Inclusion complexation of phenoxyaliphatic acid derivatives of 3,3'-bis(indolyl)methanes with β-cyclodextrin.

The inclusion complexation behavior of phenoxyaliphatic acid derivatives of 3,3'-bis(indolyl)methane (BIMs 1-5) with β-cyclodextrin (β-CD) were investigated in both solution and solid state by means of UV-Visible, fluorescence spectroscopy, FT-IR and (1)H NMR techniques. The nature of the host-guest inclusion complex between BIMs and β-CD has been elucidated. The experimental results confirmed the existence of 1:1 inclusion complex of BIMs with β-CD. The binding constants describing the extent of formation of the complexes have been determined using Benesi-Hildebrand plots using UV-Vis and fluorescence spectroscopy. BIMs exhibited an affinity for β-CD. The spectral studies suggested the phenyl ring along with alkyl substitutions of BIMs is present inside of β-CD cavity.