Alexander V. Pestov
Russian Academy of Sciences
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Alexander V. Pestov.
Molecules | 2016
Alexander V. Pestov; Svetlana Bratskaya
The polyfunctional nature of chitosan enables its application as a polymer ligand not only for the recovery, separation, and concentration of metal ions, but for the fabrication of a wide spectrum of functional materials. Although unmodified chitosan itself is the unique cationic polysaccharide with very good complexing properties toward numerous metal ions, its sorption capacity and selectivity can be sufficiently increased and turned via chemical modification to meet requirements of the specific applications. In this review, which covers results of the last decade, we demonstrate how different strategies of chitosan chemical modification effect metal ions binding by O-, N-, S-, and P-containing chitosan derivatives, and which mechanisms are involved in binding of metal cation and anions by chitosan derivatives.
Bioresource Technology | 2010
Yury A. Skorik; Alexander V. Pestov; Yury G. Yatluk
A number of chelating resins were prepared by chemical derivatization of the chitin-glucan (CG) complex isolated from Aspergillus niger biomass, namely chitosan-glucan (CsG), O-carboxymethyl-chitin-glucan (CM-CG), O-(2-sulfoethyl)chitin-glucan (SE-CG), and N-(2-carboxyethyl)chitosan-glucan (CE-CsG). The chemical modification was confirmed by FT-IR and elemental analysis. Nanosecond electron beam irradiation was used to produce insoluble resins and to preserve the reactive functional groups. Batch experiments were carried out to evaluate the adsorption selectivity and capacity of the resins toward transition metal ions (Cu(2+), Ni(2+), Co(2+), Zn(2+)). The resins showed good adsorption capability with the following selectivity series: Co(2+)Zn(2+). The total metal adsorption capacities of CG, CsG, CM-CG, SE-CG, and CE-CsG resins at pH 6.5 (ammonium acetate buffer) were found to be 0.205, 0.382, 1.752, 0.319, and 0.350 mmol g(-1), respectively. Our results suggest that, depending on the type of chemical modification, the chitin-glucan complexes can be used either for selective Cu(2+) removal (CsG) or for total transition metal adsorption (CM-CG) from aqueous effluents.
Carbohydrate Polymers | 2015
Alexander V. Pestov; Alexander Nazirov; E. B. Modin; Alexander Mironenko; Svetlana Bratskaya
The mechanism of Au(III) reduction by chitosan has been proposed on the basis of comprehensive study of kinetics of Au(III) reduction and chitosan chain degradation using UV-vis spectroscopy and viscosimetry, and identification of reaction products using colloid titration and (13)C, (1)H NMR spectroscopy. We have shown that formation of gold nanoparticles in H[AuCl4]/chitosan solutions starts with hydrolysis of chitosan catalyzed by Au(III). The products of chitosan hydrolysis rather than chitosan itself act as the main reducing species. According to (13)C and (1)H NMR spectroscopy data, chitosan/Au(0) composites contain chitosan with reduced molecular weight and acetylation degree, whereas water-soluble by-products consist of chitosan oligomers with higher acetylation degree, derivatives of glucosamine acids, and formate ion. Chitosan degradation has significantly contributed to the decrease of its efficiency as a gold nanoparticles stabilizer. The gold particle size increased from 6.9 nm to 16.2 nm, when Au(III)/chitosan molar ratio changed from 1:80 to 1:10.
Russian Journal of Applied Chemistry | 2007
Alexander V. Pestov; N. A. Zhuravlev; Yu. G. Yatluk
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.
Carbohydrate Polymers | 2012
Yury A. Skorik; Alexander V. Pestov; M. I. Kodess; Yury G. Yatluk
This study presents a new approach for direct carboxyalkylation of chitosan in the gel state by using aza-Michael addition and substitution reactions. Various reagents were applied including acrylic and crotonic acids, and α-, β-, γ-, δ-, and ɛ-halocarboxylic acids. The reaction of chitosan with γ- and δ-halocarboxylic acids showed no target product formation either in solution or in the gel state. In the case of acrylic, crotonic, α- and β-halocarboxylic acids, the reaction performed in the gel state (concentration of chitosan 20-40%) shows higher degree of substitution at lower reaction time and temperature than in diluted solutions (concentration of chitosan 0.5-2%). The results were discussed in terms of kinetics of the target and side reactions. (1)H and (13)C NMR confirmed that in all cases the carboxyalkylation of chitosan proceeds exclusively at the amino groups.
Carbohydrate Polymers | 2016
Alexander Nazirov; Alexander V. Pestov; Yuliya Privar; Alexander Yu. Ustinov; E. B. Modin; Svetlana Bratskaya
Water soluble luminescent gold nanoparticles with average size 2.3nm were for the first time synthesized by completely green method of Au(III) reduction using chitosan derivative-biocompatible nontoxic N-(4-imidazolyl)methylchitosan (IMC) as both reducing and stabilizing agent. Reduction of Au(III) to gold nanoparticles in IMC solution is a slow process, in which coordination power of biopolymer controls both reducing species concentration and gold crystal growth rate. Gold nanoparticles formed in IMC solution do not manifest surface plasmon resonance, but exhibit luminescence at 375nm under UV light excitation at 230nm. Due to biological activity of imidazolyl-containing polymers and their ability to bind proteins and drugs, the obtained ultra-small gold nanoparticles can find an application for biomolecules detection, bio-imaging, drug delivery, and catalysis. Very high catalytic activity (as compared to gold nanoparticles obtained by other green methods) was found for Au/IMC nanoparticles in the model reaction of p-nitrophenol reduction providing complete conversion of p-nitrophenol to p-aminophenol within 180-190s under mild conditions.
Acta Crystallographica Section C-crystal Structure Communications | 2005
Alexander V. Pestov; E. V. Peresypkina; Alexander V. Virovets; N. V. Podberezskaya; Yury G. Yatluk; Yury A. Skorik
The Cu(II) ion in the title complex, [Cu(C5H10NO3)2] or [Cu(He-ala)2] [He-ala = N-(2-hydroxyethyl)-beta-alaninate], resides at the inversion centre of a square bipyramid comprised of two facially arranged tridentate He-ala ligands. Each He-ala ligand binds to a Cu(II) ion by forming one six-membered beta-alaninate chelate ring in a twist conformation and one five-membered ethanolamine ring in an envelope conformation, with Cu-N = 2.017 (2) angstroms, Cu-O(COO) = 1.968 (1) angstroms and Cu-O(OH) = 2.473 (2) angstroms. The [Cu(He-ala)2] molecules are involved in a network of O-H...O and N-H...O hydrogen bonds, forming layers parallel to the (10-1) plane. The layers are connected into a three-dimensional structure by van der Waals interactions, so that the molecular centres form pseudo-face-centered close packing.
Russian Journal of Coordination Chemistry | 2008
Alexander V. Pestov; Alexander V. Virovets; N. V. Podberezskaya; Yu. G. Yatluk
AbstractThe 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 (MoKα radiation, graphite monochromator, ϑ = 1.11°−27.5°), 8016 reflections, space group P
Carbohydrate Polymers | 2016
Alexander V. Pestov; Alexander V. Mehaev; M. I. Kodess; M. A. Ezhikova; Yulya A. Azarova; Svetlana Bratskaya
International Journal of Biological Macromolecules | 2016
Alexander V. Pestov; Alexander Nazirov; Yuliya Privar; E. B. Modin; Svetlana Bratskaya
noverline 1 n