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 Найдено в других БД:Труды сотрудников Института химии твердого тела УрО РАН (3)Публикации Чарушина В.Н. (1)
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Общее количество найденных документов : 19
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 1-10    11-19 
1.
Инвентарный номер: нет.
   
   N 10


   
    N-(2-Carboxyethyl)chitosans: Regioselective synthesis, characterisation and protolytic equilibria [Text] / Yu. A. Skorik, C. A. R. Gomes, M. T.S.D. Vasconcelos, Yu. G. Yatluk // Carbohydrate Research. - 2003. - Vol. 338, № 3. - P271-276
ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Кл.слова (ненормированные):
CARBOXYETHYLATION POLYSACCHARIDES -- N-(2-CARBOXYETHYL)CHITOSAN -- POLYAMPHOLYTE
Аннотация: N-(2-Carboxyethyl)chitosans were obtained by reaction of low molecular weight chitosan with a low degree of acetylation and 3-halopropionic acids under mild alkaline media (pH 8-9, NaHCO3) at 60°C. The chemical structure of the derivatives obtained was determined by 1H and 13C NMR spectroscopies. It was found that alkylation of chitosan by 3-halopropionic acids proceeds exclusively at the amino groups. The products obtained are described in terms of their degrees of carboxyethylation and ratio of mono-, di-substitution and free amine content. The protonation constants of amino and carboxylate groups of a series of N-(2-carboxyethyl)chitosans were determined by pH-titration at ionic strength 0.1 M KNO3 and 25°C. © 2002 Elsevier Science Ltd. All rights reserved.

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2.
Инвентарный номер: нет.
   
   C 74


   
    Complexation models of N-(2-carboxyethyl)chitosans with copper(II) ions [Text] / Yu. A. Skorik, C. A. R. Gomes, N. V. Podberezskaya, G. V. Romanenko, L. F. Pinto, Yu. G. Yatluk // Biomacromolecules. - 2005. - Vol. 6, № 1. - P189-195 . - ISSN 1525-7797
ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Аннотация: The copper(II) complex formation equilibria of N-(2-carboxyethyl)chitosans with three different degrees of substitution (DS = 0.42, 0.92, and 1.61) were studied in aqueous solution by pH-potentiometric and UV-spectrophotometric techniques. It was demonstrated that the complexation model of CE-chitosans depends on DS: the [Cu(Glc-NR2)2] complexes are predominant for two lower substituted samples ("bridge model", log ?12 = 10.06 and 11.6, respectively), whereas the increase of DS leads to formation mainly of the [Cu(Glc-NR2)] complexes ("pendant model", log ?11 = 6.41). As a model for copper complexation with a disubstituted residue of CE-chitosan, the complex of N-methyliminodipropionate [CuMidp(H2O)]·(H2O) was synthesized and structurally characterized by XRD. The unit cell consists of two crystallographically nonequivalent Cu atoms having slightly distorted square pyramidal coordination; Midp constitutes the basal plane of the pyramid and acts as a tetradentate NO3 chelate-bridging ligand by the formation of two six-membered chelate rings (average Cu-O 1.99 A, Cu-N 2.04 A) and a bridge via carbonyl O atom (average Cu-O 1.99 A), an apical position is occupied by a water molecule (average Cu-Ow 2.30 A).

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3.
Инвентарный номер: нет.
   
   N 10


   
    N-alkylation of chitosan by beta-halopropionic acids in the presence of various acceptors [Text] / A. V. Pestov, Yu. A. Skorik, G. Kogan, Yu. G. Yatluk // Journal of Applied Polymer Science . - 2008. - Vol. 108, № 1. - P119-127
ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Аннотация: N-carboxyethylation of chitosan by -halopropionic acids in the presence of various proton and halogen ion acceptors was investigated. It has been observed that carboxyethylation of chitosan in aqueous medium is accompanied by the by-processes of hydrolysis and dehydrohalogenation of the -halopropionic acids yielding -hydroxypropionic acid, bis(2-carbox-yethyl) ether, and acrylic acid. Degree of carboxyethyl substitution (DS) of chitosan and the relative rates of the by-processes varied significantly depending on the conditions used and nature of the proton or halogen ion acceptor. At carboxyethylation of chitosan with the alkaline -bromopropionates, the DS increased in the order Cs+ Rb- K+ sim; Na+ Li-.

