catena-Poly[[tetraaquanickel(II)]-μ-(9,10-dioxo-9,10-dihydroanthracene-1,4,5,8-tetracarboxylato)-κ2O1:O8-[tetraaquanickel(II)]-μ-4,4′-bipyridine-κ2N:N′]

Abstract

In the crystal of the title polymeric complex, [Ni2(C18H4O10)(C10H8N2)(H2O)8]n, each NiII cation is coordinated by four water molecules in the equatorial plane, and is further bridged by an 9,10-dioxo-9,10-dihydroanthracene-1,4,5,8-tetracarboxylate anion and a 4,4′-bipyridine ligand in the axial directions, forming a distorted octahedral geometry. The 9,10-dioxo-9,10-dihydroanthracene-1,4,5,8-tetracarboxylate anion is centrosymmetric with the centroid of the quinone ring located about an inversion center; the 4,4′-bipyridine ligand is also centrosymmetric with the mid-point of the C—C bond linking two pyridine rings located about another invertion center. The 9,10-dioxo-9,10-dihydroanthracene-1,4,5,8-tetracarboxylate anion and bypiridine ligand bridge the NiII cations, forming a polymeric chain along the b axis. π–π stacking is observed between pyridine and benzene rings [centroid–centroid distance = 3.705 (2) Å]. All of the coordinating water molecules are involved in O—H...O hydrogen bonding.