Ресурсный центр «Магнитно-резонансные методы исследования»

L. Sobczyk, D. Chudoba, P.M. Tolstoy, A. Filarowski

“Some Brief Notes on Theoretical and Experimental Investigations of Intramolecular Hydrogen Bonding”

Molecules, 2016, 21, 1657-1/19
DOI:10.3390/molecules21121657

A review of selected literature data related to intramolecular hydrogen bonding in ortho-hydroxyaryl Schiff bases, ortho-hydroxyaryl ketones, ortho-hydroxyaryl amides, proton sponges and ortho-hydroxyaryl Mannich bases is presented. The paper reports on the application of experimental spectroscopic measurements (IR and NMR) and quantum-mechanical calculations for investigations of the proton transfer processes, the potential energy curves, tautomeric equilibrium, aromaticity etc. Finally, the equilibrium between the intra- and inter-molecular hydrogen bonds in amides is discussed.

B. Koeppe, S.A. Pylaeva, C. Allolio, D. Sebastiani, E.T.J. Nibbering, G.S. Denisov, H.-H. Limbach, P.M. Tolstoy

“Polar solvent fluctuations drive proton transfer in hydrogen bonded complexes of carboxylic acid with pyridines: NMR, IR and ab initio MD study”

Phys. Chem. Chem. Phys., 2016, accepted
DOI:10.1039/C6CP06677A

We study a series of intermolecular hydrogen-bonded 1 : 1 complexes formed by chloroacetic acid with 19 substituted pyridines and one aliphatic amine dissolved in CD₂Cl₂ at low temperature by ¹H and ¹³C NMR and FTIR spectroscopy. The hydrogen bond geometries in these complexes vary from molecular (O–H…N) to zwitterionic (O…H–N+) ones, while NMR spectra show the formation of short strong hydrogen bonds in intermediate cases. Analysis of CQO stretching and asymmetric CO2 stretching bands in FTIR spectra
reveal the presence of proton tautomerism. On the basis of these data, we construct the overall proton transfer pathway. In addition to that, we also study by use of ab initio molecular dynamics the complex formed by chloroacetic acid with 2-methylpyridine, surrounded by 71 CD₂Cl₂ molecules, revealing a dualmaximum distribution of hydrogen bond geometries in solution. The analysis of the calculated trajectory shows that the proton jumps between molecular and zwitterionic forms are indeed driven by dipole–dipole solvent–solute interactions, but the primary cause of the jumps is the formation/breaking of weak CH…O bonds from solvent molecules to oxygen atoms of the carboxylate group.

A.V. Artem’ev, E.P. Doronina, M.I. Rakhmanova, A.O. Sutyrina, I.Yu. Bagryanskaya, P.M. Tolstoy, A.L. Gushchin, A.S. Mazur, N.K. Gusarova, B.A. Trofimov

“Luminescent CuI thiocyanate complexes based on tris(2-pyridyl)phosphine and its oxide: from mono-, di- and trinuclear species to coordination polymer”

New J. Chem., 2016, 40, 10028-10040
DOI:10.1039/C6NJ02087A

Tris(2-pyridyl)phosphine oxide reacts with CuSCN to form a variety of luminescent complexes, depending on the specified metal-to-ligand ratio and the solvent used, viz. mononuclear [Cu(N,N′,N′′-Py3P=O)(NCS)], dinuclear (N,N′-Py3P=O)Cu(SCN NCS)Cu[(N,N′-Py3P=O)], their co-crystal (2 : 1, correspondingly) and trinuclear {Cu(NCS)[SCNCu(N,N′,N′′-Py3P=O)]2}. In the solid state, these complexes feature red-orange emission upon UV photoexcitation. The reaction of tris(2-pyridyl)phosphine with CuSCN quantitatively produces an almost insoluble coordination polymer, [Cu(Py3P)NCS]n, which exhibits bright green emission. The synthesized compounds are the first members of the hitherto unknown family of Cu(I) thiocyanate complexes supported by tripodal ligands.

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.

Получено первое прямое экспериментальное подтверждение существования головного мозга у директора РЦ МРМИ. С привлечением иностранных специалистов (Dr. Jing Guo, Dr. Benjamin Koeppe), а также бывших сотрудников РЦ Светланы Пылаевой и д-р Андрея Гуринова в клинике Charite (Берлин, Германия) были зарегистрированы слабые сигналы магнитного резонанса от головы П.М. Толстого. Сделанная на их основе реконструкция (см. рисунок) свидетельствует в пользу гипотезы о существовании у пациента головного мозга.

A.A. Osipov, V.E. Eremyashev, A.S. Mazur, P.M. Tolstoi, L.M. Osipova

“Coordination State of Aluminum and Boron in Barium Aluminoborate Glass”

Glass Physics and Chemistry, 2016, 42(3), 230–237
DOI:10.1134/S1087659616030111

This paper considers the coordination state of boron and aluminum ions in barium aluminoborate glass with a constant ratio of BaO : B₂O₃ = 0.5 and a variable ratio of Al₂O₃ : BaO = 0–3. The dependence of the concentrations of boron and aluminum atoms with a variable coordination number on the Al₂O₃ content was estimated by IR, ¹¹B and ²⁷Al NMR spectroscopy. The nonlinear nature of the obtained dependences was attributed to variations in the aluminum oxide properties. At a content of less than 30 mol % Al₂O₃ serves primarily as a network former, while an increase in the Al₂O₃ concentration results in its higher modifying role in the studied glass.