Synthesis of deuterium-labeled DL-threo-thiamphenicol

Journal of Radioanalytical and Nuclear Chemistry - A convenient and inexpensive approach for the synthesis of deuterium-labeled thiamphenicol was described. DL-threo-Thiamphenicol-methyl-d3 was...     

Unveiling the Layer‐Dependent Catalytic Activity of PtSe2 Atomic Crystals for the Hydrogen Evolution Reaction

Two‐dimensional (2D) PtSe₂ shows the most prominent layer‐dependent electrical properties among various 2D materials and high catalytic activity for hydrogen evolution reaction (HER), and therefore, it is an ideal material for exploring the structure–activity correlations in 2D systems. Here, starting with the synthesis of single‐crystalline 2D PtSe₂ with a controlled number of layers and probing the HER catalytic activity of individual flakes in micro electrochemical cells, we investigated the layer‐dependent HER catalytic activity of 2D PtSe₂ from both theoretical and experimental perspectives. We clearly demonstrated how the number of layers affects the number of active sites, the electronic structures, and electrical properties of 2D PtSe₂ flakes and thus alters their catalytic performance for HER. Our results also highlight the importance of efficient electron transfer in achieving optimum activity for ultrathin electrocatalysts. Our studies greatly enrich our understanding of the structure–activity correlations for 2D catalysts and provide new insight for the design and synthesis of ultrathin catalysts with high activity.     

Electrochemiluminescence Enhanced by the Synergetic Effect of Porphyrin and Multi-walled Carbon Nanotubes for Uric Acid Detection

The design and exploration of efficient, stable and environmentally compatible organic emitters for an electrochemiluminescence (ECL) sensor is a promising topic. Herein, a novel environmentally-friendly luminophore, ZnBCBTP@MWCNTs, were fabricated via self-assembly of porphyrin molecules (ZnBCBTP) onto multi-walled carbon nanotubes (MWCNTs). The resulting luminophore ZnBCBTP@MWCNTs displayed not only the highly ECL property and but also the good accelerated electron mobility. Then, a label-free ECL biosensor based ZnBCBTP@MWCNTs was constructed for the ultrasensitive detection of uric acid. Excitingly, this proposed ECL biosensor performed a good linear relationship in the range of 0–300 μM with a low detection limit of 1.4 μM, thus offering another reliable and feasible sensing platform for clinical bioanalysis with good selectivity, stability, and repeatability.     

Recent Progress in High-Performance Lithium Sulfur Batteries: The Emerging Strategies for Advanced Separators/Electrolytes Based on Nanomaterials and Corresponding Interfaces

Lithium-sulfur (Li−S) batteries, possessing excellent theoretical capacities, low cost and nontoxicity, are one of the most promising energy storage battery systems. However, poor conductivity of elemental S and the “shuttle effect” of lithium polysulfides hinder the commercialization of Li−S batteries. These problems are closely related to the interface problems between the cathodes, separators/electrolytes and anodes. The review focuses on interface issues for advanced separators/electrolytes based on nanomaterials in Li−S batteries. In the liquid electrolyte systems, electrolytes/separators and electrodes system can be decorated by nano materials coating for separators and electrospinning nanofiber separators. And, interface of anodes and electrolytes/separators can be modified by nano surface coating, nano composite metal lithium and lithium nano alloy, while the interface between cathodes and electrolytes/separators is designed by nano metal sulfide, nanocarbon-based and other nano materials. In all solid-state electrolyte systems, the focus is to increase the ionic conductivity of the solid electrolytes and reduce the resistance in the cathode/polymer electrolyte and Li/electrolyte interfaces through using nanomaterials. The basic mechanism of these interface problems and the corresponding electrochemical performance are discussed. Based on the most critical factors of the interfaces, we provide some insights on nanomaterials in high-performance liquid or state Li−S batteries in the future.     

Growth of Sb(2)E(3) (E = S, Se) polygonal tubular crystals via a novel solvent-relief-self-seeding process

A novel solvent-relief-self-seeding (SRSS) process was applied to grow bulk polygonal tubular single crystals of Sb(2)E(3) (E = S, Se), using SbCl(3) and chalcogen elements E (E = S, Se) as the raw materials at 180 degrees C for 7 days in ethanol solution. The products were characterized by various techniques, including X-ray powder diffraction (XRD), scanning electronic microscope (SEM), transmission electronic microscope (TEM), electronic diffraction (ED), and X-ray photoelectron spectra (XPS). The calculated electrical resistivities of the tubular single crystals in the range 20-320 K were of the order of 10(5)-10(6) Omega cm for Sb(2)S(3) and 10(3)-10(4) Omega cm for Sb(2)Se(3), respectively. The studies of the optical properties revealed that the materials formed had a band gap of 1.72 eV for Sb(2)S(3) and 1.82 eV for Sb(2)Se(3), respectively. The optimal reaction conditions for the growth of bulk tubular single crystals were that the temperature was not lower than 180 degrees C and the reaction time was not shorter than 7 days. The possible growth mechanism of tubular crystals was also discussed.     

