catena-Poly[[[(di-2-pyridylamine-κ2N2,N2')copper(II)]-μ-benzene-1,3-dicarboxylato-κ3O1,O1':O3] monohydrate], a zigzag coordination polymer with strong π-π interactions.

The novel title coordination polymer, {[Cu(C(8)H(4)O(4))(C(10)H(9)N(3))]·H(2)O}(n), synthesized by the slow-diffusion method, takes the form of one-dimensional zigzag chains built up of Cu(II) cations linked by benzene-1,3-dicarboxylate (ipht) anions. An exceptional characteristic of this structure is that it belongs to a small group of metal-organic polymers where ipht is coordinated as a bridging tridentate ligand with monodentate and chelate coordination of individual carboxylate groups. The Cu(II) cation has a highly distorted square-pyramidal geometry formed by three O atoms from two ipht anions and two N atoms from a di-2-pyridylamine (dipya) ligand. The zigzag chains, which run along the b axis, further construct a three-dimensional metal-organic framework via strong face-to-face π-π interactions and hydrogen bonds. A solvent water molecule is linked to the different carboxylate groups via hydrogen bonds. Thermogravimetric and differential scanning calorimetric analyses confirm the strong hydrogen bonding.