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EPR Spectroscopy of Mercury-Organic Compounds with Nitroxide Radicals |
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| Authors: | A I Kokorin S Landgraf A B Shapiro G Grampp |
| Institution: | 1. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, Russian Federation 3. Institute of Physical and Theoretical Chemistry, Graz University of Technology, Graz, Austria 2. N. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russian Federation |
| Abstract: | Intramolecular electron spin exchange as a function of temperature, solvent viscosity and polarity has been studied by X-band electron paramagnetic resonance (EPR) spectroscopy for two nitroxide biradicals containing mercury-organic groups in the bridge connecting two 1-oxyl-2,2,6,6-tetramethylpiperidine-3,4-ene-nitroxide rings, R. The temperature dependence of the isotropic hyperfine splitting (hfs) constant a N and the exchange integral value |J/a| of the biradicals were measured from EPR spectra and subsequently analyzed comparing to a N and a Hg hfs constants of ClHgR radical dissolved in the same solvents. In all cases, the interaction of solvent molecules (SM) with >N–O fragments of nitroxide rings led to a slight decrease in a values with increasing temperature. The |J/a| value varied slightly with temperature T changes. The changes of |J/a| are much less comparing to those with variation of the solvent polarity. The interaction between SM and Hg atoms inside the bridge is observed and discussed. |
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