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1.
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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2.
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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3.
Li-Wen Xu Ming-Song Yang Jian-Xiong Jiang Hua-Yu Qiu Guo-Qiao Lai 《Central European Journal of Chemistry》2007,5(4):1073-1083
Ionic liquid-functionalized mesoporous materials exhibited high catalytic activity in versatile organic reactions, such as
cycloaddition of carbon dioxide (CO2) with epoxide, aza-Michael addition of amines to α, β-unsaturated carbonyl compounds, and the Biginelli reaction of aldehyde, ethyl acetoacetate and urea. Recycling of the catalyst
in these reactions could be carried out and the catalyst used at least five times without significant loss in activity.
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4.
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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5.
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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6.
Petr Bělina Petra Šulcová Miroslav Trojan Pavel Mazurek 《Central European Journal of Chemistry》2007,5(3):706-714
New binary lanthanum-aluminum triphosphates were synthesized by thermal-condensation method from H3PO4, La2O3 and Al(OH)3. These pigments could be potentially used as special inorganic pigments; their corrosion-inhibition properties were widely
studied. Synthesis conditions were determined on the basis of DTA and TG measurements. The products were also characterized
by X-ray diffraction analysis. Physical properties — density by pycnometric method, particle size distribution, oil number
and critical pigment volume concentration (CPVC), pH and specific conductivity of their aqueous extracts were also determined.
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7.
Zenonas Kuodis Albertas Rutavičius Algirdas Matijoška Olegas Eicher-Lorka 《Central European Journal of Chemistry》2007,5(4):996-1006
New hydrazones of 2-(5-thioxo-4,5-dihydro-1,3,4-thiadiazol-2-ylthio)acetohydrazide have been obtained and the percentages
of anti/syn - conformers were determined. Based on the analyses of 1H NMR spectra, it was concluded that for hydrazones obtained from the 2- hydroxybenzaldehydes and 2’-hydroxycetophenones the
ratio between the anti-and syn-conformers depends on the strength of intramolecular hydrogen bond (IMHB) between the nitrogen atom of the imino group and
the proton of the 2-hydroxy group. It was shown that increase in IMHB strength results in stabilization of the anti-conformer in solution.
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8.
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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9.
Voltammetric and potentiometric studies of some sulpha drug-Schiff base compounds and their metal complexes 总被引:1,自引:0,他引:1
M. M. Ghoneim E. M. Mabrouk A. M. Hassanein M. A. El-Attar E. A. Hesham 《Central European Journal of Chemistry》2007,5(3):898-911
The electrochemical behavior of some sulpha drug-Schiff bases at a mercury electrode was examined in the Britton-Robinson
universal buffer of various pH values (2.5–11.7) containing 20% v/v) of ethanol using DC-polarography, cyclic voltammetry
and controlled-potential electrolysis. The DC-polarograms and cyclic voltammograms of the examined compounds exhibited a single,
2-electron, irreversible, diffusion-controlled cathodic step within the entire pH range which is attributed to the reduction
of the azomethine group-CH=N- to -CH2-NH-. The symmetry transfer coefficient (α) of the electrode reaction and the diffusion coefficient (D
0) of the reactant species were determined. The electrode reaction pathway of the compounds at the mercury electrode was suggested
to follow the sequence: H+, e−, e−, H+. The dissociation constant of the sulpha drug-Schiff bases, the stability constant and stoichiometry of their complexes with
various divalent transition metal ions (Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) were determined potentiometrically at room temperature.
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10.
Electrochemical determination of dopamine (DA) in the presence of ascorbic acid (AA) was achieved on boron-doped diamond (BDD)
film electrode by differential pulse voltammetry. The experimental results indicated that the oxidative peaks of DA and AA
could be separated completely on anodically-treated (BDD) electrode without further modification, although these two peaks
can not be separated on glassy carbon electrode. The peak separation of DA and AA was developed to be 0.44 V. High sensitivity
was obtained to determine DA selectively with the coexisting of a large excess of AA in acidic media by DPV. The detection
limit of DA was achieved to be 1.1 × 10-6 M in the presence of AA with the concentration of 200 times more than DA. This technique was also applied to the determination
of DA in real samples.
