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

The asymmetric unit of the title compound, -poly[[[(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ , , , )nickel(II)]-μ-cyanido-κ :-[bis-(cyanido-κ)nickel(II)]-μ-cyanido-κ :] dihydrate], {[Ni(CN)(CHN)]·2HO] or [{[Ni(CHN)][Ni(CN)]}·2HO] , 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 -III conformation, and the mutually N atoms of the tetra-cyano-nickelate anion in a slightly tetra-gonally distorted NiN octa-hedral coordination geometry. The [Ni(CN))] 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⋯O (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 O-H⋯N (c = cyanide) hydrogen bonds, giving two-dimensional layers oriented parallel to the (100) plane and thus generating a three-dimensional network.