Large-angle X-ray scattering study and magnetic properties of amorphous complexes [MM′(cdta)]·n H2O (M, M′= CoII, NiII, CuII, or ZnII; cdta =trans-cyclohexane-1,2-diamine-NNN′N′-tetra-acetate)

Abstract

Investigation by large-angle X-ray scattering of the amorphous complexes [MM′(cdta)]·nH₂O (M = M′= Ni^II, Co^II, or Cu^II; M = Zn^II, M′= Cu^II; M = Ni^II, M′= Cu^II; M = Co^II, M′= Cu^II; and M = Co^II, M′= Ni^II) has revealed that such complexes consist of binuclear entities, made up of cationic and anionic octahedral complexes bridged by a carboxylate group from the cdta ligand (trans-cyclohexane-1,2-diamine-NNN′N′-tetra-acetate). Their magnetic properties have been studied by assuming a Heisenberg exchange coupling between the two metal ions. All the compounds (except ZnCu) exhibit a weak antiferromagnetic interaction, with 2J values ranging from –1.6 to –4.7 cm^–1.