Separation and simultaneous determination of seven bioactive components in Tripterygium wilfordii Hook. F. and Tripterygium preparations by micellar electrokinetic capillary chromatography

A simple, comprehensive, and highly selective MEKC method has been developed for simultaneous analysis of seven bioactive components (triptolide, wilfortrine, wilfordine, wilforgine, wilforine, triptophenolide, and triptonide) in the root extracts of Tripterygium wilfordii Hook. F. (TWHF) and Tripterygium preparations (TPs). Optimal BGE consisted of 10 mM sodium tetraborate, 30 mM SDS, and 30% v/v methanol. The separation voltage was 20 kV and the temperature was 25°C. A DAD was used and the detection wavelength was at 218 nm. Under the optimum conditions, the baseline separation of seven components was achieved in less than 26 min. Excellent precision, good stability, and accuracy were obtained. For all analytes, linear calibrations were established within 10–100 μg/mL. The LOD and LOQ were within 1.2–4.2 μg/mL and 4.0–14 μg/mL, respectively. The developed method was suitable for the determination of key components in TWHF and TPs.     

高温毛细管气相色谱柱的制备及应用

研究了臭氧交联法制备毛细管气相色谱柱的方法,即用镀铝石英毛细管,涂渍ＳＥ３１,经臭氧交联,最高使用温度可达３６０℃。测试的结果表明其柱效高,吸附性小,热稳定性好,适用于烃类、醇类、多环芳烃及二硝基甲苯和三硝基甲苯的分离。     

Rational design of core–shell molecularly imprinted polymer based on computational simulation and Doehlert experimental optimization: application to the separation of tanshinone IIA from Salvia miltiorrhiza Bunge

Computational simulation and Doehlert experimental optimization were done for the rational design of a core-shell molecularly imprinted polymer (CS-MIP) for use in the highly selective separation of Tanshinone IIA (TSIIA) from the crude extracts of Salvia miltiorrhiza Bunge (SMB). The functional monomer layer of the polymer shells directed the selective occurrence of imprinting polymerization at the surface of silica through the copolymerization of vinyl end groups with functional monomers and also drove TSIIA templates into the formed polymer shells through the charge-transfer complex interactions between TSIIA and the functional monomer layer. As a result, the maximum rebinding capacity was achieved with the use of optimal grafting ratio by the Doehlert design. The CS-MIP exhibited high recognition selectivity and binding affinity to TSIIA. When the imprinted particles were used as dispersive solid phase extraction sorbents, the recovery yield of TSIIA reached 93% by a one-step extraction from the crude extracts of SMB, and the purity of TSIIA was larger than 98% by HPLC analysis. These results show the possibility of a highly selective separation and enrichment of TSIIA from the SMB using the TSIIA-imprinted core-shell molecularly imprinted polymers.     

离子交换色谱法分离纯化鸡卵黄免疫球蛋白

建立了高效、经济、大规模获得鸡卵黄免疫球蛋白(IgY)的生产方法。在对传统的水稀释法改良的基础上,结合聚乙二醇沉淀与离子交换色谱进行IgY的分离纯化。结果显示,用8倍无菌水稀释蛋黄液,用0.1 mol/L HCl调节pH为5.2,在4 ℃下静置8 h,于5000×g力离心可得上清粗IgY液,经测定回收率可达93.47%。然后用6%聚乙二醇沉淀后经DEAE-Toyopearl 650 M离子交换纯化,最佳的纯化条件: 0.05 mol/L磷酸盐缓冲液(PBS, pH 7)平衡上样,0.075 mol/L PBS(pH 7)洗脱。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)分析结果显示所得的IgY的纯度为95.02%,活性保持率高达73.77%。本研究弥补了传统分离方法不能同时达到高纯度和高回收率的缺点,且可用于大规模生产。     

Neutral mononuclear, dinuclear, tetranuclear d7/d10 metal complexes containing bis-pyrazole/pyridine ligands supported by 2,6-bis(3-pyrazolyl)pyridine: synthesis, structure, spectra, and catalytic activity

A series of novel bis-pyrazole/pyridine complexes, [Zn(2)(HL(1))(2)(μ(2)-SO(4))](2)·EtOH·H(2)O (1), [Co(2)(HL(1))(2)(μ(2)-SO(4))](2)·2DMF·6H(2)O (2), [Zn(4)(HL(1))(4)(μ(4)-SO(4))][OH](2) (3), [Zn(2)(HL(2))(2)(μ(2)-SO(4))]·2H(2)O (4), [Zn(H(2)L(2))(H(2)O)(2)](SO(4))·0.87H(2)O (5) (H(2)L(1) = 2,6-di-(5-phenyl-1H-pyrazol-3-yl)pyridine, H(2)L(2) = 2,6-di-(5-methyl-1H-pyrazol-3-yl)pyridine), were synthesized hydrothermally from the self-assembly of Zn(II) or Co(II) with different types of bipyrazolyl/pyridine derivative ligands. All the complexes were characterized by elemental analysis, IR and UV-vis spectroscopy, powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction. Structural analyses revealed that metal atoms (Zn and Co) in complexes 1-5 are five-coordination modes, forming slightly distorted trigonal bipyramidal geometries. In complexes 1-3, H(2)L(1) ligand connected the two metal centers via the tetradentate fashion, and the same form of connection was found in complex 4 with H(2)L(2) ligand. While in complex 5, H(2)L(2) only connected with one metal center via the tridentate fashion, which was different from those in complexes 1-4. Additionally, there are abundant hydrogen bonding interactions in complexes 1-4. Interestingly, for hydrogen bonding connecting fashions being different, the molecules for the complexes 1 and 4 are held together by the hydrogen bond to form a 1D supramolecular structure, whereas complexes 2 and 3 are a hydrogen bonded dimer. In addition, quantum chemical calculations for 1, 3, and 4, thermal behaviors and photoluminescent properties for 1 and 3-5 were performed and discussed in detail. In the mean time, we found that these complexes had potential catalytic activity for the oxidation reaction of cyclohexane.