Heterometallic Ni/Zn amine complexes possessing extended 2D and 3D hydrogen-bonded networks prepared from zinc oxide

Five novel heterometallic Ni/Zn coordination compounds [Ni(en)3][ZnCl4] (1), [Ni(en)(Hea)2][ZnCl4] (2), [Ni(dien)2][ZnCl4] (3), [Ni(en)3][ZnCl4] · 2DMSO (4) and [Ni(en)3][Zn(NCS)4] · CH3CN (5), where en = ethylenediamine (ethane-1,2-diamine), Hea = monoethanolamine (2-aminoethanol) and dien = diethylenetriamine (1,4,7-triazaheptane), have been synthesized by means of the open-air reaction of zinc oxide, nickel chloride (or nickel powder), NH4X (X = Cl, NCS) and ligand (en, dien, Hea) in non-aqueous solvents, such as DMSO, DMF, CH3OH and CH3CN. The choice of a counter-anion in the initial ammonium salt as well as selection of the ligand and solvent provides an effortless approach to the controlled assembly of two- or three-dimensional extended networks assisted by hydrogen bonding. Crystallographic investigations reveal that 1, 2 and 5 possess 3D, while 3 and 4 exhibit 2D H-bonded crystal structures. The structures of the compounds exhibit six-coordinated Ni(II) centers and four-coordinated Zn(II) centers in distorted octahedral and tetrahedral geometries, respectively.