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

This paper delineates some results on the twisted intramolecular charge transfer (TICT) dynamics of 4-N,N-dimethylamino cinnamaldehyde (DMACA) encapsulated in β-cyclodextrin in aqueous and non-aqueous solvents at room temperature. 4-N,N-Dimethylamino cinnamaldehyde is found to form a 1:1 inclusion complex with β-CD in both aqueous and non-aqueous solvents with a binding constant higher in aqueous solvent. The most important feature of the inclusion complexes of 4-N,N-dimethylamino cinnamaldehyde, as revealed from photophysics of normal and twisted intramolecular charge transfer bands, is that there is a preferential orientation of 4-N,N-dimethylamino cinnamaldehyde inside β-CD cavity in aqueous solvent with dimethyl group sticking outside and in non-aqueous solvents it is just the opposite.