A theoretical study on the inclusion complexation of cyclodextrins with inorganic cations and anions

PM3 and B3LYP/3-21+g(d) calculations were performed on the inclusion complexation of alpha- and beta-cyclodextrin with inorganic cations and anions including Li+, Na+, F-, and Cl-. Both the gas-phase interaction and solvent effect were taken into consideration. The CD complex with an anion was more stable than that with a cation, which was in agreement with the experimental findings. It was proposed that hydrogen bonding between the anion and the cyclodextrin cavity was the physical origin of such behavior.