Spectroscopic studies of inclusion complexes of 1-naphthol-4-sulfonate with β-cyclodextrin in aqueous solution

The photophysical properties of 1-naphthol-4-sulfonate (1N4S) in some solvents and in aqueous β-cyclodextrin solution have been investigated. The effect of β-cyclodextrin on the fluorescence quantum yield and on the proton transfer is examined. Fluorescence measurements show 1:1 inclusion of 1N4S in the β-cyclodextrin cavity with an association constant of 108 M−1. NMR studies are used to study the inclusion phenomena and to provide information on the geometry of 1N4S inside the cavity of β-cyclodextrin.