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Dive into the research topics where Larysa V. Penkova is active.

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Featured researches published by Larysa V. Penkova.


Journal of Physical Chemistry Letters | 2016

Polymorphism in a Cobalt-Based Single-Ion Magnet Tuning Its Barrier to Magnetization Relaxation

Alexander A. Pavlov; Yulia V. Nelyubina; Svitlana V. Kats; Larysa V. Penkova; N. N. Efimov; Artem O. Dmitrienko; Anna V. Vologzhanina; Alexander S. Belov; Yan Z. Voloshin; Valentin V. Novikov

A large barrier to magnetization reversal, a signature of a good single-molecule magnet (SMM), strongly depends on the structural environment of a paramagnetic metal ion. In a crystalline state, where SMM properties are usually measured, this environment is influenced by crystal packing, which may be different for the same chemical compound, as in polymorphs. Here we show that polymorphism can dramatically change the magnetic behavior of an SMM even with a very rigid coordination geometry. For a cobalt(II) clathrochelate, it results in an increase of the effective barrier from 109 to 180 cm-1, the latter value being the largest one reported to date for cobalt-based SMMs. Our finding thus highlights the importance of identifying possible polymorphic phases in search of new, even more efficient SMMs.


Inorganic Chemistry | 2014

Chloride ion-aided self-assembly of pseudoclathrochelate metal tris-pyrazoloximates.

Oleg A. Varzatskii; Larysa V. Penkova; Svitlana V. Kats; Alexander V. Dolganov; Anna V. Vologzhanina; Alexander A. Pavlov; Valentin V. Novikov; Artem S. Bogomyakov; Victor N. Nemykin; Yan Z. Voloshin

Chloride ion-aided one-pot template self-assembly of a mixed pyrazoloxime ligand with phenylboronic acid on a corresponding metal(II) ion as a matrix afforded the first boron-capped zinc, cobalt, iron, and manganese pseudoclathrochelate tris-pyrazoloximates. The presence of a pseudocross-linking hydrogen-bonded chloride ion is critical for their formation, as the same chloride-capped complexes were isolated even in the presence of large excesses of bromide and iodide ions. As revealed by X-ray diffraction, all complexes are capped with a chloride ion via three N-H···Cl hydrogen bonds that stabilize their pseudomacrobicyclic frameworks. The MN6 coordination polyhedra possess a distorted trigonal prismatic geometry, with the distortion angles φ between their nonequivalent N3 bases of approximately 0°. Temperature dependences of the effective magnetic moment for the paramagnetic complexes showed the encapsulated metal(II) ions to be in a high-spin state in the temperature range of 2-300 K. In the case of the iron(II) pseudoclathrochelate, density functional theory (DFT) and time-dependent DFT calculations were used to assess its spin state as well as the (57)Fe Mössbauer and UV-vis-NIR parameters. Cyclic voltammetry studies performed for these pseudomacrobicyclic complexes showed them to undergo irreversible or quasi-reversible metal-localized oxidations and reductions. As no changes are observed in the presence of a substantial excess of bromide ion, no anion-exchange reaction occurs, and thus the pseudoclathrochelates have a high affinity toward chloride anions in solution.


Journal of Physical Chemistry Letters | 2014

A Mononuclear Mn(II) Pseudoclathrochelate Complex Studied by Multi-Frequency Electron-Paramagnetic-Resonance Spectroscopy.

Mykhailo Azarkh; Larysa V. Penkova; Svitlana V. Kats; Oleg A. Varzatskii; Yan Z. Voloshin; Edgar J. J. Groenen

Knowledge of the correlation between structural and spectroscopic properties of transition-metal complexes is essential to deepen the understanding of their role in catalysis, molecular magnetism, and biological inorganic chemistry. It provides topological and, sometimes, functional insight with respect to the active site properties of metalloproteins. The electronic structure of a high-spin mononuclear Mn(II) pseudoclathrochelate complex has been investigated by electron-paramagnetic-resonance (EPR) spectroscopy at 9.5 and 275.7 GHz. A substantial, virtually axial zero-field splitting with D = -9.7 GHz (-0.32 cm(-1)) is found, which is the largest one reported to date for a Mn(II) complex with six nitrogen atoms in the first coordination sphere.


