Mo(W)-Cu(Ag)-S簇合物的非线性光学性能研究

本文介绍了非线性光学性测试中的Ｚ－扫描方法。总结了Ｍｏ（Ｗ）－Ｃｕ（Ａｇ）－Ｓ簇合物的光限制效应、非线性吸收和非线性折射等光学性质。讨论了簇合物结构与光学性能的关系。     

铁氰化镍/银复合无机膜修饰电极对肼的催化氧化作用

在含有Ag+、Ni2+的胶体混合溶液中,多次循环扫描在电极表面形成复合无机膜(Ag/NiCHF),此复合膜修饰电极对肼有显著的催化氧化作用。N2H4的浓度在5.0×10-6～6.0×10-3mol/L范围内与电流呈线性关系,检出限达到1.0×10-6mol/L。该电极已成功的用于水样中肼的测定。     

Synthesis of polyanionic glycopolymers for the facile assembly of glycosyl arrays

Polyanionic glycopolymers were synthesized aiming at establishing a simple process for assembling glycosyl arrays. The synthetic glycopolymers carry the key carbohydrate epitopes of α-d-galactobioside (Gb₂), β-lactoside, and α-d-mannopyranoside, each of which serves as a ligand of bacterial toxins and adhesion proteins. The Gb₂ epitope, prepared from penta-O-acetyl-d-galactopyranose, was coupled with poly(ethylene-alt-maleic anhydride) in a polymer reaction to afford a Gb₂-embedded glycopolymer having also carboxylate (COO⁻) polyanions at the side chain. The polyanionic glycopolymer was then applied to a preparation of sugar-coated gold electrodes, which involves an alternating layer-by-layer adsorption based on electrostatic interactions. The presence of the Gb₂-coat on the surface was evidenced by Fourier transform infrared reflection absorption spectroscopy. The Gb₂-coated glyco-chip was stable in 10 mM HEPES buffer containing 150 mM NaCl aq. Other glycopolymers carrying the β-lactoside and α-d-mannopyranoside epitopes were applied to the same assembling process. The derived glycosyl arrays will be useful for detecting Shiga toxins, other pathogenic toxins and viruses when applied as glyco-chips for surface plasmon resonance or quartz crystal microbalance technique.     

In situ friction study of Ag Underpotential deposition (UPD) on Au(111) in aqueous electrolyte

The electrodeposition of silver on Au(111) was investigated using lateral force microscopy (LFM) in Ag⁺ containing sulfuric acid. Friction force images show that adsorbed sulfate forms structure ( on Au(111) prior to Ag underpotential deposition (UPD) and structure ( ) on a complete monolayer or bilayer of Ag. Variation of friction with normal load shows a non-monotonous dependence, which is caused by increasing penetration of the tip into the sulfate adlayer. In addition, the friction force is influenced by the varying coverage and mobility of Ag atoms on the surface. Before Ag coverage reaches the critical value, the deposited silver atoms may be mobile enough to be dragged by the movement of AFM tip. Possible penetration of the tip into the UPD layer at very high loads is discussed as a model for self-healing wear. However, when the coverage of Ag is close to 1, the deposited Ag atoms are tight enough to resist the influence of the AFM tip and the tip penetrates only into the sulfate adlayer.     

Penicillamin-Komplexe des Nickels,Chroms und Molybdäns — Strukturelle Besonderheiten und biologische/medizinische Relevanz

Penicillamine Complexes of Nickel, Chromium, and Molybdenum — Structural Particularity and Biological/Medical Relevance The compounds Tl₂[Ni^II(H₂O)₆][Ni^II(D-pen)(L-pen)]₂[Ni^II(SCN)₂(H₂O)₄] 1 , Tl[Ni^II(D-pen)₂H] · H₂O 2 , Tl[Cr^III(D-pen)₂] 3 , and Na₂[MoO₄(pen)₂] · 3 CH₃OH · 3 H₂O 4 have been prepared by the reaction of nickel nitrate (for 1 ), nickel acetate (for 2 ), potassium chromate (for 3 ), and sodium molybdate (for 4 ) with D- and D, L-penicillamine, respectively. They were characterized by single-crystal X-ray structure analysis and other physical methods. Whereas penicillamine acts as a bidentate (N, S)-ligand in 1 and 2 , Cr^III (in 3 ), and Mo^V (in 4 ) are coordinated to the three ligand atoms N, O, and S. The presence of three different types of Ni^II-complexes a cationic, a neutral, and an anionic one in 1 is remarkable. For crystal data see Inhaltsübersicht.     

