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′= NiII, CoII, or CuII; M = ZnII, M′= CuII; M = NiII, M′= CuII; M = CoII, M′= CuII; and M = CoII, M′= NiII) 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.