Tag Archive for Vovk

J. Phys. Chem. B, 2015, 119, 13358-13366

A nice surprise for the Centers team was to see the publication in collaboration with the staff on the front cover of “Journal of Physical Chemistry B”.

S.O. Rabdano, A.V. Donets, M.A. Vovk, D.Michel, V.I. Chizhik

“ “Hydration Shells” of CH2 Groups of ω‑Amino Acids as Studied by Deuteron NMR Relaxation”

J. Phys. Chem. B, 2015, 119, 13358-13366


Hydration phenomena play a very important role in various processes, in particular in biological systems. Water molecules in aqueous solutions of organic compounds can be distributed among the following substructures: (i) hydration shells of hydrophilic functional groups of molecules, (ii) water in the environment of nonpolar moieties, and (iii) bulk water. Up to now, the values of hydration parameters suggested for the description of various solutions of organic compounds were not thoroughly analyzed in the aspect of the consideration of the total molecular composition. The temperature and concentration dependences of relaxation rates of water deuterons were studied in a wide range of concentration and temperature in aqueous (D2O) solutions of a set of ω-amino acids.
Assuming the coordination number of the CH2 group equal to 7, which was determined from quantum-chemical calculations, it was found that the rotational correlation times of water molecules near the methylene group is 1.5−2 times greater than one for pure water. The average rotational mobility of water molecules in the hydration shells of hydrophilic groups of ω-amino acids is a bit slower than that in pure solvent at temperatures higher that 60 °C, but at lower temperatures, it is 0.8−1.0 of values of correlation times for bulk water. The technique suggested provides the basis
for the characterization of different hydrophobic and hydrophilic species in the convenient terms of the rotational correlation times for the nearest water molecules.

Dalton Trans. 2015, accepted

A. S. Antonov, A. F. Pozharskii, V. A. Ozeryanskii, A. Filarowski,
K. Yu. Suponitsky, P. M. Tolstoy, M. A. Vovk

“Ring Lithiation of 1,8-Bis(dimethylamino)naphthalene: Another Side of the ‘Proton Sponge Coin’”

Dalton Trans., 2015, accepted

Ring lithiation

It has been found that 1,8-bis(dimethylamino)naphthalene (DMAN), unlike N,N-dimethylaniline, undergoes ring metallation in n-BuLi–TMEDA–Et2O system with low selectivity and in poor total yield. The situation is significantly improved in t-BuLi–TMEDA–n-hexane system when 3- and 4-lithium derivatives become the only reaction products in good yield. The formation of 3-Li-DMAN is especially fortunate since no method of direct meta-functionalization of DMAN has been known to date. The relative stability and structure of DMAN lithium derivatives have been examined with the help of X-ray and multinuclear NMR measurements as well as DFT calculations.

Applied Magnetic Resonance 2014

M. Popova, D. Michel

“Behavior of Sodium Lauroyl Sarcosinate in Solution and Binary Mixtures by Means NMR”

Applied Magnetic Resonance 2014, 45, 353-364

DOI 10.1007/s00723-014-0531-9

Measurements of the 1H and 13C chemical shifts as well as 1H spin–lattice relaxation times of sodium lauroyl sarcosinate (SLAS) in aqueous solutions and mixed binary systems with co-surfactants were carried out at various concentrations. It will be shown that changes in the chemical shifts for the N–CH2 groups in SLAS with increasing surfactant concentration can be used to estimate the ratio pcis /ptrans of cis– and trans-isomers. The relative fraction p trans of molecules in trans-configurations increases the most in a narrow concentration range 0.007–0.034 mol/l, i.e., at the transition from the monomeric state to the micelle. The ratio pcis /ptrans asymptotically decreases with increasing concentration, reaching a constant value at concentrations significantly above the critical micelle concentration. Thus, the ratio can be related to the process of micellization. If micellization takes place, the cis-isomer starts to transform into trans-isomer because the trans-isomer is more favorable in micelles. Because of the smaller cross section of the polar group region, the trans-conformation can be more easily incorporated into the micelle. In summary, the occurrence of micellar aggregates at low SLAS concentration in mixed systems can be clearly inferred from the nuclear magnetic resonance spectra.

Central European School on Physical Organic Chemistry 2014

We participated in a Central European School on Physical Organic Chemistry, which was held in Psheseka (Poland) 26-30.05.2014

with a lecture

P.M. Tolstoy, S.A. Pylaeva, B. Koeppe, E.Yu. Tupikina, C. Allolio, D. Sebastiani, G.S. Denisov, H.-H. Limbach
«Aprotic Polar Solvent Dynamics and Proton Tautomerism in Strong Hydrogen Bonds. NMR, UV-vis and MD Study»

and a poster

M.A. Vovk, A. Kwocz, T. Kozlecki, P. Tretyakov, P.M. Tolstoy, A. Filarowski
«NMR study of hindered internal rotation in β-hydroxynaphthylamides».

On the trail of Mendeleev

RC MRMI received the thanks of organisers of the conference “Mendeleev 2014” for assistance in conducting the tour and master class.

Among the talks presented at the conference was a talk coauthored with the employee of the Center.

А.С. Конева, Е.А. Сафонова, М.А. Вовк, Н.А. Смирнова

“Влияние температуры и содержания воды на коэффициенты самодиффузии в микроэмульсиях «вода в декане», стабилизированных смесью неионных ПАВ (Span80+Tween80)”.

First 3D NMR spectrum

The first HNCO 3D NMR spectrum of uniformly 13C and 15N labeled ubiquitin was recorded in our Center for a new Biomolecular NMR Laboratory working under the leadership of N. R. Skrynnikov. The Laboratory stuff particularly thank our specialist M. A. Vovk.


High school students

Four students of the Second St. Petersburg Gymnasium have visited our Center. They got acquainted with the theory and practice of experiments on nuclear and electron magnetic resonance

Internal seminar 31.10.2013


Mikhail Vovk and Sevastyan Rabdano presented a talk about strategies for protein structure determination by NMR.

Mikhail Vovk and Sevastyan Rabdano got certificates


Employees of the Center for Magnetic Resonance Mikhail Vovk and Sevastyan Rabdano have completed the training course “NMR methods for labeled proteins” in Bruker, Switzerland, and got certificates.



Our contribution to the cluster of conferences «Orgchem-2013» (Repino, 17-21.06.2013)

  • Е.Ю. Тупикина, П.М. Толстой, Г.С. Денисов, «Изменение геометири 1,1-динитроэтана при переходе CH-протона к различным основаниям в комплексах с водородной связью C-H…B»
  • А.А. Гуринов, И.Г. Шендерович, A. Zukal, J. Cejka, «Исследование кислотных центров на поверхности мезопористых кремнеземов методом ЯМР спектроскопии»
  • М.А. Вовк, М.С. Павлова, В.И. Чижик, «Расчет констант квадрупольной связи для кластеров CH3COO * N H2O (N > 24) методом квантовой химии»
  • С.О. Рабдано, А.В. Донец, «Свойства гидратации отдельных функциональных групп органических молекул»