Structure of the inclusion complex of beta-cyclodextrin with lipoic acid from laboratory powder diffraction data

The crystal structure of the inclusion complex of beta-cyclodextrin with lipoic acid was determined from laboratory powder diffraction data. Thermogravimetric data was used to estimate the number of water molecules in the crystal structure. Lipoic acid is included in beta-cyclodextrin through its primary face with the five-membered ring reaching the center plane of the cyclodextrin cavity and its fatty acid chain adopting a bent conformation. Lipoic acid and beta-cyclodextrin form a channel-like packing which is stabilized by guesthost hydrogen bonding and close contacts, host-host intermolecular interactions and hydrogen bonding involving the water molecules.