共查询到20条相似文献,搜索用时 890 毫秒
1.
Ramin Ghorbani-Vaghei Seyedeh Mina Malaekehpour 《Central European Journal of Chemistry》2010,8(5):1086-1089
N,N,N,’N’-Tetrabromobenzene-1,3-disulfonamide [TBBDA] is found to be a reusable catalyst for efficient synthesis of various amidoalkyl
naphthols from β-naphthol, aromatic aldehydes and urea in good to high yields under solvent-free conditions.
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2.
Rodion Yu. Iliashenko Olexiy S. Zozulia Andrey O. Doroshenko 《Central European Journal of Chemistry》2011,9(6):962-971
A series of novel nitro-substituted ortho-analogs of POPOP was synthesized. Like the most of the other known compounds of this class, the synthesized molecules demonstrate
high Stokes shift fluorescence emission owing to the planarization of their molecules at electronic excitation. Significant
fluorescence quenching in polar solvents was described as the “energy gap law” action rather than the specific effect of the
dialkylamino group excited state twisting.
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3.
Renata Farkas Mercedesz Törincsi Pal Kolonits Jenö Fekete Oscar Jimenez Alonso Lajos Novak 《Central European Journal of Chemistry》2010,8(2):300-307
During the diazo-coupling reaction, nucleophilic displacement of a nitro group was also observed. This was the main reaction
(1→7) when the starting amine bore either a chlorine or methoxy group at the para position (1b–c). The newly prepared compounds (7) might serve as convenient building blocks in synthesis of some heterocycles.
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4.
Mi?osz Mi?tkiewski Beata Powa?a Bartosz Staniszewski Maciej Kubicki W?odzimierz Urbaniak Cezary Pietraszuk 《Central European Journal of Chemistry》2011,9(4):728-736
Selected β-diketones bearing unsaturated derivatives have been demonstrated to undergo homo-metathesis and cross-metathesis with selected
olefins in the presence of Grubbs catalysts. The reactions led to respective homo- and cross-metathesis products mainly with
good yields and selectivities.
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5.
Charles A. Mebi Joshua J. Trujillo Anwar A. Bhuiyan 《Central European Journal of Chemistry》2012,10(4):1218-1222
A new organometallic complex coupling photoactive coumarin to a diironhexacarbonyl unit has been successfully prepared and its composition and electronic structure confirmed by elemental and spectroscopic analyses. Emission spectral analysis of the complex reveals photoinduced intramolecular electron transfer from coumarin to the iron-carbonyl moiety. The compound is electrochemically reduced at −1.24 V vs. Fc/Fc+. This reduction is irreversible, attesting to the instability of the complex. Electrochemical evolution of hydrogen in the presence of the complex has been studied and results are discussed. 相似文献
6.
Abdülhadi Baykal Nermin Kasapoğlu Yüksel Köseoğlu Ali Cemil Başaran Hüseyin Kavas Muhammet S. Toprak 《Central European Journal of Chemistry》2008,6(1):125-130
A series of Ni-doped cobalt ferrites NixCo1−xFe2O4 (x = 0.0, 0.4, 0.6, 0.8, and 1.0) were prepared using microwave-induced combustion. Nickel, cobalt, and ferric nitrates were
used as starting materials and glycine as fuel. The influence of Ni content on the lattice parameter, stretching vibrations,
and magnetization was studied. XRD, FTIR, and SEM were used for structure, composition, and morphology investigation. A porous
network structure was observed with average particle size 60–67 nm. All samples had a cubic spinel structure. The unit cell
parameter “a” decreases linearly with nickel concentration due to the smaller ionic radius of nickel. Magnetization measurements
showed that coercivity decreased as Ni content increased; it increased with decreasing temperature.
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7.
