Synthesis and characterization of tetraaza macrocycle and its mono-and trinuclear metal complexes

The complexes of Mn (II), Co (II), Ni (II), Cu (II), Zn (II) and La (III) with a 13-membered macrocycle 1,5,8,11-tetra-azacyclotridecane-2, 4-dione (tatd) of the types [M(tatd)(H2O)(2)]Cl-2 and [La(tatd)(H2O)(3)Cl-2]Cl have been prepared by template reaction of 1,8-diamino-3,6-diaza octane, diethyl malonate and metal chlorides in dry methanol. The complex [La(tatd)Cl-2(H2O)(3)]Cl is reacted with metal chlorides in dry methanol to yield the trinuclear complexes of type [2{La(tatd)(H2O)(2)Cl-2}. MCl2]Cl-2 [where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)]. The chemical compositions of the complexes have been established by analytical, molar conductance and FAB mass data The structures of the complexes have been elucidated on the basis of IR, electronic and ESR spectra and magnetic susceptibility data. The macrocycle is bonded in tetrakis fashion in monomer unit while hexakis bonding in trinuclear complex. The synthesis of free macrocycle has also been achieved under dilute condition without the use of coordination template effect, albeit with very low yield. It has also been characterized by elemental analysis, IR NMR and mass spectral methods.