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Institute of Chemical Kinetics and Combustion
International Tomography Center
Faculty of Natural Sciences Novosibirsk State University
III School for young scientists
Magnetic Resonance and Magnetic
Phenomena in Chemical and Biological
Physics
Book of abstracts
Novosibirsk 2014
2
Organizers
Institute of Chemical Kinetics and
Combustion of the Siberian
Branch of the Russian Academy
of Sciences
International Tomography Center
of the Siberian Branch of the
Russian Academy of Sciences.
Faculty of Natural Sciences
Novosibirsk State University
Sponsors
Russian Foundation for Basic
Research
3
Organizing Committee
Victor A. Bagryansky – Chairman
Leonid V. Kulik – Vice-chairman
Petr A. Purtov – Vice-chairman
Tatiana Yu. Karogodina – Scientific Secretary
Elena G. Bagryanskaya
Konstantin L. Ivanov
Daniil I. Kolokolov
Irina S. Tretyakova
Nikolay P. Isaev
4
Program
September 7
9.00 – 13.00 Registration, arrival
12.30-14.00 Lunch
14.00 – 14.10 Opening of the School.
14.10 – 14.30 Voevodsky Prize awarding ceremony
Lectures Chairman - Gerd Kothe
14.30 – 15.30 Kev Salikhov (Kazan, Russia) "Theory of the pulse electron double
resonance spectroscopy"
15.30 – 16.30 Maxim Yulikov (Zurich, Switzerland) "Studies of structure and
conformational changes of biomacromolecules and their complexes: pulse EPR
techniques based on static and stochastic electron-electron dipolar interaction"
16.30 – 17.00 Coffee break
Lectures Chairman – Ulrich Steiner
17.00 – 18.00 Michael K. Bowman (Alabama, USA) "Measurement of hyperfine
couplings by pulsed EPR"
18.00 – 19.00 Sergey A. Dzuba (Novosibirsk, Russia) "Structure and dynamics of spin-
labeled biological systems"
19.00 - … Welcome party
September 8
Lectures Chairman – Hans-Martin Vieth
9.00 – 10.00 Robert Kaptein (Utrecht, the Netherlands) "Protein-DNA interaction: how
do proteins find their target?"
10.00 – 11.00 Christian Griesinger (Goettingen, Germany) "Protein dynamics and
neuroprotection: Approaches by NMR"
11.00 – 11.30 Coffee break
Lectures Chairman – Sergey Dzuba
11.30 – 12.30 Gerd Kothe (Freiburg, Germany) "Nuclear hyperpolarisation and spin
entanglement in photoexcited triplet states"
12.30 – 13.30 Peter Tolstoy (Saint Petersburg, Russia) "Cooperativity of functional
hydrogen bonds in active sites of enzymes: NMR study of model systems"
13.30-15.00 Lunch
5
14.00 – 16.00 Cultural program (Excursion to Open-air Historical and Architectural
Museum)
16.00 – 18.00 Free time
18.00 – 20.00 Poster session
September 9 Lectures Chairman – Christian Griesinger
9.00 – 10.00 Torsten Gutmann (Darmstadt, Germany) "Investigation of structure and
surface chemistry of heterogeneous catalysts employing advanced solid-state NMR
techniques"
10.00 – 11.00 Olga Lapina (Novosibirsk, Russia) "Advanced solid state NMR
spectroscopy for structural characterization of supported catalysts"
11.00 – 11.30 Coffee break
Lectures Chairman – Maxim Yulikov
11.30 – 12.30 Anatoly Dvurechenskii (Novosibirsk, Russia) "Spin resonance of
electrons localized in Ge/Si quantum dot nanoheterostructures"
12.30 – 13.30 Jan Behrends (Berlin, Germany) "EPR in solar cell research"
13.30-15.00 Lunch
Oral presentations by young scientists Chairman – Nikolay Isaev
15.00 – 15.20 Fedor Mushenok (Chernogolovka, Russia) “FMR study of Cr1/3NbS2
helical magnet”
15.20 – 15.40 Alexandr Chushnikov (Kazan, Russia) “Possibilities of EPR diagnostics
for monitoring the sportsmen’s state of health”
15.40 – 16.00 Anatoly R. Melnikov (Novosibirsk, Russia) “Highly efficient exciplex
formation in case of X-ray irradiation of non-polar solutions”
16.00 – 16.20 Andrey N. Pravdivtsev (Novosibirsk, Russia) “Exploiting Level Anti-
Crossings in the rotating frame for transferring spin hyper polarization”
16.20 – 16.40 Kirill Levin (Winnipeg, Canada) “Experimental and theoretical NMR
analysis of paramagnetic M(acac)3 (M = Cr, Mn) coordination compounds”
16.40 – 17.00 Irina Yu. Barskaya (Novosibirsk, Russia) “The EPR study of light-
induced thermally inaccessible spin state in copper-nitroxide based molecular magnet”
17.00 – 17.30 Coffee break
Oral presentations by young scientists Chairman – Daniil Kolokolov
17.30 – 17.50 Elena Tupikina (Saint-Petersburg, Russia) “Proton transfer process in C-
H···X hydrogen bonds”
17.50 – 18.10 Alekper Huseynzada (Baku, Azerbaijan) “Investigation of some
acetophenone derivatives in solution by NMR”
18.10 – 18.30 Alexey Chubarov (Novosibirsk, Russia) “Fluorinated homocysteine
derivatives as potential molecular probes for 19
F magnetic resonance spectroscopy and
imaging: synthesis and characterization”
18.30 – 18.50 Alexander Khudozhitkov (Novosibirsk, Russia) “2H NMR study of the
rotational dynamics of terephatalate phenylenes in metal-organic frameworks CoMOF,
NiMOF and ZnMOF: effect of different metal centers”
6
18.50 – 19.10 Olga Selyutina (Novosibirsk, Russia) “Influence of glycyrrhizin on cell
membrane properties”
19.10 – 19.30 Danila Barskiy (Novosibirsk, Russia) “Low-field NMR spectroscopy and
imaging via parahydrogen based hyperpolarization: Towards catalyst-free molecular
contrast agents and MRI of industrial hydrogenation”
September 10 Lectures Chairman – Michael Bowman
9.00 – 10.00 Ulrich E. Steiner (Konstanz, Germany) "Spin-orbit-coupling based spin
chemistry"
10.00 – 11.00 Kiminori Maeda (Saitama, Japan) "Magnetoreception of molecular
systems and spin selective chemical reactions"
11.00 – 11.30 Coffee break
Lectures Chairman – Robert Kaptein
11.30 – 12.30 Hans-Martin Vieth (Berlin, Germany) "The role of level-anti-crossings in
spin hyperpolarization"
12.30 – 13.30 Alexandra Yurkovskaya (Novosibirsk, Russia) "Time-resolved and field
dependent CIDNP"
13.30-15.00 Lunch
15.00 – 19.00 Practical work. Tutorial on pulse EPR and NMR spectrometers (parallel)
19.00 - … Banquet
September 11 Lectures Chairman – Leonid Kulik
10.00 – 11.00 Tatyana Leshina (Novosibirsk, Russia) "The study of radical stages
practically important processes by methods of spin chemistry"
11.00 – 11.30 Coffee break
Lectures Chairman – Leonid Kulik
11.30 – 12.30 Nikolay Polyakov (Novosibirsk, Russia) "Application of NMR in medical
research"
12.30 – 13.30 Anatolii Vanin (Moscow, Russia) "EPR analysis of biologically active
dinitrosyl iron complexes with thiolate ligands"
13.30-15.00 Lunch
15.00 – 15.30 Closing of the School
15.30 Group photo
7
LECTURES
8
Theory of the pulse electron double resonance spectroscopy
K.M. Salikhov
Zavoisky physical-technical institute of Russian academy of sciences, Kazan
420029, Russian Federation
E-mail: salikhov@kfti.knc.ru
Content of the lecture
1. Survey of the early years studies of the electron spin-spin interaction using pulse EPR
methods.
2. Current theory of the pulse electron double resonance spectroscopy
3. Recent development of the pulse electron double resonance (PELDOR) spectroscopy
theory
4. Perspectives of PELDOR in studying structure in nanoscale region
References
[1] K.M. Salikhov, A.G. Semenov, Yu.D. Tsvetkov. Electron spin echo and its
applications. Nauka, Novosibirsk (1976)
[2] Milov A.D., Salikhov K.M., Schirov M.D., Fiz. Tverd. Tela 23, pp. 975-982 (1981)
[3] Spiess H.W. J. Magn. Reson.213, pp. 326-328 (2011)
[4] Salikhov K.M., I.T. Khairuzhdinov I.T., Zaripov R.B.. Appl. Magn, Reson. 45, pp.
573-620 (2014)
Lectues, September 7, 14:30 Lecture, September 7, 14:30
9
Studies of structure and conformational changes of
biomacromolecules and their complexes: pulse EPR
techniques based on static and stochastic electron-electron
dipolar interaction
Maxim Yulikov
ETH Zurich, Department of Chemistry and Applied Bioscience, Laboratory of Physical
Chemistry, Vladimir Prelog Weg 2, 8093, Zurich, Switzerland
E-mail: maxim.yulikov@phys.chem.ethz.ch
Over the last two decades pulse EPR techniques attract growing attention as a tool
for determination of structure and for studies of conformational changes of
biomacromolecules and their complexes. Paramagnetic centers can be introduced to a
biomacromolecule by the so-called site-directed spin labeling (SDSL) technique, based
on chemically-specific attachment of paramagnetic labels at selected and appropriately
modified sites in a biomolecule under study. The magnetic dipolar interaction between
two spin labels encodes distance between them, and the measurement of this interaction
can thus provide a constraint for the distance between the two labeling sites.
The most broadly used approach exploits different types of nitroxide radicals for
spin labeling and pulse electron-electron double resonance (abbreviated as PELDOR or
DEER) for distance measurements. While PELDOR/DEER experiments, based on the
measurement of static dipolar interaction, are the most broadly spread, other pulse EPR
experiments to measure static (double quantum coherence (DQC)) or stochastic dipolar
interaction (relaxation enhancement (RE), relaxation induced dipolar modulation
enhancement (RIDME)) can be used.
During the previous few years pulse EPR experiments with non-identical spin label
pairs that significantly differ in their spectroscopic properties have been intensively
studied. While PELDOR/DEER technique is considered to be the most appropriate in
measurements of nitroxide-nitroxide distances, for the new combinations of spin labels
other experiments might be more favorable. In this lecture we will overview some
distance measurement experiments in pulse EPR with a particular accent on
measurement of stochastic dipolar interactions in pairs of identical and non-identical
(‘spectroscopically orthogonal’) spin labels.
Lecture, September 7, 15:30
10
Measurement of Hyperfine Couplings by Pulsed EPR
Michael K. Bowman
Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487-0336
USA
E-mail:mkbowman@as.ua.edu
Hyperfine couplings between an unpaired electron and nuclear spins are an
important source of information about the electronic and physical structure of
paramagnetic species. The unpaired spin density, the partially-occupied molecular
orbitals, and the physical structure can all be probed through hyperfine couplings.
A brief introduction to hyperfine coupling tensors will be presented, with a more
detailed look at how they behave in systems with large g-factor anisotropy. The
measurement of hyperfine tensors by pulsed EPR measurements based on electron
nuclear double resonance (ENDOR) and electron spin echo envelope modulation
(ESEEM) will be presented. Practical approaches to extraction of hyperfine tensors
from one- and two-dimensional ESEEM, including HYSCORE will be demonstrated.
The two common forms of pulsed ENDOR developed by Mims and Davies will be
described and important experimental parameters affecting the spectral shapes will be
illustrated.
This work is supported by NSF-RFBF Grant 14-03-93180 and National Institutes of
Health HL095820 and GM110790.
Lecture, September 7, 17:00
11
Pulsed EPR of Spin-Labeled Biological Systems
Sergei A. Dzuba
Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of
Sciences, Institutskaya, 3, 630090 Novosibirsk, Russia
and Novosibirsk State University,Pirogova 2, 630090 Novosibirsk, Russia
E-mail: dzuba@kinetics.nsc.ru
Methods of pulsed EPR based on electron spin echo (ESE) spectroscopy include
ESE envelope modulation (ESEEM) induced by electron-nuclei interactions, electron-
electron double resonance (PELDOR or DEER) induced by electron-electron
interactions, ESE signal decay induced by molecular motions, and others. Their
applications to study various biological systems using spin labels and probes provides
information on the conformations of peptides, proteins, DNAs and other biomolecules,
supramolecular structure of biological membranes and other multicomponent systems,
the orientational cooperative dynamics of molecules in disordered media and others.
Lecture, September 7, 18:00
12
Protein-DNA interaction: how do proteins find their target?
Robert Kaptein
Bijvoet Centre, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
e-mail: r.kaptein@uu.nl
The E.coli lac repressor is a text-book example of a bacterial gene regulatory
protein. Our NMR studies of the structure and dynamics of complexes of a dimeric lac
headpiece with lac operator DNA have provided a detailed picture of how the various
lac operator sequences are recognized (1).
We have also addressed the problem of non-specific DNA interaction and the NMR
structure of dimeric headpiece with a non-operator DNA has been solved (2). Generally,
these non-specific interactions are assumed to be crucial for rapid target-site location by
DNA-binding proteins. The NMR structure of the non-specific lac headpiece-DNA
complex suggested how the repressor searches for its target site by sliding along random
DNA and binds to the operator through a folding-coupled-to-binding transition (2).
However, surprisingly the 1D diffusion constant for sliding on DNA obtained from
NMR line-broadening is much smaller than that determined by single-molecule
fluorescence methods and cannot account for an enhanced target location by lac
repressor (3). In the lecture I will discuss possible reasons for this discrepancy.
References
1a. C.G. Kalodimos, A.M.J.J. Bonvin, R. Kopke Salinas, R. Wechselberger, R.
Boelens and R. Kaptein, “Plasticity in protein-DNA recognition: lac repressor interacts
with its natural operator O1 through alternative conformations of its DNA-binding
domain” , EMBO J. 21 (2002), 2866-2876.
1b. J. Romanuka, et al., “Specificity and Affinity of Lac Repressor for the
Auxiliary Operators O2 and O3 Is Explained by the Structures of Their Protein-DNA
Complexes”, J.Mol.Biol. 390 (2009), 478-489.
2. C.G.Kalodimos, et al., “Structure and Flexibility Adaptation in Nonspecific and
Specific Protein-DNA Complexes”, Science 305 (2004), 386-389.
3. K. Loth et al., “Sliding and target location of DNA-binding proteins: an NMR
view of the lac repressor system”, J.Biomol. NMR 56 (2013) 41-49.
Lecture, September 8, 9:00
13
Protein dynamics and Neuroprotection: Approaches by NMR
David Ban1, Colin Smith
1,2, Supriya. Pratihar
1, T. Michael Sabo
1, Sergey Ryazanov
1,3,
Andrei Leonov1, Saskia Villinger
1, Robert Schneider
1, Luigi Russo
1,Maestre, Mitcheell
1,
Vytautas. Gapsys2, Jan Hennig
2, R. Bryn Fenwick
4, Korvin F. A. Walter
1, Karin Giller
1,
Stefan Becker1, Xavier Salvatella
4, Berend L. de Groot
2, Armin Giese
5, Markus
Zweckstetter1,3
, Adam Lange1, Donghan Lee
1, C. Griesinger
1
1NMR based Structural Biology and
2Theoretical and computational biophysics, Max
Planck Institute for Biophysical Chemistry, Göttingen, Germany,3CNMPB
Göttingen,4Laboratory of Molecular Biophysics, ICREA and Institute for Research in
Biomedicine Barcelona, Barcelona, Spain
The possibility to explore dynamics of proteins specifically ubiquitin which
promiscuously recognizes many binding partners will be presented based on the
accurate measurement of anisotropic parameters such as residual dipolar couplings (1).
This approach allows to characterize at unprecendented detail the ground state ensemble
of the protein (2). Modulation of the distributions of conformations within the ground
state ensemble by mutations that do not involve the binding interface allows to make
ubiquitin more specific to recognition proteins (3). Rates of interconversion between
ground state ensemble members have been measured by low temperature relaxation
dispersion (4), dielectric relaxation and temperature jump SAXS and were compared to
MD results (5). Further, with high-power relaxation dispersion measurements (6) it is
possible to characterize motion kinetically to one digit µs time scales. With these
measurements a rotamer shuffling for the side chains is detected that occurs both for
ubiquitin and protein G.
Similar approaches can be used to characterize motion of membrane proteins and
multidomain proteins as shown on the examples of VDAC (7) and Calmodulin/peptide
complexes (8).
In a second part of the presentation, NMR results and beyond are presented towards
neuroprotective strategies in Parkinson’s and Alzheimer’s disease in which lipophilic
small molecules (9) are effective in various animal models of the diseases. They change
the aggregation landscape of the proteins populating and interfere with membrane pore
formation by these proteins.
References
1) Peti, W., Meiler, J., Brüschweiler, R. and Griesinger ,C. (2002)
Model free Analysis of Protein Backbone Motion from Residual Dipolar Couplings. J. Am.
Chem. Soc. 124, 5822-5833; T. M. Sabo, C. A. Smith, D. Ban, A. Mazur, D. Lee, C.
Griesinger, „Orium: Optimized RDC based Iterative and Unified Model-free analysis” J.
Biomol. NMR 127, 287-301 (2014)
2) Lange, O., Lakomek, N. A., Farès, C., Schröder, G.,Becker, S., Meiler, J., Grubmüller, H.,
Griesinger, C., de Groot, B.: Recognition dynamics up to microseconds revealed from an
RDC-derived ubiquitin ensemble in solution. Science, 2008, 320, 1471-1475
Lecture, September 8, 10:00
14
3) Servaas Michielssens, Jan Henning Peters, David Ban, Supriya Pratihar, Daniel Seeliger,
Monika Sharma, Karin Giller, Thomas Michael Sabo, Stefan Becker, Donghan Lee,
Christian Griesinger, and Bert L. de Groot, A Designed Conformational Shift To Control
Protein Binding Specificity, Angew. Chem. Int Ed. In press 2014
4) Ban, D., M.F. Funk, R. Gulich, D. Egger, T. M. Sabo, K.F.A. Walter, R. B. Fenwick, K.
Giller, F, Pichierri, B.L. de Groot, O. F. Lange, H. Grubmüller, X. Salvatella, M. Wolf, A.
Loidl, R. Kree, S. Becker, N.-A. Lakomek, D. Lee, P. Lunkenheimer, C. Griesinger: Kinetics
of Conformational Sampling in Ubiquitin. Angew. Chem. Int. Ed. 50, 11437-11440 (2011)
5) Shaw, David E.; Maragakis, Paul; Lindorff-Larsen, Kresten; Piana, Stefano; Dror, Ron O.;
Eastwood, Michael P.; Bank, Joseph A.; Jumper, John M.; Salmon, John K.; Shan, Yibing;
Wriggers, Willy. Atomic-Level Characterization of the Structural Dynamics of Proteins.
Science 330, 341-346 (2010)
Fenwick, R.B., Esteban-Martin, S ., Richter, B ., Lee, D ., Walter, K.F.A., Milovanovic, D.
Becker, S., Lakomek, N.A., Griesinger, C ., Salvatella, X.: Weak Long-Range Correlated
Motions in a Surface Patch of Ubiquitin Involved in Molecular Recognition. Journal of the
American Chemical Society 133, 10336-10339 (2011)
6) Ban, David, A. D. Gossert, K. Giller, S. Becker, C. Griesinger and D. Lee: Exceeding the
limit of dynamics studies on biomolecules using high spin-lock field strengths with a
cryogenically cooled probehead. Journal of Magnetic Resonance, 221, 1- 4 (2012)
7) Bayrhuber, M., Meins, T., Habeck, M., Becker, S., Giller, K., Villinger, S., Vonrhein, C.,
Griesinger, C., Zweckstetter, M. and Zeth, K. (2008) Structure of the human voltage-
dependent anion channel, Proceedings of the National Academy of Sciences of the United
States of America, 105 (40): 15370-15375
Villinger, S., Briones, R., Giller, K., Zachariae, U., Lange, A., De Groot, B. L., Griesinger,
C., Becker, S. and Zweckstetter, M. (2010)
Functional dynamics in the voltage-dependent anion channel, Proceedings of the National
Academy of Sciences of the United States of America, 107 (52): 22546-22551; Schneider,
R., Etzkorn, M., Giller, K., Daebel, V., Eisfeld, J., Zweckstetter, M., Griesinger, C., Becker,
S. and Lange, A. (2010)
The Native Conformation of the Human VDAC1 N Terminus, Angewandte Chemie-
International Edition, 49 (10): 1882-1885; Villinger, S., Briones, R., Giller, K., Zachariae,
U., Lange, A., De Groot, B. L., Griesinger, C., Becker, S. and Zweckstetter, M. (2012)
Functional dynamics in the voltage-dependent anion channel, Febs Journal, 279 433-433;
Villinger, Saskia; Giller, Karin, Bayrhuber, Monika, Lange, Adam, Griesinger, Christian,
Becker, Stefan, Zweckstetter, Markus, Nucleotide Interactions of the Human Voltage-
dependent Anion Channel J. Biol. Chem. 289, 13397-13406 (2014)
8) Russo, Luigi, Maestre-Martinez, Mitcheell, Wolff, Sebastian, Becker, Stefan, Griesinger,
Christian, Interdornain Dynamics Explored by Paramagnetic NMR; J. Am. Chem. Soc. 135,
17111-17120 (2013)
9) Giese, Bertsch, Habeck, Wagner, Weber, Kretzschmar, Hirschberger, Tavan, Geissen,
Groschup, Griesinger, Leonov, Ryazanov; WO 2010/000372 A2, Jan. 7. 2010
J. Wagner, S. Ryazanov, A. Leonov, J. Levin, S. Shi, F. Schmidt, C. Prix, F. Pan Montojo,
U. Bertsch, G. Mitteregger-Kretzschmar, M. Geissen, M. Eiden, F. Leidel, T. Hirschberger,
A.A. Deeg, J.J. Krauth, W. Zinth, P. Tavan, J. Pilger, M. Zweckstetter, T. Frank, M. Bähr,
J.H. Weishaupt, M. Uhr, H. Urlaub, U. Teichmann, M. Samwer, K. Boetzel, M. Groschup,
H. Kretzschmar, C. Griesinger, A. Giese, Acta Neuropath. 125, 795-813 (2013)
Levin, Johannes, Schmidt, Felix, Boehm, Cathrin, Prix, Catharina, Boetzel, Kai, Ryazanov,
Sergey , Leonov, Andrei, Griesinger, Christian, Giese, Armin, The oligomer modulator
anle138b inhibits disease progression in a Parkinson mouse model even with treatment
started after disease onset. Act. Neuropath. 127, 779-780 (2014)
15
Nuclear Hyperpolarization and Spin Entanglement in
Photoexcited Triplet States
Gerd Kothe
Department of Physical Chemistry, University of Freiburg, Freiburg 79104,
Germany
E-mail: gerd.kothe@physchem.uni-freiburg.de
In this lecture, I should like to discuss two novel quantum mechanical mechanisms
which generate nuclear hyperpolarization in photoexcited triplet states. The first
mechanism is the basic mechanism which applies to any given field strength and
orientation. The second mechanism induces electron and nuclear hyperpolarization only
at level anti-crossing (LAC) conditions. Here, we explore these two mechanisms using
pulsed magnetic resonance in combination with pulsed laser excitation.
Recently, nuclear quantum oscillations have been detected in an organic triplet state
subject to an external magnetic field.1 Analysis reveals that the nuclear spins participate
in the intersystem crossing process. The novel mechanism also acts as a source of
oscillatory nuclear spin polarization which gives rise to NMR signal enhancement even
at very high magnetic fields.1
This opens new perspectives for the analysis of photo-
CIDNP in mechanistic studies of photoactive proteins. Here, we report on magnetic
field dependent 13
C NMR studies of the blue light receptor phototropin demonstrating
that a triplet state is the major photo-CIDNP source.2
More than 35 years ago, nuclear hyperpolarization has been observed in organic
triplet states at LAC conditions.3,4
Here, we identify the underlying mechanism
employing phosphorescent crystals. First, a laser pulse generates the triplet state and
initiates the formation of multipartite entanglement between the electron spin and all
hyperfine coupled nuclear spins. This gives rise to huge oscillatory electron and nuclear
spin polarization. Then, by the action of a resonant high-power microwave pulse, the
electron spin is disentangled from the nuclear spins. As a result, the longitudinal nuclear
magnetization evolves separately under the nuclear spin Hamiltonian. Due to robust
entanglement of the nuclear spins, one observes quantum oscillations at the nuclear
Larmor frequency. Thus, at triplet LAC conditions, strongly entangled nuclear spin
states are created simply by light excitation. Because of the huge polarization, generated
at LAC, these quantum systems are capable of room temperature operation. This makes
them promising candidates for various applications in quantum information processing.
[1] Kothe G., Yago T., Weidner J.-U., Link G., Lukaschek M. and Lin T.-S. J. Phys.
Chem B 2010, 114, 14755-14762.
[2] Kothe G., Lukaschek M., Link G., Kacprzak S., Illarionov B., Fischer M.,
Eisenreich W., Bacher A., Weber S., unpublished results.
[3] Veeman, W.S., van der Poel, A.L.J. and van der Waals J.H. Mol. Phys. 1975, 29,
225-248.
[4] Colpa, J.P. and Stehlik D. Chem. Phys. 1977, 21, 273-288.
Lecture, September 8, 11:30
16
Cooperativity of Functional Hydrogen Bonds in Active Sites
of Enzymes: NMR Study of Model Systems
Peter M. Tolstoy,1 Monique Chan-Huot,
2 Sharif Shasad,
2 Michael D.
Toney,3 Ilja G. Shenderovich,
4 Gleb S. Denisov,
5 Hand-Heinrich Limbach
2
1 Institute of Chemistry, St. Petersburg State University, Universitetskij pr. 26, 198504 Peterhof, Russia
2 Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
3 Department of Chemistry, University of California-Davis, 95616 Davis, USA 4 University of Regensburg, Universitätsstr. 31, 93040 Regensburg, Germany
5 Institute of Physics, St. Petersburg State University, Universitetskij pr. 26, 198504 Peterhof, Russia
peter.tolstoy@spbu.ru
In this presentation we discuss geometric hydrogen bond cooperativity effects in
view of their role in enzymatic catalysis. In many enzymes, such as Photoactive Yellow
Protein (PLP), Aspartic Proteases (such as chymotrypsin or HIV-1 Pr), vitamin B6-
dependent enzymes (f.e. aspartate aminotransferase, AspAT) and many others, the
mechanism of catalysis requires two or more H-bonds to mutually influence each other
(i.e. displacement of the bridging proton in one of the H-bonds changes the proton
position in the other one), thus facilitating certain chemical reactions.
