Study of the magnetic exchange within the cluster polymer [NaCu6(gly)8(ClO4)3(H2O)]n(ClO4)2n

The synthesis and structure of a new member of the family of complexes containing the [NaCu6(aa)8]5+ (aa = amino-acid) cage moiety are presented. The formula of this new compound is [NaCu6(gly)8(ClO4)3(H2O)]n(ClO4)2n (1); it is formed by hexanuclear clusters linked into chains through axial-equatorial CuII–O–CuII coordination links along the crystallographic a axis and connected via  ClO4- ligands in the b direction. Magnetic susceptibility measurements have revealed intra-cluster ferromagnetic interactions leading to and ST = 3 ground state for each hexanuclear unit, and the presence of weak inter-cluster ferromagnetic exchange. The coupling within the hexanuclear moieties has been investigated by means of DFT calculations that have corroborated the interpretation of the experimental results.

In the cluster polymer [NaCu6(gly)8(ClO4)3(H2O)]n (ClO4)2n (1), the hexanuclear cages organize as extended sheets. The magnetic interaction between Cu(II) ions within the clusters is ferromagnetic leading to S = 3 units that in turn exhibit ferromagnetic interactions between them. DFT calculations suggest that the magnetic coupling changes with the temperature.Figure optionsDownload as PowerPoint slide