Acta Crystallographica Section E-structure Reports Online | 2012

Bis-{(E)-3-[2-(hy-droxy-imino)-propan-amido]-2,2-dimethyl-propan-1-aminium} bis[μ-(E)-N-(3-amino-2,2-dimethyl-prop-yl)-2-(hy-droxy-imino)-propanamido-(2-)]bis-{[(E)-N-(3-amino-2,2-dimethyl-prop-yl)-2-(hy-droxy-imino)-propanamide]-copper(II)} bis-((E)-{3-[2-(hy-droxy-imino)-propanamido]-2,2-dimethyl-prop-yl}carbamate) acetonitrile disolvate.

Andrii I. Buvailo; Anna V. Pavlishchuk; Larysa V. Penkova; Natalia V. Kotova; Matti Haukka

The reaction between copper(II) nitrate and (E)-N-(3-amino-2,2-dimethylpropyl)-2-(hydroxyimino)propanamide led to the formation of the dinuclear centrosymmetric copper(II) title complex, (C8H18N3O2)2[Cu2(C8H15N3O2)2(C8H17N3O2)2](C9H16N3O4)2·2CH3CN, in which an inversion center is located at the midpoint of the Cu2 unit in the center of the neutral [Cu2(C8H15N3O2)2(C8H17N3O2)2] complex fragment. The Cu2+ ions are connected by two N—O bridging groups [Cu⋯Cu separation = 4.0608 (5) Å] while the CuII ions are five-coordinated in a square-pyramidal N4O coordination environment. The complex molecule co-crystallizes with two molecules of acetonitrile, two molecules of the protonated ligand (E)-3-[2-(hydroxyimino)propanamido]-2,2-dimethylpropan-1-aminium and two negatively charged (E)-{3-[2-(hydroxyimino)propanamido]-2,2-dimethylpropyl}carbamate anions, which were probably formed as a result of condensation between (E)-N-(3-amino-2,2-dimethylpropyl)-2-(hydroxyimino)propanamide and hydrogencarbonate anions. In the crystal, the complex fragment [Cu2(C8H15N3O2)2(C8H17N3O2)2] and the ion pair C8H18N3O2 +.C9H16N3O4 − are connected via an extended system of hydrogen bonds.


Acta Crystallographica Section E-structure Reports Online | 2012

Bis{4-[(3,5-dimethyl-1H-pyrazol-4-yl)selan­yl]-3,5-dimethyl-1H-pyrazol-2-ium} chloride monohydrate

Maksym Seredyuk; Vadim A. Pavlenko; Kateryna O. Znovjyak; Elzbieta Gumienna-Kontecka; Larysa V. Penkova

In the title compound, 2C10H15N4Se+·Cl−·OH−, a singly protonated molecule of the organic selenide participates in hydrogen bonding with neighboring molecules, forming zigzag chains along [001]. The molecule adapts a cis bridging mode with a C—Se—C angle of 102.13 (15)°. π–π stacking interactions are observed between the closest pyrazole rings of neighboring chains [centroid–centroid distance = 3.888 (1) Å] and hydrogen bonding occurs through bridging chloride anions and hydroxide groups. Additionally, O—H⋯Cl hydrogen bonds are formed.


Acta Crystallographica Section E-structure Reports Online | 2011

1-{3-[1-(Hydroxyimino)ethyl]-4-methyl-1H-pyrazol-5-yl}ethanone.

