Crystal structure of a Cu(II) complex with a bridging ligand: poly[[penta­kis­[μ(2)-1,1′-(butane-1,4-di­yl)bis­(1H-imidazole)-κ(2) N (3):N (3′)]dicopper(II)] tetranitrate tetra­hydrate]

A novel two-dimensional→three-dimensional Cu(II) coordination polymer, {[Cu(2)(C(10)H(14)N(4))(5)](NO(3))(4)·4H(2)O}(n), based on the 1,1′-(butane-1,4-di­yl)bis­(1H-imidazole) (biim) ligand and containing one crystallographically unique Cu(II) atom, has been synthesized under hydro­thermal conditions. The Cu(II) atom is coordinated by five N atoms from biim ligands, one of which has crystallographically imposed inversion symmetry, giving rise to a slightly distorted CuN(5) square-pyramidal geometry. The Cu(II) cations are linked by biim ligands to give a 4(4) layer; the layers are further bridged by biim ligands, generating a double sheet with a thickness of 14.61 Å. The sheet features rhombic Cu(4)(biim)(4) windows built up from four Cu(II) centers and four biim ligands with dimensions of 14.11 × 14.07 Å(2). Each window of a layer is penetrated directly by the biim ligand of the adjacent net, giving a two-dimensional→three-dimensional entangled framework.