共查询到20条相似文献,搜索用时 31 毫秒
1.
Amin Rostami Sadegh Rahmati Ardeshir Khazaei 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):663-667
Abstract Molecular iodine generated in situ from Fe(NO3)3·9H2O/NaI acts as a highly efficient catalyst for tetrahydropyranylation of various alcohols and phenols with 3,4-dihydro-2H-pyran in almost quantitative yields. The reaction occurs rapidly in dichloromethane at room temperature, and use of toxic
molecular iodine is avoided.
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2.
An atomistic simulation study of oxygen-vacancy migration in perovskite electrolytes based on LaGaO3
Abstract Static lattice simulation techniques were used to calculate the energetic barriers for oxygen-vacancy migration in the perovskite-type
oxide LaGaO3 substituted with alkaline earth cations. The calculated migration energies are found to vary with the number and size of
the substituting cations in the immediate neigbourhood of the migrating defect. It is argued that not only the size but also
the charge of the cations constituting the saddle-point configuration play a role in determining the migration energy.
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3.
Mohammad Rahimizadeh Mehdi Pordel Mehdi Bakavoli Zahra Bakhtiarpoor Ala Orafaie 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):633-638
Abstract New imidazo[4,5-a]acridone derivatives were synthesized from the rearrangement of 3H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. New imidazo[4,5-a]acridines were obtained from the reaction of imidazo[4,5-a]acridones in boiling POCl3. All of these compounds exhibited antimicrobial activities comparable to streptomycin as reference drug.
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4.
Enrique Ruiz-Trejo José-Francisco Gómez-García 《Monatshefte für Chemie / Chemical Monthly》2009,140(9):1031-1039
Abstract In the search of new materials for solid oxide fuel cells, a study of the structure and electrical conductivity of Mg-doped
and nominally pure CeNb3O9-δ was undertaken. This material exhibits an orthorhombic crystal structure as determined by Rietveld refinement. Through a
combined study of 4-point DC and AC impedance spectroscopy, it was determined that the material presents oxygen ion conductivity,
electron conductivity and electron-hole conductivity according to the partial pressure of oxygen and temperature in agreement
with a simple defect chemistry model. Finally, some experiments seem to indicate the presence of proton conduction.
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5.
Kurt Kalcher Ivan Svancara Marijo Buzuk Karel Vytras Alain Walcarius 《Monatshefte für Chemie / Chemical Monthly》2009,140(8):861-889
Abstract An overview of the use of electrochemical sensors made from heterogeneous carbon materials (carbon paste electrodes, screen-printed
carbon electrodes) in the field of food analysis is presented. Sensors for inorganic and organic analytes as well as biosensors
are summarized.
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6.
Marco Rupprich Clemens Decristoforo Barbara Matuszczak 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):405-407
Abstract In contrast to the results presented in a previous report, the direct conversion of alcohols to alkyl fluorides with triphenylphosphine
and potassium fluoride in CCl4/DMF under mild conditions failed.
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7.
Hussein A. Khalaf 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):669-674
Abstract Aluminum-promoted sulfated iron hydroxide samples were prepared by a coprecipitation method with different loading levels
of AlIII followed by sulfation and calcination at 870 K. These samples were characterized by means of thermal gravimetric analysis,
X-ray powder diffraction, nitrogen adsorption at 77 K, diffuse reflectance spectroscopy, and FT-IR spectroscopy using KBr
pellets. TGA profiles showed sulfated species with different thermal stabilities in the samples, and incorporation of AlIII causes an increase in the thermal stability of the surface sulfate species. The presence of sulfate ions and AlIII promotion did not modify the crystal phase of α-Fe2O3, but it did increase the crystallite size. A textural study showed that the incorporation of AlIII into the sulfated samples led to diminished surface area and pore volume. The pore size distribution exhibited a wide spectrum
of mesoporosity in all samples.
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8.
