Host-guest complexes : spectroscopic and thermodynamic studies of cyclodextrins-dyes

Department of Chemistry, North-Eastern Hill University, Shillong-793 022, India Manuscript received 24 October 2000 The interactions between hosts α- and β-cyclodextrins and guests phenolphthalein, acridine, 4-(p-N,N-dimethyi-N-amyl)- styrylpyridinium bmmide, azurenc-A, azurene-B and azurene-C have been studied spectroscopically. Spectroscopic and thermodynamic parameters indicate that the interaction between the cyclodcxtrins and the above dyes is weak. β-Cyclodextrin forms relatively stronger complexes with the above dyes. In most of the cases the complexation is enthalpy-controlled rather than entropy-controlled