Fluorescence quenching studies of cyclodextrin complexes of pyrene and naphthalene in the presence of alcohols

Fluorescence quenching of naphthalene- and pyrene-cyclodextrin complexes using iodide ion is examined. A model describing the fluorescence intensity quenching of naphthalene:β-cyclodextrin complexes is proposed and evaluated. This model assumes that cyclodextrin-complexed naphthalene is essentially unquenched by iodide ion. This was found to be true for naphthalene:cyclodextrin complexes in the presence of benzyl alcohol. Pyrene fluorescence lifetime data are presented which support the conclusion that cyclodextrin inclusion complexes in the presence of alcohols are quenched to a significantly lesser extent than in the absence of alcohols.