Firstly, a short overview of the NMR-based research of H-bond structure and
geometry will be given. Secondly, we will present a series of model systems mimicking
H-bond motifs in active sites of PYP (Figure, left) and AspAT (Figure, right). The
results and predictions of the NMR studies on model systems will be followed by the
investigation of the actual biomolecule. We conclude that NMR approach based on
model systems can help in localizing functional bridging protons and deducing catalytic
mechanisms.
NH2
HO2C RH
“internal aldimine” “external aldimine”
Lysine enyzme
H3N
transimination
AspAT PYP
O S
O
H H
OTyrO
OGlu
H
O
Thr
O
O S
H
446 nm
h
darkstate
signallingstate
This work was partially funded by RFBR grant 14-03-00111, as well as by the German-
Russian Interdisciplinary Science Center (G-RISC) funded by the DAAD.
Lecture, September 8, 12:30
17
Investigation of Structure and Surface Chemistry of
Heterogeneous Catalysts employing Advanced Solid-State
NMR Techniques
Torsten Gutmanna, Liu Jiquan
a, Niels Rothermel
a, Karine Philippot
b, Bruno
Chaudretc, Hergen Breitzke
a, and Gerd Buntkowsky
a.
a TU Darmstadt; Eduard-Zintl-Institut für Anorg. und Phys. Chemie, Petersenstraße 20,
D-64287 Darmstadt, Germany
e-Mail: gutmann@chemie.tu-darmstadt.de
b Université de Toulouse; UPS, INPT; LCC; 205 Route de
Narbonne, F-31077 Toulouse, France
c Université de Toulouse; INSA, UPS, CNRS; LPCNO, 135 avenue de Rangueil, F-31077 Toulouse,
France nk line)
In recent years, a large number of catalytically active hybrid materials organized on
the meso- and nanoscale such as immobilized homogeneous catalysts or metal
nanoparticles (MNPs) have been developed and investigated. Such heterogeneous
catalysts are important due to their high application potential for environmental friendly
organic transformations and easy recyclability. Solid-state NMR spectroscopy has
evolved into an important tool for the characterization of the structure of these
heterogeneous catalysts and the chemical processes on their surface.
The main part of the lecture presents recent examples for structure investigations of
immobilized catalysts containing rhodium or ruthenium employing standard solid state
NMR techniques 1-3
and signal enhanced dynamic nuclear polarization (DNP)
experiments. Furthermore, the analysis of binding sites and the interaction between
ligands and small probe molecules on the surface of ruthenium MNPs employing cross
polarization (CP) and rotational echo double resonance (REDOR) experiments is
demonstrated.4 These distance informations are important to understand their behavior
in catalytic reactions. Finally, some recent advances of temperature dependent studies of
ruthenium MNPs are shown which shed more light on the structure and dynamics of
hydrogen/deuterium on the surface of these particles.
(1) Gutmann, T., Gruenberg, A., Rothermel, N., Werner, M., Srour, M.,
Abdulhussain, S., Xu, Y., Breitzke, H., Buntkowsky G., Solid State NMR 55-56,
(2013), 1-11
(2) Grünberg, A., Gutmann, T., Rothermel, N., Xu, Y., Breitzke, H., Buntkowsky G.,
Z. Phys. Chem. 227, (2013), 901-915
(3) Abdulhussain, S., Breitzke, H., Ratajczyk, T., Grünberg, A., Srour, M., Arnaut, D.,
Weidler H., Kunz, U., Kleebe, H. J., Bommerich, U., Bernarding, J., Gutmann, T.*,
Buntkowsky, G, Chem. Eur. J. 20, (2014), 1159-1166
(4) Gutmann, T., Bonnefille, E., Breitzke, H., Debouttière, P.-J., Philippot, K.,
Poteau, R., Buntkowsky, G., Chaudret, B., Phys. Chem. Chem. Phys. 15, (2013),
17383-17394
(5) Gutmann, T., del Rosal, I., Chaudret, B., Poteau, R., Limbach, H.-H.,
Buntkowsky, G., Chem. Phys. Chem. 14, (2013), 3026-3033
(6) Rafter, E., Gutmann, T., Löw, F., Buntkowsky, G., Philippot, K., Chaudret, B.,
van Leeuwen, P. W. N. M., Catal. Sci. Technol. 3, (2013), 595-599
Lecture, September 9, 9:00
18
Advanced Solid State NMR Spectroscopy for Structural
Characterization of Supported Catalysts
Olga B.Lapina1,2
, Alexander A.Shubin1,2
1 Boreskov Institute of Catalysis, pr. Lavrentieva, 5, 630090, Novosibirsk, Russia
2 Novosibirsk State University, Pirogova, 2, 630090, Novosibirsk, Russia
E-mail:olga@catalysis.ru
The majority of the industrial catalysts are high-surface area solids on to which an
active component is dispersed in the form of very small particles. Catalyst performance
is sensitive to particle size since the surface structure and electronic properties can vary
greatly with the size range. The importance of small particles to the performance of
catalysts has stimulated extensive efforts to develop tools for their characterization. In
this presentation we are going to demonstrate the advanced solid state nuclear magnetic
resonance spectroscopy (SSNMR) for the characterization of supported oxide catalysts.
The following problems will be considered:
- dispersion of active sites: using high speed 1H MAS NMR it is possible to get
information about surface OH groups and their interaction with the supported active
component, thus to get information about the dispersion of active component;
- the structure of active sites: often active sites appear to be quadrupole nuclei (51
V, 93
Nb, 27
Al, 95
Mo, 7Li,
11B etc.), therefore the possibilities of modern multinuclear
SSNMR for quadrupole nuclei will be discussed. Special attention will be given to
applications of modern solid-state NMR methods, including very high magnetic
field (up to 21 Tesla) measurements, very fast magic angle spinning (MAS) up to 70
kHz speed of rotation, and specialized pulse techniques such as SATRAS, MASSA,
MQMAS, and CPMAS. Based on NMR data, several types of supported surface
domains could be revealed, the structure of these sites could be suggested using
known experimental correlations. To verify experimental model quantum chemical
calculations (DFT cluster and periodic GIPAW-DFT) are very useful to perform.
These approaches will be demonstrated on the example of supported binary
M1Ox/M2Ox and multilayered M3Ox/M1Ox/M2Ox catalysts (M1-3 = Si, Al, Ti, V, Nb).
Acknowledgement
This work has been supported in part by RFBR (13-03-00482) and by MES. The
Siberian Supercomputer Centre (Novosirirsk, Russia, http://www2.sscc.ru) is
acknowledged for granting access to its computational facilities (integration grant no.
130).
Lecture, September 9, 10:00
19
Spin resonance of electrons localized in Ge/Si quantum dot
nanoheterostructures
Anatoly V. Dvurechenskii
Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Science,
Novosibirsk State University. 630090 Novosibirsk, Russian Federation.
E-mail: dvurech@isp.nsc.ru
Electron spins in quantum dots are a promising object for the implementation of
quantum computation ideas and spintronics devices. One of the main requirements to
select materials for quantum computation is the spin coherence time. For information
exchange in quantum calculations the electronic states should be coupled usually by
exchange interaction. Quantum calculations need selective access to individual qubits
for implementation of one-qubit and two-qubit operations. There are many ideas to
realize access to individual qubits based on magnetic field, coherent light, and electric
field. One of the ability is to distinguish electrons by g-factor value. And qubit array
should be large enough for parallel computing. Many these requirements hold true in
silicon based quantum dot nanoheterostructure grown by molecular beam epitaxy. The
strain-induced potential wells in Si around Ge dots provide electron localization. The
weak spin orbit coupling in Si and existence of developed technology to reduce none
zero magnetic moment isotopes make provision for long decoherence time of electron
spin in Si. The present report aimed to review results on spin dynamics in array of Ge/Si
quantum dot nanoheterostructure. The main items of the talk are following:
• Electronic and atomic configuration of Ge quantum dot in Si.
• Electron localization in double quantum dot molecules grown with effect of
vertical alignment of nanocrystal nucleation. g-factor engineering.
• Spin relaxation in ordered quantum dot array Ge/Si structures by growth on
strained heterophase and pit-patterned substrates.
Lecture, September 9, 11:30
20
EPR in Solar Cell Research
Jan Behrends
Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin,
Arnimallee 14, D-14195 Berlin, Germany
E-mail: j.behrends@fu-berlin.de
Although the electron spin does not play a central role in the operation of most
solar cells, it can provide valuable insight into charge transport and recombination
processes in these devices. Due to the fact that defects and impurities in semiconductors
are often paramagnetic or can be made paramagnetic (e.g. by illumination), EPR is the
method of choice to reveal quantitative as well as structural information. However, the
defect concentration in fully processed solar cells is often too low to be detectable by
EPR. The sensitivity limitation can be overcome by applying electrically detected
magnetic resonance (EDMR) spectroscopy. This technique measures changes in the
electrical conductivity of a semiconductor arising from manipulation of spin-dependent
transition rates that involve paramagnetic states. In this way we establish a connection
between microscopic transport and recombination pathways and the electrical
conductivity as an important macroscopic observable.
After a general introduction into the EDMR technique, its application to thin-film
silicon solar cells and their analogues based on organic semiconductors will be
presented. Besides discussing the impact of spin-dependent processes on charge
transport in solar cells, we will address the differences and similarities between radical
pairs in biological systems and spin pairs in organic and inorganic semiconductor
devices. In particular, we will outline how time-resolved EPR techniques, which are
commonly employed to investigate the role of radical pairs in biological processes, may
help to understand the kinetics of weakly-coupled polaron pairs created by
photogeneration and subsequent charge transfer at polymer/fullerene interfaces.
Lecture, September 9, 12:30
21
Spin-Orbit-Coupling Based Spin Chemistry
Ulrich E. Steiner
Department of Chemistry, University of Konstanz, D-78457 Konstanz, Germany
E-mail: Ulrich.steiner@uni-konstanz.de
In spin chemistry, the role of spin-orbit coupling is manifested in two types of
effects: (i) the induction of intersystem crossing (ISC) processes between molecular
singlet and triplet states and (ii) the stationary entanglement of different spin-orbit states
in radicals or in general Kramers doublet species. In both cases, the resulting effects are
anisotropic.
In case (i), this means that ISC processes are selective for the population and
depopulation of triplet substates, which gives rise to electron spin polarization (CIDEP)
of the triplets and of the radicals, eventually formed from such triplets. Only under
conditions of triplet depopulation by ISC, magnetic field effects on the yield of radical
products may be observed (d-type triplet mechanism)[1].
In case (ii), the spin-orbit coupling effects are manifested as anisotropic g-tensors
of radicals with components that may significantly deviate from the free electron value
ge. Kinetic consequences are (a) enhanced spin-relaxation due (a1) to the modulation of
Zeeman interaction by rotational diffusion and (a2) to spin-rotational interaction, a
mechanism explicable in terms of adiabatic rotation of effective spin (ARES)[2,3],
furthermore (b) coherent coupling of S and T substates of radical pairs by the so-called
g- or Zeeman mechanism. Systems in which such effects of type (ii) are particularly
pronounced have been studied involve transition metal complexes of Ru[4] and Fe[5]
and the small inorganic radical NO[6].
The theoretical principles of the various spin-orbit coupling effects will be
presented and possible applications illustrated by experimental examples from the work
of the author.
References
(1) Katsuki, A.; Kobori, Y.; Tero-Kubota, S.; Milikisyants, S.; Paul, H.; Steiner, U.
E. Mol. Phys. 2002, 100, 1245.
(2) Steiner, U. E.; Serebrennikov, Y. A. J. Chem. Phys. 1994, 100, 7503.
(3) Serebrennikov, Y. A.; Steiner, U. E. J. Chem. Phys. 1994, 100, 7508.
(4) Bürßner, D.; Wolff, H. J.; Steiner, U. E. Angew. Chem. Int. Ed. 1994, 33, 1772.
(5) Gilch, P.; Pöllinger-Dammer, F.; Musewald, C.; Michel-Beyerle, M. E.; Steiner,
U. E. Science 1998, 281, 982
(6) Karogodina, T. Y.; Dranov, I. G.; Sergeeva, S. V.; Stass, D. V.; Steiner, U. E.
Chem. Phys. Chem. 2011, 12, 1714
.
Lecture, September 10, 9:00
22
Magnetoreception of Molecular Systems and Spin Selective
Chemical Reactions
Kiminori Maeda1)
, Paul Liddel2)
, Devens Gust2)
, and P. J. Hore3)
1)Department of Chemistry, Graduate School of Science and Engineering, Saitama
University, Saitama 338-8570, Japan.
2)Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona,
85287-1604 USA
3)Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry
Laboratory, Oxford, United Kingdom
E-mail:kiminorimaeda@mail.saitama-u.ac.jp
Many experimental results of magnetic field effects (MFEs) on animal behaviour
suggested the photochemical reaction of blue light receptor proteins as the molecular
magneto reception mechanisms. Since then we have been seeing radical pair (RP)
mechanism in a new view point. Now, let us discuss the optimum conditions of RPs
for the high sensitivity to weak magnetic fields.
The coherent electron-nuclear spin motion of RP is an essential factor for the
sensitivity to extremely low magnetic field. Indeed, the low field effect (LFE) is very
sensitive to electron spin relaxation or dephasing. Since Kominis showed the doubt on
the conventional Haberkorn superoperator[1] from the quantum Zeno approach [2], the
theoretical debates about the spin dephasing accompanying with the spin selective
chemical reaction has continued. Some discussion was developed for supporting the
Haberkorn superoperators[3-5] and an alternative superoperator based on the theory of
quantum measurements was proposed by Jones et al.[6] (Jones superoperator).
Afterward, the relationship between Jones and Haberkorn superoperators was discussed
by various approaches [7-8]. However, the clear experimental test that discriminates
those two mechanisms has not been presented.
We present here the first experimental attempt to discriminate between Haberkorn
and Jones operators[9]. Pulse electron paramagnetic resonance (EPR) spectroscopy was
used to investigate in the radical pair of a carotenoid-porphyrinfullerene molecular
triad. The rate of transverse relaxation of the fullerene radical in the triad was found to
be inconsistent with the quantum measurement description (Jones) of the spin-selective
kinetics, and in accord with the conventional model (Haberkorn) combined with spin-
dephasing caused by rotational modulation of the anisotropic g-tensor of the fullerene
radical. References [1] R. Haberkorn, Mol. Phys. 32, 1491 (1976). [2] I. K. Kominis, Phys. Rev. E, 81, 029901 (2010): 83, 56118 (2011): 86, 026111
(2012). [3] P. A. Purtov, Chem. Phys. Lett. 496, 335 (2010). [4] A. I. Shushin, J. Chem. Phys. 133, 044505 (2010). [5] K. L. Ivanov, M. V. Petrova, N. N. Lukzen, K. Maeda, J. Phys. Chem. A,114, 9447
(2010). [6] J. A. Jones, P. J. Hore, Chem. Phys. Lett. 488, 90 (2010). [7] J. A. Jones, K. Maeda, and P. J. Hore, Chem. Phys. Lett. 507, 269 (2011). [8] M. Tiersch, U. E. Steiner, S. Popescu, H. J. Briegel, J. Phys. Chem. A,116, 4020
(2012). [9] K. Maeda, P. Liddell, D. Gust, P. J. Hore, J. Chem. Phys. 139, 234309 (2013)
Lecture, September 10, 10:00
23
The role of level-anti-crossings in spin hyperpolarization
Hans-Martin Vieth
Freie Universität Berlin, Institut für Experimentalphysik, Arnimallee14, 14195, Berlin,
Germany
E-mail:hans-martin.vieth@fu-berlin.de
The use of nuclear spin hyperpolarization is a successful strategy for increasing
the sensitivity of NMR in spectroscopy and imaging. Signal enhancements can be as
large as 3 to 4 orders of magnitude. In hyperpolarization experiments, usually the high
spin order of electronic spin systems or spin isomers is transferred to nuclei; moreover,
it is often desirable to transfer such initial polarization to other target nuclei of choice,
either protons or insensitive nuclei such as 13
C and 15
N. This situation arises in
hyperpolarization techniques such as Optical Nuclear Polarization (ONP), Chemically
Induced Dynamic Nuclear Polarization (CIDNP), Para-Hydrogen Induced Polarization
(PHIP), and the related Signal Amplification By Reversible Exchange (SABRE). Here
we give a tutorial introduction into polarization transfer mechanisms, in particular
focusing on the role of Level Anti-Crossings (LACs) therein.
So-called “spontaneous” polarization transfer may occur both at low and high
magnetic fields. Also, transfer of spin polarization can be accomplished by using
especially designed radio-frequency pulse sequences. It is now clear that at low field
spontaneous polarization transfer is primarily due to coherent spin-state mixing under
strong coupling conditions. However, thus far the important role of LACs in this
process has not received much attention. At high magnetic field, polarization may be
transferred by cross-relaxation effects. Another promising high-field technique is to
generate the strong coupling condition by spin locking using strong radio-frequency
fields. Here, an analysis of polarization transfer in terms of LACs in the rotating frame
is very useful to predict which spin orders are transferred depending on the strength and
frequency of the B1 field. Finally, we will examine the role of strong coupling and
LACs in magnetic-field dependent nuclear spin relaxation and the related topic of long-
lived spin-states.
Lecture, September 10, 11:30
24
Time resolved and field dependent CIDNP
Alexandra V.Yurkovskaya and Olga B.Morozova
International Tomography Center, Institutskaya 3a, 630090, Novosibirsk, Russia
E-mail:Yurk@tomo.nsc.ru
Chemically induced dynamic nuclear polarization (CIDNP) is a useful tool for
studying elusive radical pairs, which are often beyond the reach of EPR spectroscopy
because of their short lifetimes and low stationary concentration. Nonetheless, spin
dynamics in transient RPs can produce significant CIDNP effects, which are stored in
the diamagnetic reaction products for the time periods equal to the nuclear T1-relaxation
times and can be studied by NMR spectroscopy. We have recently shown that in many
cases CIDNP formed after geminate recombination of RPs is directly proportional to
HFCs. This enables determination of relative HFC constants in RPs. However, when
one of the RP partners is a radical with precisely known HFC constants this method
allows one to obtain the absolute values of HFC constants of the other radical. Thus,
CIDNP gives an NMR way to obtain EPR parameters and enables investigating kinetics
of radical reactions in room-temperature solutions. At the same time, the analysis of
CIDNP is often more complicated than that in EPR and requires modeling of spin
evolution in RPs. A way to obtain the EPR parameters is measuring CIDNP dependence
on the external magnetic field strength; theoretical modeling of such field dependences
potentially allows one to obtain EPR parameters, in particular, hyperfine couplings
(HFCs) in RPs, the difference, Δg , in the electronic g-factors of the RP partners and
electronic exchange interaction. However, analysis of the CIDNP field dependence is
not as straightforward as it was previously believed. This is because at low magnetic
field spin dynamics in RPs is not the sole factor, which affects the observed CIDNP.
Coherent polarization re-distribution among scalar coupled spins creates problems in
interpreting CIDNP at low fields by transferring spin hyperpolarization. .
Lecture, September 10, 12:30
25
The study of practically important radical processes by spin
chemistry methods.
Tatyana V. Leshina
Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya str., 3,
630090, Novosibirsk, Russia
E-mail: leshina@kinetics.nsc.ru
The role of paramagnetic particles (ions and free radicals, singlet oxygen) in
chemical and biological processes is difficult to overestimate. Radical reactions that are
known to occur under mild conditions (room temperature, normal pressure) are
increasingly used for the organic synthesis. On the other hand growing attention paid to
the radical species involved in biological processes. Since free radicals and toxic
oxygen species are, according to modern concepts, the cause of many diseases,
medications with antioxidant properties are developed. All this makes studies of radical
transformations in organic and biological processes, as well as their role in the drugs
action high demand. One of the most powerful and modern methods of research into the
mechanisms of processes involving radical species are spin chemistry techniques. Spin
chemistry is a branch of physical chemistry that studies the effects of nuclear and
electron spins on the rates of radical chemical reactions. Two basic methods of spin
chemistry are chemically-induced dynamic nuclear polarization (CIDNP) and the
magnetic field effect. The latter studies the result of an external magnetic field action on
the rate and often also the direction of radical reactions. The basis of these phenomena
is the dependence of the spin evolution of the radical pair (RP) on the interaction of the
nuclear spins with the spins of unpaired electrons. Because of the differences in the RP
recombination rates for α and β orientations of the nuclear spins in the NMR spectra of
diamagnetic products, recorded during the reaction, the signals signs and intensities
differ from those of the equilibrium (Boltzmann) spectra. This is CIDNP effects
analysis of which allows high precision identification of free radicals involved in the
reaction. The same results can be obtained by analysis of the dependence of radical
reaction rate on the strength of the external magnetic field. This report discusses
examples of using spin chemistry techniques to determine the elementary stages of
enzymatic oxidation, the mechanisms of action of several drugs, and other important
practical processes.
Lecture, September 11, 10:00
26
Application of NMR in Medical Research
Nikolay E. Polyakov
Institute of chemical kinetics and combustion, Institutskaya 3, 630090, Novosibirsk, Russia
E-mail: Polyakov@kinetics.nsc.ru
Nuclear magnetic resonance (NMR) spectroscopy is a powerful scientific
instrument which allows to shed light on molecular structure, but its greatest potential in
medical research probably lies in the information that it can reveal about molecular
interactions at the atomic level. NMR parameters, such as the chemical shift, are highly
sensitive to the exact environment of the atom, and therefore yield information about the
binding of small molecule with a target proteins or nucleic acids. Moreover NMR
technique allows to determine what parts of drug molecule are interacting with the
receptor, and to which part of the macromolecular target the drug molecule is bound.
Various NMR techniques, such as the saturation transfer, NMR relaxation
measurements (both T1 and T2), are sensitive to the overall molecular motion of organic
molecule in solution, which is very different for free and bound ligands. These simple
approaches can be used to elucidate the structure and stability of various drug delivery
systems, to identify potential ligands binding to the specific target, or to measure the
influence of various chemical compounds on the physical and functional properties of
cell membranes.
The important area of modern medical research is the investigation the
mechanisms of drug activity on molecular level, in particular, elucidation the role of
electron transfer and free radicals in drugs activity and toxicity. Some NMR
applications, for example, NMR based CIDNP technique (chemically induced dynamic
nuclear polarization), allow to determine the structure of free radical intermediates of
the drugs and their transformation into final or intermediate products by investigation
model processes in solution.
These possibilities of NMR application in medical research will be illustrated by
some recent results obtained in the Laboratory of magnetic phenomena of the Institute
of chemical kinetics and combustion (Novosibirsk).
Lecture, September 11, 11:30
27
EPR discovery and identification of dinitrosyl iron complexes
with thiol-containing ligands in living systems
Anatoly F. Vanin
Semenov Institute of Chemical Physics Russian Academy, Moscow, Kosygin Str.4, 119991, Russia
E-mail: vanin@polymer.chph.ras.ru or vanin.dnic@gmail.com
EPR discovery and identification of paramagnetic mononuclear dinitrosyl iron complexes (M-DNIC) with thiol-containing (RS) ligands { formula [(RS)2Fe(NO)2]}in biological systems will be considered. The complexes were discovered by our group in the 1960
th due their characteristic EPR signal at g =2.04, g = 2.014, gav.=2.03 (2.03
signal) at first, in dry yeast cells and then in animal tissues. High shift of the g-factor values from pure spin value (g=2.0024), disappearance of 2.03 signal in yeast preparation at 80-90
0C as well as safe-keeping anisotropic shape of the signal when the
registration temperature was increased from 77K to ambient one pointed, firstly, to non-free organic nature of the paramagnetic centers responsible for the 2.03 signal, and, secondly, to these center binding with protein molecules. The identity of these centers was recognized when it was demonstrated that the shape and EPR spectroscopic parameters of 2.03 signal and EPR signals of low-molecular DNIC with cysteine or glutathione in a frozen solution were similar. Subsequent studies confirmed that the paramagnetic species giving 2.03 signal in cells and tissues are really protein-bound DNIC or DNIC with low molecular endogenous thiol-containing ligands. The properties of electronic structures of the latter underlying their ability to act as NO and NO
+
donors will be also discussed in my report. From our point of view this ability can be explained only from the paradigm of the model of the [Fe
+(NO
+)2]
+ core ([Fe(NO)2]
7
according to the Enemark-Feltham classification). Similarly, the {[(RS)2Fe(NO)2]+}
structure describing the distribution of unpaired electron density in M-DNIC corresponds to the low-spin (S=1/2) state with a d
7 electron configuration of the iron
atom and predominant localization of the unpaired electron on MO(dz2) and the square-plane spatial structure of M-DNIC. The chemical equilibrium characteristic of Fe
+(NO
+)2 fragment and its constituents {Fe
+(NO
+)2 Fe
2+ + NO + NO
+} ensures NO
and NO+ generation by the complexes. EPR and optical studies of M-DNIC as well
diamagnetic binuclear DNIC { formula [(RS)2Fe2(NO)4]} demonstrating NO and NO+
release from the complexes will be presented in the report.
Our opponents who studied M- and B-DNIC in crystalline state proposed that the distribution of unpaired electron density in M-DNIC is described as {[RS
-
2)Fe3+
(NO-)2]
-}. Spin-pairing of electron density on iron (Fe
3+, S=5/2) and two nitroxyl
ligands (NO-, S=1) resulted in the sum spin of the complexes S=1/2 with a d
9 electron
configuration of the iron atom ([Fe(NO)2]9 according to the Enemark-Feltham
classification). The complex in the crystalline state is characterized with tetrahedron structure. The investigators propose that electronic and spatial structures of the complexes do not change during the process of complex dissolving. In the frame of this model, it is hardly to explain the ability of DNICs with thiolate ligands to act as NO and NO
+ donors.
Miscellaneous effects of M- and B-DNIC with thiol-containing ligands as NO and NO
+ donors
on various physiological and biochemical processes will be considered.
The complexes hold considerable promise as a base in the design of a radically new generation of drugs with a broad spectrum of therapeutic activities.
Lecture, September 11, 12:30
28
ORAL PRESENTATIONS
OF YOUNG SCIENTISTS
29
Oral presentation of young scientists, September 9, 15:00-19:30
FMR study of Cr1/3NbS2 helical magnet
Fedor B. Mushenok Institute of Problems of Chemical Physics,
Ak. Semenova st., 1, 142432, Chernogolovka, Russia
E-mail: mushenokf@ya.ru
Incommensurate magnetic structures are intrigue objects of the solid state
physics. The pressing problem is the influence of the magnetic anisotropy on a magnetic
phase diagram and a spectrum of the spin excitations. The aim of the present work is to
establish how magnetocrystalline anisotropy influents on spin excitation in the chiral
“easy-plane” helimagnet Cr1/3NbS2.
High frequency spin excitations were studied by ferromagnetic resonance (FMR)
method [1]. At low temperature (T < 50 K) FMR spectra consist of two lines with
different temperature dependences of resonance fields Hres (Fig. 1). The line I with
“usual” ferromagnetic temperature dependence of resonance field corresponds to
homogeneous (q = 0) magnetization precession in a helical phase. The resonance field
of the line I is determined by uniaxial magnetocrystalline anisotropy K2. The line II with
“abnormal” temperature dependence of resonance field corresponds to the Goldstone
mode with a wave factor q = ±Q (Q is wave vector of the modulated magnetic
structure). The finite value of the Goldstone mode energy q = ±Q is due to
magnetocrystalline anisotropy in basal ab plane. Unusual temperature dependence of
the resonance field is explained by decreasing of anisotropy constant K6 with
temperature increasing.
