drug resistance poses a challenge to existing antiviral drugs, and hence, there is an urgent need for developing new antiviral drugs. In this study, we obtained a phenolic compound SG -7, a derivative of natural compound 2-hydroxymethyl-1,4-hydroquinone, which exhibits inhibitory activity toward a panel of influenza viruses and has low cellular toxicity. Mechanistic studies have shown that SG -7 exerts its anti-IAV properties by acting on the virus itself and modulating host signaling pathways. Namely, SG -7 targets the HA2 subunit of hemagglutinin (HA) to block the fusion of viral-cellular membranes and inhibits IAV-induced oxidative stress and overexpression of pro-inflammatory factors by activating the Nrf2/HO-1 pathway and reducing NF-κB activation. In addition, SG -7 can enhance type I IFN antiviral response by inducing Nrf2 expression. Importantly, SG-7 showed the ability to inhibit viral replication in the lungs of IAV-infected mice and reduce their mortality. Therefore, SG-7 may be a promising lead compound for anti-influenza drug development .

Solid-liquid equilibrium of 1-[4-(4-hydroxyphenyl)piperazin-1-yl]ethenone in twelve mono-solvents: Solubility determination, Hansen solubility parameter and thermodynamic analysis

Pengshuai Zhang,Ruping Ge,Chunxia Jin,Jixiu Deng,Feiyang Dai,Yameng Wan,Beibei Zhang,Shuwei Yu,Xing Li,En Zhang,Lan Zhang,Lu Zhang

The mole fraction solubility of 1-[4-(4-hydroxyphenyl)piperazin-1-yl]ethenone (1-HPE) in twelve mono-solvent systems namely “2-methoxyethanol (2-ME), methanol (MeOH), ethanol (EtOH), butan-1-ol ( n -BuOH), 2-propoxyethanol (2-PE), propan-2-ol ( i -PrOH), 2-methylpropan-1-ol ( i -BuOH), Acetonitrile (MeCN), ethane-1,2-diol (EG), 2-ethoxyethanol (2-EE), propan-1-ol ( n -PrOH), 2-butoxyethanol (2-BE)” were determined from 283.15 K to 323.15 K under 0.1 MPa. The experimental solubility order follows: 2-ME > 2-EE > 2-PE > 2-BE > MeOH > EtOH >  n -PrOH >  i -PrOH ≈  n -BuOH >  i -BuOH ≈ MeCN > EG. The UNIQUAC model, modified Apelblat model, NRTL model, Wilson model, Jouyban model and NRTL-SAC model equation were used to correlate of 1-HPE solubility, and the average 10 4 RMSD of them was 0.89, 1.21, 0.94, 4.72, 0.60 and 1.25, respectively. Furthermore, Hansen solubility parameters analysis (HSP) was used to evaluate the miscibility of 1-HPE in the selected solvents. Hirshfeld surface (HS) analysis was performed to discuss the electrostatic features and the patterns of intermolecular interactions of 1-HPE. Thermodynamic properties (Δ mix G , Δ mix S , Δ mix H , Δ dis G , Δ dis S , Δ dis H ) were calculated by the UNIQUAC model. The calculated results indicated that the dissolution and mixing process of 1-HPE in the mono-solvents selected in this work was spontaneous and entropy increment.

Controlled Formation of Pyrazines: Inhibition by Ellagic Acid Interaction with N-(1-Deoxy-d-xylulos-1-yl)-glycine and Promotion through Ellagic Acid Oxidation

Ziyan Wang,Heping Cui,Mengyu Ma,Khizar Hayat,Xiaoming Zhang,Chi-Tang Ho

The effect of ellagic acid on the formation of pyrazine, methylpyrazine, 2,3-methylpyrazine, 2,6-methylpyrazine, 2,5-methylpyrazine, and trimethylpyrazine in the xylose–glycine Maillard reaction model was researched. Ellagic acid could either inhibit or promote pyrazine formation, depending on its addition time point and the pH of the system. The addition of ellagic acid during the accumulation period of an Amadori compound inhibited pyrazine formation by capturing the Amadori compound in the xylose–glycine Maillard system and decreasing the pyrazine precursors. The inhibitory effect of ellagic acid on pyrazine formation got more obvious with an increase in the pH of the system. However, when ellagic acid was added at the beginning of the xylose and glycine Maillard system and when the oxidizing substances such as glyoxal and methylglyoxal were significantly formed in the Maillard system, its oxidation could promote the formation of pyrazines.

