The Current State of Measuring Bimolecular Spin Exchange Rates by the EPR Spectral Manifestations of the Exchange and Dipole–Dipole Interactions in Dilute Solutions of Nitroxide Free Radicals with Proton Hyperfine Structure
- Authors: Bales B.L.1, Bakirov M.M.2, Galeev R.T.2, Kirilyuk I.A.3, Kokorin A.I.4, Salikhov K.M.2
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Affiliations:
- Department of Physics and Astronomy, The Center for Biological Physic, California State University at Northridge
- Zavoisky Physical-Technical Institute, Russian Academy of Sciences
- Novosibirsk Institute of Organic Chemistry of the Siberian Branch of the Russian Academy of Sciences
- Semenov Institute of Chemical Physics of the Russian Academy of Sciences
- Issue: Vol 48, No 11-12 (2017)
- Pages: 1399-1445
- Section: Original Paper
- URL: https://journals.rcsi.science/0937-9347/article/view/248000
- DOI: https://doi.org/10.1007/s00723-017-0958-x
- ID: 248000
Cite item
Abstract
Experimental studies of 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (Tempol) in 60 wt% aqueous glycerol were carried out for temperatures from 273 to 340 K. Selective isotope substitution allowed comparisons between the experimental spectral manifestations of spin exchange and dipole–dipole interactions for protonated, deuterated, 15N, and 14N Tempol. Theoretical spectra were computed from a rigorous theory specifically formulated to include proton hyperfine interactions over a wide range of spin exchange and dipole–dipole interactions to compare with the experimental data. For spin exchange and dipole–dipole interactions small compared with the proton hyperfine coupling constant, spectra were calculated with perturbation theory to gain insight into the behavior of individual proton lines. The theoretical and experimental spectra were analyzed by least-squares fitting to Voigt shapes or by a new two-point method. For most accessible experimental designs, the comparisons are rather good; however, for an experiment constrained to low concentrations and high viscosities, the methods are less accurate.
About the authors
Barney L. Bales
Department of Physics and Astronomy, The Center for Biological Physic, California State University at Northridge
Author for correspondence.
Email: barney.bales@csun.edu
United States, Northridge, CA, 91330
M. M. Bakirov
Zavoisky Physical-Technical Institute, Russian Academy of Sciences
Email: barney.bales@csun.edu
Russian Federation, Sibirsky trakt 10/7, Kazan, 420029
R. T. Galeev
Zavoisky Physical-Technical Institute, Russian Academy of Sciences
Email: barney.bales@csun.edu
Russian Federation, Sibirsky trakt 10/7, Kazan, 420029
I. A. Kirilyuk
Novosibirsk Institute of Organic Chemistry of the Siberian Branch of the Russian Academy of Sciences
Email: barney.bales@csun.edu
Russian Federation, Novosibirsk
A. I. Kokorin
Semenov Institute of Chemical Physics of the Russian Academy of Sciences
Email: barney.bales@csun.edu
Russian Federation, Moscow
K. M. Salikhov
Zavoisky Physical-Technical Institute, Russian Academy of Sciences
Email: barney.bales@csun.edu
Russian Federation, Sibirsky trakt 10/7, Kazan, 420029