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1.
Melinda Fekete Mercedesz Töröncsi Lajos Novak 《Central European Journal of Chemistry》2008,6(1):33-37
Palladium-catalyzed amination reactions of quinoline triflate and the effect of a Pd catalyst, its ligands, solvents, bases,
and temperature were studied. This method facilitated an easier pathway for the preparation of aminoquinoline derivatives
as potential precursors of new serotoninerg agents.
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2.
A palladium complex with an aminophosphine ligand has been prepared and investigated as a catalyst precursor in Suzuki coupling
reactions in toluene. Nanoparticles composed of elemental palladium have been isolated from the reaction media and analyzed
using transmission electroscopic microscope (TEM), which shows the essential catalysts palladium nanoparticles to have a size
of ca. 3.0 nm.
dedicate to the 60th birthday of Prof. Dr. Yuan Kou 相似文献
3.
Agata Siwek Monika Wujec Maria Dobosz Ewa Jagiełło-Wójtowicz Anna Chodkowska Agnieszka Kleinrok Piotr Paneth 《Central European Journal of Chemistry》2008,6(1):47-53
By the reaction of 2-methyl-furan-3-carboxylic acid hydrazide with isothiocyanates, 1-[(2-methyl-furan-3-yl)carbonyl]-4-substituted
thiosemicarbazides 1 were obtained. Further cyclization with 2% NaOH led to the formation of 3-(2-methyl-furan-3-yl)-4-substituted-Δ2-1,2,4-triazoline-5-thiones 2. The pharmacological effects of 2 on the central nervous system in mice were investigated. Strong antinociceptive properties
of the investigated derivatives were observed in a wide range of doses.
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4.
Li-hua Yu Shou-min Zhang Xianzhi Guo Da Wang Shu-rong Wang Shi-hua Wu 《Central European Journal of Chemistry》2007,5(1):144-155
The Co-Pd/SiO2 and Co-Cu/SiO2 catalysts were prepared via solvated metal atom impregnation (SMAI) method and investigated for the Fischer-Tropsch (F-T)
synthesis. The catalysts contained 5wt.% Co and a weight ratio of Pd (or Cu) to Co of 1/30. XPS indicated that Co, Pd and
Cu were in metallic state. The results of XPS and magnetic measurements showed that Co and Pd (Cu) were alloyed. The Co particles
on the catalysts were very highly dispersed and they displayed superparamagnetic behavior. FT-IR indicated that the electrons
shifted from Cu and Pd to Co. Catalytic tests showed that CO hydrogenation rates followed the order Pd-Co > Cu-Co > Co.
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5.
Andris Zicmanis Galina Vavilina Svetlana Drozdova Peteris Mekss Maris Klavins 《Central European Journal of Chemistry》2007,5(1):156-168
Alkylation of indole salts in different ionic liquids is reported. Ionic liquids increase the alkylation reaction rate of
ambident indole anion and reduce the effects of counter ions and/or additives, the alkylation reaction rates being independent
of the presence of small amounts of protic solvents or water.
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6.
Ksenija R. Kumrić Tatjana M. Trtić-Petrović Ljubiša M. Ignjatović Jožef J. Čomor 《Central European Journal of Chemistry》2008,6(1):65-69
Lutetium has been determined by differential pulse anodic stripping voltammetry in an acidic solution containing Zn-EDTA.
Lutetium (III) ions liberated zinc (II), which was preconcentrated on a hanging mercury drop electrode and stripped anodically,
resulting in peak current linearly dependent on lutetium (III) concentration. Less than 0.4 ng mL−1 lutetium could be detected after a 2 min deposition.
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7.
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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8.
Water soluble PEG cored dendritic hexa-acid which comprises peripheral carboxylic acidic groups were prepared via nucleophilic
substitution reactions. Novel anhydrous proton conducting electrolytes were prepared by incorporation of the heterocyclic
protogenic solvent imidazole (Im) into PEG cored dendritic hexa acid, (PEG-HA), at several molar ratios of Im to-COOH units
of PEG-HA. The complexation of PEG-HA and Im was illustrated by infrared spectroscopy (FT-IR). The materials are thermally
stable up to 150 °C as evidenced by thermogravimetry analysis (TGA). Differential scanning calorimetry (DSC) results verified
that the organic electrolytes are homogeneous and amorphous. The proton conductivities were characterized by means of AC impedance
spectroscopy and a maximum conductivity of 1 × 10−3 S/cm was measured at 120 °C in the anhydrous state.