Figure 1. Temperature dependences of resonance fields of lines I and II for
Cr1/3NbS2 single crystal, H ┴ c (┴ Q). Critical field of transition to ferromagnetic state
is shown by dashed line. FMR spectra at T = 5 K is shown on inset.
The work was supported by grant of President of Russia MK-1474.2014.
[1] F.B. Mushenok, J.Eur. Phys. Journ. B, 86 (2013) 1-4.
30
Oral presentation of young scientists, September 9, 15:00-19:30
Possibilities of EPR diagnostics for monitoring the
sportsmen’s state of health
Chushnikov A. I., Ibragimova M. I., Petukhov V. Yu., Cherepnev G. V.
Kazan E. K. Zavoisky Physical -Technical Institute, Sibirsky Tract, 10/7, 420029, Kazan, Russia, State
Autonomous Healthcare Institution Republican Clinical Hospital №2 Heath Ministry of Tatarstan Republic
Email: shuran2003@mail.ru
The work is devoted to study the possibilities of EPR application for monitoring
the professional sportsmen’s health state. Measurements of ~ 120 serum blood samples
collected from players of continental hockey league teams were carried out using
Bruker EMXplus spectrometer at a frequency ~ 9.5 GHz in the temperature range T=5-
80K and haematological and biochemical laboratory tests as well. The control group
included healthy individuals and patients with different diseases.
The main peculiarities of sportsmen EPR spectra are the appearance of the
additional absorption lines in comparison with norm. In particular, in the 20 spectra
measured at T=77 K the significant portion of new signals have the spectroscopic
parameters close to signals from the oxygenic active isolated form of cytochrome-c-
oxidases. Moreover, the anisotropic signals with g1 2.02; g2 1.94 and g3 1.86
registered in some spectra pointed to the sulfur-iron centers. In experiments carried out
at T=5K other additional lines with g-factors ~ 11, 8.6 and 5.85 were detected. In
accordance with literature data they correspond to lines from cytochrome-c-oxidases.
Intensity of these lines decreases with temperature and become almost zero at T=40K
(in agreement with literature review).
There was nearly linear correlation between the concentration of Fe3+
in transfferin
(Fe3+
-Tf) obtained from the EPR spectra and the serum iron concentration measured by
absorption photometry both for sportsmen and controls. The Spirmen correlation
coefficient for Fe3+
-Tf and serum iron values was of 0.84 in sportsmen versus r=0.97 in
controls. The possible reasons of lower correlation between Fe3+
-Tf and serum iron
concentration for sportsmen in comparison with controls are discussed.
Application of the EPR method can be useful for monitoring of sportsmen health
state so far as the routine biochemical and haematological tests are insufficient to
discover, for example, such enzymes as cytochrome-c-oxidase.
The work is supported by RFFR Grant #13-02-97065.
31
Oral presentation of young scientists, September 9, 15:00-19:30
Highly efficient exciplex formation in case of X-ray
irradiation of non-polar solutions
Anatoly R. Melnikov1,2
, Evgeny V. Kalneus1, Valeri V. Korolev
1,
Igor G. Dranov1, Alexander I. Kruppa
1, Dmitri V. Stass
1,2
1 Institute of Chemical Kinetics and Combustion SB RAS, 3, Institutskaya Str., 630090
Novosibirsk, Russian Federation 2 Novosibirsk State University, 2, Pirogova Str., 630090 Novosibirsk, Russian Federation
E-mail: melnikov@kinetics.nsc.ru
This work reports the spectra of photo- and radiation-generated luminescence from
several donor-acceptor systems typical for radiation spin chemistry, i.e., alkane
solutions of naphthalene/N,N-dimethylaniline (DMA), p-terphenyl/DMA, and other.
One component of the system (DMA, positive charge acceptor) was held constant, and
as the other component (electron acceptor, luminophore) were chosen molecules with
widely varying lifetimes of the electronically excited state τf, from about 100 ns to about
1 ns and to about 10 ps. In this work we also studied the sensitivity of the obtained
emission spectra to external static magnetic field, and obtained the close to maximally
possible under these experimental conditions magnetic field effect (up to 20%) in
exciplex emission band for the system diphenylacetylene/DMA in n-dodecane.
300 350 400 450 500 550 600
0
5
10
15
20
0 mT
20 mT
N
I, a
.u.
, nm
A + D
A
D
= A
= D
hADDADA alkanerayX *, )()(
Figure 1. X-irradiation of alkane solution of DMA and diphenylacetylene produces exciplex from
luminophore with τf equals to 8 ps, and yields magnetic field effect of 20% in exciplex emission band.
The work was supported by the Council for Grants of the President of the Russian
Federation for Support of Leading Scientific Schools (project no. NSh 2272.2012.3) and
the Russian Foundation for Basic Research (project no. 13–03–00771).
32
Oral presentation of young scientists, September 9, 15:00-19:30
Exploiting Level Anti-Crossings in the rotating frame for
transferring spin hyperpolarization
Andrey N. Pravdivtsev,a,b
Alexandra V. Yurkovskaya,a,b
Nikita N. Lukzen,a,b
Hans-Martin Vieth,c Mikhail S. Panov,
a,b Konstantin L. Ivanov
a,b
a International Tomography Center, Siberian Branch of the Russian Academy of Science,
Institutskaya 3a, Novosibirsk, 630090, Russia
b Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia
c Institut für Experimental Physik, Freie Universität Berlin, Arnimallee 14, Berlin, 14195,
Germany
E-mail:a.n.true@tomo.nsc.ru
A method of transferring hyperpolarization among scalar-coupled nuclear spins is
proposed, which is based on spin mixing at energy Level Anti-Crossing (LAC) regions.
To fulfill LAC conditions a resonant RF-field was applied with properly set frequency
and amplitude. In this situation LACs occur between the nuclear spin levels in the
rotating doubly tilted reference frame. The validity of the approach is demonstrated by
taking as an example the transfer of para-hydrogen induced polarization in a symmetric
molecule, whose coupled spin network can be modeled as a four-spin AA′MM′-system
with two pairs of ‘isochronous’ spins. For this spin system LAC positions have been
identified; rules for the sign of spin polarization have been established. The dependence
of the polarization transfer efficiency on the RF-field parameters and on the time profile
of switching off the RF-field has been studied in detail; experimental results are in
excellent agreement with the theory developed. In general, exploiting LACs in the
rotating doubly tilted frame is a powerful tool for manipulating hyperpolarization in
multispin systems.
The research was financially supported by the Russian Fund for Basic Research
(projects No. 13-03-00437, 14-03-00397) and grant of the President of Russian
Federation MD-3279.2014.2.
33
Oral presentation of young scientists, September 9, 15:00-19:30
Experimental and Theoretical NMR Analysis of
Paramagnetic M(acac)3 (M = Cr, Mn) Coordination
Compounds
Kirill Levin, Scott Kroeker
Department of Chemistry, University of Manitoba, Winnipeg, Canada, R3T 2N2
E-mail:umlevin7@cc.umanitoba.ca
Solid state nuclear magnetic resonance (NMR) spectroscopy is a widely used
technique for the characterization of materials. The versatility of NMR spectroscopy
stems from its sensitivity to variations in local structural environments. However, a
recognized drawback of NMR is its limited applicability to paramagnetic systems such
as organic radicals and many organometallic complexes, where the presence of unpaired
electrons introduces an additional layer of difficulty to spectral acquisition and
interpretation. Recent advances in instrumentation have reopened the investigation of
paramagnetic solids.
We are studying a series of isostructural metal acetylacetonate complexes to better
understand the experimental and analytical particularities of such systems. 13
C magic-
angle spinning NMR of M(acac)3 (M = Cr, Mn, Co, Al) reveals interesting spectral
differences which are related to the electronic structure and bonding, thereby providing
valuable clues about optimizing acquisition and inferring electronic distributions. For
example, Cr(acac)3 and Mn(acac)3 produce dramatically different NMR spectra due to
the presence of t2g3 and t2g
3eg
1 electronic configurations, respectively.
Density functional theory provides detailed electron distribution maps of the
complexes which are used to assign crystallographic sites and delineate spin-transfer
mechanisms. Molecular orbital theory renders the analysis more intuitive and facilitates
extensions to other materials. The use of simple model coordination compounds is
intended to provide the foundation for a more general approach to utilizing unpaired
spin density as a new tool for structural analysis of paramagnetic materials.
Figure 1. Spin density distribution through the molecular orbital for a ligand of
Cr(acac)3
34
Oral presentation of young scientists, September 9, 15:00-19:30
The EPR Study Of Light-Induced Thermally Inaccessible
Spin State In Copper-Nitroxide Based Molecular Magnet
Irina Yu. Barskaya,a*
Evgeny V. Tretyakov,a Renad Z. Sagdeev,
a Victor I.
Ovcharenko,a Elena G. Bagryanskaya,
a,b Kseniya Yu. Maryunina,
c Takeji Takui,
d,e
Kazunobu Sato,d.e
Matvey V. Fedina
aInternational Tomography Center SB RAS, Institutskaya str. 3a, 630090, Novosibirsk, Russia;
bNovosibirsk Institute of Organic Chemistry SB RAS, Pr. Lavrentjeva 16, 630090, Novosibirsk, Russia;
cDepartment of Chemistry, Graduate School of Science, Hiroshima University, Japan;
dGraduate School of Science, Osaka City University, Osaka 558-8585, Japan;
eFIRST-Quantum Information Processing Project, JSPS, Tokyo 101-8430, Japan
E-mail: ira@tomo.nsc.ru
Polymer-chain molecular magnets formed by Cu(hfac)2 and various nitroxide
radicals usually demonstrate the thermal transition between two different spin states:
weakly-coupled spin state (WS) with exchange interaction J between nitroxide and
copper spins smaller than thermal energy (J~1-10 cm-1
), and strongly-coupled spin state
(SS), where exchange interaction is higher than thermal energy (J~100-200 cm-1
). As a
rule, WS state is observed at high temperatures, whereas SS state is formed at lower
temperatures. However, a few compounds of this family could not be switched to WS
state within the temperature range of their stability (~2-350 K). Therefore, up to now the
existence of the excited spin state in such type of compounds was not realized and
evidenced. In this work we report the first example of photoswitching to the thermally-
inaccessible spin state of Cu(hfac)2Li-Pr
by visible light at cryogenic temperatures. One
of the main problems in photo-investigation of such compounds is their high optical
density. To overcome this, we developed specific method of synthesis performed in
PVC matrix and yielding thin, flexible film exhibiting photoswitching efficiency close
to 100%. Upon generation of the excited spin state spin state in Cu(hfac)2Li-Pr
by laser
illumination, we could detect and study it using continuous wave Q-band (34 GHz) and
time-resolved W-band (94 GHz) EPR. It was found that the electronic structure and
photoswitching properties of excited spin state in Cu(hfac)2Li-Pr
are very similar to its
thoroughly investigated sister compound Cu(hfac)2LPr
that does undergo thermal
transition at ~150 K. Similar to thermally switchable compounds of this family, the
relaxation rate in Cu(hfac)2Li-Pr
has a self-decelerating character due to the broad
distribution of activation energies. By analyzing the temperature dependence of
relaxation rates and the conversion depths we succeeded in estimation of the values of
energy barriers and distribution widths for both compounds. Acknowledgements: This
work was supported by the Russian Foundation for Basic Research (No. 14-03-00224)
and the RF President's Grant (МК-3241.2014.3, MD-276.2014.3).
[1] I. Yu. Barskaya, et. al., JACS, 2014, 136, 10132-10138.
35
Oral presentation of young scientists, September 9, 15:00-19:30
Proton transfer process in C-H···X hydrogen bonds
Elena Yu. Tupikina, Gleb S. Denisov, Peter M. Tolstoy
Institute of Physics, Saint-Petersburg State University, Ulyanovskaya str., 3, 198504, Saint-
Petersburg, Russia;
E-mail: elenatupikina@gmail.com
Hydrogen bonds involving CH group are extremely important for many biological
systems, inasmuch as plays crucial role in structure stabilization and crystal packing.
For example, formation of a relatively weak hydrogen bond between OH-group of
ibuprofen and one of carbon atoms of tyrosine most likely is the basis of medical action
mechanism of ibuprofen [1]. Furthermore, formation of CH···X bond is also a primary
step of CH proton transfer – the most ubiquitous reaction in biochemical synthesis [2].
In this work we focused on proton transfer process between CH-acids (e.g. 1,1-
dinitroethane, trinitromethane) and different proton acceptors (e.g. acetone, pyridine,
2,4,6-collidine, fluoride anion). In such systems formation of relatively strong hydrogen
bonded complexes and even zwitterionic complexes is possible. Our main goal was to
investigate processes of hydrogen bond formation and proton transfer for complexes
with CH-acids, which schematically depicted for 1,1-dinitroethane and 2,4,6-collidine
system at figure 1. Using ab initio calculations and different experimental techniques
(NMR spectroscopy, X-Ray) we find some interesting features and correlations between
geometric and NMR parameters.
Figure 1. Scheme of hydrogen bond formation and proton transfer process for 1,1-
dinitroethane and 2,4,6-collidine complex.
[1] J. A. Kowalska-Baron1, M. Brychtova, I. Petrovic, I. Passos Sene, P.
Quinones, J. Sogorkova // Biotechnol Food Sci, , v. 75, № 2, p. 15, (2011).
[2] S. Scheiner // Curr. Org. Chem., v. 14, p. 106, (2010).
36
Oral presentation of young scientists, September 9, 15:00-19:30
I nvestigation of some acetophenone derivatives in solution
by NMR
A.M.Maharramov, M.R.Bayramov, Y.V.Mamedova, A.E.Huseynzada,
I.G.Mamedov
Baku State University, Azerbaijan, Z.Khalilov-23, e-mail: alekper-92@mail.ru
Nuclear magnetic resonance (NMR) spectroscopy plays an important role in
studying various interactions in solution including hydrogen bond formation. NMR has
become an important method to evaluate the kinetics of reactions at equilibrium over a
very large dynamic range, its results have theoretical and practical significance.
Oxime compounds are used as antidotes for nerve agents, amides are widespread
in nature and technology as structural materials. Thiosemicarbazones also are used in
medicine, especially as anticancer chemotherapeutic agents, in the treatment of
tuberculosis. Because of the presence of different functionality in thiosemicarbazones
these compounds confer biological activities, such as cytotoxic and antimalarial. The
behavior of such molecules in solution as well as the presence or absence of molecular
association and dynamic processes is of considerable theoretical and practical interest.
This concerns, particularly, the dynamic transitions in solution for the some 2-hydroxy-
5-methylacetophenone derivatives.
N
O
HOH
H3C
O
N
CH3
N S
NH2H
H
N
CH3
N S
NH2
H
Br
The results confirmed the existence of two conformers for the molecule N-(2-
hydroxy-5-methylphenyl)acetamide, two conformers for the molecule (E)-4-
bromoacetophenone thiosemicarbazone and four conformers for the molecule (E)-2-
hydroxy-5- methylacetophenone thiosemicarbazone.
37
Oral presentation of young scientists, September 9, 15:00-19:30
Fluorinated homocysteine derivatives as potential molecular
probes for 19
F magnetic resonance spectroscopy and imaging:
synthesis and characterization
Alexey S. Chubarov, Makhmut M. Shakirov, Viktor I. Mamatyuk, Dmitry
G. Knorre, Tatyana S. Godovikova
Institute of Chemical Biology and Fundamental Medicine, Lavrentyev ave, 8, 630090, Novosibirsk,
Russia
Novosibirsk State University, Pirogova st., 2, 630090, Novosibirsk, Russia
E-mail: chubarovalesha@mail.ru
One of the most perspective molecular imaging modalities is magnetic resonance
imaging (MRI). It evolves as a prominent technique because MRI is a noninvasive and
nondestructive diagnostics with high spatial resolution including 3D imaging. In
addition to 1H MRI techniques, a number of attractive contrast agents based on
19F
NMR signals are increasingly emerging. The fluorine MRI is of interest for several
following reasons. Fluorine offers a strong NMR signal magnitude as large as 1H nuclei
due high gyromagnetic ratio, high natural abundance sensitivity and a much wider
frequency range thus is ideally suited for tracking objects and monitoring reactions in
vivo. Only externally administered fluorine can be imaged by the 19
F MRI because of
the absence of background signals in a living body. Highly fluorinated compounds with
a single resonance frequency are advantageous in these applications because they
provide large signal-to-noise rations, saving the acquisition time necessary for imaging.
In this study, fluorinated homocysteine thiolactone derivatives have been
synthesized and characterized as potential in vivo 19
F NMR agents. The latest
compounds have been used for preparing a fluorine-labeled N-homocysteinylated
protein, in particular 19
F-Hcy- N-Lys-human serum albumin. The protein was
characterized by SDS-PAGE, MALDI-TOF MS, UV-vis and 19
F NMR. Albumin has
been successfully modified resulting fluorine labeled biocompatible molecular probe
with useful NMR characteristics. Given the relatively high sensitivity of 19
F NMR, it
should be possible to detect exogenously administered 19
F-labeled probe molecules.
The work was supported by RFBR № 14-04-00531, President Grant (NS-
1205.2014.4) and Integration grant of SB RAS № 60.
38
Oral presentation of young scientists, September 9, 15:00-19:30
2H NMR study of the rotational dynamics of terephatalate
phenylenes in metal-organic frameworks CoMOF, NiMOF
and ZnMOF: effect of different metal centers
A.E.Khudozhitkov† , D.I.Kolokolov
†,‡ , A.G.Stepanov
†,‡ , D.N.Dybtsev
†* ,
V.A.Bolotov†*
†Novosibirsk State University, Faculty of Natural Sciences, Department of Physical Chemistry,
Pirogova Street 2, Novosibirsk 630090, Russia
‡Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt
Akademika Lavrentieva 5, Novosibirsk 630090, Russia
*Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences,
Prospekt Akademika Lavrentieva 3, Novosibirsk 630090, Russia
alexandr.khudozhitkov@gmail.com
Metal organic framework (MOFs) materials represent a new class of hybrid crystalline
porous materials whose pore structure and chemical properties can be very diverse depending
on the chemical composition and synthesis procedure. Their unique properties allow exploiting
of MOFs in many fields such as adsorptions or separation of gases and liquids, catalysis and
others. The MOFs are composed by inorganic nodes (i.e. the metal centers) bridged together by
organic linkers.
Fragments of organic framework may be mobile and their motion is a huge source of
structural information. There are two major mechanisms influencing the rate of molecular
motions: steric and the electronic structure. On the fundamental level there exists an unresolved
problem: what contribution does each of these mechanisms make?
To investigate this question a set of materials with identical structure but different nature of
the metal center was examined. In such approach the steric component remains the same for all
materials while the electronic component is affected by different electronic structure of the
metal cation. As result, the influence of the MOF metal center variation (Co, Ni, Zn) on the
dynamics of terephthalic fragment was observed.
The phenylene dynamics investigation was performed by experimental detection of the 2H
NMR spectra line shapes at different temperatures followed by numerical simulation of the
registered spectra.
39
Oral presentation of young scientists, September 9, 15:00-19:30
Influence of glycyrrhizin on cell membrane properties
Selyutina O. Yu.1,2
, Polyakov N. E.1
1Institute of Chemical Kinetics and Сombustion SB RAS, Institutskaya st.,3, 630090,
Novosibirsk, Russia
2Novosibirsk State University, Pirogova st., 2, 630090, Novosibirsk, Russia
E-mail:olga.gluschenko@gmail.com
Glycyrrhizic acid or glycyrrhizin (GA) is natural oligosaccharide contained in the
extract of licorice roots, showing a wide spectrum of biological activity. GA and its
derivatives are widely used in medicine for the treatment of asthma, eczema, dermatitis,
ulcers of the stomach and duodenum. Due to its amphiphilicity GA is capable of
forming stable complexes with various drugs and biologically important molecules,
such as cholesterol [O.Yu. Gluschenko, N.E.
Polyakov, T.V. Leshina, Appl. Magn. Res., 41
(2011) 283-294]. This, coupled with the lack of
toxicity, makes glycyrrhizic acid promising agent
for targeted drug delivery. However, for its wide
application in this field, it is necessary to establish
a mechanism as its own biological activity, as the
enhancement of the drugs activity in the presence
of GA. One way to elucidate this mechanism is
studying the effect of GA on the properties of the
cell membrane.
In this work an attempt to clarify the molecular mechanism of effect of glycyrrhizic
acid (GA) on the properties of cell membranes was made. The effects of GA on the
functional properties of the membranes of living cells have been studied for a better
understanding of the mechanism of GA activity. The effect of GA on membrane
permeability, as well as on the mobility within the membrane lipids was investigated by
NMR techniques. RBCs were selected as a model object in or study, as the most
affordable and relatively resistant to external influences, and liposomes, as a system
with the controllable composition. The significant increase in permeability of
erythrocyte membranes in presence of GA was established by means of NMR
relaxation. This fact could explain some facts of increase in drugs bioavailability in
human body.
This work was supported by grant RUC-7067-NO-12 from the U.S. Civilian
Research & Development Foundation (CRDF Global) with funding from the United
States Department of State.
Fig. 1. The structure of
glycyrrhizic acid
40
Oral presentation of young scientists, September 9, 15:00-19:30
Low-field NMR Spectroscopy and Imaging Via Parahydrogen
Based Hyperpolarization: Towards catalyst-free molecular
contrast agents and MRI of industrial hydrogenation
Danila A. Barskiya, Kirill V. Kovtunov
a, Igor V. Koptyug
a, Boyd M.
Goodsonb, Aaron M. Coffey
c, Milton L. Truong
c, Eduard Y. Chekmenev
c
International Tomography Center SB RAS, Novosibirsk State University, 630090, Russia
Southern Illinois University, Carbondale, 62901, USA
Vanderbilt University, Institute of Imaging Science, Nashville, 37232-2310, USA
High-resolution proton MRI/NMR was demonstrated at 47.5 mT magnetic field
endowed by Parahydrogen-Induced Polarization and Signal Amplification by
Reversible Exchange (SABRE). Low-field (milli-Tesla) parahydrogen-enhanced
molecular imaging (i.e. imaging of dilute hyperpolarized chemicals rather than the bulk
medium) is free from limitations of high-field magnetic resonance (MR), such as B0
susceptibility at phase interfaces, and potentially enable new application of MR in vivo
(lung imaging) and for industrial processes of hydrogenation and hydrogen exchange
for visualization of reactants, intermediates and products in chemical reactors.
Figure 1. 1H MRI of SABRE hyperpolarized
(HP) molecular contrast agent (pyridine - Py).
Two orthogonal projections of non-slice
selective MRI of a) in situ SABRE detection
(HP Py, Ir-hydride and orthohydrogen) at
47.5 mT with 0.75 0.75 mm2 in-plane spatial
resolution; b) ex situ SABRE (preparation at
5.75 mT and detection at 47.5 mT) of Py with
0.125 0.125 mm2 and 7.7 s temporal
resolution.
c) Photograph of ~3 mL solution of 100 mM
Py with 7 mM Ir catalyst in a 10 mm NMR
tube with 1/16 in. OD PTFE tubing for
parahydrogen bubbling at 1 atm.
This work is supported by the RAS (5.1.1), RFBR (12-03-00403-a, 14-03-00374-a,
14-03-31239-mol-a, 14-03-93183 МСХ_а), SB RAS (60, 61), the Ministry of
Education and Science of the Russian Federation, and the Council on Grants of the
President of the Russian Federation (MK-4391.2013.3). We also thank for funding
support NIH 5R00 CA134749-03, 3R00CA134749-02S1, DoD CDMRP Breast Cancer
Program Era of Hope Award W81XWH-12-1-0159/BC112431.
41
POSTERS
Poster 1
42
Investigation of some alkenylphenol derivatives in solution
by NMR
A.M.Maharramov, M.R.Bayramov, M.M.Agayev, I.G.Mamedov
Baku State University, Azerbaijan, Z.Khalilov-23
e-mail: agayev.mircavid@gmail.com
The NMR line shape is sensitive to temperature and chemical exchange
processes. For rational design and structure properties correlations of different systems
one need to know their structure and dynamics in solution. To this end variety of NMR
methods can be helpful. The DNMR results have theoretical and practical significance
for chemistry, medicinal chemistry, biochemistry and molecular physics.
The alkenylphenols and their aminomethyl, acetyl derivatives are used at
different organic synthesis as monomer stabilizers for polymerization, corrosion
inhibitors, and antimicrobial additives to oils and fuel, etc. All these compounds contain
hydroxyl, carbonyl groups, unsaturated bonds, sulphur and nitrogen atoms. The
behavior of such molecules in solution, the presence and absence of molecular
association are of considerable theoretical and practical interest. This concerns
particularly the formation of hydrogen bonds, inter- and intramolecular interactions in
solution for the molecules of alkenylphenols, their aminomethyl, sulfide, and acetyl
derivatives.
Our investigations confirm the formation of intermolecular hydrogen bonds in
alkenylphenols and its sulfide derivatives, and of intramolecular hydrogen bonds in
aminomethyl and acetyl derivatives. In CCl4 solution of 2-allyl-6-tert-butylaminomet-
hylphenol, no hydrogen bonds are observed due to steric effect of the tertbutyl radical.
The structure and hydrogen bond energy of the received phenols have an impact on their
practical properties. In alkenylphenol derivatives, free hydroxyl groups have high
antimicrobial and antibacterial properties. For example, as a result of joint effect of
nitrogen atom, unsaturated bond and free hydroxyl group, 2-allyl-6-tert-
butylaminomethylphenol has higher antimicrobial and antibacterial properties in jet fuel
TS-1 than other obtained alkenylphenol compounds.
Poster 2
43
Supramolecular complexes of macular carotenoids with
enhanced solubility and oxidation stability.
a,b
Irina E. Apanasenko, a
Nikolay E. Polyakov, a,b
Olga Yu. Selyutina, cLyubov P.
