Chelating and biological properties of an azo polymer resin: synthesis, characterization and its application

The polymeric ligand (resin) was prepared from 1-(4-hydroxyphenylazo)-2-naphthol (4HPA2N-F) with formaldehyde in the presence of oxalic acid as a catalyst. Poly (4HPA2N-F) was characterized by Fourier transform infrared and 1H-NMR spectroscopic techniques. The molecular weight of the polymer was determined by gel permeation chromatography. Polychelates were obtained when the dimethylformamide solution of the polymer containing a few drops of ammonium hydroxide was treated with a aqueous solution of Cu(II)/Ni(II). The Infrared spectra of polychelates suggest that the metals were coordinated through the oxygen of the phenolic–OH group and nitrogen of the azo group. The thermogravimetic analysis, differential scanning calorimetry and X-ray diffraction studies indicate that the incorporation of the metal ion significantly enhanced the degree of crystallinity. The sorption properties of the chelate-forming polymer towards various metal ion Cu(II) and Ni(II) were studied as a function of pH, nature and concentration of electrolytes. The antibacterial activities of polymer and its metal complexes against several microorganisms were also investigated by using agar well diffusion method.