The Crystal Structure and Intermolecular Interactions in Fenamic Acids-Acridine Complexes.

In order to improve pharmaceutical properties of drugs, complexes are synthesized as combinations with other chemical substances. The complexes of fenamic acid and its derivatives, such as mefenamic-, tolfenamic- and flufenamic acid, with acridine were obtained and the X-ray structures were discussed. Formation of the crystals is determined by the presence of the intermolecular O-H…N hydrogen bond that occur between fenamic acids and acridine. Intermolecular interactions stabilizing the crystals such as π…π stacking, C-H…X (X = O, Cl) intermolecular hydrogen bonds as well as C-H…π and other dispersive interactions were analyzed by theoretical methods: the quantum theory of atoms in molecules (QTAIM) and noncovalent interaction (NCI) approaches.