Arkhipov, S. G.; Sherin, P. S.; Kiryutin, A. S.; Lazarenko, V. A.; Tantardini, C., The role of S-bond in tenoxicam keto–enolic tautomerization. CrystEngComm 2019, 21 (36), 5392-5401. https://doi.org/10.1039/C9CE00874H
Kiryutin, A. S., Sauer, G., Tietze, D., Brodrecht, M., Knecht, S., Yurkovskaya, A. V., Ivanov, K. L., Avrutina, O., Kolmar, H., Buntkowsky, G., Cover Feature: Ultrafast Single-Scan 2D NMR Spectroscopic Detection of a PHIP-Hyperpolarized Protease Inhibitor (Chem. Eur. J. 16/2019). Chemistry – A European Journal 2019, 25, 3966-3966. http://doi.org/10.1002/chem.201900875
Zhukov, I. V., Kiryutin, A. S., Yurkovskaya, A. V., Grishin, Y. A., Vieth, H.-M., Ivanov, K. L., Field-cycling NMR experiments in ultra-wide magnetic field range: relaxation and coherent polarization transfer. Phys. Chem. Chem. Phys. 2018, 20, 12396-12405. http://doi.org/10.1039/C7CP08529J PCCP inside cover
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Morozova, O. B., Ivanov, K. L., Time-resolved CIDNP of biologically important molecules. ChemPhysChem 2019, 20, 197-215. http://doi.org/10.1002/cphc.201800566 Cover review
Pravdivtsev, A. N., Kiryutin, A. S., Yurkovskaya, A. V., Vieth, H.-M., Ivanov, K. L., Robust conversion of singlet spin order in coupled spin-1/2 pairs by adiabatically ramped RF-fields. J. Magn. Reson. 2016, 273, 56-64. http://doi.org/10.1016/j.jmr.2016.10.003 Cover
Pravdivtsev, A. N.; Yurkovskaya, A. V.; Lukzen, N. N.; Vieth, H. M.; Ivanov, K. L., Exploiting level anti-crossings (LACs) in the rotating frame for transferring spin hyperpolarization. Phys. Chem. Chem. Phys. 2014, 16 (35), 18707-18719. https://doi.org/10.1039/C4cp01445f
Korchak, S. E., Ivanov, K. L., Yurkovskaya, A. V., Vieth, H.-M., Para-hydrogen induced polarization in multi-spin systems studied at variable magnetic field. Phys. Chem. Chem. Phys. 2009, 11, 11146-11156. http://doi.org/10.1039/B914188j Cover
Patent No. 2746064 C1 Russian Federation, IPC G01R 33/46. Method for complete correlation NMR spectroscopy with nuclear spin mixing in ultralow magnetic field : No. 2020126154 : filed 03.08.2020 : published 06.04.2021 / A. S. Kiryutin, Yu. A. Grishin, I. V. Zhukov [et al.] ; applicant Federal State Budgetary Institution of Science Institute "International Tomography Center" of the Siberian Branch of the Russian Academy of Sciences. – EDN VOLMLQ.
Patent No. 2818882 C1 Russian Federation, IPC G01N 24/08, G01R 33/31. Large-volume internal thermostat for NMR spectrometer magnet : No. 2023134319 : filed 21.12.2023 : published 06.05.2024 / A. A. Samsonenko, N. A. Artyukhova, A. S. Kiryutin, S. L. Weber ; applicant Federal State Budgetary Institution of Science Institute "International Tomography Center" of the Siberian Branch of the Russian Academy of Sciences. – EDN LICFWZ.
Study of radical reactions modeling the chemical pathway of DNA repair
In addition to relatively slow enzymatic DNA repair processes protecting the genetic code, electron vacancies in DNA may hypothetically be filled via electron transfer from the protein environment. Such a "chemical pathway" of DNA protection can effectively prevent the formation of modified DNA sites. Fast radical reactions of guanine, the most easily oxidized purine base, have been studied as models of "chemical repair" of DNA, involving electron transfer from aromatic amino acids tryptophan (Trp) and tyrosine to oxidized guanosine-5′-monophosphate (GMP) in four different protonation states at pH values ranging from 1.3 to 13.3. Nucleotide radical generation was performed photochemically, and radical reactions were detected using time-resolved chemically induced dynamic nuclear polarization (CIDNP). It was found that GMP radical reduction by tryptophan proceeds more efficiently than by tyrosine. Rate constants of electron transfer were determined for all four possible forms of the GMP radical — from the dication radical to the anion radical, differing in the protonation degree of the purine base.
Determination of 1H and 13C hyperfine coupling constants for short-lived radicals based on detection of geminate CIDNP spectra with microsecond time resolution
For the first time, 13C CIDNP spectra were detected with microsecond time resolution in the geminate recombination of tryptophan cation radicals in its photoinduced electron transfer reactions with a series of triplet-excited molecules in aqueous solutions. It was established that the electron spin density is predominantly localized in the five-membered ring on carbon atoms C2, C3, and C9. The proposed method for determining hyperfine coupling constants from geminate CIDNP spectra was successfully tested on 1H and 13C CIDNP in photoinduced reactions involving the neutral tyrosine radical with known proton hyperfine constants and some of the 13C hyperfine constants. The obtained 1H and 13C hyperfine constants for the neutral tyrosine radical and tryptophan cation radical agree with the results of quantum-mechanical density functional theory calculations for the optimized geometry of the indole ring, accounting for 35 water molecules in the first solvation shell.
Determination of magnetic resonance parameters of short-lived radicals from geminate CIDNP spectra and establishment of conditions for linear dependence between CIDNP amplitude and hyperfine coupling constant
A simple proportional relationship between the amplitudes of geminate chemically induced dynamic nuclear polarization (CIDNP) in diamagnetic products of radical reactions and their hyperfine coupling constants (HFC) at the radical stage was theoretically derived. The limits of applicability of this relationship were established, showing that it remains highly accurate even with small differences in the g-factors of radical partners, provided the number of magnetic nuclei is sufficiently large.
Published: Kiryutin A. S., Ivanov K. L., Morozova O. B., Yurkovskaya A. V., Vieth H.-M., Pirogov Yu. A., Sagdeev R. Z. "Time-resolved CIDNP as a tool for quantitative analysis of hyperfine interactions in short-lived radicals", Dokl. Phys. Chem., 2009, 428 (3), 342-348.
Study of the influence of scalar coupling on coherent transfer of parahydrogen-induced nuclear polarization in arbitrary magnetic fields
Within the theoretical framework for describing parahydrogen-induced polarization (PHIP) effects, the dependence of PHIP effects on magnetic field was examined. Calculations were compared with experimental data for PHIP in ethylbenzene generated during catalytic para-hydrogenation of styrene. For ethylbenzene, perfect agreement between theory and experiment was observed, both for CH2 and CH3 protons and for relatively weakly polarized aromatic protons. Calculations accounting for the actual magnetic field switching profile and 10 coupled spins modeling the proton system of ethylbenzene showed excellent agreement with experiment, whereas calculations under sudden or adiabatic field switching approximations poorly matched experimental data.
Results on the magnetic field dependence of nuclear spin hyperpolarization during parahydrogenation were published in Physical Chemistry Chemical Physics, where the paper received "Hot Paper" status. A figure illustrating this work was featured on the journal cover.
In collaboration with the Laboratory of Theoretical Spin Chemistry http://www.tomo.nsc.ru/structure/lab/ltsh/, software was developed for parameter optimization in experiments creating long-lived singlet states via adiabatic radiofrequency pulse methods.