Suntsova, cAlexander V. Dushkin,
dLowell D. Kispert,
fPreejith Vachali,
fPaul S. Bernstein.
aInstitute of Chemical Kinetics and Combustion, Novosibirsk, Russia;
bNovosibirsk State University, Novosibirsk, Russia;
cInstitute of Solid State Chemistry and
Mechanochemistry, Novosibirsk, Russia; dUniversity of Alabama, Tuscaloosa, AL, USA;
fDepartment of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah
School of Medicine, Salt Lake City, UT, USA.
e-mail: airin.nsu@gmail.com
Macular carotenoids play a special role in the prevention and treatment of visual diseases. These
carotenoids are not produced by the human body and must be consumed in the diet. On the other hand,
instability of carotenoids in the presence of water, oxygen and metal ions, and their high photosensitivity
restricted their practical application as components of food or medicinal formulations. The preparation of supramolecular conjugates of macular carotenoids (zeaxanthin and lutein) with a
triterpene glycoside, glycyrrhizic acid (GA), and natural polysaccharide arabinogalactan (AG) allows to
minimize the aforementioned disadvantages when carotenoids are used in food processing (colors and
antioxidant capacity) as well as for production of therapeutic formulations considering the better
solubility and stability. We present a new approach for preparation of inclusion complexes of carotenoids
with natural oligosaccharides and polysaccharides using mechanochemical technique. This technique
allowed us to prepare water soluble complexes
of a series of very low soluble drugs and
carotenoids in one step without using of any
organic solvents [1]. It was found that complexation increases the
photostability of macular carotenoids as well as
their stability towards oxidation. In particular,
the rate of carotenoid oxidation by ozone in
aqueous solution reduced by orders of
magnitude in AG and GA inclusion complexes
(Figure 1). It is known that xanthophyll
carotenoids can self-assemble in aqueous
solution to form J- and H-type aggregates. This
feature significantly changes the photo-physical
and optical properties of these carotenoids, and
has an impact on solar energy conversion and
light induced oxidative damage. H-aggregates of
carotenoids exhibit higher photostability in
aqueous solutions as compared with monomers.
It was found that GA does not affect the
photostability of xanthophyll carotenoids. However, the significant increase (5−10 times) in
photostability was detected for AG complexes of these carotenoids [2]. Moreover, the increase in
photostability was detected for both monomer and H-aggregate of xanthophylls. This means that AG can
form inclusion complexes with monomers as well as with H-aggregates of carotenoids.
Acknowledgements. This work was supported by grant RUC-7067-NO-12 from the U.S. Civilian
Research & Development Foundation (CRDF Global) with funding from the United States Department of
State, and grant DE-FG02-86ER-13465 from the U.S. Department of Energy.
[1] N.E. Polyakov, T.V. Leshina, E.S. Meteleva, A.V. Dushkin, T.A. Konovalova, and L.D.
Kispert, J. Phys. Chem. B, 113, 275-282 (2009).
[2] N.E. Polyakov, A. Magyar, L.D.Kispert, J. Phys. Chem. B; 117, 10173-10182 (2013).
Figure 1. Kinetics of lutein decay in reaction with
ozone in 25% aqueous ethanol solution in pure form
and in the inclusion complexes.
Poster 3
44
Magnetic field effects in E.coli cells in the presence of the
isotope Mg
Avdeeva E.I., Letuta U. G., Berdinsky V.L.
Orenburg University, Orenburg, Tereshkova st. 134/2, 460000
e-mail: avdeevaelenaosu@yandex.ru
Effects of nuclear spins of magnetic isotopes 25
Mg and nn
Zn in vitro and in vivo
have proved that enzymatic electron transfer processes producing intermediate ion-
radical pairs are spin dependent processes. For example, the presence of 25
Mg (nuclear
spin I = 5/2) in active cites of some enzymes in bacterial cells E. coli accelerates growth
rate and increases their viability [1,2]. Thus such processes should be magnetic field
dependent ones and could be primary steps responsible for biological magnetoreception
in any living organisms without special magnetosensitive organs . New effects of weak
magnetic fields (0 -100 mT) were shown to be dependent on presence of magnetic 25
Mg
or nonmagnetic 24,26
Mg isotopes in E.coli cells.
1. A. L. Buchachenko, Magnetic isotope effects in chemistry and biochemistry –
New York: Nova Science Publishers, Inc. – 2009. – 152 p.
2. Shevchenko U.G, Koltover V.K., Deryabin D.G., Berdinsky V.L. Magnesium
isotope effect on enzymatic phosphorylation and growth of E. coli cells
Poster 4
45
Self-Organization Features of the Copper(II)
3-Amino-4-Ethoxycarbonylpyrazole Compound.
A.S. Berezin1,2
, V.A. Nadolinny1, L.G. Lavrenova
1,2
1Nikolaev Institute of Inorganic Chemistry, 630090, Novosibirsk, Russia
2Novosibirsk State University, 630090, Novosibirsk, Russia
berezin-1991@ngs.ru
Synthesis and study of compounds with the magnetically active structure are both
of the fundamental and practical interest in the electronics, medicine, etc. The
investigation results of the self-organization features by EPR, XRD, SQUID and Raman
scattering of the CuL2Br2 compound are presented.
The EPR spectrum of the initial powder sample is a single line with the g=2.155
that is independent of temperature, the line width equals 830 G at 300K. By lowering
the temperature of the sample to T = 77K, ∆H is reduced to 720 G. Simultaneously the
sample changes the color reversibly. After the heat treatment of the sample (from 77K
to 300K) the new absorption line appears in the zero magnetic fields in the EPR
spectrum. The heat treatment reiteration leads to increase of the new line intensity and
decrease of the intensity of the line with g=2.155 in the EPR spectra. The XRD data
indicate, after the heat treatment the phase change occurs in the sample, presumably,
with the formation of the strained structures. In Raman spectra, the disappearance of the
pyrazole rings vibrations is observed in the treated sample. Stabilization of the pyrazole
ring is expected to be due to the bromide forks. However, the dispersion or dissolution
of the trained sample leads to the return to its original state.
In the EPR spectra of the sample with new absorption line, the hysteresis loop is
observed, the maximum value of which is reduced with increasing the temperature. All
of this indicates the formation of the magnetic domain structure in the sample.
Moreover, this sample immediately is attracted to a magnet. So, the trained compound
exhibits ferromagnetic properties and ability to nonresonantly absorb the high frequency
energy. But the new absorption line intensity and line width increases with increasing
temperature. Such behavior is characteristic for the spin glass.
Based on the data, the two models of self-organization are proposed. First, polymer
chains of the sample are moved towards to each other such that the bromide forks
stabilize pyrazole rings, whereupon the additional exchange interaction channels arise
between the copper atoms. Second model, angles between the ligands and the Cu plane
change, as stated above the bromide forks stabilize pyrazole rings, thereby the
interaction between the copper atoms in the chain is changed. After self-organization,
the CuL2Br2 has a residual magnetization. Moreover, the self-organization occurs both
in the polycrystalline form and in the film structures during thermal or pressure training.
Poster 5
46
The effect of chemical reaction on the spin states evolution
of spin-correlated radical ion pairs
A. O. Bessmertnykh, V. I. Borovkov, V. A. Bagryansky ICKC, Institutskaya 3, 630090, Novosibirsk, Russia
E-mail:alena.bessmertnykh@gmail.com
A way to create an ensemble of spin-correlated radical ion pairs (RIPs) is the
ionizing irradiation of solutions. The spin evolution of the ensemble can be observed via
the fluorescence, which originates from the recombination of the RIPs. If the singlet-
triplet spin states transitions are caused by hyperfine couplings (HFCs) of the unpaired
electron spins with magnetic nuclei of the RIP partners the evolution typically appears
as oscillations (quantum beats) in the fluorescence intensity decay. Reactions between a
partner of RIP and molecules in the solution change the magnetic environment of the
unpaired electron that affects the spin evolution. Thus the quantum beats analysis is
expected to allow measuring the reaction rate with simultaneous obtaining the
spectroscopic information about the reagents involved.
The above approach was used to study reactions of positive charge transfer to
aliphatic amines in irradiated alkane solutions as well as reactions of the amine radical
cations with nitroxide radicals. To reduce complications related to taking into account
the kinetics of the geminate RIP recombination the ratio of recombination fluorescence
kinetics in nonzero and zero magnetic fields, IB(t)/I0(t), respectively was analyzed. This
method is referred as the method of time-resolved magnetic field effect (TRMFE) in
recombination fluorescence. Both solutions irradiation and fluorescence detection were
performed using the nanosecond X-ray fluorometer, developed in the ICKC SB RAS.
An emphasis has been made to
investigate the spin-selective
reactions of the positive RIP partner
with a third paramagnetic particle,
nitroxide radical (TEMPON). The
figure exemplifies the experimental
(scatter) and theoretical (lines)
TRMFE curves obtained for n-
hexane solution of
tetramethylpiperidine ([C9H19N]=3
mM) and para-terphenyl-d14 ([p-TP-
d14]=0.4 mM). At the absence of
TEMPON, the quantum beats (triangles) are mainly caused by HFC with a single
nucleus N in the RIP (C9H19N)2+
/p-TP-d14 . An addition of TEMPON causes
quenching the quantum beats (circles), which take place in the RIP subensemble which
has escaped the reaction with TEMPON. It is shown that the spin-selective reaction
with a third paramagnetic particle can be described as an additional rate of both the
phase and spin-lattice relaxation, which is proportional to the reaction rate.
Poster 6
47
The Investigation of NMR Parameters of
Heptafluoroindenyl Cation
Dmitriy S. Fadeev, Igor P. Chuykov, Victor M. Karpov, Victor I. Mamatyuk
Novosibirsk Institute of Organic Chemistry, Lavrentiev ave., 9, 630090, Novosibirsk,
Russia
E-mail:dsf@nioch.nsc.ru
Polyfluoroindenyl cations are important intermediates in the reactions of
electrophilic substitution. They could be generated as long-lived ions at superacid media
of antimony pentafluoride for spectral
investigation by NMR spectroscopy. The
interest to this type of cations arises because of
their ambiguous nature. Formally they have
antiaromatic character and this fact is known for
nonfluorinated indenyl cation. But it was shown
that aromatic features increase with a number of
F atoms as substitutions which stabilize cation
[1]. At the same time heptafluoroindenyl cation still has not been investigated in detail
by NMR when it is well known that NMR-parameters reflect geometrical and electronic
character of structure [2]. We registered 19
F and 13
C NMR spectra and interpreted them
with a help of theoretically obtained data. In order to reach accurate correspondence
between calculated and experimental data the influence of anions on heptafluoroindenyl
cation should be taken in consideration. Even in a simple case of SbF6-
anion we
reached better agreement of calculated 19
F and 13
C chemical shifts with experimental. It
can witness indirectly the existence of heptafluoroindenyl cation with anion as close
ionic pair at a media of antimony pentafluoride. We also noted an increase of accuracy
of calculated spin-spin coupling constants JCF and JFF considering anion interaction.
Decomposition of these constants into Ramsey contributions allows us to find a number
of correlations with referring to chemical shifts and electronic structure of the cation.
This study was supported in part by the Russian Foundation for Basic Research (N14-
03-31279).
1. V.M. Karpov, V.E. Platonov, G.G. Yakobson, Tetrahedron, V.34, I.21, 1978, P.
3215-3218
2. V.M. Karpov, V.E. Platonov, L.N. Shegoleva, Zh. Org. Khim., V.34, I.11, 1998, P.
1732-1737.
Poster 7
48
Kinetics and mechanism of the reversible photoinduced
oxidation of purine nucleotides in aqueous solutions.
Natalya N. Fishman1,2
, Olga B. Morozova1, Mikhail S. Panov
1,2,
Günter Grampp3 and Alexandra V. Yurkovskaya
1,2
1International Tomography Center, Institutskaya 3a, 630090, Novosibirsk, Russia
2Novosibirsk State University, Pirogova 2, 630090, Novosibirsk, Russia
3Institute of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse 9,
8010 Graz, Austria
E-mail: n_s@tomo.nsc.ru
As photosensitized electron transfer from purine DNA nucleotides mediated by
triplet-excited exogenous chromophores, such as flavins, anthraquinones,
benzophenones, is important in biological systems, in present work we study the photo-
oxidation reaction of purine nucleotides adenosine-5′-monophosphate (AMP) and
guanosine-5′-monophosphate (GMP) by water-soluble benzophenone derivative –
3,3′,4,4′-benzophenone tetracarboxylic acid (TCBP). We have combined two
techniques, namely the Time-Resolved laser flash photolysis (LFP) and the Time-
Resolved Chemically Induced Dynamic Nuclear Polarization (CIDNP) and compared
reactivity of AMP and GMP towards TCBP triplets in aqueous solutions of different pH
at room temperature in order to provide further information on the acid-base properties
of radical intermediates observed in the photo-oxidation reactions of purines in aqueous
solution. The pH dependence of the observed quenching rate constant was measured by
LFP and explained in terms of reactants pKa values. As a result, the quenching rate
constants for each pair of reactants were determined by simulating the pH dependence
of the quenching rate constant observed. In acidic solution (pH<4.9), the quenching rate
constant is close to the diffusion-controlled limit kq=1.3×109 M
−1s
−1 (GMP), and
kq=1.2×109 M
−1s
−1 (AMP), whereas in neutral and basic solutions it is significantly
lower: kq=2.6×108 M
−1s
−1 (GMP, 4.9<pH<9.4), kq=3.5×10
7 M
−1s
−1 (GMP, pH>9.4),
kq=1.0×108 M
−1s
−1 (AMP, pH>6.5). Surprisingly, the strong influence of protonation
state of phosphoric group on the oxidation of AMP is revealed: deprotonation of the
AMP phosphoric group (6.5) decreases the quenching rate constant from 5.0×108
M−1
s−1
(4.9<pH<6.5) to 1.0×108 M
−1s
−1 (pH>6.5). A complimentary study on the pH
dependence of the geminate CIDNP intensity by time-resolved CIDNP enabled us to get
information on transient radical intermediates and to establish detailed mechanisms for
the reactions between the triplet TCBP and GMP or AMP.
This work was supported by the program of RFBR (Projects No. 13-03-00437, No.
14-03-31563, No. 14-03-00453, No. 14-03-00397), Grant No. MD-3279.2014.2 of the
President of the Russian Federation.
Poster 8
49
Photooxidation of histidine by 3,3′,4,4′-benzophenone
tetracarboxylic acid in aqueous solution studied by time-
resolved and field-dependent CIDNP
Mikhail S. Panov1,2
, Alexey S. Kiryutin1, Natalya N. Fishman
1,2,
Olga B. Morozova1, and Alexandra V. Yurkovskaya
1,2
1International Toomography Center, Institutskaya 3a, 630090, Novosibirsk, Russia
2Novosibirsk State University, Pirogova 2, 630090, Novosibirsk, Russia
E-mail: n_s@tomo.nsc.ru
The interaction of excited triplet states of aromatic carbonyl compounds with amino
acids is of ongoing interest since many years. The nature of this interaction is attributed
to an electron transfer reactions, which play a significant role in biological processes
due to the migration of charge over long distance through peptide chains. Although, the
reactivity of histidine (His) toward the triplet-excited dyes is usually much lower than
that of tryptophan (Trp) and tyrosine (Tyr), earlier we found the new dye 3,3 ,4,4 -
benzophenone tetracarboxylic acid (TCBP), the excited triplets of which could be
quenched with comparable efficiencies by Trp, Tyr, and His in neutral to basic aqueous
solutions [1]. By the analysis of the pH dependences of both the geminate CIDNP and
the quenching rate constant for the His/TCBP at pH 6–9 it was proposed that the
mechanism of fully deprotonated 3TCBP quenching by His is the proton coupled
electron transfer. However the structure of radicals formed in the quenching reaction
was not determined. To remedy the situation and to determine magneto-resonance
parameters of His and TCBP radicals, in this work we used 13
C-Time-Resolved CIDNP
technique to get 13
C CIDNP spectra and field-cycling CIDNP to measure CIDNP field
dependence. As a result, relative values of 13
C isotropic HFCCs in TCBP and His
radicals were obtained from the 13
C-time-resolved CIDNP spectrum, recorded by the
photoreaction of TCBP with His with a natural abundance of magnetic isotope 13
C.
Good agreement was found for hyperfine coupling constants for TCBP ketyl radical
calculated using density functional theory methods and obtained by 13
C-time-resolved
CIDNP. The mechanism of the quenching reaction of triplet-excited TCBP by His in
neutral aqueous solution was established. 1H CIDNP field dependencies for the
photoreaction of TCBP with His were obtained and g-factor for histidyl radical was
found.
Financial support by the program of RFBR (Projects No. 13-03-00437, No. 14-03-
31563, No. 14-03-00453, No. 14-03-00397), Grant No. MD-3279.2014.2 of the
President of the Russian Federation is gratefully acknowledged.
[1] N. N. Saprygina, O. B. Morozova, G. Grampp, A. V. Yurkovskaya, J. Phys. Chem. A, 2014, 118,
339-349.
Poster 9
50
Atomistic molecular dynamics simulations of cyanobiphenyl
compounds
Egor Gerts, Andrei V. Komolkin
Faculty of Physics, St. Petersburg State University, 198504, Ulyanovskaya 3,
St. Petersburg, Russia
E-mail: gerts-e-d@yandex.ru
Liquid crystalline materials are very interesting objects for the researchers. They
are used not only in technological devices. Some biological systems also possess sort of
liquid crystallinity. Cell membranes form lamellar bi-layer mesophase, and this is the
case for cancer cells as well. One of the difficulties in the development of effective
anticancer drugs is the transportation of the drug inside the cell. And liquid crystals can
be rather useful in solving this problem. Some recent papers [1-3] showed that certain
cyanobiphenyl compounds can inhibit cell growth and even recognize normal and
cancer cells. Although the anticancer activity was observed, its mechanism still stays
unclear.
This work focuses on two cyanobiphenyl compounds: thermotropic nematic liquid
crystal 4-cyano-4’-(6-hydroxyhexyloxy)biphenyl (HO-6OCB) and 4-methyloxy-4’-(6-
hydroxyhexyloxy)biphenyl (HO-6OMeOB), that does not form mesophase. Local and
conformational structures of these substances and their equimolar mixture are studied
via fully atomistic molecular dynamics simulations. This information will help to
investigate the mechanisms of intermolecular interactions, thus giving insights into the
development of novel anticancer drugs.
Acknowledgements. It is a pleasure to thank Saint-Petersburg State University for
the research grant 11.37.159.2014. Research was carried out using computational
resources provided by Resource Center ”Computer Center of SPbU” (http://cc.spbu.ru).
References.
[1] Yoshizawa, Atsushi, et al. "Biological activity of some cyanobiphenyl
derivatives." Chemistry Letters 38, 6 (2009): 530-531.
[2] Takahashi, Yuuka, et al. "Supramolecular assembly composed of different
mesogenic compounds possessing a ω-hydroxyalkyl unit exhibits suppressive effects on
the A549 human lung cancer cell line." MedChemComm 2, 1 (2011): 55-59.
[3] Ishikawa, Junya, et al. "Suppressive effects of liquid crystal compounds on the
growth of U937 human leukemic monocyte lymphoma cells." Cancer Cell Int 12, 3
(2012).
Poster 10
51
Functional EPR Imaging of Isolated and Perfused Rat Hearts:
Monitoring of Tissue pH and Oxygenation
Artem A. Gorodetsky, Denis A. Komarov
Novosibirsk Institute of Organic Chemistry, 9 Lavrent’ev Ave., 630090, Novosibirsk,
Russia
E-mail: gorodaa@nioch.nsc.ru
Ischemic heart disease is one of the most common causes of mortality in the
developed countries. Violation of the coronary blood supply leads to a lack of oxygen
supply and metabolic substrates to a myocardium, as a result significant changes occur
in the myocardial tissue microenvironment which can lead to permanent damage of the
cardiomyocytes.
Comprehensive studies of myocardial tissue microenvironment are necessary for
understanding the mechanisms of ischemic injury and for the development of new
therapeutic approaches in the treatment of ischemic heart disease. Electron
paramagnetic resonance technique in conjunction with paramagnetic probes allows
noninvasive monitoring functional parameters of living biological objects; furthermore,
the application of EPR imaging methods provides a unique opportunity for visualization
of the tissue microenvironment.
The main aim of this work was to visualize myocardial acidosis and oxygenation in
isolated and perfused rat hearts during local ischemia by EPR imaging technique.
Isolated rat hearts were perfused directly in a resonator of an L-band EPR spectrometer
by method of Langerdorff at a constant flow. Contractile function of the hearts was
continuously monitored during the experiment using a water-filled latex balloon
inserted into the left ventricular and connected to a pressure transducer. Local ischemia
was induced by ligation of the left anterior descending coronary artery. A specially
designed pH-sensitive nitroxide radical was used for visualization of myocardial pH. A
perdeuterated 15
N nitroxide radical was synthetised and employed as a pO2-sensitive
probe for visualization of myocardial oxygenation during ischemia and reperfusion.
A map of pH of an isolated and perfused rat heart during local ischemia was
obtained and a significant acidification of ischemic area was observed down to pH 6.7 -
6.9. Also the maps of oxygenation of a heart were obtained during ischemia using pO2-
sensitive nitroxide radical and a significant decrease in the oxygen concentration was
observed in the ischemic area. In summary, this work demonstrates capability of low-
field EPR technique in combination with specially designed soluble paramagnetic
probes for visualization of functional parameters of living tissues and organs.
Poster 11
52
Proton NMR study of hydrogen site occupancy and mobility
in hydrides of disordered transition metal alloys
V.O. Ievleva1, A.V. Vyvodtceva
1, M.G. Shelyapina
1, A.V. Ievlev
1,
S.A. Lavrov1, A. Privalov
2, N.E. Skryabina
3, A. Aleksanyan
4, D. Fruchart
5
1Faculty of Physics, St Petersburg State University, St Petersburg, Russia,
2Institute für
Ferstkoerperphysik, TU Darmstadt, Darmstadt, Germany, 3Faculty of Physics, Perm State
University, Perm, Russia, 4A.B. Nalbandyan Institute of Chemical Physics of Armenian
NAS, Yerevan, Armenia, 5MCMF Institut Néel, CNRS, Grenoble, France
E-mail: valeriya_ievleva@nmr.phys.spbu.ru
Because of their potentially high hydrogen absorption capacity, the early transition
metal alloys with bcc lattice have been a subject of intensive experimental and
theoretical studies [1]. For better understanding of intrinsic mechanisms that govern the
hydrogen kinetics in these hydrides the deeper knowledge on local structure and
hydrogen mobility is required. Being a powerful tool to investigate metal-hydrogen
systems, nuclear magnetic resonance (NMR) can provide a comprehensive insight on
main characteristics (static and dynamic) of their microstructure. Here we report on the
result of our recent 1H NMR study (cw spectroscopy, relaxation measurements and
diffusometry) of hydrides of disordered binary Ti-Nb, Ti-V and ternary Ti-V-Cr alloys
with the H/M ratio close to 2. To treat the cw-NMR data the KKR-CPA calculation
were carried out. The result can be summarized as follows. In hydrides of ternary Ti-V-
Cr alloys the 1H NMR spectrum consists of two lines, narrow and broad ones, which
correspond to two states of hydrogen, more and less mobile, respectively. The broad
line can be attributed to the hydrogen localized in tetrahedral interstitial sites of the fcc
lattice [2]. In hydrides of binary Ti-V and Ti-Nb alloys an additional broad line appears.
This line can be attributed to the partly occupied octahedral hydrogen sites. The ratio
between the integral intensities of the broad and narrow components of the 1H NMR
line depends on temperature: at low temperature the hydrogen motion is frozen and the
narrow line disappears, whereas at high temperature all the hydrogen atoms are in
mobile state. However, in relaxation measurements only the narrow component is
observed, and the weight of the “faster” hydrogen fraction can be determined from the
free induction decay amplitude of the 1H NMR signal. The temperature dependence of
“faster” hydrogen fraction can be perfectly fitted by the logistic distribution function.
To explain the temperature dependencies of the spin-lattice relaxation times we
developed a model, which supposes an exchange between hydrogen states with different
mobility [3]. Using this model we have determined parameters characterizing the
hydrogen mobility: activation energies and correlations times. Spin-lattice relaxation
measurements of Ti-V-Cr hydrides, treated within the exchange model, confirm that
activation processes starts earlier in the vanadium reach hydrides. That is also in
agreement with our diffusion measurement.
References
[1] E. Akiba, H. Iba, Intermetallics 6 (1998) 461.
[2] V.S. Kasperovich et al., J.Alloys Compd. 509 (2011) S804.
[3] V.I. Chizhik et al., Int. J. Hydrogen Energy 36 (2011) 1601.
Poster 12
53
Investigation of antimicrobial peptide alamethicin pore
formation in the membrane of Bifidobacteria cell by EPR
Isaev N.P.1, Samoilova R.I.
1, De Zotti M.
2, Formaggio F.
2 Toniolo C.
2 and Raap J.
3
1Institute of Chemical Kinetics and Combustion, Institutskaya-3, 630090
2UniVersity of Padova, 35131 Padova, Italy
3Leiden Institute of Chemistry, Gorlaeus Laboratories
e-mail: isaev@kinetics.nsc.ru
The development of antibiotics may be the greatest scientific invention that saved
millions of lives and significantly increased life expectancy. However its excessive
usage formed bacterial resistance that grows faster than new drugs are designed.
Antimicrobial peptides which are the part of organism defense system may be a
possible alternative to classical antibiotics. Its mechanism of action is under hard
investigation. The most common approaches use model membrane systems and it was
shown that some peptides may form membrane pores at high peptide/lipid concentration
(around 1/20) via barrel stave or toroidal pore mechanisms. Pores formation leads to
increased membrane permeability and cell death. Bacterial membrane morphology and
composition differs a lot from model ones, but to our very best knowledge so far there
are only three works that attempt to investigate peptides mechanism of action directly in
bacteria cells [1-3].
In this work we investigated pore formation mechanism of spin-labeled peptide
alamethicin in Bifidobacterium cells using CW EPR and PELDOR. Alamethicin is
water insoluble, so we also studied efficiency of its delivery to bacteria by unilamellar
liposomes and SDS micelles.
1. A. D. Milov, R. I. Samoilova, Yu. D. Tsvetkov, V. A. Gusev, F. Formaggio, M.
Crisma, C. Toniolo, J. Raap; Appl. Magn. Reson. 23, 81-95 (2002)
2. Gee M.L., Burton M., Grevis-James A., Hossain M.A., McArthur S., Palombo E.A.,
Wade J.D., Clayton A.H., Sci Rep., 3:1557 (2013)
3. Avitabile C., D'Andrea L.D., Romanelli A., Sci Rep., 4:4293 (2014)
Poster 13
54
Theory of pulsed reaction yield detected magnetic resonance
Egor Nasibulov1,2
, Leonid Kulik3, Jan Behrends
4, Robert Bittl
4, Konstantin Ivanov
1,2
1 International Tomography Center SB RAS, Institutskaya 3a, Novosibirsk 630090, Russia. E-mail:
ivanov@tomo.nsc.ru
2 Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russia
3 Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya 3, Novosibirsk 630090, Russia
4 Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
We have developed the theory of pulsed Reaction Yield Detected Magnetic Resonance
(RYDMR) and suggest analogues of the main EPR pulse sequences in the case of non-
selective mw-pulses. We have used refocusing of the zero-quantum coherences in the
Radical Pair (RP) and formulated a criterion for observing spin echoes in RYDMR
where not the spin magnetization but the singlet state population is used as an
observable. An alternative way to monitor the spin echo is given by monitoring the
longitudinal magnetization in an RP after applying an additional 90-degree non-
selective pulse. The primary echo sequence has been studied, which can be extended to
an analogue of the Carr-Purcell sequence with multiple echoes coming from subsequent
pulses. We have suggested an Electron Spin Echo Envelope Modulation (ESEEM)
pulse sequence for observing modulations caused by the electronic spin-spin
interactions that can be used to probe the distance between the radicals in the RP.
