Synthesis, spectral, and antibacterial studies of 16-membered tetraazamacrocyclic complexes

A new series of macrocyclic complexes [M(C24H28N4)X2], where M = Co(II), Ni(II), Cu(II), or Zn(II) and X = Cl-, [image omitted], or CH3COO-, has been synthesized by [2+2] condensation of o-phenylenediamine with acetonylacetone (diacetonyl) in the presence of divalent metal ions. The complexes have been characterized by elemental analyses, conductance measurements, electronic, NMR, and infrared spectral studies. On the basis of these studies, a distorted octahedral geometry has been proposed for all of these complexes. The complexes were tested for in vitro antibacterial activity. Some show remarkable antibacterial activity against selected bacterial strains.