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9.
Paraskevas D. Tzanavaras Demetrius G. Themelis Fotini S. Kika 《Central European Journal of Chemistry》2007,5(1):1-12
The present study reviews more than twenty years (1985-present) of published research on the development and application of
analytical procedures for the determination of chlorine dioxide, a widely used disinfectant and bleaching agent. The review
covers a variety of techniques including batch and automated spectrophotometry and fluorimetry, electroanalysis and chromatography.
The analytical figures of merit to the methods are presented, while critical discussion regarding their advantages and disadvantages
is addressed.
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10.
The geometry, frequency and intensity of the vibrational bands of 8-hydroxyquinoline and its 5,7-dichloro, 5,7-dibromo, 5,7-diiodo
and 5,7-dinitro derivatives were obtained by the density functional theory (DFT) calculations with Becke3-Lee-Parr (B3LYP)
functional and 6-31G* basis set. The effects of chloride, bromide, iodide and nitro substituent on the vibrational frequencies
of 8-hydroxyquinoline have been investigated. The assignments have been proposed with aid of the results of normal coordinate
analysis. The observed and calculated spectra are found to be in good agreement.
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11.
Surface analysis of the size-fractioned urban aerosols by secondary ion mass spectrometry (ToF-SIMS)
The secondary ion mass spectrometry method (ToF-SIMS) has been applied to the analysis of some mineral and organic species
on the surface layers of airborne urban particulates. Particulate matter was collected on aluminum sheets of the 8-stage Anderson
type cascade impactor from three different sampling sites in the city of Lodz, Poland, which were different in terms of aerosol
source apportionment. The obtained results show that vehicle combustion products occur mainly in fine fraction with aerodynamic
diameters below 1μm. The main contribution to the mineral components comes from direct and traffic related soil resuspension.
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12.
Martin Přádný Lenka Martinová Jiří Michálek Tat’ána Fenclová Eva Krumbholcová 《Central European Journal of Chemistry》2007,5(3):779-792
The goal was to electrospin 2-hydroxyethyl methacrylate — based biocompatible polymers and prepare submicron fibres (nanofibers)
for biomedicinal applications. Syntheses of poly(2-hydroxyethyl methacrylate) (HEMA) and its copolymer with 2-ethoxyethyl
methacrylate (EOEMA), and their characterization by viscometry and molecular weight are described. Their relation to electrospinning
is discussed. Electrospinning of HEMA homopolymer from water-ethanol is successful for molecular weights 6.31 × 105 and 1.80 × 106 g/mol. Electrospinning of HEMA/EOEMA copolymers is feasible from ethanol.
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13.
Maria M. Milanova Dimitar S. Todorovsky Christo C. Balarew Natalia L. Minkova Katya I. Ivanova 《Central European Journal of Chemistry》2007,5(1):13-19
The cocrystallization of Ce2(SO4)3 and La2(SO4)3 is studied in aqueous and H2SO4 (150 g/dm3) solutions at 25 °C and 64 °C. The effect of the formation of inner sphere sulfate complexes of the type LnSO
4
+
in determining the composition of the equilibrium phases is revealed.
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14.
Hybrid density functional theory calculations at the mPW1PW91/6-31+G(d,p) level of theory have been used to investigate the
optimized structures and other molecular properties of five different series of thiosemicarbazones. The investigated compounds
were obtained from acenaphthenequinone, isatin and its derivatives, and alloxan. The focus of the study is the isomerism and
the NMR characterization of these thiosemicarbazones. It was found that only one isomer is expected for thiosemicarbazones
and methylthiosemicarbazones, while for dimethylthiosemicarbazones, two isomers are possible. All investigated thiosemicarbazones
exhibit a hydrazinic proton that is highly deshielded and resonates far downfield in the proton NMR spectra. This proton is
a part of a characteristic sixmembered ring, and its NMR properties are a result of its strong, intermolecular hydrogen bond.
