The weak interaction inclusion complex 1 with thymol included in the hydrophobic cavity of β-cyclodextrin, was synthesized and characterized. Its binding behavior was investigated by means of X-ray crystallography and NMR spectroscopy in solution and in the solid state. The crystallographic study has been shown that the inclusion complex 1 forms channel-type supramolecule. The solid state structure indicates that the inclusion complex consists of a head-to-head dimer of β-cyclodextrin formed by hydrogen bonding across the secondary hydroxyl faces of the adjacent β-cyclodextrin molecule, with one guest molecule in each β-cyclodextrin cavity. Furthermore, the studies of 2D NMR spectra indicate that the thymol molecule is embedded in the β-cyclodextrin cavity to form host-guest inclusion complex in aqueous solution.

Key words: β-cyclodextrin, thymol, inclusion complex, crystal structure, supramolecule