Synthesis and spectroscopic studies on the Schiff base ligand derived from condensation of 2-furaldehyde and 3,3′-diaminobenzidene, L and its complexes with Co(II), Ni(II), Cu(II) and Zn(II): Comparative DNA binding studies of L and its Cu(II) and Zn(II)

The Schiff base ligand, N,N′-bis-(2-furancarboxaldimine)-3,3′-diaminobenzidene (L) obtained by condensation of 2-furaldehyde and 3,3′-diaminobenzidene, was used to synthesize the mononuclear complexes of the type, [M(L)](NO3)2 [M = Co(II), Ni(II), Cu(II) and Zn(II)]. The newly synthesized ligand, (L) and its complexes have been characterized on the basis of the results of the elemental analysis, molar conductance, magnetic susceptibility measurements and spectroscopic studies viz, FT-IR, 1H and 13C NMR, mass, UV–vis and EPR. EPR, UV–vis and magnetic moment data revealed a square planar geometry for the complexes with distortion in Cu(II) complex and conductivity data show a 1:2 electrolytic nature of the complexes. Absorption and fluorescence spectroscopic studies support that Schiff base ligand, L and its Cu(II) and Zn(II) complex exhibit significant binding to calf thymus DNA. The highest binding affinity in case of L may be due to the more open structure as compared to the metal coordinated complexes.