ESR Studies on N-Alkylphenothiazine Radical Cation Salts

he stable radical cation salts of phenothiazine and N-alkyl-phenothiazine(alkyl =methyl , ethyl , isohutyl , isopentyl and benzyl) hexachloroantimonate ,per-chlorate , and iodide were prepared by means of one-electron oxidation with 2 ,2 , 6 ,6-tetramethyl- 4-acetoxypiperidine oxoammonium hexachloroantimonate , perchloricacid, hydrogen peroxide, and molecular iodine, respectively. The radical cationswere characterized using ESR spectroscopy. Conformational analysis based on theESR parameters suggests that the radical cations adopt a planar configuration withthe nitrogen radical as the center.