Synthesis, characterisation and antimicrobial activities of Co(II), Ni(II), and Cu(II) complexes of hexamethylenetetramine ligand

Hexamethylenetetramine (HMTA, C6H2N4) complexes of Co(II), Ni(II), and Cu(II) have been synthesized in ethanol. While the cobalt(II) and copper(II) complexes have one molecule of hexamethylenetetramine, the nickel complex has two molecules. These complexes have been characterised by elemental analyses, infrared and visible spectroscopy, H-1 NMR, conductivity and room temperature magnetic susceptibility measurements. The results suggest octahedral coordination in which the central metal ion is bonded to HMTA and aqua ligands. Antimicrobial activities of the ligand and its derived complexes show that the ligand, HMTA is active against 2 out of 11 tested organisms; the nickel complex [Ni(H2O)(4)(HMTA)(2)]Cl-2.5H(2)O is active on none and the cobalt complex is active against 4 of the organisms. The copper complex, [(CuCl2)(2) (HMTA)(H2O)(2)] is active against all the 11 tested organisms, including the yeast, Candida albicans.