ESR spectroscopy of flow-oriented cation radicals of phenothiazine derivatives and phenoxathiin intercalated in DNA.

Several derivatives of the phenothiazine cation radicals intercalated into DNA have been investigated using a new flow orientation technique. The anisotropic hyperfine coupling constants of both the parallel and the perpendicular orientation relative to the magnetic field were measured and compared to previous results, which used different techniques. The phenoxathiin cation radical could also be stabilized by intercalation into DNA at pH 4, but the orientation technique revealed no further information due to the poor resolution of the experimental spectra.