Synthesis and crystal structure of catena-poly[[hexa-aqua{μ(3)-2-[bis-(carboxyl-atometh-yl)amino]-terephthalato}dicobalt(II)] penta-hydrate] containing water tapes and penta-mers.

The title coordination polymer, {[Co(2)(C(12)H(7)NO(8))(H(2)O)(6)]·5H(2)O} (n) , was crystallized at room temperature from an aqueous solution of 2-aminodi-acetic terephthalic acid (H(4)adtp) and cobalt(II) nitrate. The asymmetric unit consists of one adtp(4-) ligand, one and two half Co(II) ions, six water ligands coordinated to Co(II) ions and five uncoordinated water mol-ecules. Two of the cobalt cations lie on centres of inversion and are coordinated in octa-hedral O(2)(OH(2))(4) environments, whereas the other adopts a slightly distorted octa-hedral NO(3)(OH(2))(2) environment. The crystal structure contains parallel stacked, one-dimensional zigzag chains, {[Co(2)(C(12)H(7)NO(8))(H(2)O)(6)]} (n) , which assemble into a three-dimensional supra-molecular architecture via networks of hydrogen bonds involving the coordinated and free water mol-ecules. One-dimensional 'water tapes' are formed, containing alternating six-membered and twelve-membered rings of water mol-ecules, together with water penta-mers, in which a central uncoordinated water mol-ecule is hydrogen bonded to two coordinated and two free water mol-ecules in a tetra-hedral arrangement.