Structural characterization of two benzene-1,2-diamine complexes of zinc chloride: a molecular compound and a co-crystal salt

The structures of two zinc complexes containing bidentate benzene-1,2-diamine ligands are reported. (Benzene-1,2-diamine-κ²N,N′)dichloroidozinc, [ZnCl₂(C₆H₈N₂)], (I), displays a distorted tetrahedral coordination sphere for the metal cation. The diamine ligand and the Zn atom reside on a crystallographic mirror plane. In the 1:1 co-crystal salttrans-diaquabis(4,5-dimethylbenzene-1,2-diamine-κ²N,N′)zinc chloride–4,5-dimethylbenzene-1,2-diamine (1/1), [Zn(C₈H₁₂N₂)₂(H₂O)₂]Cl₂·2C₈H₁₂N₂, (II), the zinc(II) complex cation exhibits a tetragonally distorted octahedral coordination sphere. The Zn atom sits on a crystallographically imposed inversion center and the diamine ligands are tilted 30.63 (6)° with respect to the ZnN₄plane. Both complexes exhibit extensive hydrogen bonding. In (I), a stacked-sheet extended structure parallel to (101) is observed. In (II), the co-crystallized diamine is hydrogen-bonded to the complex cationviaO—H...N and N—H...N linkages. These units are in turn linked into planes along (200) by O—H...Cl and N—H...Cl hydrogen bonds.