Modulation of photophysics due to orientational selectivity of 4-N,N-dimethylamino cinnamaldehyde beta-cyclodextrin inclusion complex in different solvents

This paper delineates some results on the twisted intramolecular charge tra nsfer (TICT) dynamics of 4-N,N-dimethylamino cinnamaldehyde (DMACA) encapsu lated in beta -cyclodextrin in aqueous and non-aqueous solvents at room tem perature. 4-N,N-Dimethylamino cinnamaldehyde is found to form a 1:1 inclusi on complex with beta -CD in both aqueous and non-aqueous solvents with a bi nding constant higher in aqueous solvent. The most important feature of the inclusion complexes of 4-N,N-dimethylamino cinnamaldehyde, as revealed fro m photophysics of normal and twisted intramolecular charge transfer bands, is that there is a preferential orientation of 4-N,N-dimethylamino cinnamal dehyde inside beta -CD cavity in aqueous solvent with dimethyl group sticki ng outside and in non-aqueous solvents it is just the opposite. (C) 2000 El sevier Science B.V. All rights reserved.