Finally, analogues of the stimulated echo sequence and the Mims ENDOR (Electron
Nuclear Double Resonance) sequence have been proposed. The treatment was also
extended to RYDMR with selective pulses; in this case we considered refocusing of
both zero-quantum and single-quantum coherences. This enables extending the
capabilities of pulsed RYDMR even further, for instance, by using pulse sequences of
the ELDOR (Electron Electron Double Resonance) type, which can be used for
measuring electron-electron interactions in the RP.
The theoretical results can be used to extend the scope of RYDMR spectroscopy
and fully exploit its potential. In combination with the high sensitivity of RYDMR,
techniques using pulsed methods can provide new attractive options for more detailed
study of structure, dynamics and reactivity of the short-lived RPs and properties of
paramagnetic charge carriers in organic semiconductors.
This work was supported by grant MD-3279.2014.2 of the President of RF and
Alexander von Humboldt Foundation.
Poster 14
55
Spin dynamics of ZnTPP in room-temperature ionic liquids
studied by Time-Resolved EPR
Ivanov Mikhail Y., Veber Sergey L., Fedin Matvey V.
International Tomography center, SB RAS, Intitutskaya 3a, 630090, Novosibirsk, Russia
E-mail: michael.ivanov@tomo.nsc.ru
Room temperature ionic liquids (RTILs) have drawn a significant attention of
scientific community during last few decades. This interest is caused by unique
properties exhibited by RTILs on macro- and microscopic scales, including their
thermo-stability, negligible vapor pressure, high viscosity and ability to form micro-
ordered structures in supercooled state. One of the interesting applications of ILs
concerns their influence on the formation of chemical induced electron polarization
(CIDEP) in photo-excited triplet molecules and during photochemical reactions. Up to
date, only one study of CIDEP in photo-excited triplet molecules in ILs using time-
resolved electron paramagnetic resonance (TR EPR) has been reported [1].
In this work we have studied CIDEP of zinc tetraphenylporphyrin (ZnTPP) in two
ILs ([bmim]PF6 and [bmim]BF4) of significantly different viscosity. It has been
assumed that high micro-viscosity of IL should affect the rotational motion of ZnTPP
and, consequently, the electron relaxation times between triplet sublevels. We used X-
band (9 GHz) TR EPR as one of the most appropriate methods for studying spin
dynamics of triplet molecules. The temperature dependence of micro-viscosity of
[bmim]PF6 and [bmim]BF4 in the range of 230÷294 К has been preliminarily studied by
EPR of nitroxide spin probes. Inhomogeneous freezing and micro-structuring
phenomena have been found in IL [bmim]PF6. Remarkably, owing to the high viscosity
of ILs used, the photo-excited triplet state of ZnTPP has been detected even at room
temperature, in agreement with [1]. The detailed analysis of temperature-dependent TR
EPR kinetics has been performed, which revealed crucial influence of micro-ordered
structure of RTILs on the electron relaxation rates in photo-excited triplet ZnTPP.
[1] Kawai A., Hidemori T., Shibuya K.: Molecular Physics, 2006, 104:10-11,1573–
1579.
Poster 15
56
Adaptation of NMR Imaging Techniques for Experimental
Mapping of the Static Magnetic Field
Viacheslav A. Ivanov, Viacheslav V. Frolov
Saint-Petersburg State University
Ulyanovskaya 1, Saint-Petersburg, 198504, Russia
E-mail: ivi-lamer@rambler.ru
Problem of static magnetic field homogeneity and getting the spatial field
distribution has always been an actual problem in NMR spectroscopy and imaging.
Conventional method of field scanning realized by small-size sample moving through
the volume of magnetic system and point-by-point field measuring is time-consuming,
not accurate and requires special equipment, therefore such methods which present field
map of the whole sample or at least its section after computer processing of NMR data
are an object of interest. Such methods can be developed on the basis of NMR imaging
techniques.
Tomographic methods of getting magnetostatic field spatial distribution realized
previously by their authors in strength field were studied. Experimental MRI scanner
control program in LabVIEW development environment was modified to perform the
experiments. Picture of field distribution on cylindrical sample, 35mm in diameter was
obtained as a result of the experiment. Thus the possibility of getting spatial field
distribution in relatively short time using standart equipment with minimal control
program modification in weak magnetic field was demonstrated.
Poster 16
57
Controlled radical polymerization of styrene in the
presence of nitroxides at low temperatures
Beket B. Kanagatov,
a Dmitriy A. Parkhomenko,
a,b Maria V. Edeleva,
b Ludmila E.
Tatarova,c Vadim K. Khlestkin
a
a Novosibirsk State University, Pirogova str., 2, 630090, Novosibirsk, Russia
b Institute "International Tomografic Center", Institutskaya str., 3, 630090, Novosibirsk, Russia
c Institute of Cytology and Genetics, Lavrentieva pr., 10, 630090, Novosibirsk, Russia
E-mail: beket92k@mail.ru
Controlled radical polymerization (CRP) in the presence of nitroxides is a modern
method of producing polymers with a given structure, molecular weight and low
molecular mass distribution. CRP is usually carried out at elevated temperature, which
makes polymerization process energy consuming. Typical temperature for styrene
polymerization in the presence of nitroxide is 100-140oC. Lowering the temperature of
polymerization even by 10-20°C can provide significant economic and environmental
effects. There are only a few examples of the CRP at low temperature. For example,
Guillaneuf et al. [1] describe the use of α-hydrogenated linear nitroxides, which enables
the polymerization of styrene in a controlled manner at 60oC.
This work presents synthesis of a new cyclic nitroxide of imidazole series (Figure
1). Synthetic procedure consist of six stages. NMR and EPR spectroscopy were
employed to characterize the target product and intermediates of synthetic stages. The
nitroxide was used for the polymerization of styrene at 60oC. The kinetics of
polymerization was studied by means of NMR spectroscopy. It was shown that the
polymerization is possible up to high monomer conversion (80-90%). Gel permeation
chromatography allowed to determinate molecular mass and molecular mass
distribution of the final polymer. It is shown that the polymerization proceeded in a
controlled manner as the obtained polydispersity of the polymer was 1.45 at 50% of
monomer conversion, which is below the theoretical limit for a regular uncontrolled
radical polymerization.
Figure 1
1. Guillaneuf, Y., Lamps, J. P., Catala, J. M., Gigmes, D., Drockenmuller, E. J. Polym. Sci. Part A:
Polym. Chem.2012, 50, 3750-3757.
This work was supported by RFBR (project number 12-03-01042a), OHNM 5.1.1,
President grant MK-1654.2013.3
Poster 17
58
Application of pulse EPR for investigation of lipid-
cholesterol rafts in membranes
Maria E. Kardash, Nikolay P. Isaev, Sergey A. Dzuba
The Institute of Chemical Kinetics and Combustion, Institutskaya, 3, 630090, Novosibirsk, Russia
E-mail: Kardash.marya@gmail.com
Lipid rafts are ordered regions of the lipid bilayer of the cell membrane. Rafts play
important role in membrane proteins functions regulation, but its molecular structure is
still unknown.
Lipid rafts are known to form in a ternary mixture of cholesterol and two lipids
with different melting points. The "solid" lipid aggregates with cholesterol. Here we
investigated the aggregation of cholesterol in model membranes of different lipid
composition.
In the present study spin echo phenomenon, so-called "instantaneous spectral
diffusion", was used to investigate the stage of cholesterol aggregation. Instantaneous
diffusion arises due to the dipole-dipole interactions between neighboring electron spins
and contributes echo decay exponentially. Its rate is proportional to the local
concentration of spin labels.
It was shown that method of "instantaneous diffusion" is applicable to investigate
the aggregation of cholesterol in biological membranes. Local concentration of
aggregated spin-labeled cholesterol increases several times relative to its average
concentration in the membrane.
.
Poster 18
59
EPR Study of Electron-Acceptor Sites during Catalytic
Dehydrochlorination of 1-Chlorobutane over
Nanocrystalline MgO
Roman M. Kenzhin1, Tatyana N. Akimova
2, Ekaterina I. Shuvarakova
1,3, Vladimir V.
Chesnokov1,2
, Alexander F. Bedilo1,3
1 Boreskov Institute of Catalysis SB RAS, pr. Lavrentieva, 5, 630090, Novosibirsk, Russia
2 Novosibirsk State Technical University, pr. K. Marksa, 20, 630078, Novosibirsk, Russia
3 Novosibirsk Institute of Technology, Moscow State University of Design and Technology, Potaninskaya,
5, 630099, Novosibirsk, Russia
E-mail: romankenzhin@gmail.com
It was shown earlier that the catalytic activity in dehydrochlorination of 1-
chlorobutane over nanocrystalline MgO substantially increases with time due to the
MgO conversion to MgCl2 [1]. This increase coupled with a decrease of the surface area
indicates that more active catalytic sites are formed on the surface during this reaction.
Recently we reported that weak electron-acceptor sites formed due to the MgO
halogenation may be responsible for solid-state reaction between nanocrystalline MgO
and CF2Cl2 [2]. In this study we characterized by EPR weak electron-acceptor sites
formed during this reaction using perylene as a spin probe, and found a good correlation
between their concentration and the catalytic activity.
Samples of aerogel-prepared nanocrystalline MgO and a commercial MgO sample
were studied in catalytic dehydrochlorination of 1-chlorobutane. 1-Chlorobutane
conversion to a mixture of butenes was monitored by gas chromatography. The
electron-acceptor sites were characterized using perylene adsorption from 2x10-2
M
solution in toluene. The catalytic activity was found to increase significantly during the
1-chlorobutane dehydrochlorination reaction, which is accompanied by modification of
the MgO surface and bulk with chloride ions. No electron-acceptor sites were observed
on the surface of initial MgO samples. They appeared only during the reaction. Their
concentration normalized per unit mass gradually increased during the reaction due to
the surface chlorination. A good correlation was observed between the catalytic activity
and the concentration of weak electron-acceptor sites. The obtained results indicate that
weak electron-acceptor sites tested using perylene may be the active sites accounting for
1-chlorobutane dehydrochlorination in the active state of the catalyst.
This study was supported in part by Russian Foundation for Basic Research (Grant
13-03-12227-ofi-m).
[1]. I.V. Mishakov, A.F. Bedilo et al., J. Catal. 206, 40-48 (2002).
[2]. A.F. Bedilo, E.I. Shuvarakova et al., J. Phys. Chem. C, 118, 13715-13725 (2014)
Poster 19
60
CIDNP in Naproxen - Pyrrolidine Dyads as a Model of Drug-
Enzyme Binding.
Ekaterina A. Khramtsova, Viktor F. Pluysnin, Ilya M. Magin, Tatyana V.
Leshina
Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya str., 3,
630090, Novosibirsk, Russia
E-mail: khramtsovaea@gmail.com
At present a timely problem is the investigation of the mechanisms of remedies
action on cellular and molecular levels. According to a modern view the mechanism of
medicine’s action accounts for the interaction of the active part of remedy molecule
with an enzyme. On a molecular level it generalizes to various so-called weak
interactions such as the formation of charge transfer complexes, hydrogen bonds, Van
der Waals and dipole-dipole interactions. It is widely thought that such interactions are
originated between a medicine and an amino-acid residue in the active site of an
enzyme. Under studying the regularities by which these interactions are obeyed model
systems are often used. Linked systems are most popular, such molecules contain a
donor and an acceptor connected with covalent bridges. Typically photoinitiation is
used for modeling and then the main mechanism of donor-acceptor interaction turns out
electron transfer (ET).
In this study the effects of photo CIDNP and the rates of fluorescence quenching in
three linked systems in different polarity media are analyzed, molecules contain N-
methyl pyrrolidine as a donor and naproxen as an acceptor group. The choice of the
system is due to following facts: the molecular mechanism of the action of non-steroidal
anti-inflammatory drugs, including well-known brand “Naproxen” – (S)-2-(6-methoxy-
2-naphtyl) propionic acid, lies in the binding of a remedy with amino-acid residues in
the cyclooxygenase (COX) active site. COX is a bifunctional enzyme, which performs
two activities – the cyclization of the natural substrate’s molecule and the transfer of
two electrons, that is why the ET investigation in model system is of some interest.
Obtained in this work results have demonstrated the high sensitivity of CIDNP
effects and the rates of fluorescence quenching in dyads to the influence of solvent
polarity and also to the donor/acceptor spatial position. It is quite well agreed with
previously postulated conclusions in molecular biology about the role of steric factors in
the process of naproxen-binding in COX active site.
The work was supported by the Russian Foundation for Fundamental Research
(grant 14-03-00192 A).
Poster 20
61
FMR of iron-containing nanocomposites of natural
polysaccharides
Khutsishvili S.S., Alexandrova G.P., Vakul’skaya T.I., Sukhov B.G.
A.E. Favorsky Irkutsk Institute of Chemistry Siberian Branch of the Russian Academy of
Sciences, Favorsky street, 1, 664033, Irkutsk, Russia
E-mail: khutsishvili_sp@yahoo.com
The ferromagnetic properties of nanocomposites based on natural
polysaccharides (arabinogalactan, galactomannan, carrageenan) and iron oxides
(magnetite nanoparticles), that, being covered by natural high molecular polymers, form
stable aggregation magnetic nanomaterials, have been investigated.
All the nanocomposites to a greater or lesser extent possess the ferromagnetic
properties at room temperature that has been confirmed by measurements of their
magnetization. By example arabinogalactan, the similar characteristics of FMR spectra
of the investigated nanocomposites are the asymmetric broad absorption lines,
indicating small changes in size and shape of the nanoparticles formed (for the
nanocomposites containing iron from 3.5 to 6.4%). The greatest change in the magnetic
properties of iron-containing nanomaterials is connected with the change of the domain
structure of magnetic-ordered systems at increasing particles' sizes. Dramatic changes in
the spectra character are observed at increasing iron content up to 9.2-12.5%. The
appearance of several absorption lines, which position varies at different amount of
microwave power, testifies the substantial change of nanoparticles' distribution, the
increasing of the latter sizes and the possible change of domain structure. It accords
with the appearance of inflection point at iron content 6.4% in the nanocomposites on
the dependences of geff-factor and width of EPR signal, magnetization parameters and
nanoparticles' sizes on percentage iron content in the nanocomposites and with the
found relation of magnet-activity to the sizes of the nanoparticles.
Prolonged storage of the nanocomposites has shown that at least a year there are
the stable metal nanoparticles, maintaining the EPR characteristics.
This work was supported by the Russian Foundation for Basic Research (Grants 11-
03-00022 and 14-03-00859_a).
Poster 21
62
Lipid peroxidation. Bistability and bifurcation phenomena.
Magnetic field effects
A. A. Kipriyanov, Jr.1,♦
and P. A. Purtov1,2,♠
1Voevodsky Institute of Chemical Kinetics and Combustion Siberian Branch of the Russian Academy of
Sciences, Institutskaya 3, 630090, Novosibirsk, Russia
2Novosibirsk State University, Pirogova 2, 630090, Novosibirsk, Russia
♦Email: akipriyanov@yahoo.com
♠Email: purtov@kinetics.ncs.ru
The response of living organisms to the change in the environment, including the
change of external magnetic field, is quite different. One of the feasible defense
mechanisms of organism adaptation to varying conditions is the activation of lipid
peroxidation reaction (LPR) which plays a key role in the life of cells (e.g., apoptosis or
necrosis). It is known that the normal conditions of cell vital activity involve a certain
level of LPR induced by the formation of active oxygen forms. Taking into account the
necessary of keeping certain LPR level under stationary conditions, it is assumed that
any change of LPR produces base response of living system to external action which
initiates other defense mechanisms of organism as a whole.
On the other hand, it is known that the reaction of lipid peroxidation follows a free-
radical chain mechanism in which the key role belongs to peroxide radicals LO2.
Therefore, according to the mechanism of radical pairs, this reaction is a potential target
of magnetic field effect on living systems.
We present theoretical results of investigation of magnetic field effect on LPR in
steady state condition. The model system under the investigation is an open
continuously stirred tank reactor which describes a living cell on the approximate level.
We show that under certain conditions in this reaction system, three steady states may
arise, two of which are stable and the third state is unstable. It is assumed that external
magnetic field could effect on the rates of radical reactions occurring in the system.
This, in turn, leads to bifurcation of the non-equilibrium stationary state and, thus, to a
drastic change in the concentration of reactants
.
Poster 22
63
EPR study of the hydrogen center in HPHT diamonds grown
in carbonate medium
Andrey Yu. Komarovskikh1, Vladimir A. Nadolinny
1, Yuri N. Palyanov
2, 3,
Igor N. Kupriyanov2, 3
, and Alexander G. Sokol2, 3
1Nikolaev Institute of Inorganic Chemistry SB RAS, Acad. Lavrentiev Ave., 3, 630090,
Novosibirsk, Russia 2Sobolev Institute of Geology and Mineralogy SB RAS, Acad. Koptyuga Ave., 3, 630090,
Novosibirsk, Russia 3Novosibirsk State University, Pirogova str., 2, 630090, Novosibirsk, Russia
E-mail: komarrr@ngs.ru
The issue of hydrogen incorporation into a diamond is one of the topical problems
of diamond field. Hydrogen is very widespread contamination, it being found both in
natural and synthetic diamonds. Hydrogen is technologically important impurity in
diamond effecting its conductivity. Up to date hydrogen-containing paramagnetic
centers have been found only in synthetic CVD diamonds. And hydrogen incorporation
in this case is connected with large amount of hydrogen in the precursor gas.
In this work new hydrogen containing paramagnetic center has been revealed by
EPR in diamonds grown at HPHT conditions in the Na2CO3–CO2–H2O–C system. In
the EPR spectra of the studied samples there are spectra of the substitutional nitrogen
atom, previously detected defects attributed to oxygen and the new spectrum (labeled
VOH). Study of the EPR spectra in X and Q frequency bands has shown that new
spectrum is characterized by the appearance of forbidden transitions along with allowed
ones. The analysis of the angular dependence of the spectrum in single crystal and the
analysis of powder spectra give an information that the spectrum is caused by
interaction with the nucleus of a hydrogen atom 1H and described by the spin
Hamiltonian with the following parameters: S=1/2, I=1/2, g =2.0030(1), g||=2.0023(1),
A(H) =10.7(3) Gs, A(H)||=11.8(3) Gs.
The high concentration of oxygen centers in the studied samples indicates a
possibility of oxygen incorporation into the structure of this defect. So on the basis of
EPR data on electronic state and symmetry of the VOH center the center is supposed to
have a model of vacancy–oxygen–type defect containing a hydrogen atom. In such a
model, the motional averaging may result in the C3v symmetry of the EPR spectrum.
In the IR absorption spectra of the studied diamonds a group of lines (in the range
of 3000 cm-1
) indicating the formation of C–H bonds was detected. This is
complementary evidence of hydrogen incorporation into the structure of the considered
diamond crystals.
Poster 23
64
The study of influence of sugars on the mobility of
phospholipid bilayer
K. B. Konov1, N. P. Isaev
2, S. A. Dzuba
2,3
1 Kazan Physical -Technical Institute, Kazan, 420029, Russia
2 Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090, Russia
3 Novosibirsk State University, Novosibirsk, 630090, Russia
E-mail: kostyakonov@gmail.com
Sugars, such as sucrose and trehalose, can protect biological cell and its interior
from damaging by freezing and desiccation [1]. There are two main hypothesis about
how sugars protect the cell. The water replacement hypothesis asserts that sugars
aggregate in vicinity of polar heads of phospholipids replacing the surrounding water
[2]. Sugars form hydrogen bonds with lipids polar groups stabilizing phospholipid
bilayer [3]. The another hypothesis states that sugars are excluded from membrane
surroundings and act only by changing a properties of intercellular liquid.
In this work we study the mobility of lipid bilayer by electron spin echo technique.
The model bilayer was made of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)
lipid and spin labeled stearic acid. Spin labels were attached at 5th
and 16th
position of
acyl chain. Electron spin echo technique can give useful information about the mobility
in the middle of lipid bilayer and near the surface level at temperature range from 80K
to 250K.
The obtained data shows that the action of trehalose and sucrose differ from each
other.
[1] Crowe J.H., Crowe L.M. et al., Carpenter etal., Biochimica et Biophysica Acta,
1988, 947(2), 367-84.
[2] Golovina E. A., Golovin A. V. etal., Biophysical Journal, 2009, 97, 490–499
[3] Geert van den Bogaart, N. Hermans etal., Biophysical Journal, 2007, 92, 1598–
1605
Poster 24
65
Effect of a heavy atom on magnetic anisotropy of
monobromine substituted septet trinitrene. Experimental
and theoretical (ab initio and DFT) study.
Denis V.Korchagin, Artem A. Mazitov, Aleksander V.Akimov, Sergey V. Chapyshev
and Eugenii Ya. Misochko
Institute of Problems of Chemical Physics Russian Academy of Sciences, Russian
Federation korden@icp.ac.ru
Recently we have been observed the effect of a heavy atom in the high-spin
molecules of nitrenes, which consisted of the large spin-orbit contribution to the
parameter D (DSOC
) and, as the result, a significant change not only the magnitude but
even the sign of the magnetic anisotropy parameter Dtotal
[1]. In continuation of this
work we present an experimental and theoretical study of the ZFS parameters of 1-
bromo-3,5-dichloro-2,4,6-trinitrenobenzene molecule (1).
1
EPR spectrum of matrix-isolated in solid argon (5K) of this septet (S = 3) in the
ground state molecule of trinitrene 1 was detected. From EPR spectra it has been
determined with high precision the parameters of tensor D. The values obtained were
used as reference for a detailed theoretical analysis of the ZFS parameters of molecule
1. By the high-level ab initio and DFT methods the calculations of the tensor D
parameters were performed, including both analysis spin-spin and spin-orbit
contributions to the total D value, and also orientations of DSS
and DSOC
tensors. The
high-level ab initio quantum chemical calculations have shown that the main
contribution to the DSOC
make transitions involving p-orbitals of the heavy halogen
substituent in the plane (right figure).
[1] Misochko, E. Ya.; Akimov, A. V.; Masitov, A. A.; Korchagin, D. V.;
Yakushchenko, I. K.; Chapyshev, S. V. J. Chem. Phys. 2012, 137, Article No. 064308.
Acknowledgements – This work was financially supported by the Russian Foundation for Basic Research (grant 13-03-00757) and the Russian Academy of
Sciences (program OX-1).
Poster 25
66
Inclusion compound of threonin with cucurbit[7]uril -
supramolecular chemistry in solution
Ekaterina A. Kovalenko
Nikolaev Institute of Inorganic Chemistry SB RAS, Acad. Lavrentiev Ave., 3,
630090, Novosibirsk, Russia
e.a.kovalenko@niic.nsc.ru
NMR is one of the method which can yield information about the inclusion complex on
an atomic level. This method offers the advantage of providing insights into dinamic
processes as well as structural information at a molecular level. Complexation of CB[n]
with guests molecules causes changes in the chemical shifts of the protons belonging to
the CB[n] and/or guest molecule. We measured 1H NMR spectra for system D,L-treonin
and cucurbit[7]uril in different conditions: concentration, temperatire, pH values.
Sequential adding of three fixed CB[7] amounts resulted in each aminoacid proton
signal chemical shift up field change by a different value, the multiplet structure of
aminoacids lost forming unresolved signals. 1H NMR spectra of aminoacid and CB[7]
mixture in solution demonstrated the existence of chemical equilibrium between free
aminoacid molecules (racemic mixture of treonin and allo-treonin) and associated with
CB[7] aminoacid molecule. With a change of concentration the CB[7] signals are
practically stable to be singlet, doublet and doublet.
Fig. 1. Threonine Fig. 2. 1H NMR spectra of Thr racemate, Thr racemate:
CB[7] in the molar ratio 3,4:1, 1,7:1, 1,1:1
(upwards) in DCl
The work is financially supported by Russian Federation President Grant MK-
2514.2014.3 and RFBR 14-03-31177.
Poster 26
67
Advanced SDSL with Nitroxyl and Trityl Radicals for
Distance Measurements in Nucleic Acids
O.А. Krumkacheva1,2
, M.V. Fedin1,2
, E.G. Bagryanskaya1,2,3,
, A.A. Kuzhelev2,3
,
V.M. Tormyshev2,3
, I.A. Kirilyuk
2,3, A.V. Ivanov
4, A.A. Malygin
2,4, E.S. Babaylova
2,4,
G.G. Karpova2,4
, G.Yu. Shevelev2,4
, A.A. Lomzov2,4
, D.V. Pyshnyi2,4
1 International Tomography Center SB RAS, Novosibirsk, Russia
2 Novosibirsk State University, 630090, Novosibirsk, Russia.
3 N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk, Russia
4Institute of Chemical Biology and Experimental Medicine SB RAS, Novosibirsk, Russia
E-mail: olesya@tomo.nsc.ru
Site-directed spin labeling (SDSL) is widely applied for structural studies of
biopolymers by EPR. In particular, huge attention has been drawn recently to pulsed
dipolar EPR spectroscopy (PELDOR/DEER and DQC methods) allowing distance
measurements in many biologically-important systems. Although significant progress
has been achieved in this field, a number of challenges still remain. One of these
challenges is SDSL of long (exceeding 50-70 base pairs) natural nucleic acids that is not
possible using common solid-phase synthesis. In this work, we propose novel SDSL
approach suitable for long natural RNAs, which is based on the attachment of linker
containing aliphatic amino group to the target nucleotide residue and following selective
coupling of spin label to this amino group [1]. Such linker can be attached to the desired
RNA residue via sequence-specific reaction with the derivatives of
oligodeoxyribonucleotides. To verify this approach, we applied it to model RNA duplex
with known structure and expected distance between corresponding residues. The
distance measured using Q-band pulse DEER corresponds well to the expected one.
Another current challenge in pulsed dipolar EPR spectroscopy is a design of spin
labels and SDSL strategies for distance measurements in nucleic acids at 300 K. For this
purpose, relaxation properties of trityl radicals represent a significant advantage. In this
work we report room-temperature distance measurement in trityl-labeled immobilized
DNA duplexes [2]. We succeeded to develop optimal trityl-based spin labels, efficient
SDSL and immobilization approaches that, working together, allowed us to measure as
long distances as ~4.6 nm with high accuracy at room temperature. This work was
supported by RFBR (No. 14-03-31839, 13-04-00680, 12-04-01435).
(1) Babaylova, E. S.; Ivanov, A. V.; Malygin, A. A.; Vorobjeva, M. A.; Venyaminova, A. G.; Polienko,
Y. F.; Kirilyuk, I. A.; Krumkacheva, O. A.; Fedin, M. V.; Karpova, G. G.; Bagryanskaya, E. G. Org.
Biomol. Chem. 2014, 12, 3129.
