Effect of metal coordination environment on topology of coordination polymers containing 2,5-thiophenedicarboxylate and long-spanning dipyridine ligands

Hydrothermal reaction of a metal nitrate, 2,5-thiophenedicarboxylic acid (H2tpdc), and bis(4-pyridylmethyl)piperazine (4-bpmp) afforded a series of crystalline coordination polymers with different dimensionality and topology depending on the metal coordination geometry. These materials were characterized by single-crystal X-ray diffraction. [Cu(tpdc)(4-bpmp)(H2O)]n (1), with square pyramidal coordination, shows parallel stacked (4,4) grid motifs. {[Co(tpdc)(4-bpmp)1.5(H2O)2]·4H2O}n (2) exhibits graphitic (6,3) honeycomb layer motifs and octahedral coordination at the metal. {[Cd(tpdc)(4-bpmp)(H2O)]·H2O}n (3) shows pentagonal bipyramidal geometry and manifests (4,4) grid layers as in 1, but with 2D + 2D → 3D parallel entanglement. [Zn(tpdc)(4-bpmp)(H2O)]n (4), which has distorted “5 + 1” octahedral coordination at zinc, displays an acentric 66 3-D diamondoid topology. Luminescent properties of 3 and 4 are presented, along with thermal analyses.