An Isolation and liquid phase EPR spectra of the cation radical salts of N‐methyl and N‐ethylphenothiazinium perchlorate

N ‐Methyl and N ‐ethylphenothiazines were oxidized with bromine and sodium perchlorate to give stable cation radical salts. Their well‐resolved epr spectra were obtained in nitromethane solution. In order to assign the hfs constants, the cation radicals of N ‐deuteriomethyl and N ‐deuterioethylphenothiazines were prepared with lead tetraacetate and trifluoroacetic acid in solutions.