Ordered microporous carbon : The mechanism of an electrical double‐layer capacitor containing zeolite‐templated carbons as model microporous materials was investigated in detail (see figure). Its three‐dimensionally ordered and connected micropores were found to greatly reduce ion‐transfer resistance and, therefore, exhibited a high rate performance.
The shortest asymmetric total synthesis of lycopodine (3) and the first asymmetric total synthesis of flabelliformine (4) were accomplished by a strategy that features a cascade cyclization of linear substrate (5) to construct tetracyclic structure (6). 相似文献
Our scanning tunneling microscopy and electron diffraction experiments revealed that a new two-dimensional allotrope of Bi forms on the Si(111)-7x7 surface. This pseudocubic [012]-oriented allotrope is stable up to four atomic layers at room temperature. Above this critical thickness, the entire volume of the film starts to transform into a bulk single-crystal (001) phase, as the bulk contribution in the cohesion becomes dominant. Based on ab initio calculations, we propose that the new allotrope consists of black phosphorus-like puckered layers stabilized by saturating all the p(z) dangling bonds in the film. 相似文献
Molecular dynamics simulations have been performed to investigate the structural and dynamical properties of the second hydration shell of Th4+ ion at various chloride concentrations and temperatures. When the concentration increases (ca. 5 M), the hydration of Th4+ ion involves the displacement of the water molecules by Cl− ligand and slightly decreases the total coordination number. The residence time of water molecules in the second hydration shell decreases as a function of increasing solution temperature. 相似文献
Three new gelsedine-type oxindole alkaloids, GS-1, GS-2, and GS-3, and one new iridoid, GSIR-1, were isolated from the stems and leaves of cultivated Carolina jasmine (Gelsemium sempervirens AIT. f.) and their structures were determined by spectroscopic analysis. 相似文献
Infrared spectra of matrices codeposited Ar/HX (X=Cl, Br) with Ar/H2CCO mixtures have been examined. Isotopic substitutions (HX, DX, H2CCO, D2CCO) showed that ketene formed the 1:1 hydrogen-bonded complex with HX. The HX stretching modes were observed at 2684 cm−1 in the H2CCO–HCl complex and at 2384 cm−1 in the H2CCO–HBr complex. The ν1 modes of the ketene submolecules were shifted to low frequency and the ν9 modes to high frequency. It was proposed for the structure of the complex that the acid proton is bonded to the C=C pi electron system. 相似文献
Design, synthesis, and structure-activity relationships for 3,4-dihydropyridopyrimidin-2(1H)-one derivatives, which are aza-3,4-dihydro-2(1H)-quinazolinone derivatives, as the sodium/calcium (Na+/Ca2+) exchanger inhibitors are discussed. These studies based on 3,4-dihydro-2(1H)-quinazolinone derivatives led to the discovery of a structurally novel and potent Na+/Ca2+ exchanger inhibitor, 3,4-dihydropyridopyrimidin-2(1H)-one derivative (26), with an IC30 value of 0.02 microM. Compound 26 directly inhibited the Na+-dependent Ca2+ influx via the Na+/Ca2+ exchanger after Na+-free treatment in cardiomyocytes. 相似文献
A chelating agent-loaded resin consisting of 8-quinolinol-5-sulfonic acid and an anion-exchange resin (HOx-resin) was prepared in order to concentrate trace chalcophile elements in natural water samples selectively before neutron activation analysis. The exchange capacity of the Diaion SA No. 100 for the reagent (1.8 meq . g-1 resin) corresponds approximately to that for chloride ion (1.83 meq . g-1 resin), indicating that 8-quinolinol-5-sulfonic acid is adsorbed quantitatively on the exchange site of the resin through the sulfonate anion in the reagent. The basic conditions for the adsorption of the metal ions on the resin were investigated by employing the column method. The nitrate concentration and the pH of the sample solution affect the adsorption behavior of metal ions. Several solutions containing metal ions with varying pH or varying nitrate concentration were applied to the resin column (35 mm x 7 mm phi) with a flow rate of 2.0 cm3 . min-1. As a result, the optimum conditions for the quantitative adsorption of copper(II), zinc(II), cadmium(II), cobalt(II), nickel(II) and manganese(II) were as follows: NO3- less than 0.01 mol . dm-3 pH greater than 4.6. Furthermore, the feasibility of the above conditions as well as quantitative adsorption of the chalcophile elements was confirmed through the neutron activation analysis of the synthesized metal solutions. 相似文献
Reaction of aryl and styryl methyl ketones 1a-m with dimethyl bis(methylthio)methylenemalonate ( 2 ) in the presence of potassium hydroxide in dimethyl sulfoxide gave the corresponding methyl 6-aryl- and 6-styryl-4-methylthio-2-oxo-2H-pyran-3-carboxylates 3a-m . 6-Aryl derivatives 3a-d,g were treated with sodium methoxide in methanol to give the corresponding 6-aryl-4-methoxy-2H-pyran-2-ones 8a-d and 9. Phenylcoumalin ( 7a ) and paracotoin ( 7b ) were synthesized by the desulfurization of 6-aryl-4-methylthio-2H-pyran-2-ones 4a,b. Similarly, anibine ( 8e ) was also synthesized from 3g . Treatment of 3 with hydrogen peroxide or 3-chloroperoxybenzoic acid gave the corresponding 4-methylsulfiny-2H-pyran-2-ones 10a-f in good yields. Displacement reactions of 10a-f with nucleophilic reagents are also described. 相似文献
This article reviews recent research and development of supported heteropolyacid (HPA) catalysts; focusing on the acidic and
catalytic properties. First the basic knowledge of solid HPAs is provided briefly to facilitate understanding of heterogeneous
catalysis of HPAs. Secondly, the structure as well as the physical and chemical properties of supported HPA catalysts is described.
Especially the layer structure of HPA dispersed on the surface of SiO2 and the changes in the surface acidity with the loading level of HPA are discussed. For this purpose, temperature programmed
desorption of benzonitrile devised by Okuhara and Kamiya’s group is useful. This method is capable to assess the surface acidity
of the supported HPA, which controls the catalytic activity for the reactions proceeding by surface-type catalysis. Then,
two new industrial processes developed by Showa Denko K. K. are described; (i) production of ethyl acetate from ethylene and
acetic acid and (ii) oxidation of ethylene to acetic acid. Supported HPA catalysts are utilized for both processes, which
were recently much improved by finely controlling the catalysts and reaction conditions. 相似文献