Synthesis and Spectral Studies on 16-Membered Diamidediimine Tetraazamacrocyclic Complexes, [MLCi]Cl [M.=Mn(ii), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)]

A series of 16-membered diamidediimine tetraazamacrocyclic complexes of the type [MLCl]Cl, [M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] bearing amide groups have been synthesized by the template condensation ofo-aminobenzoic acid with phthalaldehyde and 1,2-diaminoethane in the presence of transition metal ions. The stoichiometry of proposed macrocyclic complexes has been ascertained on the basis of results of elemental analyses and conductivity measurements. The mode of bonding of macrocyclic moiety and the overall geometry around metal ion have been confirmed by IR, 1H-NMR, reflectance and UV-Vis studies. A pseudo-octahedral geometry has been suggested for all the complexes in DMSO, while a pentacoordination around metal ions has been noticed in reflectance spectra of Fe(II), Co(II), Ni(II) and Cu(II) complexes.