Abstract

Molecular Magnets attracted great attention to the development of new magnetic materials. In this scenario the use of Lanthanide based coordination compounds in particular dysprosium(III) ions have given birth to second generation of Single Molecule Magnets. This magnetic coordination compounds are the so-called Lanthanide Single Ions Magnets. The dynamic magnetic properties depend directly on the geometry that the ligands can have. Dysprosium complexes based on lacunary polyoxometalates formed a rigid compound compare to complexes formed by organic ligands. The magnetic response in this compound has a dynamic response under high dc field, observing only a few maxima at 4000G. Organic ligands, which are more flexible compare to rigid ligands such as lacunary polyoxometalates can induce a different magnetic response. So, the combination of rigid ligands and a flexible organic ligand can modify and improve the dynamic magnetic properties of this hybrid inorganic-organic dysprosium (III) complex. In this work, it is present the study of the relaxation dynamics using ac susceptibility measurements of the mononuclear complex, [NBu4]3[H3O][Dy(PW11O39)(phen)2], where phen = phenanthroline. To get a deeper insight on the relaxation processes dilution with yttrium was done with the isostructural complex [NBu4]3[H3O][Dy0.25Y0.75(PW11O39)(phen)2]. The results show that the relaxation times increases 1000 times compare to a fully inorganic dysprosium complex.