共查询到20条相似文献,搜索用时 15 毫秒
1.
Sushilkumar A. Jadhav 《Central European Journal of Chemistry》2012,10(5):1640-1646
Two new long-chain carboxylic acids (1, 2) bearing strong fluorescent group pyrene as ligands for Self-Assembled Monolayers (SAMs) have been synthesized. The multistep targeted synthesis is accomplished by use of Pyren-1-yl methylamine hydrochloride and employing simplified synthetic protocols. Compound 2 contains a chiral center purposely introduced along the atom chain in order to make it suitable for chiro-optical studies of the resulting SAMs. 相似文献
2.
Nadezhda Rangelova Lachezar Radev Sanchi Nenkova Isabel M. Miranda Salvado Maria H. Vas Fernandes Michael Herzog 《Central European Journal of Chemistry》2011,9(1):112-118
Methylcellulose (MC) / SiO2 organic / inorganic hybrid materials have been prepared from MC and methyltriethoxysilane or ethyltrimethoxysilane, and characterized
by XRD, FTIR and AFM. XRD showed peak shifts. FTIR shows intermolecular hydrogen bonding between MC and SiO2. AFM depicts surface roughness which depends on the silica precursor and MC content.
相似文献
3.
Tevhide Özkaya Abdulhadi Baykal Muhammet Sadaka Toprak 《Central European Journal of Chemistry》2008,6(3):465-469
Water-soluble Mn3O4 nanocrystals have been prepared through thermal decomposition in a high temperature boiling solvent, 2-pyrrolidone. The final
product was characterized with XRD, SEM, TEM, FTIR and Zeta Potential measurements. Average crystallite size was calculated
as ∼15 nm using XRD peak broadening. TEM analysis revealed spherical nanoparticles with an average diameter of 14±0.4 nm.
FTIR analysis indicated that 2-pyrrolidone coordinates with the Mn3O4 nanocrystals only via O from the carbonyl group, thus confining their growth and protecting their surfaces from interaction
with neighboring particles.
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4.
The relative enthalpies of melts in the system KF - K2NbF7 were measured by drop-calorimetry at the temperatures 1058, 1140 and 1208 K as a function of composition. Heat capacities
of melted mixtures and enthalpies of mixing were determined using the experimental data. The molar heat capacity of melts
diverges slightly from additivity. The molar enthalpy of mixing of melts shows small negative deviation from ideality which
decreases with decreasing temperature. The thermal effect at mixing was assigned predominantly to association reactions producing
more complex fluoroniobate anions.
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5.
İlkay Şişman Çağla Tütünoğlu Ali Osman Aydın 《Central European Journal of Chemistry》2008,6(2):253-257
Sub-micrometer nickel powders of controlled size and morphology were produced by a surfactant-assisted polyol method, using
ethylene glycol (EG) as solvent and reductant in the presence of sodium dodecyl sulfate (SDS) surfactant and NaOH. The resultant
Ni powders were characterized by XRD, SEM, EDS, and FTIR. Spherical, hexagonal, and triangular fcc Ni powders from 0.30 to
0.60 μm were obtained in the presence of SDS; irregular spherical fcc Ni powders were obtained in its absence. The concentrations
of SDS, NaOH and Ni(CH3COO)2·4H2O greatly influence the product morphology and size.
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6.
This paper presents an experimental characterization of two sources of calcium carbonate, limestone and calcium carbonate precipitate (CCP) used in wet flue gas desulphurization processes. Characterization of the two carbonate sources was carried out by chemical analysis, IR spectra, thermal behavior, particle size distribution for CCP, BET surface area and absorption capacity of SO2 in calcium carbonate suspensions. The absorption temperature, suspension concentration and carbonate grain size were found to be the most influential parameters in the absorption capacity measurements. 相似文献
7.
Enthalpy increment measurements on melts in the system KF-K2TaF7 were carried out by drop calorimetry at temperatures between 298 K and 1063, 1103 and 1143 K for selected compositions. Heat
capacities of the melted mixtures and enthalpies of mixing have been determined. Careful calorimetric experiments showed small
but distinct non-ideality of the melt. The molar heat capacity of melt exhibits small positive divergence from additivity.