Efficient whole-cell biosynthesis of (S)-2-chloro-1-(3,4-difluorophenyl)-ethanol from 2-chloro-1-(3,4-difluorophenyl) ethanone in a sustainable reaction system

Linghui Kong,Bo Fan,Yu-Cai He

( S )-2-Chloro-1-(3,4-difluorophenyl)-ethanol [( S )-CFPL] is a key chiral intermediate in the manufacture of Ticagrelor. In this study, deep eutectic solvent (DES) was used as the co-solvent, and several reaction parameters were investigated and characterized. It was observed that supplementary of DES could promote the asymmetric reduction of 2‑chloro-1-(3,4-difluorophenyl) ethanone (CFPO) to ( S )-CFPL through the biological reduction by recombinant E. coli containing a NADH-dependent reductase CmCR. The high pKa value of carboxylic acid in DES and low viscosity of DES were beneficial to increase cell membrane permeability and enhancement of biocatalytic efficiency. By supplementary of DES ChCl:LA (7.5 vol%) into the bioreaction system, the efficient bioreduction reaction of 100 mM CFPO was achieved via the biocatalysis with whole-cell at 30 °C and pH 7.0, affording ( S )-CFPL in 95.9 % yield and optical purity > 99 %. The process was environmentally friendly with high biocatalytic productivity and had potential practicability in the mass production of ( S )-CFPL.

Isobaric Vapor–Liquid Equilibrium of Binary Systems of 1-Pentanol + Butyl Butyrate, 1-Pentanol + N-Formylmorpholine, and p-Xylene + Butyl Butyrate at 101.3 kPa

Xiaomin Qiu,Bingjie Huo,Qi Wang,Jingwei Yang,Zhaoyou Zhu,Yinglong Wang,Jun Gao

In this work, the effects of N-methyl pyrrolidone, N,N-dimethylformamide, cyclohexanol, butyl butyrate, and N-formylmorpholine on the separation efficiency of a p-xylene and 1-pentanol azeotropic system are investigated, and the best solvent is selected from these solvents. The vapor–liquid equilibrium data of binary systems of 1-pentanol + butyl butyrate, 1-pentanol + N-formylmorpholine, and p-xylene + butyl butyrate are measured using a modified Rose-type circulating still under 101.3 kPa. In order to check the thermodynamic consistency of the experimental vapor–liquid equilibrium data, the Herington and Van Ness methods are used. In addition, the nonrandom two-liquid, universal quasichemical, and Wilson models are used to correlate the experimental data of binary systems, and the interaction parameters of binary systems are obtained.

Engineering three-layer core–shell S-1/TS-1@dendritic-SiO2 supported Au catalysts towards improved performance for propene epoxidation with H2 and O2

Zhaoning Song,Juncong Yuan,Zhenping Cai,Dong Lin,Xiang Feng,Nan Sheng,Yibin Liu,Xiaobo Chen,Xin Jin,De Chen,Chaohe Yang

The advocacy of green chemical industry has led to the development of highly efficient catalysts for direct gas-phase propene epoxidation with green, sustainable and simple essence. The S-1/TS-1@dendritic-SiO 2 material with three-layer core–shell structure was developed and used as the support for Au catalysts, which showed simultaneously fantastic PO formation rate, PO selectivity and stability (over 100 h) for propene epoxidation with H 2 and O 2 . It is found that silicalite-1 (S-1) core and the middle thin layer of TS-1 offer great mass transfer ability, which could be responsible for the excellent stability. The designed dendritic SiO 2 shell covers part of the acid sites on the external surface of TS-1, inhibiting the side reactions and improving the PO selectivity. Furthermore, three kinds of SiO 2 shell morphologies (i.e., dendritic, net, mesoporous shell) were designed, and relationship between shell morphology and catalytic performance was elucidated. The results in this paper harbour tremendous guiding significance for the design of highly efficient epoxidation catalysts.