A New Series of Anhydrous Lanthanide-Based Octahedral Hexanuclear Complexes

The synthesis of hexanuclear lanthanide oxido/hydroxido complexes by direct hydrolysis has been reinvestigated and optimized. Lanthanide oxido/hydroxido complexes of the general formula [Ln(6)O(OH)(8)(NO3)(6)(H2O)(x)]2NO(3)center dot 2H(2)O (with x = 12 for Ln = Sm-Yb or Y, x = 14 for Ln = Pr or Nd, and x = 16 for Ln = Ce) have been obtained and characterized. The dehydration of all these complexes leads to isostructural anhydrous compounds with the general formula [Ln(6)O(OH)(8)(NO3)(8)](infinity). The crystal structure has been solved on the basis of powder X-ray diffraction of the Y-containing compound. This compound crystallizes in the triclinic system, and the crystal structure can be described as the juxtaposition of infinite chains of hexanuclear complexes linked to each other by nitrate groups. These anhydrous compounds are readily soluble in most organic solvents and can be used as molecular precursors for further chemistry. When exposed to moisture, they rehydrate reversibly, which leads to their initial hydrated phase. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)