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11.
David Krinkin 《Central European Journal of Chemistry》2007,5(4):1019-1063
Activated diffusion of water between macromolecules in swollen cellulose is accompanied by anomalously high kinetic isotope
effects of oxygen. The separation factor of heavy-oxygen water (H2
18O /H2
16O) is thousands of permilles instead of tens of permilles according to modern Absolute Rate Theory. This anomalous separation
under usual conditions is disguised by the opposing process of very fast equalization to equilibrium through water-filled
cellulose pores. This process is quicker by approximately 3 orders of magnitude than diffusion through the cellulose body.
As a consequence, this opposition-directed equalization virtually eliminates the results of isotope separation. To reveal
this anomaly it is necessary to suppress equalization, which was the primary problem for both discovery of this anomaly and
its investigation. The method of investigating the anomalous separation in cellulose was developed with suppression of this
negative influence. Discussion of the theoretical nature of the anomalous kinetic isotope effect is presented. This theoretical
study would probably permit the discovery and use for isotope separation of the anomalously high isotope effect for other
chemical elements, in particular, for those heavier than oxygen.
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12.
Zholt Kormosh Iryna Hunka Yaroslav Bazel Andriy Laganovsky Iryna Mazurenko Nataliya Kormosh 《Central European Journal of Chemistry》2007,5(3):813-823
The potentiometric response characteristics of a diclofenac selective electrode, based on ion association in different plasticizers,
were compared. The sensitivity, working range, detection limit and selectivity of membrane sensors demonstrated significant
dependence on the type of plasticizers. The potentiometric unit presented a linear response toward diclofenac concentrations
between 1 × 10−5 − 5 × 10−2 mol L−1, with slopes of approximately 60 mV dec−1, and exhibited a response time of 3 s. The potentiometric analysis of sodium diclofenac in pharmaceutical formulations was
perfomed by the membrane electrode proposed and compared with the results of potentiometric titration given by the Pharmacopoeia
of Ukraine.
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13.
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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14.
Halil Turgut Şahin 《Central European Journal of Chemistry》2007,5(3):824-834
Attempts were made to plasma deposit an oriented π-conjugated polymer of pyrrole (Py) on paper surfaces in order to produce
electrically conductive layers. The N/C atomic ratio of 0.13–0.24 was observed for all treatment conditions. This implies
the nature of the deposition formed on the paper surface via pulsed plasma is different from that of pyrrole monomer. An increase
in conductivity of all pyrrole-plasma treated papers was observed. The 50 W RF-power with 5 min plasma exposed paper sample
shows 8.15 × 10−9 S·cm−1 conductivity. The conductivity measurements indicated a plasma-enhanced ring-opening reaction mechanism of pyrrole.
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15.
A simple and convenient method for the preparation of needle-shape nanoparticles of β-Ni(OH)2 has been developed. Results show that a needle-shaped β-Ni(OH)2 can be easily obtained in the presence of ethylenediamine and sodium dodecylbenzene sulfonate within a size from 100 to 200
nm. The shape and structure of the product were characterized by XRD, TEM and FT-IR. It is noteworthy that the formation of
needle-shape β-Ni(OH)2 benefits from the addition of sodium dodecylbenzene sulfonate. The optimum preparation conditions and the possible mechanism
are also discussed.
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16.
