Two metal–organic coordination polymers assembled from a flexible iodo-dicarboxylate ligand and N-donor ancillary ligands

Two metal–organic coordination polymers, namely, {[Zn(L)(4,4′-bpy)1.5(H2O)]·H2O}n (1) and [Zn(L)(bpe)]n (2), have been hydrothermally synthesized through the reaction of 5-iodo-benzene-1,3-dioxyacetic acid (H2L) with divalent zinc salts in the presence of ancillary nitrogen ligands (4,4′-bpy = 4,4′-bipyridine, bpe = 1,2-bis(4-pyridyl)ethylene) and structurally characterized by elemental analysis, IR and X-ray diffraction. Complex 1 shows a metal–organic chain structure, the adjacent chains are further linked by hydrogen bonds and C−I⋯O halogen bonding to form a 3D supramolecular structure. Compound 2 contains interesting threefold parallel interpenetrated two-dimensional (2D) → two-dimensional (2D) network motifs which are united together to yield a 3D supramolecular structure through inter-layer C−H⋯O interactions. In addition, thermal analysis and photoluminescent properties of the complexes have also been investigated.