INFLUENCE OF ALCOHOL ADDITION ON THE GAMMA-CD-PYRENE COMPLEX

The interaction of gamma-cyclodextrin (CD) with pyrene in the presence of different linear, branched, and cyclic alcohols is reported. In the presence of gamma-CD, the fluorescence emission spectra of pyrene showed only the monomer emission. The 1:1 stoichiometry between gamma-CD and pyrene has been confirmed in the presence of the alcohols examined. Apparent formation constants were calculated by using the variation in the I/III vibronic and ratio of pyrene and nonlinear regression analysis. The apparent formation constants increased dramatically in the presence of the alcohols. Of all the alcohols examined, cyclohexanol produced the largest enhancement in the apparent formation constant (a 37-fold increase). The present work suggests that the role of the alcohol in the gamma-CD:pyrene complex is somewhat different than recently reported for the beta-CD:pyrene complex.