共查询到20条相似文献,搜索用时 93 毫秒
1.
Magda Milewska Katarzyna Guzow Wies?aw Wiczk 《Central European Journal of Chemistry》2010,8(3):674-686
The ability of new chelate ligands, benzoxazol-5-yl-alanine derivatives substituted in position 2 by heteroaromatic substituent,
to form complexes with selected metal ions in acetonitrile are studied by means of absorption and steady-state and time-resolved
fluorescence spectroscopy. Among the ligands studied, only azaaromatic derivatives form stable complexes with transition metal
ions in the ground state. Their absorption bands are bathochromically shifted enabling to use those ligands as ratiometric
sensors. The fluorescence of each ligand is quenched by metal ions, however, in the presence of Cd(II) and Zn(II) ions a new
red shifted emission band is observed.
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2.
Ayman Massoud F. Abou El-Nour H. Killa U. Seddik 《Central European Journal of Chemistry》2010,8(3):696-701
This work assesses the potential of an adsorptive material, Dowex 50w-x8, for the separation of indium ions from cadmium ions
in aqueous media. The adsorption behavior of Dowex 50 w-x8 for indium and cadmium ions was investigated. The effect of pH,
initial concentration of metal ions, the weight of resins, and contact time on the sorption of each of the metal ions were
determined. It was found that the adsorption percentage of the indium ions was more than 99% at pH 4.0. The result shows that
In (III) was most strongly extracted, while Cd(II) was slightly extracted at this pH value. The recovery of In(III) and Cd(II)
ions is around 98% using hydrochloric acid as the best eluent.
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3.
Chiral aminosulfonamides containing imidazolium group were used as ligands for the ruthenium(II)-catalyzed asymmetric transfer
hydrogenation of prochiral ketones in ionic liquid, affording good to excellent conversions and enantiomeric excesses. The
catalytic system could be easily recovered and reused several times.
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4.
Natarajan Thilagavathi Chinnasamy Jayabalakrishnan 《Central European Journal of Chemistry》2010,8(4):842-851
Ru(III) complexes of the type [RuXB(L)2] have been prepared by the reaction of 3,4-dihydropyrimidin-2(1H)-ones/thiones (HL1–HL4) with the precursors of the type [RuX3B3] where X=Cl or Br; B=PPh3 or AsPh3 and L is the deprotonated ligand. The synthesized complexes were characterized by physico-chemical methods, electrochemical
and magnetic moment data. The catalytic efficiency of the complexes were examined in the oxidation of alcohols and antimicrobial
studies were also carried out.
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5.
Maria-Gabriela Alexandru Tanja Cirkovic Velickovic Ioana Jitaru Sanja Grguric-Sipka Constantin Draghici 《Central European Journal of Chemistry》2010,8(3):639-645
This paper presents the synthesis of complex compounds of type [M(L1)2], where M(II)= Cu (1), Co (2), Zn (3), L1=2-aminothiazole-4-acetate and [Mn(L1)2(H2O)] (4) using ethyl 2-(2-aminothiazole-4-yl) acetate (L), and characterization by elemental analysis, magnetic susceptibilities,
IR, 1H-NMR, UV-Vis spectroscopy and for [Mn(L1)2(H2O)] also by X-ray diffraction. In vitro cytotoxicity studies were performed on human cervix adenocarcinoma, HeLa cells. The
antitumor selectivity was assessed using normal human peripheral blood mononuclear cells, PBMC as control.
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6.
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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7.
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.
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8.
Anuţa Câmpean Mihaela Tertiş Robert Săndulescu 《Central European Journal of Chemistry》2011,9(4):688-700
Electrochemical behaviour of some alkaloids, namely: caffeine, aminophylline, theophylline, codeine phosphate and papaverine
hydrochloride, that are in solution in various combinations or in the presence of other compounds contained in pharmaceuticals
or in real samples (urine) was investigated using cyclic voltammetry (CV), square-wave voltammetry (SWV) and differential
pulse voltammetry (DPV) on electrochemically activated glassy carbon electrode.
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9.
10.
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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11.
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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12.
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.
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13.
Jinzhang Gao Yingying Zhang Jie Ren Ming Li Wu Yang 《Central European Journal of Chemistry》2010,8(3):602-606
A sensitive and convenient method for the determination of trace europium ions using an oscillating chemical reaction involving
Ce(IV) - KBrO3 - acetone - oxalic acid - H2SO4 was proposed. The results indicated that the changes in oscillating period (T) was linearly proportional to the negative
logarithmic concentration of Eu3+ (-log C) in the range of 1.41 × 10−8 ˜ 1.41 × 10−4 mol L−1 (r = 0.9982) with a detection limit of 1.04 × 10−9 mol L−1. The recoveries were limited to the range of 99.5% to 100.8%. Under the same conditions, other rare earth ions did not interfere
with the determination of Eu3+. In addition, a perturbation mechanism was also discussed briefly.