(2) Shevelev, G. Y.; Krumkacheva, O. A.; Lomzov, A. A.; Kuzhelev, A. A.; Rogozhnikova, O. Y.;
Trukhin, D. V.; Troitskaya, T. I.; Tormyshev, V. M.; Fedin, M. V.; Pyshnyi, D. V.; Bagryanskaya, E. G.
J. Am. Chem. Soc. 2014, 136, 9874.
Poster 27
68
Development of spin labels based on triarylmethyl radicals:
pulse and CW EPR study
A.A. Kuzhelev1,2
, O.A. Krumkacheva3,1
, O.Yu. Rogozhnikova2,
V.M. Tormyshev2,1
, M.V. Fedin
3,1, E.G. Bagryanskaya
2,3,1
1 Novosibirsk State University, 630090, Pirogova str., 2, Novosibirsk, RUSSIA.
2 N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 630090, ave. Lavrentiev, 9,
Novosibirsk, RUSSIA.
3 International Tomography Center SB RAS, 630090, Institutskaya str., 3A, Novosibirsk, RUSSIA.
E-mail: andrei_kuzhelev@mail.ru.
Triarylmethyl (trityl) radicals represent a relatively new class of spin labels having
long Tm on the order of microseconds in liquids at room temperature. This profoundly
long relaxation makes trityls a promising alternative for nitroxide spin labels. Recently
we demonstrated first distance measurement of ~4.6 nm at physiological temperature
310 K (37 0C) in model DNA duplex (1). The development of this research area implies
further improvement of trityl-based labels in order to achieve longer phase memory time
Tm and identification of the factors affecting the Tm for trityl radicals at 300 K.
In this work we studied the magnetoresonance properties of mono-, di-, tris-ester
derivatives of trityl radicals by CW and pulse EPR. It was found that at room
temperature Tm depends on structure of trityl radicals, resonance frequency and solvent
polarity. We observed the reduction of Tm values with increasing of resonance
frequency (from 10 to 35 GHz) at room temperature. At the same time we found that in
frozen solution the line width of the EPR spectra at Q band 2-3 times more than at X
band. It indicates that the spin-spin relaxation for studied compounds defines by
incomplete motional averaging of g- anisotropy. It was shown that the value of g-
anisotropy is reduced by increase of the number of ether substituents and is greater in
polar solvents (H2O and CH3OH) compared with nonpolar solvent (CH2Cl2).
This work was supported by RFBR (No. 14-03-31839, 13-04-00680).
(1) Shevelev, G. Y.; Krumkacheva, O. A.; Lomzov, A. A.; Kuzhelev, A. A.;
Rogozhnikova, O. Y.; Trukhin, D. V.; Troitskaya, T. I.; Tormyshev, V. M.; Fedin, M.
V.; Pyshnyi, D. V.; Bagryanskaya, E. G. J. Am. Chem. Soc. 2014, 136, 9874.
Poster 28
69
1,2,3,5 Tetrafluorobenzene Anion Radical As Studied by
the Method of Time-Resolved Magnetic Field Effect
Gleb A. Letiagin,1,2
Irina V. Beregovaya,3 Lyudmila N. Shchegoleva,
3
Vsevolod V. Borovkov1,2
1Novosibirsk State University,Pirogova str, 2, 630090, Novosibirsk, Russia
2Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya , 3
3N. N. Vorozhtzov Novosibirsk Institute of Organic Chemistry SB RAS, pr. Lavrentieva 9
E-mail: gleb-letyagin@yandex.ru
Fluorescence response of organic solutions to an ionizing irradiation bears the
imprint of the precursors of fluorescing states. These are radical ions formed by
irradiation as spin correlated geminate cation/anion pairs. Time-resolved detection of
the fluorescence intensity, I(t), allows monitoring of the ion pair recombination while
the evolution of the spin state of the geminate pairs can be extracted from the ratio
IB(t)/I0(t). Here symbols B, 0 denote the presence of high or zero external magnetic
field, respectively. This ratio, so called Time-Resolved Magnetic Field Effect (TR
MFE), exhibits peculiarities, whose temporal behavior is determined by interactions of
unpaired electron spin in the geminate radical ions. In particular, the TR MFE method is
sensitive to hyperfine coupling (HFC) constants of magnetic nucleus in the radicals thus
allowing identification of these short-lived particles at nanosecond time scale.
In this work, the TR MFE method
has been applied to study 1,2,3,5-
tetrafluorobenzene radical anion (RA)
in nonpolar solution. As shown by
DFT quantum chemical calculations,
the potential energy surface of the RA
is the surface of pseudorotation, in
which local minima are separated by
low barriers. The motion along the
pseudorotation path effectively
averages HFC constants with fluorine
nuclei to 15 mT for F1 and F3, 14 mT
for F2, and 1.4 mT for F5.
In the figure, typical experimental TR MFE curve obtained in the experiment with
irradiated solution of ~10 mM 1,2,3,5-tetrafluorobenzene in isooctane is presented
(noisy line). It is compared with the calculated TR MFE curve (bold line). To calculate
this we have taken into account only HFC with F1, F2, F3 in the radical anion while the
counterion, solvent radical cation, was treated quasiclassically.
Positions of the peculiarities in the calculated TR MFE curve (about 0.5 ns and
2.5 ns) qualitatively agree with the experimental TR MFE curve. Possibly, the
difference in the amplitude of the peculiarities partially could be explained by the effect
of relatively wide instrumental response function (FWHM of about 1 ns).
Therefore, we conclude that comparison of the experimental results and
calculations approve that radical anion of 1,2,3,5 tetrafluorobenzene is observed in the
solution for the first time.
Poster 29
70
Charge Recombination in Р3НТ/РС70ВМ Composite
Studied by Light-Induced EPR
E.A. Lukina1,2
, M.N. Uvarov2 and L.V. Kulik
1,2
1 Novosibirsk State University, Pirogova 2, 630090, Novosibirsk, Russia
2 Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090, Novosibirsk, Russia
E-mail: katyaluk@yandex.ru
Composites of conducting polymers and fullerene derivatives attract attention of
many researchers as a promising material for active layer of organic solar cells. Free
charge carriers are formed in such composites under the light illumination. Their
recombination is one of the main processes limiting power conversion efficiency of
organic photovoltaic devices; therefore numerous works are devoted to its mechanism
determination. It is known, that recombination in widely studied composite of
conducting polythiophene Р3НТ and soluble fullerene derivative РС60ВМ is complex
and can not be described by bimolecular Langevin model.
In this work a composite of P3HT and other fullerene derivative РС70ВМ was
studied by light-induced EPR (LEPR). In contrast to Р3НТ/РС60ВМ composite, LEPR
signal in Р3НТ/РС70ВМ can be detected in a wide temperature range up to room
temperature. This signal was attributed to free charge carriers Р3НТ+ and РС70ВМ
–. The
dependence of the intensity of LEPR signal on light intensity and the decay of LEPR
signal upon switching light off are interpreted in frame of trap-limited bimolecular
recombination model with finite rate of back electron transfer kr in [P3HT+/РС70ВМ
–]
encounter complex formed at polymer-fullerene interface during recombination
reaction. The effective recombination order was found to be close to p = 3.5 for the
temperature range from 100 K to room temperature. For temperatures above 150 K
Arrhenius behavior of effective recombination rate constant was obtained with the
activation energy Ea=0.16±0.01 eV, which is larger than analogous values for
Р3НТ/РС60ВМ reported previously (Ea=0.09 eV [1]). The difference of the observed
activation energy of bimolecular recombination in Р3НТ/РС60ВМ and Р3НТ/РС70ВМ
composites is supposed to originate from the difference of kr for the encounter
complexes [P3HT+/РС60ВМ
–] and [P3HT
+/РС70ВМ
–], which can be caused by different
geometries of the encounter complexes: РС70ВМ molecule is larger than РС60ВМ and
hence larger distortion of P3HT chains is expected for Р3НТ/РС70ВМ interphase. The
weak temperature dependence of k0(T) at temperatures below 125 K was explained by
contribution of another recombination channel, namely, tunneling of charge carriers.
The work was supported by RFBR grant №12-03-00238-a, by project of Presidium
of RAS № 23/24.48 “Nanodynamics of disordered media” and by Scholarship of the
President of Russian Federation SP-3596.2013.1.
[1] H. Tanaka, Y. Yokoi, N. Hasegawa et al. J. Appl. Phys. 2010, 107, 083708
Poster 30
71
. The study of redox reactions involving anticancer
quinone-chelator in the presence of metal ions.
I.D. Markova, O.Yu. Selutina, K.Yu. Fedotov, L.G. Fedenok, N.E. Polyakov, L.M.
Weiner*
Institute of Chemical Kinetics and Combustion, 630090, Institutskaya 3,
Novosibirsk, Russia;
*Weizmann Institute of Science, Rehovot, 76100, Israel.
e.mail: irina.d.markova@gmail.com
Currently, elucidation of the mechanisms of
drug activity at the molecular level and finding ways
to increase their efficiency is an important scientific
problem. At the present work quinone which can
form complexes with various metal ions: (2-phenyl-
4-(butylamino)naphtho[2,3-h] quinoline-7,12-dione)
has been synthesized to study the effect of chelation of metal ions on the generation of
free radicals by quinone in photoinduced processes. The anticancer activity of this
compound was demonstrated earlier [1]. The purpose of the present work is to figure
out how the binding with the metal ion affects the ability of the quinone to generate free
radicals. We tried to investigate this question by using the NMR and CIDNP
(chemically induced dynamic nuclear polarization) techniques.
The chelate complex formation of this quinone with the metal ions (Fe 2+
, Ca2+
and Zn2+
) was proved using the optical absorption method. It was demonstrated that
binding with metal ions results in significant changes in absorption spectrum of
quinone. The stoichiometry of chelate complexes are 1:1 with Zn ions, and 2:1 with Fe
and Ca ions. The stability constants and extinction coefficients of all complexes were
calculated.
To study the influence of metal binding on the efficiency of the generation of
free radicals by NMR and CIDNP techniques, the photoinduced oxidation of NADH
and its synthetic analog, 2,6-dimethyl-3,5-dicarbomethoxy-1,4-dihydropyridine (DHP)
by quinone was investigated in the presence of Zn and Ca ions. The significant increase
of polarization intensity and the yield of reaction products after photolysis was observed
in the presence of metal ions. Increase in the CIDNP intensity and the yield of reaction
product allows one to suggest that the reactivity of the quinone increased in the presence
of metal ions. Taking into account that the free radicals production is the key step of
anticancer activity of this quinone, the present results indicate the perspectives of its
practical application.
[1] S.I. Dikalov, G.V. Rumyantseva, A.V. Piskunov, and L.M. Weiner, Role of
Quinone-Iron(III) Interaction in NADPH-Dependent Enzymatic Generation of
Hydroxyl Radicals. Biochemistry (1992), 31, 8947-8953.
Poster 31
72
New Spin-Labelled Photochromic System
2Andrei V. Tarataiko,
1Anna G. Matveeva,
2Denis A. Komarov,
1Victor F.
Plyusnin, 2Vladimir A. Reznikov
1Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya, 3,
630090, Novosibirsk, Russia; 2N.N.Vorozhtsov Novosibirsk Institute of Organic Chemistry
SB RAS, pr. Lavrentieva, 9, 630090, Novosibirsk, Russia
E-mail: matveeva@kinetics.nsc.ru
We have synthesized a series of new members of the class of spin-labeled
photochromic systems - benzopyranes and naphthopyranes whose spin label
incorporated directly in the "nitrogen" heterocycle, and located maximally close to the
photochromic system compared to existing analogues [1].
As expected, the synthesized compounds have typical for all spiropyranes
photochromic activity (quantum yield of «spyropyran-merocyanine» photoconversion is
equal to 0.3%), and have typical for all merocyanines pH sensitivity (pKa = 2.9).
However, a close relative positioning of functional fragments firstly allowed us to
observe the processes in this photochromic system through the changes of EPR spectra
of the spin label. Note that in previous studies [1] of spin-labeled derivatives of
spyropyranes during the photoconvertion one can observe changes only macroscopic
magnetic susceptibility of the solid phase.
[1] Kaneko, T., T. Amano, H. Akutsu, J. Yamada and S. Nakatsuji (2003) Photochromic
radical compounds based on a naphthopyran systems. Org. Lett. 5, 2127–2129
Poster 32
73
Quadrupolar Magic Angle Spinning NMR Spectra Fitted
Using the Pearson IV Function
Roman M. Mironenko, Olga B. Belskaya, Valentin P. Talsi
Institute of Hydrocarbons Processing, Siberian Branch of Russian Academy of Sciences,
Neftezavodskaya st., 54, 644040, Omsk, Russia
E-mail: ch-mrm@mail.ru
Solid-state NMR spectroscopy is a powerful tool allowing to provide information
about the structure of materials. Important structural information contained in the NMR
spectrum can be extracted by decomposition of spectral contour into components.
Presently, an analysis of quadrupolar solid-state NMR spectra from disordered materials
is often made using the Czjzek model [1] describing the distribution in quadrupolar
interaction parameters, which can be estimated by application of averaging technique
(MQMAS). But it is not always needed to know the parameters of internal interactions;
it is only required to fast estimate the integral intensities of lines attributed to different
structural units (as in the case of routine studies of solid catalysts).
In the present work, the possibility of application of the Pearson IV function [2] for
analysis of asymmetric 27
Al MAS NMR spectra of alumina based catalysts is
demonstrated. The study was carried out using high-purity -Al2O3 and the samples of
ZnAlOx with different Zn/Al molar ratio (2.0, 3.0 and 4.0). The 27
Al MAS NMR spectra
were recorded at room temperature and a Larmor frequency of 104 MHz on a Bruker
Аvance-400 spectrometer. The fitting of spectral contours was carried out by variation
of parameters of the Pearson IV distribution. Convergence of experimental and
simulated spectrum was achieved by numerical minimization of chi-square.
As a result of fitting, a high convergence (r2 is no less than 0.997) between
experimental and simulated spectra was achieved. According to the analysis of the
spectrum of -Al2O3, about 70 % of Al atoms are in octahedral oxygen environment
(chemical shift at 11 ppm), about 30 % – in tetrahedral (68 ppm) and less than 1 % – in
pentahedral (37 ppm). This result agrees with published data [3]. The decomposition of
the 27
Al MAS NMR spectra of ZnAl mixed oxides with different Zn/Al molar ratio
revealed an increased fraction (6-9 %) of pentacoordinated Al atoms in these oxides as
compared to -Al2O3. As the Zn/Al ratio is raised, the fraction of [AlO6] octahedral
units decreases, while the fraction of [AlO4] tetrahedra increases.
References:
[1] J.-B. d’Espinose de Lacaillerie et al., J. Magn. Reson. 192 (2008) 244-251. [2]
W.P. Elderton, Frequency Curves and Correlation, Cambridge University Press,
London, 2011. [3] C. Pecharromán et al., J. Phys. Chem. B 103 (1999) 6160-6170
Poster 33
74
Interatomic Interactions and NMR of [Cp*3M3Se2]2+
M = Rh, Ir
Irina V. Mirzaeva
Nikolaev Institute of Inorganic Chemistry SB RAS, Ave. Akad. Lavrentiev, 3, 630090,
Novosibirsk, Russia
E-mail:dairdre@gmail.com
NMR of transition metal complex and cluster compounds may give lots of
measurable parameters for interpretation. Unfortunately, today in this area there are no
well established structure-property relations. Two complex cations [Cp*3M3Se2]2+
M =
Rh, Ir[1,2] have almost identical geometrical structures. Nevertheless, NMR shifts for 77
Se (1683 ppm for [Cp*3Rh3Se2]2+
and 943 ppm for [Cp*3Ir3Se2]2+
) are noticeably
different. Here, we try to find if this difference is associated rather with the relativistic
effects (which should give greater impact for the Ir cation) or with the bonding structure
of the cations. Although calculated without Spin-Orbit relativistic effects, 77
Se NMR
shifts are close to experimental values (1849 ppm for [Cp*3Rh3Se2]2+
and 1131 ppm for
[Cp*3Ir3Se2]2+
), while topological analysis of electron density of [Cp*3M3Se2]2+
M =
Rh, Ir shows the presence of M-M bonds for the Ir complex and the absence of such
bonds for the Rh complex. Therefor, we consider the change in the bonding structure to
be responsible for the difference in 77
Se NMR of the two cations.
DFT calculations were performed in ADF program suit[3] using TZP basis and
BP86 functional. To account for relativistic effects, zeroth-order regular approximation
was used. NMR parameters were calculated with GIAO method. To characterize
interatomic interactions, the topological analysis of electron density and Electron
Localization Function (ELF) was performed within DGrid-4.6[4].
This work was supported by RFBR grant 14-03-31333. The author is also grateful
to Dr. Abramov P.A. for providing the author with such interesting research objects.
1. Abramov, P. A.; Sokolov, M. N.; Mirzaeva, I. V.; Moroz, N. K. Russ. J. Coord.
Chem. 2013, 39, 379.
2. Abramov, P. A.; Zakharchuk, N.F.; Virovets, A. V.; Mirzaeva, I. V.; Sokolov, M.
N.; J. Organomet. Chem. 2014, 767, 65.
3. ADF: SCM, Vrije Universiteit, Theoretical Chemistry: Amsterdam, The
Netherlands, http://www.scm.com.
4. Kohout, M. DGrid 4.6, Radebeul, http://www.cpfs.mpg.de/~kohout/dgrid.html
Poster 34
75
Huge Spin-Orbit Relativistic Effects in NMR of Bimetallic
Rh-Sn3 and Ir-Sn3 Complexes
Irina V. Mirzaeva
Nikolaev Institute of Inorganic Chemistry SB RAS, Ave. Akad. Lavrentiev, 3, 630090,
Novosibirsk, Russia
E-mail:dairdre@gmail.com
In this work, we study two complex anions [Cp*M(SnCl3)3]– M = Rh, Ir[1] that
have almost identical geometrical and bonding (according to electron density, Electron
Localization Function (ELF), and MO analysis) structures. Nevertheless, NMR shifts
for 119
Sn nuclei are noticeably different (19 ppm for [Cp*Rh(SnCl3)3]– and –307 ppm
for [Cp*Ir(SnCl3)3]–). Calculated with only scalar relativistic effects,
119Sn NMR shifts
are close to each other and far from experimental values (220 ppm for [Cp*Rh(SnCl3)3]–
and 209 ppm for [Cp*Ir(SnCl3)3]–). But when we introduce Spin-Orbit relativistic
effects into the calculations, the 119
Sn NMR shifts move to 42.5 ppm for
[Cp*Rh(SnCl3)3]– and –257.5 ppm for [Cp*Ir(SnCl3)3]
–, which is much closer to
experimental data. Thus, here we observe large Spin-Orbit HALA (heavy-atom-on-
light-atom) relativistic effects, which may be explained with a great portion of 5s Sn
orbital in M–Sn bond (according to MO analysis).
DFT calculations were performed in ADF program suit[2] using TZP basis and
BP86 functional. To account for relativistic effects, zeroth-order regular approximation
was used. NMR parameters were calculated with GIAO method. To characterize
interatomic interactions, the topological analysis of electron density and ELF was
performed within DGrid-4.6[3].
This work was supported by RFBR grant 14-03-31333. The author is also grateful
to Dr. Abramov P.A. for providing the author with such interesting research objects.
1. Abramov, P. A.; Sokolov, M. N.; Mirzaeva, I. V.; Virovets, A. V. J. Organomet.
Chem. 2014, 754, 32.
2. ADF: SCM, Vrije Universiteit, Theoretical Chemistry: Amsterdam, The
Netherlands, http://www.scm.com.
3. Kohout, M. DGrid 4.6, Radebeul, http://www.cpfs.mpg.de/~kohout/dgrid.html.
Poster 35
76
NMR Study on Methane Activation and Transformation
over In-modified ZSM-5 Zeolite
Ilya B. Moroz, Anton A. Gabrienko, Sergei S. Arzumanov, Alexander G. Stepanov
Boreskov Institute of Catalysis SB RAS, pr. Lavrentieva 5, 630090, Novosibirsk, Russia
ibmoroz@catalysis.ru
Solid-state NMR spectroscopy is a very useful tool for detection of intermediates
forming on the surface of heterogeneous catalysts during hydrocarbon conversions. In
this work, it was applied to study on the mechanism of methane activation over the In-
modified zeolite, In/H-ZSM-5, which was considered as the promising catalyst for
methane transformation to aromatic hydrocarbons. It has been suggested that activation
of CH4 over In/H-ZSM-5 proceeds by dissociation of the C–H bond on indium cations
with the formation of the indium-hydride and the surface methoxide. However, there is
still no evidence for this “carbenium” pathway, as well as it is unclear which of the
indium cations (In+ or InO
+) are responsible for the methane transformation. Thus, our
research had the following goals: (1) to elucidate the mechanism of CH4 transformation
over this catalyst and (2) to determine which of the indium species are involved in this
reaction. For this purpose, we prepared the samples with predominant content of In+ and
InO+
cationic centers (denoted as In+/H-ZSM-5 and InO
+/H-ZSM-5, respectively) and
compared them to each other using 13
C CP/MAS NMR spectroscopy for monitoring the
surface species formed from CH4 at elevated temperatures. In addition, the kinetics of
H/D exchange between methane and Brønsted acid sites (BAS) of the In+/H-ZSM-5 and
InO+/H-ZSM-5 zeolites was investigated by
1H MAS NMR spectroscopy in situ at 453-
568 К. It was found that the rates of H/D exchange between CH4 molecules and BAS of
the InO+/H-ZSM-5 and In
+/H-ZSM-5 samples exceed that over the H-ZSM-5 zeolite
lacking indium by two and one orders of magnitude, respectively. The fact that the H/D
exchange involving the InO+/H-ZSM-5 sample is much faster with a lower activation
energy in comparison with the In+/H-ZSM-5 sample (74±6 kJ mol
-1 vs 127±27 kJ mol
-1)
indicates that not only BAS, but also InO+ cations participate in the exchange reaction
and, hence, in the methane activation. The results of the 13
C MAS NMR study
confirmed that the InO+
cations unlike the In+ ones provide the dissociative adsorption
of CH4. Contrary to the previously suggested, it proceeds with the formation of the
oxyindium-methyl, CH3–In=O species as the primary products (the “alkyl” pathway).
The secondary products of transformation of CH3–In=O species are the oxyindium-
methoxy, CH3–O–In=O, and formate species, as well as ethane and acetaldehyde.
Furthermore, it has been shown that upon ethylene adding, the CH3–O–In=O species
may react with simple aromatic hydrocarbons, which were formed from ethylene over
the InO+/H-ZSM-5 catalyst, with the formation of higher methylbenzenes.
This work was supported by RFBR (Grant Nos. 14-03-00040)
Poster 36
77
In Situ Spin Probe Studies of the Effect of Terahertz
Radiation on Proteins
Eugenia F. Nemova1, Tatyana V. Kobzeva
2
1 Institute of Laser Physics SB RAS, Lavrentyev ave., 13/3. 630090, Novosibirsk, Russia
2 Voevodsky Institute of Chemical Kinetics and Combustion SB RAS
E-mail:endy@gmail.com
Methods based on magnetic resonance provide powerful tools to study the effects
of terahertz radiation (THR) on biological systems. Proteins play exclusively important
part in vital functioning, so they comprise informative model to survey the biological
effects of radiation. The present study deals with the EPR investigation of the
conformational changes caused by tetrahertz radiation in albumin, a convenient
representative of globular proteins. It was shown in previous studies [1] that the
irradiation of bovine serum albumin (BSA) within the terahertz range induces changes
in the UV and IR spectra, intensity of native fluorescence and degree of BSA binding
with biologically active ligands. It was assumed that THR excites collective transitions
in BSA molecule resulting in conformational changes. Though the energy of THR is too
low to induce direct chemical transformations, it is sufficient to cause conformational
changes manifesting themselves as changes in BSA reactivity. We used a diamagnetic
dinitrone (1,4-dihydropyrazone dioxide synthesized at Vorozhtsov Novosibirsk Institute
of Organic Chemistry SB RAS) as a precursor of spin probe to be formed in the
interaction with BSA film irradiated with THR.
Dinitrone interacted with reaction centers of BSA to form a nitroxide; its EPR
spectrum was recorded. It was discovered that irradiation causes changes in EPR signal
width and intensity. Line broadening in the case of irradiated BSA sample provides
evidence of lower rotational mobility of the paramagnetic centre in comparison with
non-irradiated BSA, i.e. THR causes changes of probe localization on BSA. The
intensity of EPR signal in irradiated BSA sample is twice as high as that in non-
irradiated one. This means that irradiation simplifies the oxidation of spin probe
precursor on the reaction centers of BSA. Special attention was paid to the time after
irradiation within which the changes in BSA reactivity are conserved. Surprisingly, this
time was found to be several hours.
Structural modeling was involved to explain the observed phenomena.
Simulation results suggest that THR-induced conformational changes in alpha helix can
be responsible for changes in oxygen sorption on BSA functional centers, which in turn
affects the transformation of dinitrone into nitroxide and the mobility of the latter.
1. Cherkasova O.P., Fedorov V.I., Nemova E.F., Pogodin A.S. Optika I
Spektroskopiya, 2009, v. 107, No. 4, p.565-568.
Poster 37
78
Time resolved and magnetic field dependence CIDNP
study of mechanism of photoreaction involving radicals of
S-methylcysteine and S-methylglutathione
Mikhail S. Panov1,2
, Olga B. Morozova1, and Alexandra V. Yurkovskaya
1,2
1International Tomography Center, Institutskaya 3a, 630090, Novosibirsk, Russia
2Novosibirsk State University, Pirogova 2, 630090, Novosibirsk, Russia
E-mail: vasnik89@gmail.com
The photoreactions of sulfur-containing amino acids and oligopeptides with excited
triplet states of aromatic carbonyl compounds have drawn some attention because of the
biological importance of these substrates and the model character of these reactions for
the damage of cell components. It has been shown that the primary photochemical
process is electron-transfer quenching of the excited triplet state of the sensitizer by the
amino acid. One of the most important reactions of the radical cations is elimination of
CO2 to give α-aminoalkyl radicals, which are key intermediates with respect to the
secondary chemistry in these systems. There is the question: what is the structure of
transient radicals in this process?
To answer this question, in present study we have investigated photoreactions
between 3,3 ,4,4 -benzophenone tetracarboxylic acid (TCBP) and S-methyl-L-cysteine
(Cys(Me)), and photo oxidation of S-methylglutathione (GSMe) by exited triplets of 4-
benzophenone carboxylic acid (4-CBP). From pH dependence of CIDNP kinetics
pKa=3.2±0.5 and pKa=9.7±0.5 were determined for amino groups of Cys(Me)• and
GSMe• radicals, respectively. At pH above these values fast decarboxylation reaction
was revealed. To determine the structure of the intermediate radicals, magnetic field
dependence of CIDNP signal intensities was measured. From comparison of
experimental data with model calculations, the g-factors of radicals
g(Cys(Me)•)=2.0077±2 and g(GSMe
•)=2.0082±3 were extracted. These g-factors are
significantly lower than typical values of S-centered radicals, which indicates that spin
density delocalization incorporates light atoms such as oxygen or nitrogen. Based on
this fact, confirmed by results of quantum-chemical calculations and CIDNP pattern we
suggest five-membered ring structure with [S∴O] bond for the Cys(Me)• radical. Close
g-factor value, influence of charge of the amino group on proceeding of decarboxylation
reaction and CIDNP pattern proves ten-membered cyclic structure to GSMe• with
[S∴O] bond between thioether group and carboxylic group of glutamic acid residue, in
contrast to what has expected on the basis of analysis of transient absorption spectra [1].
