Spectroscopic Studies of the Interaction of Tert-Butylamine and n -Propylamine with the β -Cyclodextrin: Pyrene Complex

The influence of amines on the aqueous beta-cyclodextrin ( β-CD): pyrene complex with the use of steady-state fluorescence measurements is examined. A 2:1 β-CD:pyrene complex is reported in the presence of either tert-butylamine (TBA) or n-propylamine (PA). At low amine concentrations, the role of the amine is to shield pyrene from the bulk aqueous phase. However, at higher TBA concentrations, there exists a competitive equilibrium between the amine and pyrene for the β-CD cavity. The formation constants for the various complexes in the presence of either amine were estimated to be of comparable order of magnitude.