Influence of Triethanolamine on Aqueous β-Cyclodextrin/Pyrene Complexes

Abstract

The influence of triethanolamine (TEA) on the aqueous β-CD/pyrene fluorescence is examined. Collisional quenching of pyrene by TEA is indicated by Stern-Volmer plots. However, a decrease in the quenching is observed in the presence of β-cyclodextrin, which indicates an effective protection of the included pyrene molecules against quenching from TEA. A decrease in the apparent formation constant of the β-CD/pyrene complex also occurs in the presence of TEA. This phenomenon is attributed to a combination of an increased bulk solvent hydrophobicity and a competitive equilibrium between pyrene and TEA for the β-CD cavity. The present study indicates that TEA is not co-included in the β-CD/pyrene complex.