The relationships between the calculated 1H and 13C NMR chemical shifts and various geometric parameters are reported.
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15.
A strange effect was observed while using the method of quasi-simultaneous determination of electrochemical voltage noise
and impedance to obtain information on the kinetics of the hydrogen evolution reaction on Ag and Cu microelectrodes. Beyond
a certain polarizing current density we found microvolt-amplitude potential oscillations on both electrodes with a frequency
in the 5 Hz–5 kHz range. The oscillations were observed in every single experiment with Ag and Cu, while no oscillatory behavior
was observed during the control experiments with the Pt microelectrode. The presence of the oscillations indicates that the
mechanism of hydrogen evolution is more complex compared to the original assumption.
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16.
Yuhai Sun Yujun Feng Hongwei Dong Zhi Chen Likun Han 《Central European Journal of Chemistry》2007,5(2):620-634
A series of homologous gemini surfactants possessing identical hydrophobic chains but different ionic head groups (cationic,
anionic, zwitterionic) were synthesized, and their aqueous solution properties were examined. The results showed that the
surface activities of gemini surfactants are superior to those of corresponding conventional monomeric surfactants, and molecular
arrangements of gemini surfactants at the air-water interface are tighter than those of corresponding conventional surfactants.
It was also found that zwitterionic gemini surfactant possesses the highest surface activity among the three surfactants.
The behavior at the air-water interface is closely related to the molecular structural features of surfactants, which provide
an indication for synthesizing highly-efficient surfactants.
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17.
Emil Ioan Muresan Spiridon Oprea Theodor Malutan Mihai Vata 《Central European Journal of Chemistry》2007,5(3):715-726
The esterification reaction of palmitic acid with epichlorohydrin catalyzed by an anionic macroporous resin was studied. Purolite
A-500 resin proved to be a very effective catalyst in the synthesis of 3-chloro-2-hydroxypropyl palmitate. The effects of
certain parameters such as speed of agitation, catalyst particle size, catalyst loading, temperature, initial molar ratio
between reactants on the rate of reaction were studied. It was found that the overall rate is intrinsically kinetically controlled.
The structure of synthesized ester was confirmed by FTIR and 1H NMR analyses.
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18.
Adina Raducan Alexandra Olteanu Mihaela Puiu Dumitru Oancea 《Central European Journal of Chemistry》2008,6(1):89-92
The kinetics of the reaction between malachite green (MG) and sodium hydroxide (MG fading) was studied using a spectrophotometric
method in the presence of two cationic surfactants, cetyl-benzyl-dimethyl-ammonium chloride (CBDAC) and hexadecyl-trimethylammonium
bromide (HTAB) and one anionic surfactant, sodium dodecyl sulphate (SDS) at concentrations below and above critical micellar
concentrations. The cationic surfactants have a catalytic effect, while the anionic surfactant has an inhibitory effect on
the reaction. A kinetic model describing the influence of surfactant on reaction rate was developed. The results are discussed
on the basis of electrostatic and hydrophobic interactions between the kinetic micelles and malachite green.
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19.
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.
相似文献
20.
Mariana Sládkovic̆ová Pavel Mach L’ubomír Smrc̆ok Håkan Rundlöf 《Central European Journal of Chemistry》2007,5(1):55-70
Geometries of 27 generated conformers of levoglucosan were optimized in vacuo at DFT level of theory combining several functionals with high quality basis sets. For the sake of comparison a reference
molecular and crystal geometry obtained from 30 K single crystal neutron diffraction data was used. Analysis of the conformers’
geometries revealed that in all stable conformers intramolecular two-or three centre hydrogen bonds were formed. Relative
energy of the conformer, which approximated the molecule in the crystal structure the most, was only ∼3 kcal/mol higher, than
the energy of the most stable conformer in vacuo. The largest discrepancies between the geometries calculated in vacuo and experimental geometry concentrated in the vicinity of anomeric C1. These differences were reduced by involving O1 to
intermolecular hydrogen bond using a simple model of the respective hydrogen bond in the crystal.
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