Substitution of a Fluorine Atom in Perfluorobenzonitrile by a Lithiated Nitronyl Nitroxide

A 4,4,5,5-tetramethy1-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (1) lithium derivative was found to react with perfluorobenzonitrile (2) substituting its para-fluorine atom to form 2-(4-cyanotetrafluoropheny1)4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-okide-l-okyl (3), a new nitronyl nitroxide containing a multifunctional framework of strong electron withdrawing nature. This result shows the,possibility of obtaining Multifunctional nitronyl nitroxides via the interaction of paramagnetia-litbium derivatives as C-nucleophiles with polyfluoroarenes activated for nucleophilic substitution. The reaction regioselectivity is supported by the data of quanturn-chemical Calculations, which also show that the reaction follows, a Concerted pathway without formation of an intermediate, Reduction of nitronyl nitroxide 3 in system NaNO2-AcOH yielded corresponding iminonitroxide 4. Characterization of persistent radicals 3 and 4 obtained. by the SNP, synthetic. strategy includes X-ray-crystal structures, electron spin resonance data, and static magnetic-susceptibility measurements. X-ray diffraction analysis of both nitronyl nitroxide and iminonitroxide revealed a complete match of the parameters of their crystal lattices.