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.