The molar enthalpy of mixing shows negative deviation from ideality which decreases with increasing temperature. The thermal
effect at mixing was assigned predominantly to association reactions producing more complex fluorotantalate anions. The formation
of complex anions with lower coordination number of Ta may not be excluded.
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8.
Abdülhadi Baykal Yüksel Köseoğlu Mehmet Şenel 《Central European Journal of Chemistry》2007,5(1):169-176
Heating hydrous manganese (II) hydroxide gel at 85 °C for 12 hours produces Mn3O4 nanoparticles. They were characterized by X-ray powder diffraction (XRD) and infrared spectroscopy (FTIR). The particle size
estimated from the SEM and X-ray peak broadening is approximately 32 nm, showing them to be nanocrystalline. EPR measurements
confirm a typical Mn2+signal with a highly resolved hyperfine structure.
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9.
Phase equilibria established in the PbO - BiVO4 system over the whole component concentration range up to 1000°C have been investigated. A phase diagram has been constructed
using DTA and XRD.
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10.
Y. M. Al-Angari M. W. Kadi I. M. Ismail Mohamed. A. Gabal 《Central European Journal of Chemistry》2010,8(2):331-340
In this project, nanocrystalline SnO2 powders were successfully prepared by (a) citrate sol-gel and (b) direct precipitation methods. Powders were characterized
using thermal analysis techniques (DTA-TG-DSC), X-ray powder Diffraction (XRD), surface area (BET) and electrical conductivity
measurements. XRD patterns showed the presence of the cassiterite structure. SnO2 particles, prepared through sol-gel method exhibit crystallite sizes in the range from 3.1 to 22.3 nm when the gel is heat
treated at different temperatures up to 900°C. SnO2 nanocrystallites prepared by the precipitation method are comparatively larger in size. The higher specific surface area
was obtained for the powder prepared using sol-gel method and the obtained average grain size (d) is relatively large compared with that of the average crystallite size. The powders show a semiconducting behavior with
increasing temperature. The higher conductivity obtained for SnO2 prepared by sol-gel method can be attributed to their smaller average crystallite size. XRD of alumina doped powder exhibits
finer particles than pure SnO2. TEM images showed that the particles are spherical in shape and consist of a core of SnO2 surrounded by a coating of alumina. The calculated surface area was found to decrease with temperature increases. Due to
the effective role of Al2O3 additive as a grain growth inhibitor for the matrix grains, the observed surface area for the coated materials are predominantly
higher than for the uncoated materials.
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11.
Takashiro Akitsu Chiaki Ishioka Tsubasa Itoh 《Central European Journal of Chemistry》2009,7(4):690-696
A series of organic/inorganic hybrid materials containing the single-molecule magnet [Mn12(CH3COO)16(H2O)4O12]·2CH3COOH·4H2O with the photochromic compounds azobenzene or disperse red 1 cast into polymethyl methacrylate films was prepared. To understand
the photomodulation of analogous mixtures’ AC susceptibility, we investigated the molecular alignment based on Weigert’s effect
accompanying cycles of cis-trans photoisomerization by alternate irradiations with polarized UV and visible light. Polarized
electronic spectra of the hybrid materials demonstrated gradually increasing anisotropy. These features suggest interactions
between photochromic compounds and the Mn12 complex in polymethyl methacrylate.
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12.
Sushilkumar A. Jadhav 《Central European Journal of Chemistry》2012,10(2):295-299
New symmetrical disulfides together with the corresponding thiols bearing fluorescent end-groups have been synthesized as
building-blocks for self-assembled monolayers (SAMs). The synthesis has been accomplished starting from aromatic nitrogen
heterocycles in three steps. The conversion of the tosylated intermediate into the final disulfide is accomplished by use
of sodium hydrogen sulfide (NaSH). Both products (thiols and disulfides) were isolated and characterized.
相似文献
13.
A novel hydroxyamino phosphane was synthesised through the reaction of 2-imidazolidinone with ClPPh2 and subsequently reaction
of the resulting bisphosphino derivative with the Grignard reagent BrMgC5H11. The interaction of the pentyl substituent with one of the two phosphino groups and the structure in solution is shown by
multinuclear NMR-spectroscopy..
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14.
