The behavior of 5 title nitroxides I (R = H, F, Cl, Me, MeO) in 9 solvents with different polarity has been studied by EPR spectrometry. It was observed that the hyperfine splitting constants AN of the nitroxides have good linear correlations with some solvents parameters such as Kosowere constants Z and Reichardt constants Et. It was also found that the energy difference of adjacent energy levels DE, as well as the spin-electron d. at nitrogen atom PpN has good correlation with Z and E constants Furthermore, the rotational correlation time t, the heights of the upfield EPR lines were found to be linearly correlated with the solvent viscosity h.

Key words: PIPERIDINE P, PARAMAGNETIC RESONANCE, SOLVENT EFFECT, NITRO-OXY RADICAL