Copper(II) and Zinc(II) coordination polymers based on glutaric acid and 1,2-bis(4-pyridyl)ethylene: Hydrothermal synthesis, characterization and thermal behaviors

Abstract

1,2-bis(4-pyridyl)ethylene (dpe) and glutaric acid (H2glu) with Cu(II) and Zn(II) afforded two coordination polymers namely, [Cu(µ3-glu)(µ-dpe)]n (1) and [Zn(µ3-glu)(µ-dpe)0.5]n (2), and they were characterized by elemental analysis, IR spectroscopies, single crystal X-ray diffraction and powder X-ray diffraction (PXRD) techniques. X-ray diffraction studies have shown that complex 1 crystallizes in the triclinic system, in the P-1 space group, while complex 2 crystallizes in the C2/c space group in the monoclinic system. In complexes 1 and 2, the glu ligand adopts tetradentate coordination mode that one carboxylate group bidentate, other carboxylate group bis(monodentate)-bridging. Complex 1 displayed 2D network with {44.62} point symbol and sql topology which is extended into a 3D supramolecular framework by C−H⋯O hydrogen bonds interactions. Complex 2 featured a 3D network that two identical 3D self-penetrating frameworks interpenetrate each other in a 2-fold (3D+3D →3D) mode, with a pcu; 6/4/c1; sqc1 topology with the point symbol of {412.63}. The optical band gap energy values calculated by the Kubelka–Munk function for 1 and 2 observed at 3.20 and 3.24 eV, respectively. Moreover, the thermal properties of the complexes were investigated in the study.