Zinc(II) and cadmium(II) coordination polymers containing phenylenediacetate and 4,4′-azobis(pyridine) ligands: Syntheses, structures, dye adsorption properties and molecular dynamics simulations

Abstract

Two new coordination polymers (CPs) – [Zn(µ4-ppda)(µ-abpy)0.5]n(1) and [Cd(μ3-opda)(µ-abpy)0.5(H2O)]n(2) (o/ppda = 1,2/1,4-phenylenediacetate, abpy = 4,4′-azobis(pyridine)) – have been synthesized by using Zn(II)/Cd(II) salts in the presence of o- and p-phenylenediacetic acid and abpy under hydrothermal conditions. Their structures have been characterized by FT-IR spectroscopy, elemental analysis, X-ray powder diffraction and single crystal X-ray diffraction techniques. The structural diversities were observed depending on anionic ligands and metal centers in the synthesized complexes. Complex 1 consists of a 2-fold interpenetrated 3D+3D→3D framework with pcu topology while complex 2 has a 2D structure with sql topology. The adsorption of methylene blue (MB) was studied to examine the potential of the title CPs for removal of dyes from aqueous solution. Molecular dynamics (MD) simulations were also performed to examine diffusion of MB in 1 and 2. Thermal and optical properties of two complexes were also discussed.