Synthesis and characterization of divalent metal complexes of the macrocyclic ligand derived from isatin and 1,2- diaminobenzene

A novel series of complexes of the type [M(C28H18N6)X2], where M=Co(II), Ni(II), Cu(II) or Zn(II) and X=Cl-, NO3- or CH3COO-, were synthesized by template condensation of isatin and 1,2-diaminobenzene in methanolic medium. The complexes were characterized with the help of various physico-chemical techniques, such as elemental analyses, molar conductance measurements, magnetic measurements, and NMR, infrared and far infrared spectral studies. The low value of molar conductance indicates them to be non-electrolytes. Based on various studies, a distorted octahedral geometry may be proposed for all the complexes. All the synthesized macrocyclic complexes were also tested for their in vitro antibacterial activity against some pathogenic bacterial strains. The MIC values shown by the complexes against these bacterial strains were compared with those of the standard antibiotics linezolid and cefaclor. Some of the complexes showed good antibacterial activities.