English

J. Polym. Sci. A, 2018, 387-398

V.A. Rozentsvet, O.A. Stotskaya, V.P. Ivanova, M.G. Kuznetsova, P.M. Tolstoy, S.V. Kostjuk

“Structural characterization of polybutadiene synthesized via cationic mechanism”

J. Polym. Sci. A, 2018, 56, 387-398
DOI: 10.1002/pola.28905

 

The microstructure of polybutadiene synthesized via cationic polymerization using TiCl4‐based initiating systems has been investigated using 1D (1Н, 2Н, and 13С) and 2D (HSQC and HMBC) NMR spectroscopy. It was found that trans‐1,4‐unit is predominant structure of unsaturated part of polymer chain. Besides, the small amount of 1,2‐structures was also detected, while cis‐1,4‐units were totally absent. The signals of carbon atoms of three types of head groups (trans‐1,4‐, 1,2‐, and tert‐butyl) and two types of end groups (trans‐1,4‐Cl and 1,2‐Cl) were identified for the first time in macromolecules of cationic polybutadiene. It was showed that tert‐butyl head groups were formed due to the presence in monomer of admixtures of isobutylene. The new methodology for calculation of the content of different structural units in polybutadiene chain as well as the head and end groups was proposed. It was established that main part of 1,2‐units distributed randomly along the polybutadiene chain as separate units between trans‐1,4‐structures.

FIRST

source:http://www.cimo.fi/programmes/first

П.М. Толстой провел занятие на тему «ЯМР систем с водородной связью» для студентов бакалавриата и магистратуры университета Ювяскюля (Финляндия) в рамках русско-финского студенческого семинара по программе обмена FIRST. Программа мероприятий в Институте химии СПбГУ.

Турнир школьников


Ресурсный центр МРМИ посетили участники Всероссийского химического турнира школьников. П.М. Толстой провел демонстрацию оборудования и рассказал нашим гостям о возможностях современных магнитно-резонансных методов исследования, реализованных в рц.

New Journal of Chemistry, 2017, 41, 13918-13928

A.A. Vereschagin, V.V. Sizov, P.S. Vlasov, E.V. Alekseeva, A.S. Konev, O.V. Levin

“Water-stable [Ni(salen)]-type electrode material based on phenylazosubstituted salicylic aldehyde imine ligand”

New Journal of Chemistry, 2017, 41, 13918-13928
DOI: 10.1039/c7nj03526h

source: http://pubs.rsc.org/en/Content/ArticleLanding/2017/NJ/C7NJ03526H#!divAbstract 

A novel electrode material was prepared by electrochemical oxidation of [4,4′-phenylazo-2,2′-(ethylenediimino-κ2N-methyl)diphenolate-κ2O]nickel, a [Ni(II)(salen)]-type complex, in chlorinated solvent. The chemical structure of the material was explored by FTIR, NMR and XPS techniques to determine the main components of the material and the nature of the linkage between them. The morphology of the material films was explored by SEM analysis. The electrochemical properties of the new material were studied by a set of voltammetric methods and an unusual stability of the material in aqueous medium was observed.

Tetrahedron, 2017, 73, 671-680

M.M. Efremova, R.R. Kostikov, A.V. Stepakov, T.L. Panikorovsky, V.S. Shcherbakova, A.V. Ivanov, A.P. Molchanov

“Unusual Lewis-acid catalyzed formal (3+3)-cycloaddition of azomethine imines and nitrones to N-vinylpyrroles”

Tetrahedron, 2017, 73, 671-680
DOI: 10.1016/j.tet.2016.12.034

source:https://www.sciencedirect.com/science/article/pii/S0040402016313217?via%3Dihub 

The addition of Lewis acids change the reaction mechanism of the cycloaddition of N-vinylpyrroles with azomethine imine and C,N-diarylnitrones. The formal (3+3)-cycloaddition is observed instead of (3+2)-dipolar cycloaddition, which take place in the absence of catalysts. This unusual (3+3)-cycloaddition leads to heterocyclic compounds with pyrazolo[1,2-a]pyrrolo[1,2-d][1,2,4]triazine- and pyrrolo[2,1-d][1,2,5]oxadiazine cores, which are difficultly achievable by other methods.

