Ресурсный центр «Магнитно-резонансные методы исследования»

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.

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.

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

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.