Investigation on association behavior between 1-Aminoisoquinoline and β-Cyclodextrin in solution and solid state

The interaction between 1-Aminoisoquinoline (AIQ) and (beta-Cyclodextrin (beta-CD) has been studied by absorption, steady state and time-resolved fluorescence spectroscopy and results showed that the enhancement of absorbance and fluorescence intensity occurs together with inclusion complex formation. The bi-exponential decay observed for the neutral form of AIQ during the addition of beta-CD is due to the formation of the inclusion complex between AIQ and beta-CD. The binding constant values and stoichiometry of the inclusion complex of AIQ:beta-CD at pH 7.0 and pH 1.1 are calculated using Benesi-Hildebrand plot In addition, the FT-IR spectra and SEM images of the solid complex are also discussed along with the physical mixture of AIQ and beta-CD. The ground and excited state acidity constants of AIQ in aqueous and beta-cp media are calculated. Based on the acidity constant values, the structure of the inclusion complex between AIQ and beta-CD has been proposed. Crown Copyright (C) 2016 Published by Elsevier B.V. All rights reserved.