Dmitry A. Sibgatulin Dmitry M. Volochnyuk Aleksander N. Kostyuk Sergey P. Ivonin Andriy V. Lapandin 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):639-643
Abstract The reaction of push–pull enamines with 1,2-biselectrophilic phenylglyoxal was investigated. Phenylglyoxal was found to react
depending on the structure of the push–pull enamine, affording either a hydroxyalkylation product at the methyl group or the
cyclic product via participation of the methyl group and the β-carbon of the enamine.
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9.
Abstract We use time-domain electrostatic force spectroscopy (TD-EFS) for characterizing the ion dynamics in solid electrolytes on
a nanoscopic level. For partially crystallized glass ceramics we are able to distinguish between dynamic processes in the
glassy phase, in crystallites, and at interfaces. Nanoscopic polarization spots can be created and directly visualized, and
their time evolution can be studied. By applying grid-type spectroscopic measurements, maps of the local relaxation strength
can be obtained, giving information about the spatial distribution of the glassy and crystalline phases.
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10.
Svetlana Marković Sonja Stanković Slavko Radenković Ivan Gutman 《Monatshefte für Chemie / Chemical Monthly》2009,140(2):153-156
Abstract Two mechanisms for the isomerization of cyclopenta[fg]aceanthrylene to acefluoranthene were revealed. The first pathway occurs via a cyclobutyl intermediate, whereas the second
pathway involves a transition state that contains an sp
3-hybridized carbon atom. Both patterns show that the Stone-Wales rearrangement requires extremely high activation energy and
indicate that the isomerization process can occur only under a drastic temperature regime.
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11.
Madhukar N. Jachak Sandeep M. Bagul Bhausaheb K. Ghotekar Raghunath B. Toche 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):655-662
Abstract A series of (2E)-3-(1-chloro-6-methoxy-3,4-dihydronaphthalen-2-yl)-1-(4-aryl)prop-2-en-1-ones (chalcones) have been synthesized by a new
synthetic route. The 3-pyridinecarbonitrile derivatives were synthesized by the Michael reaction of malononitrile (in base)
and aroylacetonitriles (in acid) with chalcones in one pot. The fluorescent properties and quantum yields of these compounds
were studied.
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12.
Kamal Amani Mohammad Ali Zolfigol Arash Ghorbani-Choghamarani Maryam Hajjami 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):65-68
Abstract A mild, efficient, and highly selective oxidation method of sulfides to sulfoxides using Fe(NO3)3·9H2O and catalytic amounts of KBr or NaBr in the presence of wet SiO2 (50% w/w) has been developed. A variety of aliphatic and aromatic sulfides were selectively oxidized at room temperature in good to
excellent yields.
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13.
M. Dabiri Ali A. Mohammadi Hassan Qaraat 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):401-404
Abstract An efficient and direct procedure for the synthesis of novel spiro[isoindoline-1,2′-quinazoline]-3,4′(3′H)-dione derivatives is described. The process employs a condensation reaction of 2-aminobenzamides and isatins in the presence
of a catalytic amount of KAl(SO4)2.12H2O (alum) in ethanol under reflux.
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14.
Igor Lubomirsky 《Monatshefte für Chemie / Chemical Monthly》2009,140(9):1025-1030
Abstract The chemical strain effect in solids is the deviation from linear elasticity due to the association and dissociation of point
defects. Although to date this effect has been observed and studied only in Ce0.8Gd0.2O1,9, one may expect that it will be found in other ionic and mixed conductors containing a large concentration of point defects.
In this work, some practical applications of materials exhibiting the chemical strain effect are discussed. Based on the example
of Ce0.8Gd0.2O1,9, mechanical structures built from these materials should exhibit exceptional mechanical stability and are therefore very
attractive for use as components of solid oxide fuel cells (SOFC) or other devices subjected to large and frequent temperature
variations. The ability of these materials to withstand large strain without accumulating large stress also makes them potentially
useful as flexible elements in micro-electromechanical systems (MEMS).
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15.
