catena-Poly[[[(2,2'-bipyridine-κN,N')cobalt(II)]-μ-(E)-3,3'-(but-2-ene-2,3-di-yl)dibenzoato-κO,O':O'',O'''] hemihydrate].

The title coordination polymer, {[Co(C(18)H(14)O(4))(C(10)H(8)N(2))]·0.5H(2)O}(n), features a helical polymeric chain that runs along the b axis. The Co atoms are chelated by the carboxyl-ate groups of two 3,3'-(but-2-ene-2,3-di-yl)dibenzoate ligands and the N atoms of a 2,2'-bipyridine ligand. The lattice water mol-ecule is disordered about a center of inversion and is connected to the chain by an O-H⋯O hydrogen bond. The Co(II) atom shows a distorted octa-hedral coordination.