In Vitro Bacterial Screening and Degradation Kinetics of a Terpolymer Ligand and Its Transition Metal Complexes

Abstract

ABSTRACT:A novel terpolymer ligand involving 2-amino-6-nitro-benzothiazole-semicarbazide-formaldehyde was synthesized in a 1:1:2 mole ratio with a dimethylformamide reaction medium at 150 ± 2°C for 6 h. The synthesized ligand was used to prepare various metal complexes with Cu 2+ , Ni 2+ , and Zn 2+ metal ions. The structure of the terpolymer ligand and its complexes were confirmed based on elemental analysis, molecular weight measurements, molar conductivity, magnetic susceptibilities, Fourier transform infrared, electronic, electron spin resonance, and 1 H and 13 C nuclear magnetic resonance spectroscopy. Scanning electronic microscopy and X-ray diffraction method were used to analyze the morphological features of the terpolymer and its metal complexes. The thermal stabilities of the terpolymer and its metal complexes were determined using thermogravimetric analysis. Kinetic parameters such as activation energy (E a ) and order of reaction (n), thermodynamic parameters, viz. entropy change ( S), free energy change ( F), apparent entropy (S*), and frequency factor (Z) were calculated using Sharp-Wentworth and Freeman-Carroll methods. The thermal degradation mechanism was also proposed for both the terpolymer ligand and its complexes using the Phadnis-Deshpande method. The terpolymer ligand and its complexes were screened for antibacterial activities against selected microorganisms such as Shigella sonnei, Escherichia coli, Klebsiella species, Staphylococcus aureus, Bacillus subtilis, and Salmonella typhimurium. C