Macrocyclic metal complexes derived from 2,6-diaminopyridine and isatin with their antibacterial and spectroscopic studies

Condensation reaction of 2,6-diaminopyridine with isatin in the presence of divalent metal ions results in the formation of the macrocyclic complexes of the type [M(C26H16N8)X2], where M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and X = Cl−, NO3−, CH3COO−. The complexes have been characterized with the aid of elemental analyses, conductance measurements, electronic, NMR, infrared and EPR spectral studies. The lower values of molar conductance indicate them to be non-electrolytes. On the basis of these studies, a six coordinate distorted octahedral geometry in which four nitrogen atoms are suitably placed for coordination towards metal ion, has been proposed for all the complexes. The complexes were tested for their in vitro antibacterial activity. Some of the complexes showed good antibacterial activities against some selected bacterial strains.