Experimental Observation of Free Induction Decay of Phenoxyl-Type Radical

The free induction decay (FID) of the polycrystalline sample of the phenoxyl radical derived from α-(3,5-di-tert-butyl-4-hydroxyphenyl)-N-tert-butylnitrone, which is a novel spin-trapping reagent, in a corresponding diamagnetic matrix was successfully observed after one pulse even at room temperature, while FIDs of phenoxyl radicals usually are inaccessible due to their short relaxation times and the dead time of the pulse EPR spectrometer. This may be the first experimental observation in phenoxyl-type radicals. This study thus showed the unique character of the phenoxyl radical, that is, the distribution of the electron density relative to the usefulness for the spin-trapping techniques. Authors' address: Toshiki Yamaji, Materials Characterization Division, National Metrology Institute, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan