11 research outputs found
Adsorption of Nitroxide-Alcohol Solutions on X Zeolite. Part 3. ESR and ESEM Study of Deuteriated Methanol Solutions
Dipolar and Spin Exchange Effects in the ESR Spectra of Nitroxide Radicals in Solution. Part 2. Water Solutions Adsorbed on Porous Silica Gels
Water and Other Polar Liquids in Porous Systems Studied by Electron Spin Resonance and Electron Spin Echo
Surface Effects Towards the Mobility of Charged Spin Probes: ESR Study of Nitroxide Solutions Adsorbed on Zeolites
ESR Study on the Interaction Between a Positively Charged Spin Probe and the Silica Gel Surface
Proton Hyperfine Tensors in Nitroxide Radicals
The proton hyperfine tensors of five nitroxide radicals have been obtained by ENDOR spectroscopy in frozen solution. The
spectra are interpreted by computing the dipolar hyperfine interaction and simulating the spectra. EPR spectra in solution
of the same radicals have been simulated by taking into account the effects of the proton hyperfine tensors. We have been
able to reproduce accurately the line broadening effects of the proton hyperfine structures inside each nitrogen hyperfine
component and we have determined the correlation times for the rotational motion. In the case of the radical Tempol, our
analysis allows discrimination between the effects due to the protons of the axial and equatorial methyl groups. On the basis
of experimental evidence we can attribute the larger isotropic hyperfine coupling constant to the axial methyl protons. The
possible use of the present results for interpreting the spectra of other nitroxide radicals is discussed