Heterobimetallic complexes of the type R2Si(HL)Cl2 and R2SiL2 (where R = Me, Et, Ph; L = ferrocenyl aroylhydrazone) have been synthesized at 40 °C to 50 °C and at room temperature (25
°C), respectively, and characterized by elemental analysis, molar conductance, infrared and NMR (1H, 13C and 29Si) spectral data. The ligands behave as bidentate, coordinating through the azomethine nitrogen and the oxygen in the amidic
and the imidic acid forms of the ligand at low temperature and at room temperature, respectively. The ligands and their organosilicon
complexes have been evaluated for the antifungal activity against Alternaria alternata, Fusarium oxysporum and Rhizoctonia solani, as well as antibacterial activity against gram negative, Escherichia coli and gram positive, Bacillus subtilis, at 28 °C. Organosilicon complexes of ferrocenyl aroylhydrazone were found to be more potent than the parent ligands.
相似文献
17.
Danuta Barałkiewicz Anetta Kanecka-Hanc Hanka Gramowska 《Central European Journal of Chemistry》2007,5(4):1148-1157
Pb, Mg and Ca were simultaneously determined in plant roots by slurry introduction into inductively coupled plasma optical
emission spectrometry (SS-ICP-OES). Slurries were prepared in 0.5% or 5% (v/v) HNO3 with 0.5, or 5% (v/v) Triton X-100. Omission of the Triton X-100 improved results. Compared with wet ashing of the root sample
followed by ICP-OES, ICP-MS and FAAS, the method offers: comparable results, simplification of sample preparation, less sample
contamination, and reduction in the use of dangerous and corrosive reagents. The precisions varied: 1.7% for Mg, 2.8% for
Ca and 4.3% for Pb, and were not significantly different (95% confidence level) from those of conventional analysis.
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18.
Nermin Kasapoglu Bahar Birsöz Abdülhadi Baykal Yüksel Köseoglu Muhammet S. Toprak 《Central European Journal of Chemistry》2007,5(2):570-580
A series of Ni doped cobalt ferrite compounds with the formula Ni
χ
Co1−χ
Fe2O4 where x=0, 0.2, 0.4, 0.6, 0.8, and 1.0 were prepared using a hydrothermal method and subsequently sintered/annealed at 600
°C for 3 h. The influence of the Ni content on the lattice parameter, a, stretching vibration and the magnetization of specimens were subsequently studied. XRD and FTIR were used to investigate
structure and composition variations. All samples were found to have a cubic spinel structure. SEM was used to study morphological
variations. The results indicate that the average particle sizes are between 30–35 nm with a narrow size distribution along
with nanocrystals forming of regular octahedrons. A decrease in the peak to peak line width and increase in resonance field
with increasing Ni content were observed from ESR measurements. Based on ESR results, a core-shell type of formation was proposed
where the core is made up of undoped CoFe2O4 and the shell is Ni2+ doped CoFe2O4.
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19.
A series of novel cyclic urea molecules 5,6-dihydroxy-1,3-diazepane-2,4,7-trione as HIV-1 protease inhibitors were designed
using computational techniques. The designed molecules were compared with the known cyclic urea molecules by performing docking
studies, calculating their ADME (Absorption, Distribution, Metabolism, and Excretion) properties and protein ligand interaction
energy. These novel molecules were designed by substituting the P
1/P′
1 positions (4
th
and 7
th
position of 1, 3-diazepan-2-one) with double bonded oxygens. This reduces the molecular weight and increases the bioavailability,
indicating better ADME properties. The docking studies showed good binding affinity towards HIV-1 protease. The biological
activity of these inhibitors were predicted by a model equation generated by the regression analysis between biological activity
(log 1/K
i
) of known inhibitors and their protein ligand interaction energy. The synthetic studies are in progress.
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20.
A procedure for direct electrochemical deposition of polyaniline-polypyrrole blend coating on the surface of stainless steel
wire was suggested. Incorporation of polyaniline and polypyrrole into the blend coating was confirmed by infrared spectroscopy.
Key parameters (pyrrole, aniline, dopant and sulphuric acid concentrations and deposition potential) influencing the coating’s
mechanical stability and surface homogeneity were optimised and thermostability of the coating was investigated. A possibility
to apply the coating as a new fibre for solid phase microextraction was demonstrated. The coating showed better selectivity
toward aromatic, hydrophobic compounds.
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