New antimicrobial polyurea: Synthesis, characterization, and antibacterial activities of polyurea-containing thiosemicarbazide-metal complexes

Abstract

A novel class of polymer-metal complexes was prepared by the condensation of a polymeric ligand with transition-metal ions. The polymeric ligand was prepared by the addition polymerization of thiosemicarbazides with toluene 2,4-diisocyanate in a 1 : 1 molar ratio. The polymeric ligand and its polymer-metal complexes were characterized by elemental analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy, and 13C-NMR and 1H-NMR spectroscopy. The geometries of the central metal ions were determined by electronic spectra (UV-visible) and magnetic moment measurement. The antibacterial activities of all of the synthesized polymers were investigated against Bacillus subtilis and Staphylococcus aureus (Gram positive) and Escherichia coli and Salmonella typhi (Gram negative). These compounds showed excellent antibacterial activities against these bacteria with the spread plate method on agar plates, and the number of viable bacteria were counted after 24 h of incubation period at 37°C. The antibacterial activity results revealed that the Cu(II) chelated polyurea showed a higher antibacterial activity than the other metal-chelated polyureas. © 2008 Wiley Periodicals, Inc.