SPECTROSCOPIC STUDIES OF INCLUSION OF 4H-1-BENZOPYRAN-4-THIONE IN A BETA-CYCLODEXTRIN CAVITY

Spectral and photophysical properties of 4H-1-benzopyran-4-thione (BPT ) in aqueous solutions of beta-cyclodextrin (beta-CD) and in some solv ents have been investigated by stationary methods. Both fluorescence a nd phosphorescence of BPT are observable at room temperature. Results indicate the formation of an inclusion complex. Spectral shifts in the absorption spectrum and the shape of the phosphorescence spectrum mos tly depend on the polarity of environment whereas the photophysical pr operties of the second excited singlet state depend on other structura l properties of the medium, which allows us to investigate interaction s between water molecules and complexed molecules. These properties ma ke BPT a very convenient probe in the investigation of photophysics of inclusion complexes. (C) 1997 Elsevier Science B.V.