Imine-Benzoic Acid Co-crystals as a Tool to Study Intermolecular Interactions in Schiff Bases

Through experimental and computational studies we were able to prove that the hydrogen atom of the imine group forms structurally relevant CC H· · · F hydrogen bonds, and that the fluorine atoms in the benzene ring of the molecule promote the π · · · π stacking interactions of the molecules, making this late interaction the primary tool to organize the molecules in the crystal. To extend the boundaries of single-crystal structural studies we synthesized crystals of perfluorophenyl-4-pyridinylmethanimine, 1, and co-crystals with diverse benzoic acids. We selected 1 because it is a small molecule that can form π interactions, hydrogen and halogen bonds without any steric interference among them.