Generation and Spectroscopic Characterization of Two Persistent Radical Cations from Bissquaraine

Article abstract of DOI:10.1021/j100054a007

The squarine dye bis<4-(dimethylamino)phenyl>squaraine gives a persistent radical cation upon one-electron oxidation in dichloromethane.In the presence of trifluoroacetic acid in high concentration (0.5-1.0 M), a second persistent radical cation is detectable upon oxidation, most likely formed by one-electron loss from a dye species protonated on one oxygen and one nitrogen.Both species were characterized by their UV-vis and EPR spectral properties.