Silver,iron, and nickel immobilized on hydroxyapatite‐core‐shell γ‐Fe2O3 MNPs catalyzed one‐pot five‐component reactions for the synthesis of tetrahydropyridines by tandem condensation of amines,aldehydes, and methyl acetoacetate

In this study, Ag, Ni²⁺, and Fe²⁺ immobilized on hydroxyapatite‐core‐shell γ‐Fe₂O₃ nanoparticles (γ‐Fe₂O₃@HAp‐Ag, γ‐Fe₂O₃@HAp‐Ni²⁺, and γ‐Fe₂O₃@HAp‐Fe²⁺) as a new and reusable Lewis acid magnetic nanocatalyst was successfully synthesized and reported for an atom economic, extremely facile, and environmentally benign procedure for the synthesis of highly functionalized tetrahydropyridines derivatives 4a‐t is described by one‐pot five‐component reaction of 2 equiv of aldehydes 1 , 2 equiv of amines 2 , and 1 equiv of methyl acetoacetate 3 in EtOH at room temperature in good to high yields and short reaction time. The presented methodology offers several advantages such as easy work‐up procedure, reusability of the magnetic nanocatalyst, operational simplicity, green synthesis avoiding toxic reagents and solvent, mild reaction conditions, and no tedious column chromatographic separation.     

Silver(I)‐N‐heterocyclic carbene complexes of bis‐imidazol‐2‐ylidenes having different aromatic‐spacers: synthesis,crystal structure,and in vitro antimicrobial and anticancer studies

A series of Ag(I) complexes ( 6 , 7 , 8 , 9 ) derived from imidazol‐2‐ylidenes was synthesized by reacting Ag₂O with an o‐, m‐, p‐xylyl or 1,3,5‐triazine‐linked imidazolium salts ( 1 , 2 , 3 , 4 ) and then characterizing these using various spectro‐analytical techniques. Additionally, triazine‐linked bis‐imidazolium salt 5 was characterized using the single‐crystal X‐ray diffraction method. Complexes 6–9 were formed from the N‐heterocyclic carbene ligand precursors 1–3 as PF₆^‐ salts in good yields. Conversely, salt 5 does not form Ag(I) complex even under various reaction conditions. Using ampicillin as a standard, complexes 6–9 were tested against bacteria strains Escherichia coli and Staphylococcus aureus as Gram‐negative and Gram‐positive bacteria, respectively, showing potent antimicrobial activities against the tested bacteria even at minimum inhibition concentration and bacterial concentration levels. Furthermore, the potential anticancer activities of the reported complexes were evaluated against the human colorectal cancer (HCT 116) cell lines, using 5‐fluorouracil as a standard drug. The highest anticancer activities were observed for complex 8 with an IC₅₀ value of 3.4 μm , whereas the lowest was observed for complex 9 with an IC₅₀ value of 18.1 μm . Copyright © 2013 John Wiley & Sons, Ltd.     

Exploration of silver decoration concentration to enhance photocatalytic efficiency of titanium dioxide photocatalysts

Ag decoration on TiO₂ is favorable to absorption of visible light and wider absorption range. Ag nanoparticles playing the role of electron receivers on TiO₂ surface enhance photodegradation. However, excess Ag nanoparticles caused reduced specific surface area of photocatalysts and increased probability of charge recombination, resulting in lower photocatalytic efficiency. In this study, the influence of various Ag decoration concentrations on photocatalytic activity was investigated. Surface treatment by nitric acid after Ag decoration was performed to avoid excessive Ag deposition. The extent of Ag elimination and its impacts on photocatalytic activity were also explored. An optimum Ag content in the photocatalyst was achieved and photocatalytic efficiency was obviously improved. It was found that the number of calcination times affected the crystallinity and stability of photocatalysts. Better photocatalytic efficiency could be obtained after twice calcinations.     

Preparation of high‐activity AgBr/Ag3PO4 photocatalyst based on hexadecyltrimethylammonium bromide and mechanism of photocatalytic enhancement

A high‐activity AgBr/Ag₃PO₄ heterojunction photocatalyst was synthesized based on hexadecyltrimethylammonium bromide. Its microspheres were characterized using X‐ray diffractometry, transmission electron microscopy and ultraviolet–visible diffuse reflectance spectroscopy. The new photocatalyst with high photocatalytic activity exceptionally outperforms pure Ag₃PO₄ and AgBr in methyl orange degradation. The enhancement of photocatalytic activity is attributed to the efficient separation of electron–hole pairs. In this photocatalytic reaction, h⁺ and ^?O^2? are the main reactive species that induce visible‐light‐driven degradation.     

Synthesis of V5+‐doped Ag/AgCl photocatalysts with enhanced visible light photocatalytic activity

V⁵⁺‐doped Ag/AgCl photocatalysts were prepared via the ion exchange method. The catalysts were characterized using X‐ray diffractometry, transmission electron microscopy, and energy‐dispersive X‐ray, X‐ray photoelectron, Fourier transform infrared and ultraviolet–visible spectroscopies. The V⁵⁺‐doped Ag/AgCl photocatalysts show much higher photocatalytic activities than Ag/AgCl under visible light irradiation for methyl orange (MO) decomposition. Especially, the 2.0 wt% V⁵⁺‐doped Ag/AgCl photocatalyst shows the highest photocatalytic activity and also high stability after five cycles. The MO degradation rate during each cycle is almost maintained at 97%. Electron spin resonance spectroscopy and radical trapping experiments reveal that holes play an important role in the photocatalytic process.