ULTRAVIOLET SPECTROSCOPY OF MONOHYDROXYACRIDINES

In order to interpret the experimental absorption- and fluorescence-polarization spectra of the 1-, 2-, 3- and 4-hydroxyacridine in ethanol (96%) at -183° and the bathochromic colour effect of the 1- and 3-hydroxyacridine in strongly polar solvents (H2O), PPP-calculations were preformed to get information about the changes of the π-electron-density under excitation, oscillator strengths, absolute polarization directions and transition-charge-densities for singlet-transitions. The results are in good agreement with the experimental spectra and allow characterization and classification of the different states and transitions. Furthermore it was affirmed, that the anomal colour changes of the 1- and 3-hydroxyacridine are caused by tautomeric acid-amide structures. © 1969.