Studies on the inclusion complexation between intramolecular charge transfer probe trans-ethyl p-(dimethylamino) cinamate and β-cyclodextrin in presence of ionic and nonionic surfactants

The intramolecular charge transfer (ICT) fluorescence of trans-ethyl p-(dimethylamino) cinamate (EDAC) is used to monitor the complexation behavior of this probe with surfactants/β-CD by steady state and picosecond time-resolved fluorescence spectroscopy. The ICT fluorescence band intensity was found to increase with concomitant blue shift in presence of surfactants/β-CD. The encapsulation behavior was further characterized by increase in emission yield as well as lifetime values. Detailed analyses of the spectroscopic data indicate that the probe forms 1:1 complex with β-CD in aqueous medium. However, in presence of surfactants, 1:1 complex is formed below the critical micelle concentration (cmc) value; whereas, 1:2 complexes are formed under fully micellized condition.