Crystal structure of trans-(1, 8-dibutyl-1, 3, 6, 8, 10, 13-hexaazacyclotetradecane-κ⁴N³,N⁶,N¹⁰,N¹³)bis(5-methyltetrazolato-j N)-nickel(II) from synchrotron data

The structure of the title compound, [Ni(C₂H₃N₄)₂(C₁₆H₃₈N₆)], has been characterized from synchrotron radiation. The asymmetric unit consists of one half of the Ni^II complex molecule, which is related to the other half-molecule by an inversion center. The Ni^II ion is coordinated by four secondary N atoms of the macrocyclic ligand in a square-planar fashion in the equatorial plane and by two N atoms of the 5-methyltetrazolate anions in axial positions, resulting in a tetragonally distorted octahedral geometry. The average equatorial Ni - N bond length [2.060 (8) Å] is shorter than the axial Ni - N bond length [2.2183 (11) Å]. An intramolecular N - H⋯N hydrogen bond between the secondary amine N atom of the macrocyclic ligand and the non-coordinating N atom of the 5-methyltetrazolate ion stabilizes the molecular structure. Moreover, an inter-molecular N - H⋯N hydrogen bond between the macrocyclic ligand and 5-methyltetrazolate group gives rise to a supramolecular sheet structure parallel to the bc plane.