Zehra Durmus Hüseyin Kavas Abdulhadi Baykal Muhammet S. Toprak 《Central European Journal of Chemistry》2009,7(3):555-559
A novel environmental friendly, room temperature route using an ionic liquid 1-n-butyl-3-methylimidazolium hydroxide ([BMIM]OH)
for the synthesis of Mn3O4 nanoparticles is presented. The product was characterized using Fourier transform infrared spectroscopy, X-ray powder diffraction,
and transmission electron microscopy. Phase purity was confirmed by XRD, and X-ray line profile fitting determined a crystallite
size of 42 ± 11 nm. TEM analysis revealed various morphologies. EPR measurements have indicated the existence of long-range
interactions, due to the wide range of particle sizes and morphologies observed.
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15.
Gheorghe Roman 《Central European Journal of Chemistry》2012,10(5):1516-1526
Benzimidazole, benzimidazoles diversely substituted at position 2, and 5,6-dimethylbenzimidazole have been alkylated at N
1 with ketonic Mannich bases derived from acetophenones, acetylnaphthalenes, 2-acetylthiophene and 1-tetralone to afford a
series of novel 1-(3-oxopropyl)benzimidazoles. The reduction of these transamination products with NaBH4 in methanol produced the corresponding 1-(3-hydroxypropyl)benzimidazoles in excellent yields.
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16.
Sandip A. Sadaphal Kiran F. Shelke Swapnil S. Sonar Murlidhar S. Shingare 《Central European Journal of Chemistry》2008,6(4):622-626
1-benzyl-3-methyl imidazolium hydrogen sulphate [bnmim][HSO4] was found to be an effective catalyst for the condensation reaction of indoles and derivatives with benzaldehydes in microwave
irradiation with lower reaction time and higher yields to give bis(indolyl) methanes.
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17.
Tetra-alkyl Phosphonium ionic liquids are phosphonium salts with melting points near room temperature. We report the NMR studies
of water-trihexyl (tetradecyl) phosphonium chloride ionic liquid mixtures. The proton chemical shifts were used to investigate
the intermolecular interactions in mixtures of ionic liquids and water. The OH chemical shifts were found to decrease as the
water concentration in the ionic liquid increased, and their rate of change with temperature decreased with water concentration.
The CH2 and CH3 chemical shifts were found to move downfield with the increase in temperature, and moved further downfield as water concentration
was decreased. The interface of experimental data and the results of quantum calculations suggest a significant binding of
phosphonium cations to chloride anion and water molecules. As well, the analysis of the data suggests a possible transformation
from cationchloride-water configuration at low water concentrations to cation-water-water at higher water concentrations.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
18.
(Z/E)-1-(2-Methoxyaryl)-1-phenylpropenes have been prepared in good yields by heating a mixture of a phenolic substrate, cinnamyl
chloride, tetramethylammonium chloride and K2CO3 in polyethyleneglycol at 180°C. The one-pot synthesis proceeds through four discrete reaction steps: alkylation of the
phenol with cinnamyl chloride, Claisen rearrangement, O-methylation and double-bond migration. The configuration of one crystalline product was determined using a single-crystal
X-ray diffraction analysis. The thermodynamic and structural features of the products were evaluated using computational chemistry
techniques.
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19.
Nitin A. Mirgane Sandip B. Kotwal Anil V. Karnik 《Central European Journal of Chemistry》2010,8(2):356-360
Ionic liquids (IL) are gaining importance as green solvents. Imidazolium ionic liquid [bmim]+[Cl]−, an environmentally benign solvent, was found to promote the Diels-Alder reaction between anthrone and maleimides at room
temperature with excellent yields. The ionic liquid played a dual role as solvent and catalyst.
相似文献
20.
Iwona Binkowska Włodzimierz Gałęzowski Arnold Jarczewski 《Central European Journal of Chemistry》2010,8(3):582-586
Proton transfer reactions rates between carbon acids 1-nitro-1-(4-nitrophenyl)ethane (NPNE), 2-methyl-1-nitro-1-(4-nitrophenyl)propane
(MNPNP)) and phosphazenes (BEMP, BTPP, P1-t-Oct) in tetrahydrofuran have been measured, and the activation parameters were determined. The results are compared with
those previously obtained for P1-t-Bu phosphazene, guanidines and amidines.
相似文献