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14.
Jaromíra Chýlková Renáta Šelešovská Jaroslava Machalíková Libor Dušek 《Central European Journal of Chemistry》2010,8(3):607-616
The paper describes a method of voltammetric determination of antioxidants in lubricating oils developed with the use of Linear
Sweep Voltammetry (LSV) and Fast Scan Differential Pulse Voltammetry (FSDPV). Experimental conditions have been found for
simultaneous determination of phenol-based antioxidants and amino-antioxidants: the phenols can be electrochemically oxidized
using the polarisation of gold disc electrode (AuDE) in the potential range of 0–1400 mV in 0.2 M H2SO4 in the presence of ethanol and acetonitrile at the ratio of 3:1. Secondary aromatic amines can be determined directly in
this supporting electrolyte; the presence of phenolic antioxidants does not interfere with this analysis. On the other hand,
secondary aromatic amines interfere with the determination of phenolic substances; therefore, the amines present have to be
eliminated in a suitable way. A procedure for masking the aromatic amines using their reaction with nitrous acid has been
suggested and optimised. The nitrosamines thus formed can be used for sensitive and selective determination of amino-antioxidants
by means of cathodic reduction on the hanging mercury drop electrode (HMDE) using Fast Scan Differential Pulse Voltammetry.
The method was applied in analysis of real samples of lubricating oils.
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15.
16.
The Diels-Alder reaction between cyclopentadiene and dienophiles in deanol derivatives containing bis(trifluoromethylsulfonyl)imide
anion as media have been studied. The effect of the substituents attached to the cation on the endo:exo selectivity as well
as the reaction yield have been evaluated in the absence and presence of Lewis acid catalyst - Y(OTf)3. Catalytic activity of metal triflates and the recycling of chosen catalytic systems have also been investigated
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17.
Gréta Gergely Ferenc Wéber István Lukács Levente Illés Attila L. Tóth Zsolt E. Horváth Judit Mihály Csaba Balázsi 《Central European Journal of Chemistry》2010,8(2):375-381
Hydroxyapatite (HAp) was successfully produced from recycled eggshell, seashell and phosphoric acid. The phases obtained depended
on the ratio of calcined eggshell/ seashell to phosphoric acid, the calcination temperature and the mechanochemical activation
method (ball milling or attrition milling). The HAp structures were characterized by X-ray diffraction, scanning electron
microsopy and infrared spectroscopy. Attrition milling was more effective than ball milling, yielding nanosize, homogenous
and pure Hap.
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18.
Carla Ferragina Romolo Di Rocco Pasquale Patrono Lucantonio Petrilli 《Central European Journal of Chemistry》2009,7(1):31-34
Layered compounds with CdS particles supported on the ion-exchanger, γ-titanium dihydrogen phosphate, were prepared by the
stepwise reaction of the ion-exchanger and cadmium solution, followed by reaction with H2S gas. The CdS content on the ion-exchanger is dependent on the timeframe of the H2S gas flow. The materials obtained were layered, as shown by the X-ray measurements that exhibit both precursor and CdS diffraction
peaks. The thermal treatment of the material obtained gives evidence of its stability (≤ 320°C) before the CdS decomposition,
which occurs in a single step.
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19.
Jorge Luis Sague Doimeadios 《Central European Journal of Chemistry》2008,6(4):505-508
Herein, the first example of a co-crystal system formed by an imidazolium nitrate, a carbene precursor, and copper (II) nitrate,
{[Cu(NO3)2(H2O)2]L1(NO3)2} (1) (L1 = 1,1′-dibenzyl-3,3′-butyl-diimidazolium-2,2′-diylidene) is reported. These two building blocks are connected in the solid
state through hydrogen bonds to generate a three-dimensional supramolecular network.
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20.
The oxidation processes of 2,6-diisopropylnaphthalene and 4,4′-diisopropylbiphenyl with oxygen in the presence of a catalyst,
composed of copper(II) chloride and tetrabutylammonium bromide, were investigated. It was found that, in essence, only one
isopropyl group undergoes oxidation, and obtained mixtures contained mainly peroxide, alcohol, ketone and only small amounts
of hydroperoxide.
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