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Dive into the research topics where A. A. Dvorkin is active.

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Featured researches published by A. A. Dvorkin.


Journal of Inclusion Phenomena and Macrocyclic Chemistry | 1998

STEREOCHEMISTRY OF 16-MEMBERED AZO- AND AZOXYCROWN ETHERS. STRUCTURES OF THEIR SANDWICH POTASSIUM IODIDE COMPLEXES

Anna Skwierawska; Elżbieta Luboch; Jan F. Biernat; V. Ch. Kravtsov; Yu. A. Simonov; A. A. Dvorkin; V. K. Bel'Skii

Abstract16-Membered dibenzoazo- and dibenzoazoxycrown ethers have been synthesized. The Z and E isomers of the azocrown compound have been separated and the geometry of the –N=N– and –-N(O)=N–- groups determined. Potassium iodide complexes of the azo- and azoxycrown ethers were obtained and their structures were determined by the X-ray method. The crystal of the azocrown ether complex is triclinic, space group P¯1, a = 21.071(5), b = 12.112(4), c = 8.757(2) Å α = 81.28(2), β = 84.66(2), γ = 107.49(2)°. The azoxycrown ether complex is monoclinic, space group C2/c, a = 15.648(3), b = 19.597(4), c = 14.651(3) Å; β = 111.30(3).


Polyhedron | 1995

NICKEL(II) AND COPPER(II) COMPLEXES WITH AMIDRAZONE-BASED LIGANDS: STRUCTURE AND CATALYTIC ACTIVITY

N. V. Gerbeleu; S.S. Palanciuc; Yu.A. Simonov; A. A. Dvorkin; P. N. Bourosh; Manfred T. Reetz; V.B. Arion; K. Töllner

Abstract Nickel(II) and copper(II) complexes MeL, where H2LL = [9-(2′-hydroxyphenyl)-6-methyl-3-acetyl-5,7,8-triazanona-3,6,8-trien-2-one], have been synthesized by template reaction of salicylaldehyde acetamidrazone with corresponding Me(acac)2 and Hacac in the presence of the orthoformic ester at 110°C. The crystal structure of CuL has been determined by X-ray diffraction. The square-planar mode of coordination is realized in CuL. Comparison of geometrical parameters of CuL with those of the corresponding derivative based on S--allylisothiosemicarbazide showed that substitution of the -SR group by methyl in the quadridentate ligand does not affect the mode of binding nor the main interatomic distances and angles in the ligand. The data from magnetic measurements, 1HH NMR and EI mass spectra indicate that NiL has a similarly structured coordination polyhedron. Epoxidation of norbornene can be performed efficiently with molecular oxygen (1 atm) in THF (or THF-EtOAc) in the presence of CuL at 70°C. The corresponding copper(II) derivatives based on S--substituted isothiosemicarbazides are much less active as catalysts.


Chemistry of Heterocyclic Compounds | 1991

Three-dimensional structures and spectra of 2,6- and 2,8-diethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones

É. B. Shamuratov; A. S. Batsanov; Yu. T. Struchkov; A. Yu. Tsivadze; M. G. Tsintsadze; L. I. Khmel'nitskii; Yu. A. Simonov; A. A. Dvorkin; O. V. Lebedev; Tatyana B. Markova

Isomeric 2,6- and 2,8-diethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-diones were obtained by the reaction of glyoxal with ethylurea, and their crystal structures and IR, Raman, and PMR spectra were studied.


Journal of Inclusion Phenomena and Macrocyclic Chemistry | 1994

12-MEMBERED CROWN ETHERS. LIPOPHILIC DERIVATIVES OF BENZO- AND NAPHTHO-12-CROWN-4 AND THEIR MEMBRANE ELECTRODE PROPERTIES. CRYSTAL STRUCTURES OF BENZO -12-CROWN-4 NAI AND KI COMPLEXES

Elżbieta Luboch; A. A. Dvorkin; Yu. A. Simonov

AbstractLipophilic derivatives of benzo-12-crown-4 and naphtho-12-crown-4 have been synthesized. The behavior of the parent compounds and their derivatives in membrane ion-selective electrodes have been studied. Selectivity changes have been observed with the rise in lipophilicity. Crystal structures of the NaI and KI complexes of benzo-12-crown-4 (1 and2) have been determined by X-ray analysis. The alkali metal and iodide ions are in direct contact in2 but not in1. Compound1 [Na(benzo-12-crown-4)2]·I is triclinic, witha=13.368(8),b=10.727(7),c=10.325(4) Å; α=73.56(4),β=77.73(4), γ=108.70(5)°;Z=2, space group is


Zeitschrift für Naturforschung B | 1993

Synthesis, Structure and Characterization of Trisodium Bis[N-(2-oximinopropionyl)glycinato(3 – )-O,N,N'] Cobaltate(III) Nonahydrate