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4.
Инвентарный номер: нет.
   
   A 62


   
    Antioxidant and antimutagenic activity of N-(2-carboxyethyl)chitosan [Text] / G. Kogan, Yu. A. Skorik, I. Zitnanova, L. Krizkova, Z. Durackova, C. A. R. Gomes, Yu. G. Yatluk, J. Krajcovic // Toxicology and Applied Pharmacology . - 2004. - Vol. 201, № 3. - P303-310 : ил. - Библиогр.: с. 309-310 (49 ref.)
ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Кл.слова (ненормированные):
CARBOXYETHYLATION -- CHITOSAN -- EUGLENA GRACILIS -- OFLOXACIN -- ANTIOXIDANT -- ANTIMUTAGENICITY
Аннотация: The antioxidant and antimutagenic activities of the novel carboxyethyl derivatives of chitosan with three different degrees of substitution have been assayed in vitro in the unicellular flagellate Euglena gracilis subjected to the action of genotoxic agents acridine orange and ofloxacin. It has been demonstrated that chitosan derivatives exhibit concentration-dependent protective antigenotoxic activity against both mutagens. It is suggested that different mechanisms may be involved in its protective action—antioxidant activity in case of ofloxacin-induced DNA damage, as well as possible interaction with the cell membrane that prevents acridine orange from reaching the genetic compartments and subsequent damaging DNA through intercalative binding. Direct adsorption of acridine orange on chitosan derivatives was ruled out as a possible mechanism of protection on the basis of spectrophotometric measurements. Dependence of the antimutagenic properties of the studied chitosan derivatives on the degree of substitution was reversed in experiments involving acridine orange and ofloxacin, which also indicated different mechanisms of protection involved in these two cases.????

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5.
Инвентарный номер: нет.
   
   H 43


   
    Heavy metals removal by flocculation/precipitation using N-(2-carboxyethyl)chitosans [Text] / S. YU. Bratskaya, A. V. Pestov, Yu. G. Yatluk, V. A. Avramenko // Colloids and Surfaces A: Physicochemical and Engineering Aspects. - 2009. - Vol. 339, № 1-3. - P140-144
ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Аннотация: Here we report on solution properties and flocculation performance of polyampholyte chitosan derivatives - N-carboxyethylated chitosans (CEC) - synthesized "in gel" by treatment of chitosan with acrylic acid. We show that carboxyethylation with the substitution degrees (DS) from 0.7 to 1.6 yields water-soluble derivatives, whose isoelectric points (IEP) range from 6.30 to 3.55. At pH 7.5 interaction of negatively charged CEC derivatives with positively charged colloids of the heavy metal hydroxides (Zn2+, Cu2+, Ni2+), serving as a model of postgalvanic wastewaters, results in lowering of electrokinetic potential of the hydroxide colloids and their precipitation at appropriate flocculant dose. Investigations of CEC flocculation performance depending on pH and DS show that the efficiency of metal removal decreases in the row Cu2+ Zn2+ Ni2+ corresponding to the row of the hydroxocomplex stability for these metals. The higher was pH of the system and DS of CEC derivative, the narrower was the flocculation window and the stronger was negative effect of flocculant overdosing on the efficiency of heavy metal removal. Based on the estimation of floc settling rates and the residual metal concentrations, we have concluded that the optimal DS of CEC derivatives for the precipitation of metal hydroxides is 0.7-1.0

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6.
Инвентарный номер: нет.
   
