Fluorescence Behavior of 7-Substituted Coumarin Derivatives by Inclusion Complexation with β-Cyclodextrin

Abstract

The inclusion complexes of 7-substituted coumarin derivatives (7-hydroxy-, 7-amino-, 7-dimethylamino-, 7-methoxy-, and 7-ethoxy-4-methylcoumarins) with β-cyclodextrin in aqueous solutions were formed. The equilibrium constants of these complexes were obtained by fluorescence and circular dichroism spectrophotometric methods. Fluorescence enhancement or quenching was observed upon inclusion of coumarin derivatives with β-cyclodextrin. The fluorescent behavior was discussed from the standpoint of the solvent effect of coumarin derivatives and of the geometry of the inclusion complexes assumed from their ¹H nuclear magnetic resonance spectra.