手性膦配体的设计及不对称催化氢化反应

本文综述了手性膦配体及其碳碳双键的不对称催化氢化反应研究和最新进展,并对手性膦配体的设计做了分析和总结。     

57Fe Mössbauer spectroscopic and magnetic study of a spin-crossover polymer complex, Fe(3-chloropyridine)2Ni(CN)4

The coordination polymer Fe(3-chloropyridine)₂Ni(CN)₄ (2) has been prepared by a method similar to that for Fe(pyridine)₂Ni(CN)₄ (1). The complex (2) has been characterized by⁵⁷Fe Mössbauer spectroscopy and a SQUID technique.⁵⁷Fe Mössbauer and magnetic susceptibility data show that complex (2) exhibits spin-crossover behavior. The spin transition of (2) occurs between 120 and 80 K with very small hysteresis or without hysteresis. The temperature range of the spin transition in (2) is lower than that in (1). A residual high spin iron(II) fraction is observed at low temperatures in (2), being different from (1). SQUID data also show that samples treated differently yield different spin transition curves.     

Inhibitory effect of CXC chemokine receptor 4 antagonist AMD3100 on bleomycin induced murine pulmonary fibrosis

CXC chemokine receptor 4 (CXCR4), which binds the stromal cell-derived factor-1 (SDF-1), has been shown to play a critical role in mobilizing the bone marrow (BM)-derived stem cells and inflammatory cells. We studied the effects of AMD3100, CXCR4 antagonist, on a murine bleomycin-induced pulmonary fibrosis model. Treatment of mice with AMD3100 in bleomycin-treated mice resulted in the decrease of SDF-1 in bronchoalveolar lavage (BAL) fluids at an early stage and was followed by the decrease of fibrocytes in the lung. AMD3100 treatment decreased the SDF-1 mRNA expression, fibrocyte numbers in the lung at an early stage (day 3) and CXCR4 expression at the later stage (day 7 and 21) after bleomycin injury. The collagen content and pulmonary fibrosis were significantly attenuated by AMD3100 treatment in later stage of bleomycin injury. AMD3100 treatment also decreased the murine mesenchymal and hematopoietic stem cell chemotaxis when either in the stimulation with bleomycin treated lung lysates or SDF-1 in vitro. In BM stem cell experiments, the phosphorylation of p38 MAPK which was induced by SDF-1 was significantly blocked by addition of AMD3100. Our data suggest that AMD3100 might be effective in preventing the pulmonary fibrosis by inhibiting the fibrocyte mobilization to the injured lung via blocking the SDF-1/CXCR4 axis.     

Homocoupling of arylboronic acids catalyzed by dinuclear copper(I) complexes under mild conditions

An efficient protocol for C–C coupling has been developed using three iodo-bridged copper(I) complexes as catalysts. Complexes [CuI(bpy)]₂ (1), [CuI(phen)]₂·DMF (2), and [CuI(Mephen)]₂ (3) were successfully synthesized via solvothermal method (bpy = 2,2′-dipyridyl, phen = 1,10-phenanthroline, and Mephen = 2,9-dimethylphenanthroline). The self-coupling reaction of phenylboronic acid was selected as a model reaction to evaluate the catalytic property of the complexes. Moreover, this method tolerates various substituents on the arylboronic acids such as halogens, carbonyls, and nitro groups. It shows that the iodo-bridged Cu(I) center serves as the active site to activate molecular oxygen during the catalytic process. The result illustrates that these complexes were found to be excellent catalysts for self-coupling of arylboronic acids under mild conditions.

     

Constructing Built-in Electric Field in Heterogeneous Nanowire Arrays for Efficient Overall Water Electrolysis

Efficient bifunctional electrocatalysts for hydrogen and oxygen evolution reactions are key to water electrolysis. Herein, we report a built-in electric field (BEF) strategy to fabricate heterogeneous nickel phosphide-cobalt nanowire arrays grown on carbon fiber paper (Ni₂P-CoCH/CFP) with large work function difference (ΔΦ) as bifunctional electrocatalysts for overall water splitting. Impressively, Ni₂P-CoCH/CFP exhibits a remarkable catalytic activity for hydrogen and oxygen evolution reactions to obtain 10 mA cm⁻², respectively. Moreover, the assembled lab-scale electrolyzer driven by an AAA battery delivers excellent stability after 50 h electrocatalysis with a 100 % faradic efficiency. Computational calculations combining with experiments reveal the interface-induced electric field effect facilitates asymmetrical charge distributions, thereby regulating the adsorption/desorption of the intermediates during reactions. This work offers an avenue to rationally design high-performance heterogeneous electrocatalysts.     

