2D Zinc(II)-Coordination Polymer Based on 1,3,5-Benzenetricarboxylate and Novel 4,4′-Bis((2-isopropyl-1<i>H</i>-imidazole-1-yl)methyl)-1,1′-biphenyl Ligands for the Adsorption of Methyl Orange

Abstract

A novel 2D coordination polymer with the formula {[bisopibiphenH 2 ][Zn 2 (btc) 2 (H 2 O) 2 ]} n (complex 1 ) was produced via the solvothermal interaction of benzene-1,3,5-tricarboxylic acid (H 3 btc) ligand, novel 4,4′-bis((2-isopropyl-1 H -imidazole-1-yl)methyl)-1,1′-biphenyl (bisopibiphen) compound, and Zn(II) ion. The structure of the final complex was elucidated by single crystal/powder X-ray diffraction methods (SCXRD/PXRD), scanning electron microscopy–energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and elemental analysis. According to the results obtained from the SCXRD method of the complex, it was determined that the 2D complex was formed by Zn(II) central atoms with a distorted tetrahedral geometry and btc 3– ligand. The novel bisopibiphen compound used was protonated and acted as a countercation within the asymmetric unit, thus forming the 3D supramolecular structure because of interactions between the 2D layers. Additionally, the topological and thermal characteristics of the complex were examined. In a later stage, the adsorption performance of complex 1 for methyl orange (MO) dye was examined along with the influence of various parameters. Kinetic and isotherm studies were also conducted to explain the nature of the MO adsorption process nature. According to this, the experimental data were well-matched by the pseudo-second order kinetics and Langmuir isotherm model. The maximum adsorption capacity of complex 1 was determined as 735.89 mg g –1 at 20 °C and pH 4.0. These findings indicated that complex 1 could be used as a promising effective adsorbent for MO adsorption from aqueous solutions.