Polymer-supported metal complexes as antibacterial agents: synthesis, characterization and thermal degradation kinetics

Polymeric metal complexes were prepared using a synthesized novel terpolymer ligand involving anthranilic acid-o-toluidine-formaldehyde by a polycondensation technique. The synthesized ligand and its metal complexes were characterized using elemental analysis and molar conductivity measurements, and FT-IR, electronic, electron spin resonance and NMR ((1)Hand C-13) spectral methods. The surface morphology and the nature of the synthesized compounds were examined using scanning electronmicroscopy and X-ray diffraction. The thermal stabilities of the ligand and its metal complexes were determined using thermogravimetric analysis (TGA). From the TGA results, various kinetic parameters, i.e. activation energy and order of reaction, and thermodynamic parameters, i.e. entropy change, apparent entropy, frequency factor and free energy change, were determined using the Freeman-Carroll and Sharp-Wentworth methods. In addition, a thermal degradation model was also proposed using the Phadnis-Deshpande method. The thermal stability of the ligand and its metal complexes was found to be appreciably high; in particular, the ligand showed very high stability compared to its metal complexes due to intramolecular hydrogen bonding. Furthermore, the synthesized compounds were subjected to in vitro antibacterial studies with various microorganisms. The results of the studies confirmed that the compounds showed better antibacterial results than a standard antibacterial drug. Copyright (C) 2014 John Wiley & Sons, Ltd.