Financial support by the program of RFBR (Projects No. 13-03-00437, No. 14-03-
31563, No. 14-03-00453, No. 14-03-00397), Grant No. MD-3279.2014.2 of the
President of the Russian Federation is gratefully acknowledged.
1. [1] P.Filipiak, G.L.Hug, K.Bobrowski et al. J. Phys. Chem. B, 2013, 117, 8, 2359-2368
Poster 38
79
Spin exchange effect in solutions of α-diimine radicals
Petrovskii S.K., Kuznetsova E.B., Gurinovich N.S., Saraev V.V.
Irkutsk State University, 664003, Russian Federation, Irkutsk, K. Marx str., 1
E-mail: stas1234567892007@yandex.ru
Diimine ligands have attracted substantial attention in last two decades. They are used
in plenty of catalytic systems especially for ethylene [1] and olefins [2] co- and
polymerization. One of the most important features of these ligands is the ability to
accept electrons (especially in the case of α-diimines) which leads to formation of
radical anions [3]. In our latest work we have shown [4] that in catalytic systems based
on α-diimine complexes of nickel (known as Brookhart catalysts) two types of
paramagnetic species are formed under real conditions of activation and catalysis. They
are complexes of Ni(I) with diimine ligands and radical-anions of diimine ligands bound
with Aluminium centers of cocatalyst. In the course of research of these radical anions
nature we have registered a lot of ESR spectra of diimine radical-anions bound with
different alkaline metals (Li, Na and K). It was found that Li+DAB
.- and K
+DAB
.-
complexes have normal count of lines in the spectrum, but Na+DAB
.+ one typically has
one extra line. E.g. in the case of (2,6-diisopropylphenyl)-diazabutadiene reduced by Na
in toluene we registered 8 lines in the spectrum instead of 7 lines registered when the
reduction was performed by Li or K. The fact cannot be explained by hyperfine
interaction with any nucleus in molecule. It is known that an effect of spin exchange
takes place in structured solid systems. We have applied the technique [5] described for
solid state systems for associates in solution. We have developed the technique that
allows modeling of ESR spectra in which spin exchange effect takes place. The results
of modeling have good agreement with experimental data (see the figure). These results
suggest that in some cases diimine radicals bound with Sodium exist as structured
associates in which spin exchange effect takes place. This effect has not been described
in literature for liquid systems by the present moment.
ESR spectrum of radical-anion of (2,6-diisopropylphenyl)-diazabutadiene with Sodium (a), model
spectrum with spin exchange effect (b) and model spectrum without spin exchange (c)
References:
1. Ittel S.D. et al., Chem. Rev. 2000, 100, 1169-1203
2. Gibson V.C. et al., Chem. Rev. 2003, 103, 283-315
3. Liu Y. et al., Organometallics 2008, 27, 5830–5835
4. Petrovskii S.K. et al., Russ. Chem. Bull. Int. Ed. 2013, 62, №6, 1323—1326
5. Yablokov Y.V. et al.. Moscow: Nauka, 1988, 181p.
Poster 39
80
2D NOESY/EXSY study of azide-tetrazole equilibrium of
2,4-diazidopyrimidines
Nadezhda V. Pleshkova, Elena B. Nikolaenkova, Georgy E. Sal’nikov, Victor P.
Krivopalov, Victor I. Mamatyuk.
N.N. Vorozhtsov Institute of Organic Chemistry, pr. Lavrentieva 9, 630090, Novosibirsk, Russia.
E-mail: Nadia789@nioch.nsc.ru
The specific nature of azaaromatic compounds having an azide group in the α-
position to the nitrogen atom is manifested as azide-tetrazole equilibrium. In the case of
2,4-diazidopyrimidines five different tautomers are possible.1 Azide-tetrazole
tautomerism is a slow process in the DNMR time scale, showing almost no temperature
dependence of NMR line widths up to 100 oC. Such complex multipath exchange
processes can be successfully studied by 2D NOESY/EXSY spectroscopy.2,3,4
For DMSO solutions of 5-methyl- and 5-methoxy-2,4-diazidopyrimidines four
forms (A, B, C, D) were found, their structures were determined by 2D 1H-
13C
correlation spectra. The kinetic parameters of the observed tautomerism were
determined by temperature dependence analysis of relative integral intensities of the
respective cross peaks and diagonal peaks in 1H-
1H NOESY/EXSY spectra.
1 V. P. Krivopalov et al. Dokl. Akad. Nauk SSSR Ser. Khim. – 1988, 300, 131
2 P. Denkova et al. Magn. Reson. Chem. – 2008, 46, 362
3 E. W. Abel et al. Journal of Magnetic Resonance. – 1986, 70, 34
4 http://nmr.nioch.nsc.ru/noekin/
Poster 40
81
. 19
F-MRI and 31
P-MRS in vivo visualisated theranostic with
anticancer activity
Natalya M. Antonova a,b,
, Vladimir A. Lisitskiy a,b
, Tatyana V. Popova
a,b, Olga D.
Zakharova a
, Igor V. Koptyug b,c
, Andrey E. Akulov d
, Vassily I. Kaledin d
, Tatyana S.
Godovikova a,b
aInstitute of Chemical Biology and Fundamental Medicine SB RAS, 630090, Lavrentiev prosp., 8,
Novosibirsk, Russia
bNovosibirsk State University, 630090, Pirogov av., 2,. Novosibirsk, Russia
cInternational Tomography Center SB RAS, 630090, Lavrentiev prosp, 8, Novosibirsk, Russia
dInstitute of Cytology and Genetics SB RAS, 630090, Institutskaya av.., 3a, Novosibirsk, Russia
e-mail: io197724@gmail.com
A novel 19
F-MRI and 31
P-MRS visualisated theranostic with anticancer activity
has been designed and synthesized. The agent represents a multifunctional construct
containing a pyrimidine nucleoside antimetabolite (trifluorothymidine) and groups that
are responsible for (i) detection of the agent in the body using in vivo 31
P NMR
spectroscopy (amidophosphate group) and 19
F magnetic resonance spectroscopy and
tomography (CF3 group in the heterocyclic base); (ii) increased affinity of the agent to
tumor cells (residues of polyunsaturated fatty acid); (iii) efficient binding of the agent
with the cellular membrane and penetration into a cell (polyethyleneimine modified
with urocanic acid moieties); (iv) prolonged antitumor action of the agent (an acid-labile
imidazolide of 5-trifluoromethyl-2’-deoxyuridine-5’-monophosphate). Using in vivo
NMR spectroscopy it was shown that the theranostic agent can be detected directly in
the organisms of animals models. In vivo 31
P NMR (31
P-MRS) resulted in detection an
amidophosphate signal at ~ 12 ppm, 19
F MRI gave CF3 signal at 101 ppm. Using
MTT test the therapeutic construct was found to possess the highest cytotoxicity for the
MCF-7 cell line (IC50 = 0.43 М). The multifunctional construct containing 30 residues
of urocanic acid and 40 residues of trifluorothymidine 5’-monophosphate was tested
against the murine Krebs-II ascites carcinoma. The intraperitoneal injection of the
conjugates resulted in prolongation of the animals’ life and to the complete
disappearance of the tumor after three injections.
The work was supported by Integration grant #60 from SB RAS, by the RFBR
grant No 12-04-01454.
Poster 41
82
Electron Spin Echo of Light-Induced Spin Correlated Radical
Pairs in PCBM/P3HT Composite
Alexander A. Popov, Leonid V. Kulik
Institute of Chemical Kinetics and Combustion SB RAS, Instituskaya, 3, 630090,
Novosibirsk, Russia
Email: rastopyakin@gmail.com
The composite of [6,6]-Phenyl C61 butyric acid methyl ester (PCBM) and poly(3-
hexylthiophene) (P3TH) is a good model material for studying processes which take place in
active layer of organic solar cells. Its electrical and optical properties are well-known. After
light absorption the charge transfer occurs in this material with quantum yield close to unity.
Short-living spin-correlated radical pairs PCBM /P3HT are formedi, which can be further
separated to free charge carriers.
In this work the spin dynamics of photoinduced radicals PCBM and P3HT was studied
by pulse EPR spectroscopy. The radicals were generated by laser flashes with 532nm
wavelength. Two-pulse sequence /2- - -echo was used to perform ESE experiment.
Computer modeling of ESE signal allows to interpret experimental data and to estimate
parameters of spin Hamiltonian of photoinduced radical pairs. For laser flash-generated radical
pairs PCBM /P3HT the temporal shape of ESE signal is quite unusual, but it is well reproduced
numerically.
Fig. 1. Comparison of experimental time-domain ESE signal (left) and its simulation (right).
Lengths of pulses are 16ns for /2 pulse and 32ns for pulse respectively, gap between pulses 400ns.
Resonant g-factor is equal to 2.0023.
The strength of exchange interaction in photoinduced radical pair PCBM /P3HT was
estimated during computer modeling of the experimental ESE signal. The average magnitude of
exchange interaction was approximately 1MHz. This value distributed normally with
distribution width approximately equal to 0.5 MHz.
The work was supported by RFBR grant №12-03-00238-a.
i Behrends, J.; Sperlich, A.; Schnegg et al. R. Direct detection of photoinduced
charge transfer complexes in polymer fullerene blends. Phys. Rev. B 2012, 85, 125206.
Poster 42
83
Possibility of application of diazaperylene derivatives as an
acceptor in organic photovoltaic cells.
Alexandr G. Popov, Mikhail N. Uvarov, Denis S. Baranov, Leonid V. Kulik
Institute of Chemical Kinetics and Combustion, Rzhanov street 3, 630090,Novosibirsk, Russian
Federation
E-mail: popovag1988@gmail.com
Organic electron accepting materials are essential for the fabrication of organic
photovoltaic cells. The most mentioned materials are molecules based on fullerene
derivatives. Power conversion efficiency with this substance reached more than 8%.
However synthesis of these compounds is expensive. Alternative way to the fabrication
OPV is using conjugated small molecules. In this work diazaperylene derivatives were
investigated as an acceptor in OPV.
2,8-substituted diazaperylene was synthesized. Regioregular poly(3-
hexylthiophene) was chosen as a donor. The thin films of composites were prepared
using the method of spin-coating.
Diazaperylene derivatives intensively absorb in visible region. The energy of
HOMO/LUMO of diazaperylene derivatives was measured by cyclic voltammetry. The
values -3eV/-5,61eV for a); -3,08eV/-5,63eV for b); -3,07eV/5,57eV for c) were
founded.
Morphology of films was investigated by the atomic force microscope. The films
reveal crystals which are related to the diazaperylene derivatives. The sizes of crystals
depend on preparation conditions and lies in a sub micrometer region.
Electron transfer from donor to acceptor was studied by the method of electron
paramagnetic resonance (EPR). For photoexcitation of samples laser with wavelength
660 nm was used. Kinetics of the accumulation of the signal EPR after switching laser
on was measured. Assuming that main limiting process in growth signal EPR is
diffusion of the charges, the diffusion coefficient was evaluated.
The work was supported by RFBR grant №14-03-31183.
N
N
N
N
O
O
N
N
O
O
a) b) c)
Fig. 1. a) 2,8-diehexyl-dieazaperylene b)2,8-diebutylhydroxymethyl-
dieazaperylene c) 2,8-isopropylhydroxymethyl-dieazaperylene
Poster 43
84
Level Anti-Crossings are a Key Factor for Understanding
Magnetic Field Dependence of Hyperpolarization in SABRE
Experiments
Andrey N. Pravdivtsev,a,b
Konstantin L. Ivanov a,b
Alexandra V.
Yurkovskaya,a,b
Hans-Martin Vieth,c Mikhail S. Panov,
a,b Robert Kaptein
d
a International Tomography Center, Siberian Branch of the Russian Academy of Science,
Institutskaya 3a, Novosibirsk, 630090, Russia
b Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia
c Institut für Experimental Physik, Freie Universität Berlin, Arnimallee 14, Berlin, 14195,
Germany
d Utrecht University, Bijvoet Center, Padualaan 8, NL-3584 CH, Utrecht, the Netherlands
E-mail:a.n.true@tomo.nsc.ru
Various hyperpolarization methods are able to enhance the sensitivity of NMR and
MRI by several orders of magnitude. Important among these are Para-Hydrogen
Induced Polarization and Signal Amplification By Reversible Exchange (SABRE),
which exploit the strong nuclear alignment of para-hydrogen. Several SABRE
experiments have been reported but it was thus far not possible to account for the
experimentally observed sign and magnetic field dependence of the substrate
polarization. Here we present an analysis based on Level Anti-Crossings (LACs) that
provides a complete understanding of the SABRE effect. The field dependence of both
net and anti-phase polarization was measured for several ligands and could be well
reproduced by the theory. We also explain why the SABRE field dependence for
different ligands can be quite similar. In general, the LAC concept allows unraveling of
complex spin dynamics and is crucial for optimizing the performance of novel
hyperpolarization techniques in NMR and MRI.
The research was financially supported by the Russian Fund for Basic Research
(projects No. 13-03-00437, 14-03-00397) and grant of the President of Russian
Federation MD-3279.2014.2.
.
Poster 44
85
New approaches for production and application of
parahydrogen-induced polarization (PHIP) using
heterogeneous hydrogenations
O.G. Salnikov, K.V. Kovtunov, D.A. Barskiy, I.V. Koptyug
International Tomography Center, SB RAS, Institutskaya, 3A, 630090, Novosibirsk, Russia
E-mail: salnikov@tomo.nsc.ru
Parahydrogen-induced polarization (PHIP) is a highly promising technique for
sensitivity enhancement of NMR and magnetic resonance imaging (MRI). Moreover, it
is a very useful method for the investigation of mechanisms of hydrogenation reactions.
This approach is based on the pairwise addition of two hydrogen atoms from the same
parahydrogen molecule to a double or a triple bond of a substrate molecule.
Toxicity of transition metal complexes which are usually used for production of
PHIP-hyperpolarized substances is a serious obstacle for potential biomedical
applications. Here we present a new approach for production of hyperpolarized gases by
gas-liquid biphasic hydrogenation with parahydrogen using a dissolved catalyst and
gaseous reactants. The reaction product is shown to return to the gas phase while
retaining a substantial level of nuclear spin hyperpolarization, providing a complete
separation of the hyperpolarized fluid from homogeneous catalyst.
Another promising approach is the use of heterogeneous catalysts. In this work it
was shown for the first time that PHIP effects can be successfully observed in
heterogeneous hydrogenations catalyzed by bulk metals and metal oxides. This result
confirms the existence of pairwise hydrogen addition route for both types of catalysts.
Also in this work PHIP technique was applied for studying the heterogeneous
hydrogenation of α,β-unsaturated carbonyl compounds. It was shown that hydrogen can
be added pairwise to C=C bonds of acrolein and crotonaldehyde over several supported
metal catalysts. The significant NMR signal enhancement provided by PHIP allowed to
detect by-products of different side reactions which occur on the metal surfaces.
The heterogeneously produced PHIP was also applied for kinetic studies of propene
hydrogenation over Pt/Al2O3. It was found that the reaction orders with respect to H2 are
different for the non-pairwise and the pairwise hydrogen addition. Therefore, different
types of active sites on catalyst surface are responsible for these two routes of
hydrogenation reaction.
This work was supported by the RAS (5.1.1), RFBR (14-03-00374-а, 14-03-31239-
mol-a, 12-03-00403-a, 14-03-93183 МСХ_а), SB RAS (57, 60, 61, 122), МК-
4391.2013.3
Poster 45
86
Association of lipid-lowering drugs – statins with
natural triterpene – glycyrrhizic acid.
Schlotgauer A.A., Petrova S.S., Kruppa A.I., Leshina T.V.
Institute of Chemical Kinetic and Combustion SB RAS, Institutskaya str., 3, 630090,
Novosibirsk, Russia
E-mail:schlotgauer_a@mail.ru
Supramolecular complexes of drugs are now widely used for targeted drugs
delivery to improve their solubility, bioavailability and stability. This approach is
particularly useful for poorly soluble medicine with side effects. Such compounds
include statins. Despite the fact that statins are generally accepted for treating and
preventing cardio – vascular diseases and atherosclerosis, unfortunately, they possess
several undesirable side properties. Therefore, the search and creation of new statins
with a lower daily dose, safer, is so actual. It's very important to choose the complexant.
We selected a natural compound triterpene glycoside - glycyrrhizic acid. It is known
that the use of some medications in the form of compositions with GA reduces drugs
therapeutic dose and reduce side effects. As a results of research by dynamic NMR
following results were obtained: 1) confirmed postulated in pharmacology association
of glycyrrhizic acid (GA) with statins; 2) glycyrrhizic acid associates, formed in acidic
media, include molecules of statins in the form of free acids; 3) the statin is rigidly
attached to associate and they rotate integrally. Furthermore an example of the
association effect on the reactivity of simvastatin is given.
Fig.1.Free induction decay of the atorvastatin (ATR) protons in the absence and presence of GA.
Poster 46
87
Reaction of benzene with bromine without catalyst: study of
kinetics and elucidation of product structures by NMR
Andrey V. Shernyukov, Alexander M. Genaev, George E. Salnikov,
Vyacheslav G. Shubin
N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry of Siberian Branch of
the Russian Academy of Sciences, Lavrentiev Ave. 9, 630090, Novosibirsk, Russia
E-mail: andreysh@nioch.nsc.ru
Inability of benzene to be involved in non-catalytic reactions with bromine is noted
in many textbooks and looks as a dogma.
We have found that bromination of benzene with bromine occurs without any
catalyst or solvent at room temperature when a high concentration of bromine is used
(20 vol. % and more). The primary product of the substitution reaction is
bromobenzene, which is capable of further reaction to form o- and p-dibromobenzenes.
The reaction rate increases greatly with increasing the bromine concentration. Studies of
the reaction kinetics by NMR show that the order of the reaction on bromine is very
high (4.8).
Along with the products of the aromatic substitution reaction tetrabromocyclo-
hexenes and hexabromocyclohexanes are formed, the total amount of these products
does not exceed 1% relative to benzene.
From six possible isomers of tetrabromocyclohexene (Fig., left) only three were
observed in the reaction mixture (Fig., right). Their structures were determined from
NMR spectra and the results of quantum chemical calculations by riMP2/L1 method.
Poster 47
88
Investigation of Electron-Acceptor Sites on the Surface of
Sulfated Alumina Using EPR
Ekaterina I. Shuvarakova1,2
, Alexander F. Bedilo1,2
1Boreskov Institute of Catalysis SB RAS, Prospekt Lavrentieva 5, Novosibirsk 630090, Russia
2 Novosibirsk Institute of Technology, Moscow State University of Design and Technology, Krasny
Prospekt 35, Novosibirsk 630099, Russia
katerina.shuv@gmail.com Alumina is widely used in catalysis. The surface of the low-temperature Al2O3
phases is known to have both acid and base sites of different types. Electron-donor and
electron-acceptor sites can be investigated using suitable spin probes. This method is
based on using specific molecules which selectively interact with the surface sites
yielding surface paramagnetic species1,2
.
In the present work, relations between the concentrations of electron-acceptor
sites with different strength and concentrations of deposited sulfates were studied.
Recommendations on the use of spin probes for testing electron-acceptor sites with
different strength were suggested. The mechanism of the polycondensation of aromatic
probes on the surface electron-acceptor sites explaining experimental results was
proposed.
Sulfated Al2O3 samples with the different concentrations of SO3 (2, 4, 8, 12, 16
wt.%) were studied. Solutions of antracene (4×10-2
M), perylene and
hexamethylbenzene (2×10-2
M) in toluene and pure toluene were used as spin probes.
Two experimental techniques were used. In the first method changes of the
concentration of paramagnetic particles over time were monitored at room temperature.
The first measurement was carried out immediately after the activation of the sample;
the following measurements were carried out every 24 hours during the week. The
second technique included a study of the changes in the concentration of paramagnetic
particles after heating the activated samples with the probes for 18 hours at 80°C.
It was found that the concentration and the strength of electron-acceptor sites
significantly grew with an increase of the sulfate concentration. The strongest electron-
acceptor sites tested with toluene immediately after absorption were only detected with
a SO3 concentration 4% or higher. The weakest sites tested with perylene were present
on the surface of all the samples, with their concentration on 12% SO3 sample being
3×1019
g -1
.
1 A.F. Bedilo, E.I. Shuvarakova, A.A. Rybinskaya and D.A. Medvedev.: J. Phys.
Chem. C, 118, (2014). DOI: 10.1021/jp503523k.
2 A.F. Bedilo, E.I. Shuvarakova, A.M. Volodin, E.V. Ilyina, I.V. Mishakov, A.A.
Vedyagin, V.V. Chesnokov, D.S. Heroux and K.J. Klabunde.: J. Phys. Chem. C,
118, 13715-13725 (2014).
This work was supported by RFBR Grants 12-03-00905 and 13-03-12227-ofi_m
Poster 48
89
Reversible and irreversible recombination in spin chemistry
D.V. Sosnovsky, P.A. Purtov
Institute of Chemical Kinetics & Combustion, SB RAS; Novosibirsk State
University
Novosibirsk,630090, Institutskaya str.3, Russia
e-mail: dul0ng@mail.ru
The spin chemistry of electron and nuclear spins behavior as well as of the
manifestation of magneto-spin interactions in chemical reactions is well developed both
experimentally and theoretically. The evolution of the spin density matrix of a radical
pair (RP) obeys the phenomenological equation (the main equation of spin chemistry)
()€ €(q) ,
2
SS S
Kt iL HQQt h
The last operator in equation characterizes a change in density matrix due to
reaction.
In the present work, the reaction operator of the main equation of spin chemistry
has been modified on the basis of an exactly solvable model. The model contains both
the reversible and irreversible transitions. For this model, expression for the reaction
operator is more complex due to the expanded basis of spin states. The reaction operator
of a phenomenological equation is a particular case of a more general approach and only
in the limiting case of the completely irreversible recombination process, these
operators coincide.
Figure show the functions of the time of system staying in the singlet state. The
probability of transition to the singlet reservoir decreases with spectrum center shifting
from resonance. As a result, the amplitude of S T oscillations increases. A decrease in
spectrum width for the matrix elements of transition causes oscillations determined by
S S (singlet reservoir) transitions which leads to the overlap of the oscillations in the
S T and S S transitions. The amplitude of the oscillations increases noticeably with
increasing shift of the spectrum center from resonance.
1. P.A. Purtov, Chem. Phys. Letters 496 (2010) 335
2. D.V. Sosnovsky, P.A. Purtov, Chem. Phys. Letters 608 (2014) 136
Poster 49
90
NMR and CIDNP Study of Phototransformation of Iron
Chelator Deferiprone in the Presence of Metal Ions
1,2Viktor A. Timoshnikov,
1,2Olga. Yu. Selyutina,
1Nikolay E. Polyakov
1Institute of Chemical Kinetics and Combustion, Institutskaya, 3, Novosibirsk, 630090 Russia;
2Novosibirsk State University, Pirogova 2, Novosibirsk, 630090, Russia
e-mail: angrymodern@rambler.ru
Deferiprone (L1) is an effective iron chelating drug which is widely used for the
treatment of iron overload diseases, such as thalassaemia. Moreover, L1 is supposed to
be an effective antioxidant that prevents oxidative stress and biomolecular, subcellular,
cellular, and tissue damage caused mostly by iron and copper induced free radicals
formation in vivo. There are many studies of pharmacological properties of L1, but so
far nothing was known about its photochemical activity and the structure of its radical
intermediates.
Recently it was demonstrated by CIDNP method that L1 undergoes fast
decomposition via electron transfer mechanism under direct and photosensitized UV
irradiation (< 310 nm) [1]. But no data exist on the influence of chelation on the
photochemical stability of deferiprone. Within this context the photochemistry of L1
and its chelate complexes are of chemical, biochemical, pharmacological and
toxicological importance. So, the goal of present study was to elucidate the effect of
metal ions on the photochemical behavior of L1.
The formation of chelate complexes with Zn, Ca and Al ions was proved by the
optical absorption technique. For all metals the formation of chelate complexes results
in appearance of additional long-wavelength absorption band, which greatly accelerates
the photodegradation of deferiprone when irradiated with ultraviolet light at a
wavelength of 308 nm. The mechanism of photodegradation was studied by NMR and
CIDNP techniques in the absence and in the presence of electron donors, NADH and
triptophan. The appearance of CIDNP effects for all systems is the evidence of free
radical mechanism of deferiprone photolysis. This information is particularly important
for the thousands of patients treated with L1 and other chelating drugs, since iron
overload diseases like thalassaemia are mainly distributed in the Mediterranean, Middle
East and South East Asian countries where extremely high sun light irradiation level is
present.
[1] V.A. Timoshnikov, V.K. Klimentiev, N.E. Polyakov, G.J. Kontoghiorghes,
Photoinduced Transformation of Iron Chelator Deferiprone: Possible Implications in
Drug Metabolism and Toxicity. J. Photochem. Photobiol. A: Chem., 289 (2014) 14-21
Poster 50
91
Magnetic spin phenomena in C-N2-O2 system under the
conditions of low-temperature plasma
I.A. Ushakov, E.A. Baranov, V.F. Myshkin
National Research Tomsk Polytechnic University, Institute of Physics and Technology,
Department of Applied Physics Engineering, Lenin Avenue, 30, 634050, Tomsk, Russia
E-mail:mamay2008@bk.ru
It is known that electron spine resonance (ESR) leads to the isotope selectivity in
liquid-phase radical chemical reactions in the external magnetic field. The reaction
products are transformed to the other phase unlike reagents to the separation of isotopes
with magnetic and nonmagnetic nuclei. The search of new isotope effects is actual due
to permanent expansion of stable isotope application.
Plasma allows transforming the different substances to the radical form. It is shown
that chemical reactions between carbon and oxygen in the magnetic field are selective
on 12
C and 13
C isotopes [1]. At carbon oxidation in the magnetic field the oxides are
enriching on 13
C at oxygen lack. The carbon residue with 12
C excess forms the soot.
This process demand of precise control of oxygen in the plasma-forming gas at 1500-
3000 K.
The other method of carbon isotope separation is conversion into the other one-
phase-substances at hardly isotope exchange. At the same time it is necessary to
increase the rate of reaction one isotope with the first reagent and another isotope with
the second reagent.
We study the physical and chemical processes at chemical reaction in the external
magnetic field in plasma-forming mixture Ar-O2-N2. Also we estimate the isotope effect
at magnetic field change. Using the carbon valence electron angular moment precession
rate we estimate the 13
C oxidation rate change at 1 T magnetic field. The experimental
device discussed in the [1] is used.
