New heteropolynuclear Bi-Sm and Bi-Ho complexes with ethylenediaminetetraacetic acid

The search for bismuth-lanthanide coordination compounds that could be used as molecular precursors for Bi-Ln-based oxide-type materials displays a wide interest in the relationship with the numerous applications of such inorganic materials as ion conductors (Bi-La, Nd, Sm), ferroelectrics (Bi-Sm, La) or inorganic pigments (Bi-Ho).[1] When compared with the traditional ceramic route involving oxides of the component metals, these precursor methods actually provide materials displaying a higher homogeneity and specific surface area. As an ongoing effort to syntheses new potential precursors for inorganic materials, we have obtained two new heterometallic coordination compounds with ethylenediaminetetraacetate ion as ligand with the following general formulae: LnBiEdta(NCS)2∙4H2O (Ln = Sm, Ho). The composition has been confirmed by element analysis, TG/TGA study, IR spectroscopy and single crystal X-ray diffraction. The results of X-ray study revealed that the compounds are isomorphous, crystallizing in P21/n space group with the average cell parameters: a = 9.3, b =16.7, c = 14.5 (A), Β=103 o.