mu-Squarato-k(2)O(1): O-2-bis{[2-(2-aminoethyl) pyridine-k(2)N,N ']aquanickel(II)} squarate 0.25-hydrate

Abstract

The asymmetric unit of title compound, [Ni-2(C4O4)-(C7H10N2)(4)(H2O)(2)]C4O4 center dot 0.25H(2)O, contains one-half of a squarate ligand, one-half of an uncoordinated squarate dianion, two 2-(2-aminoethyl) pyridine ligands and one aqua ligand, all coordinated to an Ni-II ion. The compound also contains 0.25 solvent water molecules. The Ni-II ion has distorted octahedral geometry. The squarate ligand adopts a mu-1,2 coordination mode, the intradimer Ni-II center dot center dot center dot Ni-II separation being 7.1442 (7) angstrom, while the other squarate unit acts as a counter-anion. The crystal structure is stabilized by intermolecular O - H center dot center dot center dot O and N - H center dot center dot center dot O hydrogen-bond interactions, forming a three-dimensional network.