SCHIFF BASE COMPLEXES DERIVED FROM SALICYLALDEHYDE WITH AMINE, [Ni(1,2-pn)2Cl2]·3H2O AND [Cu(1,2-pn)2]SO4·2H2O, AS COMPLEX LIGANDS

Abstract

Schiff base complexes known as complex ligands were prepared by the condensation of dichlorobis(1,2-diaminopropane)nickel(II), [Ni(1,2-pn)2Cl2]·H2O, or bis(1,2-diaminopropane)copper(II) sulphate, [Cu(1,2-pn)2]SO4·H2O, with salicylaldehyde producing the Schiff base complex ligands [ML] (M = Ni or Cu). The complex ligands [ML] act as bidentate ligands through the bridged di-μ-phenoxy oxygen atoms. These Schiff base complexes react with transition metal ions yielding homo- and heteronuclear complexes of the types [MLM′Cl2] or [(ML)2M′Cl2], [(ML)2M′]Cl2, [(ML)2M′](ClO4)2 and [(ML)2M′(NO3)2](NO3)n, M = Ni or Cu; M′ = Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ce(III) and Th(IV). The complexes were characterized by elemental analyses, thermal analyses, IR, visible and ESR spectra, magnetic susceptibility measurements as well as mass spectra. Magnetic moments were altered by the introduction of additional metal cations besides the one already present in the complex ligands. The M′ cations were linked to the outer phenoxo oxygen atoms in the [NiL]·½H2O and [CuL]·H2O complex ligands. All homo- and hetero bi- and tri-nuclear complexes show antiferromagnetic interactions which are attributed to inter- or intramolecular interactions of the metal cations. Mass spectra of the complex ligands and selected homo- and hetero bi- and trinuclear complexes support the formula weights of these complexes. Visible and ESR spectra as well as magnetic moments indicated that the parent mononuclear complex ligands [ML] have square-planar geometry. The binuclear and trinuclear complexes have similar or different geometries, octahedral or square-planar. The octahedral configuration is completed by chlorine atoms, nitrate groups and/or solvent molecules.