μ-Squarato-κO:O-Bis-{[2-(2-Amino-Ethyl)pyridine-κN,N']aqua-Nickel(II)} Squarate 0.25-Hydrate

Abstract

The asymmetric unit of title compound, [Ni2(C4O4)(C7H10N2)4(H2O)2] C4O4·0.25H2O, contains one-half of a squarate ligand, one-half of an uncoordinated squarate dianion, two 2-(2-amino-ethyl)pyridine ligands and one aqua ligand, all coordinated to an NiII ion. The compound also contains 0.25 solvent water mol-ecules. The NiII ion has distorted octa-hedral geometry. The squarate ligand adopts a -1,2 coordination mode, the intra-dimer NiII⋯NiII separation being 7.1442 (7) Å, while the other squarate unit acts as a counter-anion. The crystal structure is stabilized by inter-molecular O - H⋯O and N - H⋯O hydrogen-bond inter-actions, forming a three-dimensional network.