Original Articles: 2011 Vol: 3 Issue: 3
Synthesis, characterisation and biological activities of Mn(II), Co(II) and Ni(II) complexes of hexamethylenetetramine
Abstract
Mn(II), Co(II) and Ni(II) complexes of hexamethylenetetramine (HMTA) have been synthesized in water and ethanol. All the complexes are hydrogen-bonded, except the cobalt complex [Co(HMTA)2(NO3)2(H2O)2] which is polymeric. These complexes have been characterized by elemental analyses, infrared and visible spectroscopy as well as conductivity. The results suggest octahedral coordination in which the central metal ion is bonded to aqua ligands and the HMTA is bonded to the aqua ligands through hydrogen-bonding. Antibacterial activities of the ligand and its complexes show that the ligand is active against 1 out of 10 tested bacteria species; the cobalt complexes [Co(H2O)6](HMTA)2(NO3)2. 4H2O, and [Co(HMTA)2(NO3)2(H2O)2] are the most active, showing activity against all the microorganisms. These cobalt complexes also show greater activity than the reference antibiotic gentamycin against Klebsiella pneumonia.