Square-grid coordination networks of diaquabis(4,4'-bipyridyl)copper(II) crosslinked by hydrogen bonds through two monoanions of 1-benzofuran-2,3-dicarboxylic acid and five molecules of water.

The title compound, poly[[[diaquacopper(II)]-di-mu-4,4'-bipyridyl] bis(3-carboxy-1-benzofuran-2-carboxylate) pentahydrate], {Cu(C(10)H(8)N(2))(2)(H(2)O)(2)(2).5H(2)O}(n), crystallizes in a single-framework architecture. It is composed of two-dimensional square-grid coordination networks of 1:2:2 copper-4,4'-bipyridine-water units, wherein each copper ion coordinates equatorially to four bipyridyl units and axially to two water ligands. The polymeric nets are intercalated by layers of the benzofurandicarboxylic acid monoanions and additional water species. An extensive array of hydrogen bonds interlinks the various components of the structure. The Cu atom and the bipyridyl entities are located on axes of twofold rotation. This study confirms the preferred monoanionic nature of the benzofurandicarboxylic acid molecule. It reveals a rarely observed extended coordination polymer composed only of copper ions and bipyridyl linkers, and an interesting hydrogen-bonding connectivity between the polymeric layers aided by the benzofurandicarboxylic acid and water components intercalated in the structure.