Synthesis and Characterization of Cobalt(II)/(III), Nickel(II) and Copper(II) Complexes of New 14, 15 and 16-Membered Macrocyclic Ligands

Abstract

A new series of nickel(II), cobalt(II)/(III) and copper(II) complexes of 14, 15 and 16-membered of macrocyclic ligands have been prepared and characterized by elemental analyses, IR, UV-VIS and <TEX>$^1H-NMR$</TEX> spectra, magnetic susceptibilities, conductivities, DTA and ESR measurements. Molar conductances in DMF solution indicate that, the complexes are nonelectrolytes except (9-12) complexes. The electronic spectra show that, all complexes are square planar or distorted octahedral geometry. The ESR spectra of solid complexes (4), (8) and (11) show square planar of axial type symmetry <TEX>$(d_{x2-y2})$</TEX> with considerable covalent bond character. However, complex (12) shows a spectrum of octahedral geometry with <TEX>$d_{z2}$</TEX> ground state. Complex (12) shows exploitation in reducing the amount of electron adducts formed in DNA during irradiation with low radiation products.