IMINOXY FREE-RADICALS DERIVED FROM PHENYL-2-PYRIDYLKETOXIME - AN EPR STUDY OF SOLVENT INFLUENCE ON THE HYPERFINE INTERACTION

Phenyl-2-pyridylketoxime undergoes one- or two-electron oxidation form ing two different paramagnetic species distinguishable by EPR. The ani sotropic EPR spectra of the free radicals can be obtained by gamma-irr adiation of the solid sample of the oxime. Due to the asymmetry of the molecule, two distinct isomers of each radical are observed in a solu tion. Interaction of the radicals with the solvent appears to be diffe rent from those observed for other iminoxy radicals. The analysis of N -14 hyperfine interactions allowed us to determine the spin density di stribution in the radical molecules. The isomers present in solutions were characterised by means of a computer simulation of experimental E PR spectra.