Spectroscopic approach in characterization of chromium(III), manganese(II), iron(III) and copper(II) complexes with a nitrogen donor tetradentate, 14-membered azamacrocyclic ligand

The complexes of Cr(III), Mn(II), Fe(III) and Cu(II) were synthesized with the macrocyclic ligand i.e. 2,3,9,10-tetraketo-1,4,8,11-tetraazacyclotetradecane. The ligand was prepared by the [2 + 2] condensation reaction of diethyloxalate and 1,3-diamino propane. These complexes were found to have the general composition M(L)X3 and M′(L)X2 [where M = Mn(II) and Cu(II), M′ = Cr(III) and Fe(III), L = ligand (N4) and X = Cl−, NO3−, 1/2SO42− and [CH3COO−]. The ligand and its transition metal complexes were characterized by the elemental analyses, molar conductance, magnetic susceptibility, mass, IR, electronic, and EPR spectral studies.On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been assigned for Cr(III), Mn(II) and Fe(III) and a tetragonal geometry for Cu(II) complexes.