Igor O. Fritsky; Rostislav D. Lampeka; Victor V. Skopenko; Yury A. Simonov; A. A. Dvorkin; Tadeusz I. Malinowsky


Chemistry of Heterocyclic Compounds | 1990

Basic hydrolysis of 3-acetoxy-7-bromo-5-(o-chlorophenyl)-1-ethoxycarbonylmethyl-1,2-dihydro-3H-1,4-benzadiazepin-2-one

A. A. Mazurov; A. A. Dvorkin; Yu. A. Simonov; S. A. Andronati

P\bar 1


Chemistry of Heterocyclic Compounds | 1995

Synthesis and crystalline and molecular structure of hydrochloride of 1-[2(2,3-dihydro-1,3,4-oxadiazolyl-5-one)]methyl-7-bromo-5-prenyl-1,2-dihydro-3H-1,4-benzodiazepin-2-one

V. I. Pavlovskii; Yu. A. Simonov; A. A. Dvorkin; A. S. Yavorskii; M. G. Rokachinskaya; S. A. Andronati


Journal of Structural Chemistry | 1993

Synthesis and molecular structure of 1,4-dimethyl-4,5,7,8-tetrahydro-6H-imidazo[4,5-e][1,4]-diazepine-5,8-dithione

E. I. Ivanov; G. D. Kalayanov; L. V. Grishchuk; A. A. Dvorkin; Yu. A. Simonov; T. I. Malinovskii; Yu. E. Shapiro; E. G. Pikhteeva

. Compound2 [K(benzo-12-crown-4)2·I] is monoclinic, witha=15.807(8),b=12.043(4),c=15.601(6) Å,β=117.74(3)°;Z=4, space groupC2/c. In both compounds the cations interact with all oxygen atoms of two crown ether molecules. Correlation of the crystal structures and behavior of the crown ethers in ion-selective membrane electrodes is discussed.


Chemistry of Heterocyclic Compounds | 1992

Synthesis and structure of 9,10,11,12-Dibenz[a,c]-7,14-diaza-1,4-dioxacyclohexadecane-8,13-dione

A. A. Dvorkin; E. V. Ganin; Yu. A. Simonov; G. S. Musienko; T. I. Malinovskii

A cobalt(III) complex with pyruvylglycine oxime (H3G) of composition Na3[CoG2] · 9 H2O is synthesized and investigated by means of X-ray analysis, infrared, electronic and NMR spectroscopy. The crystals are triclinic, space group P1̄, a = 15.477(5), b = 9.931(4), c = 7.773(4)Å; α = 75.60(3); β = 82.86(4); γ = 93.54(3)°; Ζ = 2. The structure was refined to final R = 0.036 for 3347 independent observed reflections. The structure consists of the complex anions, Na+ cations and water molecules. The ligands are coordinated via the deprotonated oxime and amide nitrogen and the carboxyl oxygen atoms in a meridional fashion (Co—O(carboxyl) = 1.971 and 1.947 Å; Co— N(oxime) = 1.891 and 1.909; Co— N(amide) = 1.876 and 1.866Å). The Co(III) coordination octahedron is slightly distorted; the Co—O and Co—N distances are in agreement with the data for oxime and peptide complexes of Co(III). The unit cell contains 2 enantiomeric complex anions related by a center of symmetry. The electronic, IR and NMR (1H and 13C) spectra of the complex are compared to those of the free ligand and of dipeptidato complexes of Co(III).


Chemistry of Heterocyclic Compounds | 1992

STRUCTURE OF THE PRODUCT OF THE REACTION OF 3,6-DIOXA-1,8-(DI-2,3-DICHLOROMALEIMIDO)OCTANE WITH 3,6-DIOXAOCTANE-1,8-DIAMINE

V. Ganin; Yu. A. Simonov; A. A. Dvorkin; G. S. Musienko; G. G. Shagas; T. I. Malinovskii

The selective basic hydrolysis of 3-acetoxy-7-bromo-5-(o-chlorophenyl)-1-ethoxycarbonylmethyl-1,2-dihydro-3H-1,4-benzdiazepin-2-one has been carried out, resulting in the sequential formation of 3-hydroxy-1-ethoxycarbonylmethyl-, 3-hydroxy-1-methoxycarbonylmethyl-, and 3-hydroxy-1-carboxymethyl derivatives. The structure of the 1-methoxycarbonylmethyl derivatives has been established by x-ray structural analysis.

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S. A. Andronati

National Academy of Sciences of Ukraine

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Rostislav D. Lampeka

Taras Shevchenko National University of Kyiv

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Yu. A. Simonov

Academy of Sciences of Moldova

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Jan F. Biernat

Gdańsk University of Technology

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