References
[1] Isotope effects of plasma chemical carbon oxidation in a magnetic field / V. F.
Myshkin, V. A. Khan, D. A. Izhoykin, I. A. Ushakov // Natural Science. – 2013. –
Vol.5, № 1. – P. 57–61. DOI: 10.4236/ns.2013.51010
Poster 51
92
Resonance phenomena in plasma chemical reactions in C-O2
system in the magnetic field
D.A. Izhoykin, I.A. Ushakov, V.A. Neyman
National Research Tomsk Polytechnic University, Institute of Physics and Technology,
Department of Applied Physics Engineering, Lenin Avenue, 30, 634050, Tomsk, Russia
E-mail:mamay2008@bk.ru
Plasma technologies are often used for etching, welding and cutting of metals. At
the moment the plasma technologies possibilities are used not fully.
Low-temperature plasma contains the significantly amount of radicals. The
chemical reaction rate defined by probability of singlet pair’s formation by valence
electron spines of radicals. In the magnetic field the magnetic moments of radical’s
unpaired electrons precess around power lines direction. Radical’s excited states differ
by g-factors that lead to different spine precession rate. We experimentally studied that
magnetic field can change the relation between plasmachemical radical reactions rates.
The difference between nuclear spines values is also lead to the change of radical
reactions rates relation. Therefore the magnetic field leads to isotope redistribution
between reagents and products as a radical processes result [1].
We experimentally studied the carbon isotopes oxidation in the magnetic field. The
high-frequency torch discharge is used for low-temperature plasma torch formation and
for atomic carbon feeding. It is established that carbon monoxide enriched by 13
C to
1,78% from natural abundance at oxygen lack and constant magnetic field 1.2 T on the
desired area of a torch.
Gas temperature decreases along plasma torch which is accompanied by C and O
collisions frequencies reduction. It is shown that at conjunction between 13
С and O
collision frequency and difference of its valence electrons spines precession rates the 13
C oxidation rate increases.
References
[1] Isotope effects of plasma chemical carbon oxidation in a magnetic field / V. F.
Myshkin, V. A. Khan, D. A. Izhoykin, I. A. Ushakov // Natural Science. – 2013. –
Vol.5, № 1. – P. 57–61. DOI: 10.4236/ns.2013.51010
Poster 52
93
Optical and Light-Induced Superparamagnetic
Properties in γ-Fe2O3 Nanoparticles Formed in PPI
Dendrimers
Valerya E. Vorobeva1, Natalia E. Domracheva
1, Matvey S. Gruzdev
2
1Kazan E.K. Zavoisky Physical-Technical Institute, Sibirsky Tract, 10/7,420029, Kazan,
Russia 2 Institute of Solution Chemistry, Akademischeskaya St. 1, 153045 Ivanovo, Russia E-mail:
vvalerika@gmail.com
We are presenting the joint study of the optical (fig. 1) and photoinduced
superparamagnetic properties (fig. 2) of a single-domain γ-Fe2O3 NPs formed in PPI-
dendrimer of the second generation. The optical absorption studies indicated direct
allowed transition with the band gap (4.5 eV), which is blue shift with respect to the
value of the bulk material (2.2 eV). This shift is explained by quantum size effects. The
influence of pulsed laser irradiation on the superparamagnetic properties of γ-Fe2O3 NPs
was studied by EPR spectroscopy. It has been shown that irradiation of the sample in
vacuo and cooled in zero magnetic field to 6.9 K leads to the appearance of a new EPR
signal, which decays immediately after the irradiation is stopped. The appearance and
disappearance of this new signal can be repeated many times at 6.9 K when we turn
on/turn off the laser. We suppose that the generation of conduction band electrons by
irradiation into the band gap of the γ-Fe2O3 changes the magnetic anisotropy and
superparamagnetic properties of NPs. This effect is suppressed in the sample containing
oxygen, since oxygen captures the conduction band electrons.
Fig. 1. Experimental (solid line) and
simulated (dashed line) absorption spectra.
The contributions from two components at
254 and 287 nm are indicated by symbols
pure PPI-dendrimer of the second
generation (G2) is shown in the inset.
Fig. 2. Changes in the EPR signal during
laser irradiation with a wavelength of 266
nm at 6.9 K for FC-sample held in vacuo.
Poster 53
94
Probe EPR study of the acidity of boric acid modified
γ-aluminas
Vyacheslav L. Yurpalov, Vladimir A. Drozdov, Evgeniya D. Fedorova,
Alexander V. Lavrenov
Institute of Hydrocarbon Processing SB RAS, Neftezavodskaya St., 54, 644040, Omsk,
Russia
E-mail: yurpalovv@mail.ru
Electron acceptor (Lewis) and proton donor (Brönsted) surface sites play essential
role in the adsorption and catalytic properties of oxide materials. Thermally activated
modified aluminas have found broad application as a catalyst support or as a catalyst
due to ability to vary its acid/base properties by the introduction of different
modification agents. It has been recently founded [1] that NiO/γ-Al2O3 - B2O3 catalysts
demonstrate high activity in ethylene oligomerization reaction. So it’s important to
determine the influence of B2O3 content on the acidity of modified supports.
The samples of γ-Al2O3•B2O3 with 1, 3, 5, 10, 15, 20, 30 % wt of B2O3 and pristine
alumina were studied by EPR spectroscopy on Bruker EMXplus X-band spectrometer
after their activation at 400-600oC using TEMPO in n-hexane or anthracene in toluene
solutions as probes.
The decomposition of TEMPO molecule on a boric acid modified γ-aluminas
indicated the appearance of proton donor sites and extinction or decreasing of accessible
Lewis acid sites. The application of anthracene molecule resulted in the formation of
aromatic radicals (g = 2.0038) after its interaction primary with proton donor (Brönsted)
sites.
The maxima concentrations of aromatic radicals (7-8•1015
m-2
, ~2•1018
g-1
) are
observed for alumina samples with 10, 15 and 20 % of B2O3. Catalysts based on these
supports (NiO/γ-Al2O3 - 15-20% B2O3) also demonstrated maximal catalytic activity in
ethylene oligomerization reaction [1]. That may deals with optimal fixing of supported
NiO or/and preferential for the process composition and distribution of surface acid
sites.
All measurements were carried out on the instrumental base of Omsk Research
Collaboration Centre SB RAS.
References 1. Lavrenov, A.V.; Buluchevskii, E.A.; Moiseenko, M.A.; Drozdov, V.A.; Arbuzov,
A.B.; Gulyaeva, T.I.; Likholobov, V.A.; Duplyakin, V.K. Kinet. Catal. 2010, 51, 3,
404–409.
Poster 54
95
Active oxidizing species of the biomimetic catalyst systems
based on dinuclear aminopyridine ferric complexes, hydrogen
peroxide and acetic acid: An EPR spectroscopic and reactivity
studies
Alexandra M. Zima, Oleg Y. Lyakin, Konstantin P. Bryliakov,
and Evgenii P. Talsi
Boreskov Institute of Catalysis, Lavrentieva Pr. 5, 630090, Novosibirsk, Russia
Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
E-mail: zima-aleksandra@yandex.ru
The development of efficient methods for catalytic oxidation of organic substrates
has become an important goal in chemical industry and pharmaceutics. One of the main
problems of the modern organic synthesis is the selective oxidation of unactivated
aliphatic C=C and C−H bonds. On the other hand, it is very important to make such
processes economic and environmentally friendly and to avoid the use of toxic or
expensive reagents.
Natural metalloenzymes catalyze oxidation of various organic substrates with 100%
regio- and stereoselectivity under mild conditions inspiring researchers to design
biomimetic catalysts (synthetic models of nonheme iron oxygenases). The systems
based on aminopyridine iron complexes and H2O2 as an oxidant were found to be one of
the best biomimetic catalyst systems in terms of activity and selectivity towards
epoxidation. Despite intensive research efforts, the nature of the active species in these
catalyst systems has still not been clearly established. The aim of this work was to study
the active species of the catalyst systems for selective olefin epoxidation based on
biomimetic ferric complexes bearing ligands with electron-donating substituents in
pyridine rings.
Herein, we report EPR spectroscopic and reactivity studies of the catalyst systems
[(L)FeIII
(μ-OH)2FeIII
(L)](CF3SO3)4/H2O2/CH3COOH in CH2Cl2/CH3CN mixture (L =
tris(3,5-dimethyl-4-methoxypyridyl-2-methyl)amine or bis(3,5-dimethyl-4-
methoxypyridylmethyl)-(S,S)-2,2 -bipyrrolidine). The obtained data show the formation
of extremely unstable and highly reactive iron-oxygen intermediates in the catalyst
systems studied. These species directly epoxidized cyclohexene even at −85 °C. Its EPR
parameters were very close to those of previously well characterized model oxoiron(V)
complex that allowed us to assign the observed intermediates to the FeV=O species.
The authors thank the Russian Foundation for Basic Research for the financial
support of this work, grant 14-03-00102.
Poster 55
96
ESR intensity evolution during storage of chemically modified
poly(vinylidene fluoride)
Natalia A. Zlobina, Vladimir E. Zhivulin, Leonid A. Pesin
Chelyabinsk State Pedagogical University, Lenin av., 69, 454080, Chelyabinsk, Russia
E-mail:tasha558559@mail.ru
Poly(vinylidene fluoride) (PVDF) is a polymer material, the molecules of which
consist of a carbon chain skeleton and alternately attached two hydrogen or two fluorine
atoms to each carbon atom. Dehydrofluorination of PVDF is prospective for synthesis
of carbynoids - carbon nanostructures having predominantly chain-like atomic
arrangement. Chemical or radiative treatment cleaves the fluorine and hydrogen atoms
out of the carbon skeleton. Broken bonds resulting from this reaction lead to the
appearance of the magnetic activity of the material. They can be saturated via formation
double or triple carbon-carbon bonds within chains or linking with the molecules from
air. At deep stages of dehydrofluorination interchain crosslinking becomes possible.
The kinetics of the ESR reduction could clarify the role of each of these processes
during storage of chemically modified PVDF.
The samples have been prepared by chemical modification of PVDF films F-2M
(JSC "Plastpolymer", St. Petersburg). Dehydrofluorinating mixture consisted of a
saturated solution of KOH in ethanol and acetone. Before and after the reaction the
films were rinsed sequentially with acetone and distilled water. Thus three samples were
obtained with different chemical exposure duration (1, 3 and 15 hours). ESR spectra
were recorded using spectrometer RE-1306.
As expected, longer dehydrofluorination leads to an increase in the ESR intensity.
After the end of chemical treatment the ESR signal decreases. Experimental
dependences are well described by a sum of three first-order reactions with different
kinetic parameters. Each of these reactions corresponds to one of the ways of the broken
bonds saturation.
The study is supported by the Ministry of Education and Science of the Russian
Federation (a project No 2531 "Synthesis and properties of magnetically active layer on
the surface of a poly(vinylidene fluoride) film").
Poster 56
97
EPR study of single-molecule magnet behavior of
dysprosium(III) complexes
A. Sukhanov1, V. Voronkova
1, A. Baniodeh
2, A. K. Powell
2
1Zavoisky Physical-Technical Institute, Kazan, Russian Federation
2Karlsruhe Institute of Technology, University of Karlsruhe, Karlsruhe, Germany
E-mail: ansukhanov@mail.ru
Since discovery of the single-molecule magnets (SMMs) [1] they have been the
focus of extensive research. It was shown that, at low temperatures (2K) SMMs retain
magnetization over long periods. Magnetic bistability is observed in molecules that
possess a large spin ground state in addition to large Ising-type magnetic anisotropy.
This anisotropy barrier opposes the reversal of the spin at low temperature. Lanthanides
are strategic materials play a remarkable role in single-molecule magnetism thanks to
their large magnetic moments and large anisotropy.
Recently a family of isostructural {Fe2Dy2} coordination clusters which differ only
by substituent on their benzoate rings were synthesized [2]. It has been found that there
are indeed clear effects on the SMMs properties resulting from not only varying the
nature of substituent (–CN versus –Me) but also their position on the ring (para- versus
meta-) [2].
In this work, we present the EPR study of these clusters. The EPR measurements in
X- and Q-bands at low temperature (4-15K) for these clusters were carried out. It was
found that change of CN position effects on g-factor of Dy ions that probably reflects
the change of the ground state of these ions. The shape of the EPR spectrum in Q-band
changes after the compound is subjected to the effect of the external magnetic field.
This change can be described by the appearance of some ordering as it indicates that the
number of clusters with gz oriented along external magnetic field increases after the
effect of the external magnetic field. This effect was observed only for clusters with
meta-CN and para-Me substituents.
[1] Caneschi A., Gatteschi D., Sessoli R. et al.: J. Am. Chem. Soc., 113, 5873 (1991).
[2] Baniodeh A., Mereacre V., Magnani N. et al.: Chem. Commun., 49, 9666 (2013).
Acknowledgements: We are grateful to the Russian Foundation for Basic Research № 13-02-01157 for
partial financial support.
98
Table of Contents
Program…………………………………………………………………………………………………………………………. 4
Lectures
Theory of the pulse electron double resonance spectroscopy Kev M. Salikhov…………………………………………………………………………………………………………….. 8 Studies of structure and conformational changes of biomacromolecules and their complexes: pulse EPR techniques based on static and stochastic electron-electron dipolar interaction Maxim Yulikov………………………………………………………………………………………………………......... 9 Measurement of Hyperfine Couplings by Pulsed EPR Michael K. Bowman………………………………………………………………………………………………………. 10 Pulsed EPR of Spin-Labeled Biological Systems Sergei A. Dzuba………………………………………………………………………………………………………........ 11 Protein-DNA interaction: how do proteins find their target? Robert Kaptein………………………………………………………………………………………………………......... 12 Protein dynamics and Neuroprotection: Approaches by NMR Christian Griesinger……………………………………………………………………………………………............ 13 Nuclear Hyperpolarization and Spin Entanglement in Photoexcited Triplet States Gerd Kothe ……………………………………………………………………………………………………….............. 15 Cooperativity of Functional Hydrogen Bonds in Active Sites of Enzymes: NMR Study of Model Systems Peter M. Tolstoy………………………………………………………………………………………………………...... 16 Investigation of Structure and Surface Chemistry of Heterogeneous Catalysts employing Advanced Solid-State NMR Techniques Torsten Gutmann………………………………………………………………………………………………………..... 17 Advanced Solid State NMR Spectroscopy for Structural Characterization of Supported Catalysts Olga B.Lapina………………………………………………………………………………………………………........... 18 Spin resonance of electrons localized in Ge/Si quantum dot nanoheterostructures Anatoly V. Dvurechenskii ……………………………………………………………………………………………… 19 EPR in Solar Cell Research Jan Behrends………………………………………………………………………………………………………............ 20
99
Spin-Orbit-Coupling Based Spin Chemistry Ulrich E. Steiner………………………………………………………………………………………………………....... 21 Magnetoreception of Molecular Systems and Spin Selective Chemical Reactions Kiminori Maeda……………………………………………………………………………………………………….......
22
The role of level-anti-crossings in spin hyperpolarization Hans-Martin Vieth………………………………………………………………………………………………………... 23 Time resolved and field dependent CIDNP Alexandra V.Yurkovskaya ……………………………………………………………………………………………… 24 The study of practically important radical processes by spin chemistry methods. Tatyana V. Leshina ……………………………………………………………………………………………………….. 25 Application of NMR in Medical Research Nikolay E. Polyakov……………………………………………………………………………………………………….. 26 EPR discovery and identification of dinitrosyl iron complexes with thiol-containing ligands in living systems Anatoly F. Vanin………………………………………………………………………………………………………....... 27
Oral presentations of young scientists
FMR study of Cr1/3NbS2 helical magnet Fedor B. Mushenok………………………………………………………………………………………………………..
29
Possibilities of EPR diagnostics for monitoring the sportsmen’s state of health Alexandr I. Chushnikov……………………………………………………………………………………………......
30
Highly efficient exciplex formation in case of X-ray irradiation of non polar solutions Anatoly R. Melnikov……………………………………………………………………………………………………….
31
Exploiting Level Anti-Crossings in the rotating frame for transferring spin hyperpolarization Andrey N. Pravdivtsev……………………………………………………………………………………………………
32
Experimental and Theoretical NMR Analysis of Paramagnetic M(acac)3 (M = Cr, Mn) Coordination Compounds Kirill Levin……………………………………………………………………………………………………….................
33
The EPR Study Of Light-Induced Thermally Inaccessible Spin State In Copper-Nitroxide Based Molecular Magnet Irina Yu. Barskaya………………………………………………………………………………………………………....
34
100
Proton transfer process in C-H•••X hydrogen bonds Elena Yu. Tupikina………………………………………………………………………………………………………....
35
Investigation of some acetophenone derivatives in solution by NMR Alakbar E. Huseynzada……………………………………………………………………………………………………
36
Fluorinated homocysteine derivatives as potential molecular probes for 19F magnetic resonance spectroscopy and imaging: synthesis and characterization Alexey S. Chubarov……………………………………………………………………………………………………….. 37 2H NMR study of the rotational dynamics of terephatalate phenylenes in metal-organic frameworks CoMOF, NiMOF and ZnMOF: effect of different metal centers Alexandr E. Khudozhitkov….…………………………………………………………………………………………..
38
Influence of glycyrrhizin on cell membrane properties Olga Yu. Selyutina…………………………………………………………………………………………………….......
39
Low-field NMR Spectroscopy and Imaging Via Parahydrogen Based Hyperpolarization: Towards catalyst-free molecular contrast agents and MRI of industrial hydrogenation Danila A. Barskiy………………………………………………………………………………………………………......
40
Posters
Investigation of some alkenylphenol derivatives in solution by NMR Mircavid M. Agayev………………………………………………………………………………………….............
P1 42
Supramolecular complexes of macular carotenoids with enhanced solubility and oxidation stability. Irina E. Apanasenko……………………………………………………………………………………………………….
P2 43
Magnetic field effects in E.coli cells in the presence of the isotope Mg Elena I. Avdeeva…………………………………………………………………………………………………............
P3 44
Self-Organization Features of the Copper(II) 3 Amino 4 Ethoxycarbonylpyrazole Compound. Alexey S. Berezin………………………………………………………………………………………………..............
P4 45
The effect of chemical reaction on the spin states evolution of spin-correlated radical ion pairs Alena O. Bessmertnykh………………………………………………………………………………………………….
P5 46
The Investigation of NMR Parameters of Heptafluoroindenyl Cation Dmitriy S. Fadeev……………………………………………………………………………………………………….....
P6 47
101
Kinetics and mechanism of the reversible photoinduced oxidation of purine nucleotides in aqueous solutions. Natalya N. Fishman………………………………………………………………………………………………………..
P7 48
Photooxidation of histidine by 3,3′,4,4′-benzophenone tetracarboxylic acid in aqueous solution studied by time-resolved and field-dependent CIDNP Natalya N. Fishman………………………………………………………………………………………………………..
P8 49
Atomistic molecular dynamics simulations of cyanobiphenyl compounds Egor Gerts……………………………………………………………………………………………………...................
P9 50
Functional EPR Imaging of Isolated and Perfused Rat Hearts: Monitoring of Tissue pH and Oxygenation Artem A. Gorodetsky……………………………………………………………………………………..………………
P10 51
Proton NMR study of hydrogen site occupancy and mobility in hydrides of disordered transition metal alloys Valeriya O. Ievleva………………………………………………………………………………………….…………...
P11 52
Investigation of antimicrobial peptide alamethicin pore formation in the membrane of Bifidobacteria cell by EPR Nikolay P. Isaev ……………………………………………………………………………………………………….......
P12 53
Theory of pulsed reaction yield detected magnetic resonance Konstantin Ivanov………………………………………………………………………………………………………....
P13 54
Spin dynamics of ZnTPP in room-temperature ionic liquids studied by Time-Resolved EPR Mikhail Y. Ivanov……………………………………………………….…………………………………………………..
P14 55
Adaptation of NMR Imaging Techniques for Experimental Mapping of the Static Magnetic Field Viacheslav A. Ivanov………………………………………………………………………………………………………
P15 56
Controlled radical polymerization of styrene in the presence of nitroxides at low temperatures Beket B. Kanagatov………………………………………………………………………………………………………...
P56 57
Application of pulse EPR for investigation of lipid-cholesterol rafts in membranes Maria E. Kardash……………………………………………………………………………………………………………
P17 58
EPR Study of Electron-Acceptor Sites during Catalytic Dehydrochlorination of 1-Chlorobutane over Nanocrystalline MgO Roman M. Kenzhin…………………………………………………………………………………………………………
P18 59
102
CIDNP in Naproxen - Pyrrolidine Dyads as a Model of Drug-Enzyme Binding. Ekaterina A. Khramtsova………………………………………………………………………………………………..
P19 60
FMR of iron-containing nanocomposites of natural polysaccharides Spartak S. Khutsishvili S.S. …………………………………………………………………………………….………
P20 61
Lipid peroxidation. Bistability and bifurcation phenomena. Magnetic field effects Alexey A. Kipriyanov………………………………………………………………………………………………………
P21 62
EPR study of the hydrogen center in HPHT diamonds grown in carbonate medium Andrey Yu. Komarovskikh………………………………………………………………………………………………
P22 63
The study of influence of sugars on the mobility of phospholipid bilayer Konstantin B. Konov………………………………………………………………………………………………………
P23 64
Effect of a heavy atom on magnetic anisotropy of monobromine substituted septet trinitrene. Experimental and theoretical (ab initio and DFT) study. Denis V.Korchagin………………………………………………………………………………………………………....
P24 65
Inclusion compound of threonin with cucurbit[7]uril - supramolecular chemistry in solution Ekaterina A. Kovalenko………………………………………………………………………………………………….
P25 66
Advanced SDSL with Nitroxyl and Trityl Radicals for Distance Measurements in Nucleic Acids Olesya А. Krumkacheva………………………………………………………………………………………………….
P26 67
Development of spin labels based on triarylmethyl radicals: pulse and CW EPR study Andrey A. Kuzhelev………………………………………………………………………………………………………..
P27 68
1,2,3,5 Tetrafluorobenzene Anion Radical As Studied by the Method of Time-Resolved Magnetic Field Effect Gleb A. Letiagin………………………………………………………………………………………………………........
P28 69
Charge Recombination in Р3НТ/РС70ВМ Composite Studied by Light-Induced EPR Ekaterina A. Lukina………………………………………………………………………………………………………..
P29 70
The study of redox reactions involving anticancer quinone-chelator in the presence of metal ions. Irina D. Markova………………………………………………………………………………………………………......
P30 71
New Spin-Labelled Photochromic System Anna G. Matveeva………………………………………………………………………………………………………….
P31 72
103
Quadrupolar Magic Angle Spinning NMR Spectra Fitted Using the Pearson IV Function Roman M. Mironenko……………………………………………………………………………………………………
P32 73
Interatomic Interactions and NMR of [Cp*3M3Se2]2+ M = Rh, Ir Irina V. Mirzaeva………………………………………………………………………………………………………......
P33 74
Huge Spin-Orbit Relativistic Effects in NMR of Bimetallic Rh-Sn3 and Ir-Sn3 Complexes Irina V. Mirzaeva………………………………………………………………………………………………………......
P34 75
NMR Study on Methane Activation and Transformation over In-modified ZSM-5 Zeolite Ilya B. Moroz………………………………………………………………………………………………………............
P35 76
In Situ Spin Probe Studies of the Effect of Terahertz Radiation on Proteins Eugenia F. Nemova………………………………………………………………………………………………………..
P36 77
Time resolved and magnetic field dependence CIDNP study of mechanism of photoreaction involving radicals of S-methylcysteine and S-methylglutathione Mikhail S. Panov……………………………………………………………………………………………………….......
P37 78
Spin exchange effect in solutions of α-diimine radicals Stanislav K. Petrovskii……………………………………………………………………………………………………
P38 79
2D NOESY/EXSY study of azide-tetrazole equilibrium of 2,4-diazidopyrimidines Nadezhda V. Pleshkova………………………………………………………………………………………………….
P39 80
19F-MRI and 31P-MRS in vivo visualisated theranostic with anticancer activity Tatyana V. Popova ………………………………………………………………………………………………………..
P40 81
Electron Spin Echo of Light-Induced Spin Correlated Radical Pairs in PCBM/P3HT Composite Alexander A. Popov……………………………………………………………………………………………………….
P41 82
Possibility of application of diazaperylene derivatives as an acceptor in organic photovoltaic cells. Alexandr G. Popov………………………………………………………………………………………………………..
P42 83
Level Anti-Crossings are a Key Factor for Understanding Magnetic Field Dependence of Hyperpolarization in SABRE Experiments Andrey N. Pravdivtsev…………………………………………………………………………………………………..
P43 84
New approaches for production and application of parahydrogen-induced polarization (PHIP) using heterogeneous hydrogenations Oleg G. Salnikov………………………………………………………………………………………………………........
P44 85
104
Association of lipid-lowering drugs – statins with natural triterpene – glycyrrhizic acid. Anna A. Schlotgauer……………………………………………………………………………………………………..
P45 86
Reaction of benzene with bromine without catalyst: study of kinetics and elucidation of product structures by NMR Andrey V. Shernyukov…………………………………………………………………………………………………..
P46 87
Investigation of Electron-Acceptor Sites on the Surface of Sulfated Alumina Using EPR Ekaterina I. Shuvarakova……………………………………………………………………………………………….
P47 88
Reversible and irreversible recombination in spin chemistry Denis V. Sosnovsky……………………………………………………………………………………………………....
P48 89
NMR and CIDNP Study of Phototransformation of Iron Chelator Deferiprone in the Presence of Metal Ions Viktor A. Timoshnikov…………………………………………………………………………………………………..
P49 90
Magnetic spin phenomena in C-N2-O2 system under the conditions of low-temperature plasma Ivan A. Ushakov………………………………………………………………………………………………………........
P50 91
Resonance phenomena in plasma chemical reactions in C-O2 system in the magnetic field Ivan A. Ushakov………………………………………………………………………………………………………........
P51 92
Optical and Light-Induced Superparamagnetic Properties in γ-Fe2O3 Nanoparticles Formed in PPI Dendrimers Valerya E. Vorobeva…………………..……………………………………………………………………..............
P52 93
Probe EPR study of the acidity of boric acid modified γ-aluminas Vyacheslav L. Yurpalov……………………………………………………………………………………………………
P53 94
Active oxidizing species of the biomimetic catalyst systems based on dinuclear aminopyridine ferric complexes, hydrogen peroxide and acetic acid: An EPR spectroscopic and reactivity studies Alexandra M. Zima………………………………………………………………………………………………………....
P54 95
ESR intensity evolution during storage of chemically modified poly(vinylidene fluoride) Natalia A. Zlobina……………………………………………………………………………………………………......
P55 96
EPR study of single-molecule magnet behavior of dysprosium(III) complexes
Andrey Sukhanov……………………………………………………………………………………………………........ P56 97
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