Petar T. Todorov Rosica N. Petrova Emilia D. Naydenova Boris L. Shivachev 《Central European Journal of Chemistry》2009,7(1):14-19
The crystal structures of 3-amino-cycloheptanespiro-4′-imidazolidine-2′,5′-dione (I) {systematic name: 3-amino-1,3-diazaspiro[4.6]
undecane-2,4-dione} and 3-amino-cyclooctanespiro-4′-imidazolidine-2′,5′-dione (II) {systematic name: 3-amino-1,3-diazaspiro[4.7]
dodecane-2,4-dione}, have been determined. In both compounds the polar hydantoin groups cause molecules to aggregate via N-H...O
and N-H...N interactions, forming a layer structure, in which the cycloalkane rings project outwards from the central, more
polar, region. The observed molecular structure is compared with that calculated by density functional theory methods.
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8.
Violeta D. Kassabova-Zhetcheva Lilyana P. Pavlova Bisserka I. Samuneva Zara P. Cherkezova-Zheleva Ivan G. Mitov Mikhail T. Mikhov 《Central European Journal of Chemistry》2007,5(1):107-117
Structural and magnetic properties of Mg
x
Zn1−x
Fe2O4 powders have been studied with respect to the application for thermal cancer therapy (magnetic hyperthermia). Mg
x
Zn1−x
Fe2O4 (x=0.1–0.5) powders with particle sizes between 5 and 8 nm were produced by citrate method. The X-ray diffraction patterns
of the samples correspond to a spinel phase. The lattice constant and the volume of the elementary cell increase when x changes
from 0.1 to 0.5. The FTIR-spectra ascertain the spinel phase formation. The Mossbauer studies reveal the presence of extremely
small particles, which undergo superparamagnetic relaxation at room temperature. The core-shell model has been applied to
explain quadruple doublets. The quadruple splitting at “shells” is bigger than those at “cores” whereas the isomer shifts
remain close. Magnetic studies confirm the presence of extremely small particles that behave as superparamagnetic ones.
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9.
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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10.
Mehdi Ghandi Parham Asgari Abuzar Taheri Alireza Abbasi 《Central European Journal of Chemistry》2010,8(4):899-905
One-pot, three-component condensation of 2-hydroxybenzaldehyde derivatives, primary amines with alkyl isocyanides is reported.
N-alkyl-2-(2-hydroxyphenyl)-2-iminoacetamide derivatives are generated presumably via the preliminary formation of N, N′-disubstituted benzo[b]furan-2,3-diamines and subsequent oxidation with molecular oxygen.
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11.
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.
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12.
Fyodor S. Kot Vladimir L. Rapoport Galina V. Kharitonova 《Central European Journal of Chemistry》2007,5(3):846-857
The results of the laboratory pot experiments on soil mercury (Hg) immobilisation with a non-toxic and price-reasonable agent
— colloidal sulphur (S) water suspension, are presented. It was shown that fertilisation with small agrochemical doses of
colloidal S reduces excess Hg effectively as follows: in interstitial waters by a factor 2 – 12 times for total Hg, and 22–
680 times for “reactive” Hg; in stems and leaves of oats – 7 – 22 times; and in moss bags, reflecting soil Hg degassing, 7
– 15 times, for the most heavily Hg-spiked soils. The results obtained allowed to conclude that the immobilization of Hg occurs
through Hg binding to the newly formed S-bearing functional groups in humic acids and/or sulphides.
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13.
Hafid Anane Soufiane El Houssame Abdelali El Guerraze Abdeladim Guermoune Abderrahim Boutalib Abedellah Jarid Ignacio Nebot-Gil Francisco Tomás 《Central European Journal of Chemistry》2008,6(3):400-403
The complexation energies of H3BNHnCl3−n (n= 3-0) complexes and the proton affinities of NHnCl3−n compounds have been computed at the G2(MP2) level of theory. G2(MP2) results show that the successive chlorine substitution
on the ammonia decreases both the basicity of the NHnCl3−n ligands and the stability of H3BNHnCl3−n complexes. The findings are interpreted in terms of the rehybridisation of the nitrogen lone-pair orbital. The NBO partitioning
scheme shows that the variation of the N-H and N-Cl bond lengths, upon complexation, is due to variation of “s” character
in these bonds.