Sergey Malinkin; Larysa V. Penkova; Vadim A. Pavlenko; Matti Haukka; Svetlana Pavlova

In the title compound, C8H11N3O2, the oxime and the acetyl groups adopt a transoid conformation, while the pyrazole H atom is localized in the proximity of the acetyl group and is cis with respect to the acetyl O atom. In the crystal, dimers are formed as the result of hydrogen-bonding interactions involving the pyrazole NH group of one molecule and the carbonyl O atom of another. The dimers are associated into sheets via O—H⋯N hydrogen bonds involving the oxime hydroxyl and the unprotonated pyrazole N atom, generating a macrocyclic motif with six molecules.


Acta Crystallographica Section E-structure Reports Online | 2011

Dibromidobis(3,5-dimethyl-1H-pyrazole-κN)cobalt(II).

Stefania V. Tomyn; Vadim A. Pavlenko; Elzbieta Gumienna-Kontecka; Larysa V. Penkova; Natalia V. Kotova

In the mononuclear title complex, [CoBr2(C5H8N2)2], the CoII atom is coordinated by two N atoms from two monodentate 3,5-dimethylpyrazole ligands and two Br atoms in a highly distorted tetrahedral geometry. In the crystal, the complex molecules are linked by intermolecular N—H⋯Br hydrogen bonds into chains along [101]. An intramolecular N—H⋯Br hydrogen bond is also present.


Acta Crystallographica Section E-structure Reports Online | 2008

catena-Poly[[[trans-diaqua­bis(pyridine-κN)cobalt(II)]-μ-(4-{N′-[1-(3-acetyl-4-methyl-1H-pyrazol-5-yl)ethyl­idene]hydrazino}benzoato-κ3O:N,N′)-[bis­(pyridine-κN)cobalt(III)]-μ-(4-{N′-[1-(3-acetyl-4-methyl-1H-pyrazol-5-yl)ethyl­idene]hydrazino}benzoato-κ3N,N′:O)]perchlorate 3.66-hydrate]

Larysa V. Penkova; Mikhail P. Azarkh; Matti Haukka; Franc Meyer; Igor O. Fritsky

The title compound, {[Co2(C15H14N4O3)2(C5H5N)4(H2O)2]ClO4·3.66H2O}n, is a one-dimensional coordination polymer, with both CoII and CoIII centres in its structure. The ligand environment surrounding CoIII is formed by two N,N-chelating pyrazole-containing ligands and two pyridine molecules in axial positions. The high-spin CoII ions, situated at crystallographic centres of inversion, exhibit a distorted octahedral coordination mode. The ClO4 − anion is linked to the polymer chain via hydrogen bonds. The chains are connected by hydrogen bonds to produce a three-dimensional structure.


Inorganic Chemistry | 2009

Efficient Catalytic Phosphate Ester Cleavage by Binuclear Zinc(II) Pyrazolate Complexes as Functional Models of Metallophosphatases

Larysa V. Penkova; Anna Maciag; Elena V. Rybak-Akimova; Matti Haukka; Vadim A. Pavlenko; Turganbay S. Iskenderov; Henryk Kozlowski; Franc Meyer; Igor O. Fritsky


European Journal of Inorganic Chemistry | 2014

Heterobinuclear Zn–Ln and Ni–Ln Complexes with Schiff-Base and Carbacylamidophosphate Ligands: Synthesis, Crystal Structures, and Catalytic Activity

Oleksiy V. Amirkhanov; Olesia V. Moroz; Kateryna O. Znovjyak; Tetiana Yu. Sliva; Larysa V. Penkova; Tetyana Yushchenko; Lukasz Szyrwiel; Irina S. Konovalova; Viktoriya V. Dyakonenko; Oleg V. Shishkin; Vladimir M. Amirkhanov

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Vadim A. Pavlenko

Taras Shevchenko National University of Kyiv

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Igor O. Fritsky

Taras Shevchenko National University of Kyiv

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Matti Haukka

University of Jyväskylä

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Franc Meyer

University of Göttingen

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Oleg A. Varzatskii

National Academy of Sciences of Ukraine

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Yan Z. Voloshin

Russian Academy of Sciences

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Svitlana V. Kats

Taras Shevchenko National University of Kyiv

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Sergey Malinkin

Taras Shevchenko National University of Kyiv

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