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

In the reaction of ZnCl(2) with tacrine hydrochloride in water novel tetracoordinated (C(13)H(15)N(2))(2)[ZnCl(4)]-H(2)O complex was obtained and characterized by elemental analysis, molar conductivity and X-ray analysis. The complex 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 [ZnCl(4)](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, pi center dot center dot center dot pi stacking interactions between the rings of protonated tacrine were evidenced. The [ZnCl(4)](2-) complex anion has a distorted tetrahedral geometry. Three out of the four Cl atoms are involved in intermolecular hydrogen bonding. The intermolecular H-bond interactions involving the Cl atoms affect the Zn-CI bond lengths.