Synthesis and crystal structure of 1,2,3,4-tetrahydro-9-aminoacridine tetrachlorozincate(II) monohydrate

In the reaction of ZnCl2 with tacrine hydrochloride in water novel tetracoordinated (C13H15N2)2(ZnCl4)⋅H2O complex was obtained and charac- terized by elemental analysis, molar conductivity and X-ray analysis. The com- plex crystallizes in the space group P−1 of the triclinic crystal system. The structure contains two crystallographically different molecules of protonated tacrine present as counter cations, the (ZnCl4) 2- complex anion and one water solvent molecule. The counter cations slightly differ in the puckering of the cyclohexene ring. The molecules of protonated tacrine are involved in different intermolecular hydrogen bonds. In the crystal, the hydrogen bonding generates a 3D assembly. In the crystal, π⋅⋅⋅π stacking interactions between the rings of protonated tacrine were evidenced. The (ZnCl4) 2- complex anion has a dis- torted tetrahedral geometry. Three out of the four Cl atoms are involved in intermolecular hydrogen bonding. The intermolecular H-bond interactions in- volving the Cl atoms affect the Zn-Cl bond lengths.