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Конгресс Университета Арктики

кадры после трансляции

В рамках Конгресса Университета Арктики (12-16.09.2016, Санкт-Петербург; http://www.uarctic.spbu.ru/) П.М. Толстой выступил с докладом о работе Научного парка СПбГУ на примере РЦ «Магнитно-резонансные методы исследования». Был организован телемост с ресурсным центром, во время которого специалисты А.С. Мазур и М.А. Вовк отвечали на вопросы о текущей работе и выполняемых проектах.

Экскурсия


Сегодня в РЦ проведена экскурсия для учеников 10 классов Академической Гимназии. Наши гости познакомились с магнитно резонансными методами исследования и современным оборудованием представленным в РЦ МРМИ.

 

День открытых дверей


В рамках Дня открытых дверей Института химии СПбГУ в РЦ проведена ознакомительная экскурсия для школьников “Современное оборудование и методы спектроскопии ЯМР”.

Экскурсия для студентов ЛЭТИ


В рамках экскурсии специалистом РЦ Михаилом Вовк продеманстрировано оборудование РЦ МРМИ для решения исследовательских задач методами спектроскопии ЯМР, Станиславом Михайловичем Сухоржевским и Екатериной Гребенюк проведена демонстрация работы на ЭПР спектрометре Bruker Elexsys E580, освещены некоторые особенности спектроскопии ЭПР и областей применения данного метода исследования.

Экскурсия для физиков


Михаил Вовк проводит обзорную экскурсию в РЦ для студентов физиков первого года обучения.

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

Приятным сюрпризом для коллектива РЦ было увидеть публикацию в соавторстве с сотрудниками на обложке “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

DOI:10.1021/acs.jpcb.5b06584

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
DOI:10.1039/C5DT02482J

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.

Spectrochimica Acta, Part A 2015

T. Kozlecki, P.M. Tolstoy, A. Kwocz, M.A. Vovk, A. Kochel, I. Polowczyka, P.Yu. Tretyakov, A. Filarowski

“Conformational state of β-hydroxynaphthylamides and barriers for the rotation of the amide group”

Spectrochimica Acta, Part A, 2015, accepted

2015 04 20

Three β-hydroxynaphthylamides (morpholine, pyrrolidine and dimethylamine derivatives) have been synthesized and their conformational state was analysed by NMR, X-ray and DFT calculations. In aprotic solution the molecules contain intramolecular OHO hydrogen bonds, which change into intermolecular ones in solid state. The energy barriers for the amide group rotation around the CN bond were estimated from the line shape analysis of 1H and 13C NMR signals. A tentative correlation between the barrier height and the strength of OHO bond was proposed. Calculations of the potential energy profiles for the rotations around CC and CN bonds were done. In case of morpholine derivative experimental indications of additional dynamics: chair-chair ‘ring flip’ in combination with the twisting around CC bond were obtained and confirmed by quantum chemistry calculations.

Семинар, М. А. Вовк

02.12.14 в центре прошел семинар М.А. Вовк (специалист РЦ МРМИ) на тему «Исследование подвижности обратных мицелл методом ЯМР: коэффициенты диффузии и корреляции между ними»

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.