Mendeleev Commun., 2017, 27, 95-96

G. P. Kantin, M. Yu. Krasavin

“Microwave-promoted reaction of N-alk-1-enyl chloroacetamides with sodium azide unexpectedly yields 1H-imidazol-5(4H)-ones”

Mendeleev Commun., 2017, 27, 95-96
DOI: 10.1016/j.mencom.2017.01.031

source: https://www.sciencedirect.com/science/article/pii/S0959943617300317?via%3Dihub

A novel method to prepare biologically relevant 1H-imidazol-5(4H)-ones from aliphatic amines, isobutyraldehyde, chloroacetyl chloride and sodium azide under microwave irradiation has been developed.

Февраль

В Феврале выполнено 2014 заявок на сервисные измерения.

Измерено:

  • 1848 спектр 1H
  • 366 спектра 13C
  • 87 спектров DEPT
  • 41 спектров COSY
  • 22 спектра NOESY
  • 85 спектра 31Р
  • 91 спектров 19F

Выполнено 239 заявок на исследовательскую работу.

Лекция

22.02.18 в актовом зале школы №20 Санкт-Петербурга прошла открытая лекция директора ресурсного центра «Магнитно-резонансные методы исследования» П.М. Толстого «Достижения физической химии». В лекции было рассказано о наиболее значимых для повседневной жизни человека открытиях последних лет в области химии, физики, материаловедения. После лекции общение с учащимися продолжилось в форме беседы о перспективах обучения в Санкт-Петербургском университете по специальностям «Физика» и «Химия».

Tetrahedron Letters, 2017, 3470-3473

M. Chizhova, D. Dar’in, M. Krasavin

“Complications in the Castagnoli-Cushman reaction: An unusual course of reaction between cyclic anhydrides and sterically hindered indolenines”

Tetrahedron Letters, 2017, 58(35), 3470-3473
DOI: 10.1016/j.tetlet.2017.07.077

source: https://www.sciencedirect.com/science/article/pii/S0040403917309395?via%3Dihub

Attempted reaction of indolenines (which represent rather sterically hindered cyclic imines) with a series of dicarboxylic acid anhydrides yielded no expected product, the Castagnoli-Cushman lactam. Instead, products presumably formed via N-acyliminium species trapping by a carboxylate anion. Among them, hydrolytically labile 2:2 adducts of an indolenine and a cyclic anhydride, containing a 16-membered cyclic core, are particularly intriguing. This result contradicts the recently reported successful Castagnoli-Cushman reaction of indolenines with homophthalic anhydride suggesting a mechanistic switch in the course of the reaction.

Scientific Reports, 2017, 7, 11161

S. O. Rabdano, S. A. Izmailov, D. A. Luzik, A. Groves, I. S. Podkorytov, N. R. Skrynnikov

“Onsеt of Disоrdеr and Protein Aggregation Due to Oxidation-Induced Intermolecular Disulfide ”

Scientific Reports, 2017, 7, 11161
DOI: 10.1038/s41598-017-10574-w

source: https://www.nature.com/articles/s41598-017-10574-w/figures/11

We have investigated the behavior of second RNA-recognition motif (RRM2) of neuropathological protein TDP43 under the effect of oxidative stress as modeled in vitro. Toward this end we have used the specially adapted version of H/D exchange experiment, NMR relaxation and diffusion measurements, dynamic light scattering, controlled proteolysis, gel electrophoresis, site-directed mutagenesis and microsecond MD simulations. Under oxidizing conditions RRM2 forms disulfide-bonded dimers that experience unfolding and then assemble into aggregate particles (APs). These particles are strongly disordered, highly inhomogeneous and susceptible to proteolysis; some of them withstand the dithiothreitol treatment. They can recruit/release monomeric RRM2 through thiol-disulfide exchange reactions. By using a combination of dynamic light scattering and NMR diffusion data we were able to approximate the size distribution function for the APs. The key to the observed aggregation behavior is the diminished ability of disulfide-bonded RRM2 dimers to refold and their increased propensity to misfold, which makes them vulnerable to large thermal fluctuations. The emerging picture provides detailed insight on how oxidative stress can contribute to neurodegenerative disease, with unfolding, aggregation, and proteolytic cleavage as different facets of the process.