The Polarized Absorption Spectra of Some α-Aminoanthraquinones

The π–π* electronic absorption spectra of 1-amino-, 1,4-diamino-, and 1,4,5,8-tetraaminoanthraquinones were investigated by means of the polarized absorption spectra using stretched PVA sheets and theoretical calculations. Each of these compounds has four absorption bands in the near-ultraviolet region (210–340 nm) and one in the visible region. The bands of the aminoanthraquinones which appear in the visible region can be assigned to the intramolecular charge-transfer transitions associated with the charge migration from the ami no group to the carbonyl groups.