Synthesis, characterization and antimicrobial activity of transition metal chelated thiourea-formaldehyde resin

A polymeric ligand (thiourea-formaldehyde resin - TUFR) bearing nitrogen and sulfur donor groups was synthesized by the polycondensation of thiourea and formaldehyde in acidic medium and its polychelates were prepared in alcoholic solution of metal ions such as Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The TUFR polymeric ligand and its TUFR-M(II) polychelates were characterized with micro-analytical analysis and spectral studies. The FTIR spectra of polychelates indicated that the metal ions were coordinated through the sulfur of the thionyl (C=S) groups and formed a covalent bond with the nitrogen of the NH groups. Electronic spectra, electronic spin resonance (ESR) spectra and magnetic moments revealed that the polychelates of Mn(II), Co(II) and Ni(II) were octahedral; however, Cu(II) and Zn(II) polychelates were square-planar and tetrahedral, respectively. The thermogravimetric analysis data indicated that the polychelates were more stable than the corresponding ligand. The antimicrobial activities of all the compounds against several bacteria and fungi were also investigated by using the agar well diffusion method. (C) 2006 Society of Chemical Industry.