Lanthanide-based hexanuclear complexes usable as molecular precursor for new hybrid materials : state of the art.
Résumé
Lanthanide containing octahedral hexanuclear complexes with general chemical formula [Ln6O(OH)8(NO3)6(H2O)x].2NO3.yH2O where Ln = Ce-Lu (except Pm) or Y, x = 0, 6, 12, 14 or 16 and y = 0, 2, 4 or 5 constitute a great family of polymorphic compounds. The synthesis and the crystal structures of all these compounds are overviewed. The hydration/dehydration processes that allow the structural transitions from one compound to another are described. The crystal structure of compounds with general chemical formula [Ln6O(OH)8(NO3)6(H2O)6].2NO3 where Ln = Ce-Lu (except Pm) or Y is described. It has been solved on the basis of a powder XRD diagram. The use of such hexanuclear complexes as molecular precursors for new materials is also discussed.