Effects of selected alcohols on cyclodextrin inclusion complexes of pyrene using fluorescence lifetime measurements

Abstract

This study focuses on the Inclusion complexes of γ-cyclodextrin with pyrene as Indicated by fluorescence lifetime measurements and the effects of alcohols on these systems. The pyrene complex has a longer lifetime than free pyrene, yet quenching is observed in the presence of γ-cydodextrin. This apparent conflict is discussed. Also, short-chain alcohols participate In the pyrene/γ-cyclodextrln inclusion complexes producing a longer lifetime of the pyrene complex. This participation is described through evaluation of the lifetime data. The changes in fluorescence lifetime with Increasing cyclodextrin concentration are observed to follow the changes in equilibrium fractions of the pyrene/cyclodextrln system. The study of these systems using fluorescence lifetime measurements yields a method of evaluating this equilibrium and estimating the formation constants for pyrene/cyclodextrln complexes. © 1988, American Chemical Society. All rights reserved.