A Dinuclear Nickel(II) Compound: μ-{N,N,N',N'-Tetrakis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]-1,2-ethylenediamine}-bis[aqua(nitrato-O,O')nickel(II)] Dinitrate Dimethanol Solvate

The title compound, [Ni₂(NO₃)₂(C₃₀H₄₈N₁₀)(H₂O)₂](NO₃)₂.2CH₃OH, contains a doubly charged cation which lies across an inversion center. The hexadentate ligand N,N,N',N'-tetrakis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]-1,2-ethylenediamine (tped) holds two Ni^II ions at a distance of 6.3721 (13) Å. A distorted octahedron around each Ni^II ion is defined by two pyrazole N atoms of tped at 2.023 (4) and 2.048 (4) Å, one amine N atom of tped at a distance of 2.161 (4) Å, two O atoms of a chelating nitrate anion at distances of 2.144 (3) and 2.205 (4) Å, and a water O atom at 2.032 (4) Å. A one-dimensional hydrogen-bonding network running along the a axis connects the methanol molecule of crystallization to the nitrato and aqua ligands of different cations, and an aqua ligand to the non-coordinated nitrate ion. The structure is essentially isomorphous with the previously reported Cu^II analog [Driessen, Haanstra & Reedijk, (1992). Acta Cryst. C48, 1585–1587], the main differences being that NO₃ is involved in bidentate coordination to Ni^II and in a bifurcated hydrogen bond with methanol, whereas in the Cu^II complex, it is monodentate and only one of its O atoms hydrogen bonds to methanol.

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