Molecular geometry of antimalarial amodiaquine in different crystalline environments

The crystal structures of antimalarial drug amodiaquine in the form of its free base and two salts, dihydrochloride monohydrate and tetrachlorocobaltate(II), were determined with X-ray single crystal diffractometry. Their conformations and intermolecular interactions are compared to those found in the crystalline amodiaquine dihydrochloride, postulated to contain hydroxyl anion, and in the powder amodiaquine dihydrate dihydrochloride. The molecular structures of the amodiaquine cation and its free base were optimized by the B3LYP calculations and compared to those observed in the crystalline state.