Electron Paramagnetic Resonance Study of Gamma-Irradiated [(CH3)4N]H2F3 Single Crystals

Abstract

γ-Irradiated [(CH<inf>3</inf>)<inf>4</inf>N]H<inf>2</inf>F<inf>3</inf> single crystals and powders were investigated by electron paramagnetic resonance (EPR) technique at ambient temperature. It has been found that this compound indicates the existence of (CH<inf>3</inf>)<inf>3</inf> over(N, {radical dot})+ radicals after γ-irradiation. The isotropic g factor and the isotropic hyperfine constant for H atoms were measured as 2.0031 and 28.8 G, respectively. The hyperfine coupling constant of the N nucleus, observed in (CH<inf>3</inf>)<inf>3</inf> over(N, {radical dot})+ radical was found to be anisotropic with A<inf>z</inf>=15.9 G, A<inf>y</inf>=21.9 G and A<inf>x</inf>=22.1 G values. These results indicate that each methyl group rotates around its C<inf>3v</inf> axis and three methyl groups also rotate around the C<inf>3v</inf> axis of (CH<inf>3</inf>)<inf>3</inf> over(N, {radical dot})+ radical. In addition to these motions, the C<inf>3v</inf> axis of the radical seem to rotate around the c-axis of the crystal. These results were compared with the literature data for similar compounds and the EPR properties of the (CH<inf>3</inf>)<inf>3</inf> over(N, {radical dot})+ radical were discussed. © 2007 Elsevier Ltd. All rights reserved.