Pyridinium tribromide catalyzed condensation of indoles and aldehydes to form bisindolylalkanes

An efficient synthetic method for bis(indol-3-yl)alkane derivatives has been developed.In the presence of 5 mol%of pyridinium tribromide(PTB),the condensation of indoles and aldehydes proceeded smoothly under mild conditions,giving rise to the corresponding bis(indol-3-yl)alkanes in good to excellent yields.     

A New Pyridoxal Derivative for Transamination of N‐Terminus of Proteins

A new pyridoxal‐5‐phosphate (PLP) derivative FHMDP was developed for the transamination of different peptides with three most hindered amino acid residues (Leu, Ile, Val) as their N‐terminus. Compared to the previously reported reactions of PLP derivatives, the N‐terminus transamination could be accomplished efficiently with the new compound.     

Synthesis, Crystal Structure, and Herbicidal Activities of 2-Cyanoacrylates Containing 1,3,4-Thiadiazole Moieties

Three series of novel 2‐cyanoacrylates 7a – 7f , 9a – 9f , 10a – 10f containing 1,3,4‐thiadiazole ring moieties were synthesized as herbicidal inhibitors of photosystem II (PS II) electron transportation. Their structures were clearly verified by ¹H NMR, ¹³C NMR, elemental analysis (or HRMS analysis) and single‐crystal X‐ray diffraction analysis. Bioassay showed that a suitable group at the 3‐position of acrylates was essential for high herbicidal activity. In particular, compound 7e showed the best herbicidal activities and gave 100% inhibitory activity against rape and amaranth pigweed at a dose of 1.5 kg/ha. Introduction of substituent with higher polarity such as sulfinyl or sulfonyl to the 5‐position of 1,3,4‐thiadiazole decreased herbicidal activities.     

高效液相色谱-电感耦合等离子体质谱联用技术用于环境中元素形态分析的最新进展

综述了高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)联用技术在环境科学中的应用情况.参考过去十年内的国内外文献,从方法学的角度论述了HPLC联用ICP-MS技术的发展,重点探讨了该技术在环境领域,尤其是在元素形态分析(包括生物学,生物无机化学和生物医学)中的应用.     

High-light induced superoxide radical formation in cytochrome b₆f complex from Bryopsis corticulans as detected by EPR spectroscopy

The generation of superoxide radical (O?·?) in Cyt b?f of Bryopsis corticulans under high light illumination was studied using electron paramagnetic resonance (EPR) spectroscopy. This could be evidenced by the addition of SOD which specifically reacted with O?·?. The generation of O?·? was lost in the absence of oxygen and was found to be suppressed in the presence of NaN? and be scavenged by extraneous antioxidants such as ascorbate, β-carotene and glutathione which could also scavenged 1O?*. These results indicated that O?·? which produced under high light illumination in Cyt b?f of B. corticulans might rise from a reaction which 1O?* could participated in. Also the photo-protection mechanism to Cyt b?f complex by antioxidants which might contain in thylakoid was speculated.     

A Third‐Generation Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase Immobilized in Carbon Nanotubes/ SBA‐15 Film

A new third‐generation biosensor for H₂O₂ assay was developed on the basis of the immobilization of horseradish peroxidase (HRP) in a nanocomposite film of carbon nanotubes (CNTs)‐SBA‐15 modified gold electrode. The biological activity of HRP immobilizing in the composite film was characterized by UV‐vis spectra. The HRP immobilized in the nanocomposite matrix displayed excellent electrocatalytic activity to the reduction of H₂O₂. The effects of the experimental variables such as solution pH and working potential were investigated using steady‐state amperometry. Under the optimal conditions, the resulting biosensor showed a linear range from 1 µM to 7 mM and a detection limit of 0.5 µM (S/N=3). Moreover, the stability and reproducibility of this biosensor were evaluated with satisfactory results.     

Chiral salen-metal derivatives of polyoxometalates with asymmetric catalytic and photocatalytic activities

Immobilization of the chiral salen-metal complex [Mn(III)(salen)(H(2)O)(2)ClO(4)] on the Keggin-type polyoxometalate (POM) skeletons leads to the isolation of POM derivatives functionalized with chiral salen-metal complexes, which represent the first examples of introducing chiral salen-metal complexes into the POM systems.     

Metal-carboxylate coordination polymers with redox-active moiety of tetrathiafulvalene (TTF)

Though numerous metal-organic frameworks or polymers have been reported, the organic building blocks are usually not redox-active. On the other hand, some mono-, di- or tri-nuclear compounds with tetrathiafulvalene (TTF) have been prepared, although little is known about the coordination polymers combined with paramagnetic metals and organic TTF ligands. We report herein a series of coordination polymers of copper(II) and manganese(II) with TTF dicarboxylate ligand (L). Compound 1, [CuL(2,2-bpy)](n), is a one-dimensional (1-D) coordination polymer with five-coordinated square-pyramidal Cu(II) centers. Mn(II) complex 2, [MnL(2,2-bpy)](n), also takes a 1-D structure, showing a double-bridged mode by carboxylate groups. The 4,4-bipyridine compound 3, [MnL(4,4-bpy)(H(2)O)](n)·CH(3)CN, takes a 2-D grid network. A zinc(II) compound 4, [ZnL(4,4-bpy)(H(2)O)](n)·CH(3)CN, isomorphous structure with 3, is also presented. The electrochemical properties of the solid-state compounds were investigated by cyclic voltammetry using surface-modified electrodes. As usually observed in TTF derivatives, two sets of redox-waves were observed. The values of E(1/2)(1) of compounds 1-4 are in the order of 2(Mn) ≈ 3(Mn) < 1(Cu) < 4(Zn), indicating that the metal coordination can affect the potential shift of the TTF ligand. Weak antiferromagnetic exchanges are observed for compounds 1, 2, and 3.     

An effective Cu(II) quenching fluorescence sensor in aqueous solution and 1D chain coordination polymer framework

In the article, a novel fluorescent probe for the copper cation based on fluorescence quenching mechanism was designed. It exhibited high selectivity for Cu(II) over other common metal ions in aqueous media. Furthermore the coordination between Cu(II) and the organic molecule sensor fabricated an interesting 1D chain coordination polymer framework.     

The synthesis of the near-spherical AgCl crystal for visible light photocatalytic applications

The near-spherical AgCl micro-crystals were prepared by an ionic liquids-assisted hydrothermal method. The influence of ionic liquids (C(x)MimCl x = 4, 8, 12, 16) on (001) facet growth of AgCl was studied systemically. The composition of the as-prepared samples was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and FTIR spectra. The morphological structures were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Based on experimental data and the classical crystal growth theory, a plausible growth mechanism of the near-spherical AgCl was proposed. The plasmonic photocatalyst Ag@AgCl prepared from the near-spherical AgCl showed higher activity than that of cubic morphologies.