Synthesis, characterization and crystal structure of [Ni(DACH)2](H2O)2(CH3COO)2 (DACH = 1,4-diazacycloheptane): a three-dimensional (3-D) hydrogen-bonded network embodying 1-D water chains

The mononuclear complex [Ni(DACH)2](H2O)2(CH3COO)2 (DACH = 1,4-diazacyclo-heptane) has been synthesized and characterized by IR, UV-Vis, elemental analysis and single crystal X-ray diffraction. The complex crystallizes in monoclinic system, P21/n space group with a=7.500(3) Å, b=8.788(3) Å, c=16.429(6) Å, β=93.395(5)°, Dc=1.269 g cm−3, μ=0.930 mm−1, V=1080.9(6) Å3, Z=2. The central NiII atom is in a square-planar coordination geometry formed by four N atoms of two DACH chelated ligands. The notable feature of the title compound resides in the formation of a three-dimensional network through hydrogen bonds between the [Ni(DACH)2]2+ cations, the CH3COO− counter anions and the guest water molecules trapped in the crystal lattice.