Electron Paramagnetic Resonance of γ-Irradiated [(CH3)4N]2ZnF4 and [(CH3)4N]2CdF4 Single Crystals and Vibrational Spectra of Their Unirradiated Forms

Abstract

γ-Irradiated [(CH<inf>3</inf>)<inf>4</inf>N]<inf>2</inf>ZnF <inf>4</inf> and [(CH<inf>3</inf>)<inf>4</inf>N]<inf>2</inf>CdF<inf>4</inf> single crystals were investigated by electron paramagnetic resonance (EPR) and vibrational spectroscopy of their unirradiated forms at ambient temperature. It has been found that both compounds indicate the existence of (CH <inf>3</inf>)<inf>3</inf> Ṅ+ radicals. The g factors were found to be isotropic and the hyperfine constant for protons of the methyl groups was measured as 28.9G for this radical in these substances. Each methyl group rotates around its C<inf>3ν</inf>-axis and also rotates around the C <inf>3ν</inf>-axis of the (CH<inf>3</inf>)<inf>3</inf> Ṅ+ radical. In addition to these motions, the C<inf>3ν</inf>-axis of the (CH<inf>3</inf>)<inf>3</inf> Ṅ+ radical seems to rotate around the z-axis. These results were compared with the earlier studies in (CH <inf>3</inf>)<inf>3</inf> Ṅ+ radical and discussed. The vibrational spectra of these two compounds were discussed in relation to other compounds containing tetramethylammonium salts. The assignments of the observed bands were discussed. © 2008 Elsevier Ltd. All rights reserved.