Chemistry of the phenoxathiins and isosterically related heterocycles. XX. Assignment of the 13C-NMR spectra of phenarsazine-10-chloride and several substituted analogs. The effect of substitution on the anisotropic reorientation of the phenarsazine system

The total assignment of the ¹³C-nmr spectra of phenarsazine-10-chloride and several substituted analogs is reported. Spin-lattice (T₁) relaxation measurements have shown these systems to reorient anisotropically. In the case of the parent system and the 3-chloro substituted system, the axis of anisotropic reorientation has been shown to pass approximately through the center of the molecule. In the case of benzo[c]phenarsazine-7-chloride, the axis of anisotropic reorientation, which has been accurately defined, is shifted 23° from that in the previous cases, the shift occurring in the direction of the benzo-moiety.