Binding of N-substituted anthracenecarboxamides to double-stranded DNA: an electronic spectral study

The electronic absorption and fluorescence spectra of two isomeric anthracenecarboxamides substituted with quaternary alkyl ammonium groups were studied as a function of solvent polarity, solvent rigidity, and state of protonation. These relatively simple environmental perturbations of the electronic spectra were employed to interpret spectral shifts caused by complexation with the bases or base pairs of DNA. The exocyclic side chains of the compounds studied have some freedom of movement when the spectroscopic probes are bound to double-stranded DNA.