Abstract: The resonance Raman spectra of phenothiazine radical cation, phenothiazine dication and phenoxazine dication have been recorded, which have been formed by chemical oxidation of their parent compounds with Br_2 or Pb(Ac)_4. The bands of CNC and CSC skeletal deformations show the most enhancement and large positive shifts from the corresponding parent after one or two electrons are subtracted from phenothiazine. The number of bands in ring C=C stretching frequency range are increased obviously in the spectrum of phenothiazine dication. The spectral data reveal that the degree of fold along the S—N axis vanishes and a greater aromatic resonance structure comes into being with the loss of two electrons in phenothiazine. The spectrum of phenoxazine dication is more similar to that of its parent, which shows that the loss of electrons in phenoxazine leads to less structureal change compared with phenothiazine.

Key words: Phenoxazine, Phenothiazine, Resonance Raman spectra