Crystal structure of [{[Ni(C10H24N4)][Ni(CN)4]}·2H2O] n , a one-dimensional coordination polymer formed from the [Ni(cyclam)]2+ cation and the [Ni(CN)4]2- anion.

The asymmetric unit of the title compound, catena-poly[[[(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ4 N 1,N 4,N 8,N 11)nickel(II)]-μ-cyanido-κ2 N:C-[bis-(cyanido-κC)nickel(II)]-μ-cyanido-κ2 C:N] dihydrate], {[Ni2(CN)4(C10H24N4)]·2H2O] n or [{[Ni(C10H24N4)][Ni(CN)4]}·2H2O] n , consists of a pair of crystallographically non-equivalent macrocyclic cations and anions. The nickel(II) ions (all with site symmetry ) are coordinated by the four secondary N atoms of the macrocyclic ligands, which adopt the most energetically stable trans-III conformation, and the mutually trans N atoms of the tetra-cyano-nickelate anion in a slightly tetra-gonally distorted NiN6 octa-hedral coordination geometry. The [Ni(CN)4)]2- anion exhibits a bridging function, resulting in the formation of parallel polymeric chains running along the [10] direction. The water mol-ecules of crystallization play a pivotal role in the three-dimensional supra-molecular organization of the crystal. Acting as acceptors, they form N-H⋯Ow (w = water) hydrogen bonds with the secondary amino groups of the macrocycles, forming layers oriented parallel to the (001) plane. At the same time, as donors, they inter-act with the non-coordinated cyano groups of the anion via Ow-H⋯Nc (c = cyanide) hydrogen bonds, giving two-dimensional layers oriented parallel to the (100) plane and thus generating a three-dimensional network.