Radical formation in lithium trifluoromethane-sulfonate for ESR dosimetry

Abstract

Lithium trifluoromethane-sulfonate (Li-TFMS:CF 3 SO3Li) irradiated by y-rays showed an electron spin resonance (ESR) powder spectrum having the rhombic g-factor of g 2.0259 ± 0.0005, g,,,, = 2.0112 ± 0.0005 and g 2.0025 ± 0.0005 and a triplet hyperfine coupling constant of A yrlgß = 0.8 ± 0.15 mT. A A. are not obtained because of the broadened spectrum. The energy levels, g-factor, A, r/gß and optical absorption spectrum of several conceivable radicals such as C'F2SO3Li, CF3 -S-O and CF3-S-O-O' have been calculated by softwares MOPAC-V2 and Gaussian-98 based on ROHF (Restricted Hatree -Fock for open shell molecule). The most probable radical was ascribed to CF 3 -SO' from both calculated and experimental results. The response to y-ray dose and the thermal stability have been studied in addition to the effect of UV illumination for possible use of the signal intensity in ESR dosimetry. The obtained number of free radicals per 100 eV (G-value) was 1.23 ± 0.40.

Synthesis, structures, and solid-state photoresponsive color change behavior of boronium complexes bearing a pyridine-imine, diimine, or pyridine-ketone bidentate ligand

“…29 The g -values higher than 2.01 were reported for the sulfur-containing organic radicals including trifluoromethanesulfonate-derived ones. 29,30 Because the observed g -values from the photoproducts of 1 and 2a–e showed no large shifts due to the sulfur atom and exhibited characteristics of organic radicals consisted from only light atoms, the possibility of the formation of the trifluoromethanesulfonate-derived radicals was low. However, further elucidation of their structures based on these spectra was hard because their ESR signals were weak and broad without coupling structures due to interactions in the solid state.…”