Crystal structure of a binuclear nickel(II) complex of 1,4-dihydrazinophthalazine

The structure of a 1 : 1 complex between nickel chloride and 1,4-dihydrazinophthalazine, [Ni(C8H10N6)(H2O)2]2-Cl4,2H2O, has been determined by three-dimensional single-crystal X-ray methods. The purple crystals are triclinic, space group P, with a= 7·51, b= 8·77, c= 11·97 Å, α= 107·6, β= 99·8, and γ= 91·3°. The unit cell contains a single centrosymmetric cation in which both ring nitrogen atoms and both amino-groups of two dihydrazinophthalazine molecules are chelated to two Ni2+ ions in a nearly planar arrangement with a Ni–Ni distance of 3·79 Å. Approximately octahedral co-ordination of the nickel ions is completed by four water molecules, the remaining two water molecules and the four chloride ions being outside the co-ordination sphere. The Ni–N bond-lengths are ca. 2·08 Å and the Ni–O bond-lengths 2·16 Å.