Template synthesis and physico-chemical characterization of 14-membered tetraimine macrocyclic complexes, [MLX2] [M = Co(II), Ni(II), Cu(II) and Zn(II)]. DNA binding study on [CoLCl2] complex

The template condensation reaction between glyoxal and 1,8-diaminonaphthalene resulted a few novel mononuclear 14-membered tetraimine macrocyclic complexes of the type, [MLX2] [M = Co(II), Ni(II), Cu(II) and Zn(II), for X = Cl or NO3]. The stoichiometry and the nature of the complexes have been deduced from the results of elemental analyses and conductance data. The formation of macrocyclic framework has been inferred from the appearance of imine υ(CN) and υ(MN) band in IR spectra and the resonance signals observed in 1H and 13C-NMR spectra. However, the overall geometry of the complexes has been assigned on the positions of bands in electronic spectra and magnetic moment data. The distortion in Cu(II) complexes has been deduced on EPR data. The thermal behavior of these complexes has been studied by TGA analysis. Absorption and circular dichroism studies on the complex proved a significant binding to calf thymus DNA.