   A 10


   
    A generalized model of protolytic, complexing and colloidal properties of polyelectrolytes. Case study : N-(2-carboxyethyl)chitosans [] : доклад, тезисы доклада / S. YU. Bratskaya, A. Golikov, A. V. Pestov, A. Voit, Yu. G. Yatluk, V. A. Avramenko // EUCHIS 2009 - 9th International Conference of the European Chitin Society , Venice, Italy, 23-26 May 2009 : conference book. - Venice, Italy, 2009. - 21 (P1-5)
ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ

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7.
Инвентарный номер: нет.
   
   Y 32


    Yatluk, Yu. G.
    Novel unique reagent for preparation of carboxyethyl chitosan-beta-acryloyloxyproprionic acids [] : доклад, тезисы доклада / Yu. G. Yatluk, A. V. Pestov, Yu. A. Skorik // 10-th International Conference on Chitin and Chitosan - 7th International Conference of the European Chitin Society, Le Corum, Montpellier, France, 6-9 September 2006 : book of abstracts . - Le Corum, Montpellier (France), 2006. - 77 (PC 13)
ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ

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8.
Инвентарный номер: нет.
   
   P 49


    Pestov, A. V.
    In-gel synthesis of N-(2-carboxyethyl)chitosan [] : доклад, тезисы доклада / A. V. Pestov, Yu. G. Yatluk, Yu. A. Skorik // Proceedings of the 7th Asia-Pacific Chitin and Chitosan Symposium "Advances in chitin science and technology", Bexco, Busan, Korea, 23-26 April 2006. - Handrimwon, 2006. - С. 90-91. - Библиогр.: с. 91 (9 ref.)
ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ

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9.
Инвентарный номер: нет.
   
   P 49


    Pestov, A. V.
    Synthesis in a gel as a new procedure for preparing carboxyethyl chitosan [Electronic resource] / A. V. Pestov, N. A. Zhuravlev, Yu. G. Yatluk // Russian Journal of Applied Chemistry. - 2007. - Vol. 80, № 7. - P1154-1159. - Bibliogr. : p. 1159 (14 ref.)
ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Аннотация: A fundamentally new procedure of synthesis of carboxyethyl chitosan in a physical gel, ensuring higher degree of substitution at lower temperatures and lower consumption of time and chemicals, compared to the existing procedures, was developed. The structure of the resulting products was examined by diffuse reflection IR and 1H NMR spectroscopy in solutions and also 1H and 7Li broad line NMR

\\\\Expert2\\nbo\\Russian Journal of Applied Chemistry\\2007, v. 80, N. 7, p.1154.pdf
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10.
Инвентарный номер: нет.
   
   T 44


   
    The first cubane-like complex of copper based on N -carboxyethyl-tris(hydroxymethyl)aminomethane: Synthesis and crystal structure [Electronic resource] / A. V. Pestov, A. V. Virovets, N. V. Podberezskaya, Yu. G. Yatluk // Russian Journal of Coordination Chemistry. - 2008. - Vol. 34, № 1. - P1-7. - Bibliogr. : p. 7 (9 ref.)
ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Аннотация: The interaction of acrylic acid with tris(hydroxymethyl)aminomethane (I) was studied. A simple method was suggested for preparing N-carboxyethyl-tris(hydroxymethyl)aminomethane (homotricin) (II). On the basis of compound II, the 1:1 Cu complex, [Cu(OCH2C(CH2OH)2NHCH2CH2COO)]4·nH2O (n = 4–11.25) (III), which is alkoxycarboxylate, was synthesized. The crystal structure of III was found to correspond to a cubane-like tetranuclear cluster (an automated Bruker X8Apex diffractometer with CCD detector (MoK radiation, graphite monochromator, v = 1.11°-27.5°), 8016 reflections, space group P , a = 12.5573(3), b = 19.1012(4), c = 21.2903(5) A, a = 80.7770(10)°, beta = 75.7430(10)°, y = 75.2260(10)°, V = 4761.62(19) A3, p(calcd.) = 1.704 g/cm3, Z = 4). The crystals are unstable due to the large number of water molecules

\\\\Expert2\\nbo\\Russian Journal of Coordination Chemistry\\2008, v. 34, N. 1, p.1.pdf
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