马来酸酐聚合反应动力学的回归模拟

本文从函数变量相关内函规律出发，引用动力学物理概念，用数值逼近方法，对马来酸酐聚合反应的实验结果进行了模拟，得到了一符合实验规律的动力学方程。     

Highly Reactive Nonheme Iron(III) Iodosylarene Complexes in Alkane Hydroxylation and Sulfoxidation Reactions

High‐spin iron(III) iodosylarene complexes bearing an N‐methylated cyclam ligand are synthesized and characterized using various spectroscopic methods. The nonheme high‐spin iron(III) iodosylarene intermediates are highly reactive oxidants capable of activating strong C? H bonds of alkanes; the reactivity of the iron(III) iodosylarene intermediates is much greater than that of the corresponding iron(IV) oxo complex. The electrophilic character of the iron(III) iodosylarene complexes is demonstrated in sulfoxidation reactions.     

Determination of Capsaicinoids in Red Pepper Products from South Korea by High-Performance Liquid Chromatography with Fluorescence Detection

This study aimed at determining the concentrations of the major capsaicinoids, namely, capsaicin and dihydrocapsaicin, in commonly consumed red pepper products from South Korea. The capsaicinoids were extracted with 95% methanol and determined by high-performance liquid chromatography with florescence detection. The analytical method was validated by quality assurance parameters such as the linearity, limits of detection and quantification, precision, and accuracy. Satisfactory results were obtained in accordance to the specified criteria for application of analytical techniques in food. The concentration of capsaicinoids was the highest for red pepper powder (4.18–139.4?mg/100?g), followed by gochujang (0.93–23.20?mg/100?g), kimchi (0.05–1.16?mg/100?g), and sliced kimchi (0.06–0.88?mg/100?g). Comparing the capsaicinoid contents in samples from different production areas, no significant differences were found. This research concluded that the capsaicinoid content of red pepper products provided valuable information regarding the samples.     

Stereoselective Solid‐State Synthesis of Substituted Cyclobutanes Assisted by Pseudorotaxane‐like MOFs

Regioselective photodimerization of trans‐4‐styrylpyridine (4‐spy) derivatives is performed using pseudorotaxane‐like Zn‐based metal organic frameworks MOFs as templates. The formation of rctt‐HT (head‐to‐tail) dimers is achieved by confining pairs of coordinated 4‐spy derivative ligands within hexagonal windows and then irradiating them with UV light. It is also possible to achieve a photodimerization reaction where two different substituted 4‐spy ligands are included in such a MOF material. The ether bond formation is employed to protect the sensitive ‐OH group of HO‐spy and the methyl group of CH₃O‐spy is subsequently removed after the formation of cyclobutane derivative in the CH₃O‐spy‐based MOF. Introducing substituents at the 2‐ or 3‐position of the phenyl group of 4‐spy does not significantly affect the rate of the dimerization process except in the case of the strongly electron‐withdrawing nitro group where the rate is significantly decreased. These results are in striking contrast to the mixtures of photoproducts and low yields obtained by untemplated photodimerization in organic solvents.     

Synthesis,Crystal Structure and Biological Activity of Two 1,2,3-Thiadiazole Derivatives

Abstract  

The title compounds, quinolin-8-yl 4-methyl-1,2,3-thiadiazole-5-carboxylate 2a and 2-nitrophenyl 4-methyl-1,2,3-thiadiazole-5-carboxylate 2b, synthesized by the reaction of 4-methyl-1,2,3-thiadiazole-5-carbonyl chloride with 8-hydroxyquinoline and 2-nitrophenol, were confirmed by single-crystal X-ray diffraction [CCDC 783328 and 784970]. The 2a crystallizes in triclinic space group P-1 with cell parameters a = 7.957(7) ?, b = 8.378(7) ?, c = 10.097(10) ?, α = 100.63(2)°, β = 112.742(17)°, γ = 93.287(4)° and Z = 2. The 2b crystallizes in triclinic space group P-1 with cell parameters a = 7.134(4) ?, b = 8.154(4) ?, c = 10.254(5) ?, α = 99.501(9)°, β = 91.311(7)°, γ = 109.518(8)° and Z = 2. Packing in the compound 2a is dominated by weak C–H···N and C–H···O hydrogen bonds. In the compound 2b, molecules are linked through intermolecular C–H···O hydrogen bonds interactions. The preliminary bioassay showed that the title compound 2a had excellent antifungal activity with the EC₅₀ detected as from 2.99 to 28.35 μg/mL and the EC₉₀ detected as from 21.041 to 175.17 μg/mL. Both of the title compounds 2a and 2b had good inhibition activity of tobacco mosaic virus (TMV) and good induction activity of tobacco against TMV with potential systemic acquired resistance.