Arash Ghorbani-Choghamarani Maryam Hajjami Hamid Goudarziafshar Mohsen Nikoorazm Shadpour Mallakpour Fatemeh Sadeghizadeh Gouhar Azadi 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):607-610
Abstract A simple and efficient catalytic oxidation of urazoles and a bis-urazole to the corresponding triazolinediones by treatment
with Al(NO3)3.9H2O in the presence of a catalytic amount of silica sulfuric acid is described. A good range of urazole derivatives was selectively
oxidized in CH2Cl2 at room temperature in good to excellent yields.
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16.
Miki Hasegawa Shunsuke Kunisaki Hideki Ohtsu Franz Werner 《Monatshefte für Chemie / Chemical Monthly》2009,140(7):751-763
Abstract On ultra-thin films, Tb(III) shows polarized ff-emission in the visible wavelength region induced by intramolecular energy
transfer from the photoexcited organic ligand, such as phenanthroline. Pr(III) causes polarized ππ* emission from the chromophore
in the ultra-thin film (Langmuir–Blodgett film). Here, the unique optical properties of molecular devices with lanthanide
complexes are summarized.
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17.
Sangtae Kim 《Monatshefte für Chemie / Chemical Monthly》2009,140(9):1053-1057
Abstract In this paper I summarize our recent investigations (Park and Kim, Phys Chem C 111:14903, 2007; Solid State Ionics 179:1329,
2008) on the origin of the grain-boundary resistance in a doped LaGaO3, a perovskite-structured solid electrolyte. The partial electronic and ionic resistances of the bulk and the grain boundaries,
as well as the total resistance, in 1 mol% Sr-doped LaGaO3 were measured separately by means of a dc-polarization method and ac-impedance spectroscopy. Both of the partial resistances
at the grain boundaries were greater than the bulk counterparts, indicating that the grain boundaries impede the ionic as
well as the electronic transport in this material. The transference number of the partial electronic conductivity at the grain
boundary was however greater than that in the bulk. This fact strongly suggests that both electronic and ionic charge carriers
deplete at the grain boundaries to form the space-charge zones and that the grain-boundary cores in this material are positively
charged. In light of the fact that the effective charge of the oxygen vacancy (+2) is greater than that of the electron hole
(+1), the oxygen vacancies deplete more sharply in the space-charge zones compared to the electron holes such that the grain
boundaries become more mixed conducting relative to the bulk. These observations verify that the electrical conduction across
the grain-boundaries in 1 mol% Sr-doped LaGaO3 is governed by the space charge.
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18.
Jian-Feng Zhou Gui-Xia Gong Kun-Bo Shi Yu-Lan Zhu 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):651-654
Abstract A facile procedure for the synthesis of quinoxalines is being reported starting from 3-(2-bromoacetyl)coumarins or 3-(2-bromobutanoyl)coumarins
and substituted o-phenylenediamines. The reactions were carried out under catalyst-free and microwave irradiation conditions producing the
title compounds in moderate to excellent yields in a short time with easy workup. The structures of all new compounds have
been confirmed on the basis of their IR, 1H NMR, 13C NMR, and HRMS data.
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19.
S. Makarem A. R. Fakhari Ali A. Mohammadi 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):645-649
Abstract Electrochemical oxidation of 2,3-dimethylhydroquinone has been studied in the presence of β-diketones as nucleophiles in aqueous
solution using cyclic voltammetry and controlled-potential coulometry. The results indicate that the derivatives of 2,3-dimethylhydroquinone
participate in a Michael addition reaction to form the corresponding benzofuran derivatives. The electrochemical synthesis
has been successfully performed at pH 7.0 and E = 0.1 V versus an Ag|AgCl|KCl (3 M) in an undivided cell in good yield and purity.
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20.
Fangfang Dang Xinwei Wang Guoping Han Yahong Yao 《Monatshefte für Chemie / Chemical Monthly》2009,140(6):615-617
Abstract A 3D metal-organic framework, [C6H3CdN2O4]·NH4, was synthesized solvothermally and structurally characterized by single-crystal X-ray structure determination. This compound
crystallizes in the tetragonal system with the space group P42/nmc. The crystal structure presents a 3D framework and open channels, exhibiting guest-coordination sites at channel walls and
strong fluorescent emission.
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