Synthesis and Spectral Investigation of Co(II), Ni(II), Cu(II) and Zn(II) Complexes with Novel N4 Ligands

Four new tetradentate amine-N donor ligands have been prepared by reducing Schiff bases derived from the condensation of 2-aminonicotinaldehyde with 1,2-diaminoethane (APMED)/ 1,2- diaminopropane (APMPD)/1,3-diaminopropane (APMP'D)/trans-cyclohexane-1,2-diamine (APMCD). The ligands react with transition metal (Co(II)/Ni(II)/Cu(II)/Zn(II)) salts to give microcrystalline solid complexes of 1 : 1 (M : L) composition. The ligands and the metal complexes have been characterized with analyses, molar conductance measurements, magnetic susceptibility measurements and spectroscopic investigations like mass, IR, electronic, NMR and ESR. All the complexes were found to have octahedral geometry holding 0-6 water molecules in the lattice with a general molecular formula (MLCl2).n H2O.