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14.
Rayna Bryaskova Nelly Georgieva Dimitar Peshev 《Central European Journal of Chemistry》2010,8(5):1053-1058
Polyvinyl alcohol (PVA) and tetraethoxysilane (TEOS) hybrid materials were prepared by sol-gel methods and tested as matrices
for immobilization of Trichosporon cutaneum R57, capable of removing cadmium and copper ions from aqueous solutions. A kinetic model was applied and the effects of matrix
TEOS content on the copper and cadmium uptake equilibria and rate constants were investigated.
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15.
α-Amino acid-derived 2-phenylimidazole derivatives were designed, synthesized, and further investigated as potential antimycobacterial agents. The synthesis of target imidazole derivatives involved the transformation of Cbz-protected α-amino acids (Ala, Val, Phe, Leu, iLe, and Pro) into α-diazoketones and α-bromoketones, respectively. Subsequent treatment of α-bromoketones with (4-nitro)benzamidine afforded imidazole derivatives bearing α-amino acid residue appended to the imidazole C4 and (4-nitro)phenyl ring in the position C2. Antimycobacterial activities of both series of compounds against M. tuberculosis, M. avium, and M. kansasii were screened and basic structure-activity relationships were further evaluated. 相似文献
16.
Magnesium-based composites of 75 wt% Mg — (10, 15, 20) wt% Mg2Ni0.7Co0.3 — (15, 10, 5) wt% C mechanically activated for 30
min under argon in a planetary mill, were obtained. Their absorption-desorption characteristics were investigated under a
pressure P = 1 MPa and temperatures of 623, 573, 473, 423 and 373 K. Desorption was carried out at 623 K and 573 K and a pressure
of 0.15 MPa. All the three composites showed improved hydriding kinetics as compared to pure magnesium. However, the desorption
temperature was somewhat higher than needed for practical application.
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17.
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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18.
Nikolai N. Kolesnikov Elena B. Borisenko Dmitrii N. Borisenko Boris A. Gnesin 《Central European Journal of Chemistry》2011,9(4):619-623
In the present study newly produced semiconductor ceramic nanopowder materials made of CdTe and Cd1−xZnxTe (CZT) are considered. Common features and differences in microstructures, phase transformations, grain growth and properties
of the ceramic materials of the binary and ternary compositions are studied.
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19.
Alina M. Simion Mitsunori Kakeda Naoyoshi Egashira Yoshiharu Mitoma Cristian Simion 《Central European Journal of Chemistry》2012,10(5):1547-1555
We report hereby the first method of direct treatment of a wet soil containing toxic polychloroderivatives. Using a system with metallic Ca and 5% Rh fixed on charcoal in methanol, soil samples artificially polluted with fly ash containing polychloro-dibenzodioxins (PCDDs), polychloro-dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (co-PCBs), and having 69.2% to 84.6% moisture content, were successfully treated and decontaminated. This treatment afforded excellent hydrodechlorination yields for the 29 most toxic congeners of PCDDs, PCDFs and PCBs (98.3% degradation yield based on toxic equivalent quotient — or TEQ) after a 24 h treatment, at room temperature. 相似文献
20.
During the last decade, atom transfer radical polymerization (ATRP) received significant attention due to its exceptional
capability of synthesizing polymers with pre-determined molecular weight, well-defined molecular architectures and various
functionalities. It is economically and environmentally attractive to adopt ATRP to aqueous dispersed media, although the
process is challenging. This review summarizes recent developments of conducting ATRP in aqueous dispersed media. The issues
related to retaining “controlled/living” character as well as colloidal stability during the polymerization have to be considered.
Better understanding the ATRP mechanism and development of new initiation techniques, such as activators generated by electron
transfer (AGET) significantly facilitated ATRP in aqueous systems. This review covers the most important progress of ATRP
in dispersed media from 1998 to 2009, including miniemulsion, microemulsion, emulsion, suspension and dispersed polymerization.
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