Formation of large clusters in the reaction of lanthanide cations with heptamolybdate

Abstract

A series of new lanthanide polyoxomolybdates was synthesised by reaction of lanthanide cations with the heptamolybdate anion (Mo7O 24)6-. The heteropolyanions [Ln4(MoO 4)(H2O)16(Mo7O24) 4]14- (Ln = LaIII, CeIII, Pr III, SmIII, GdIII) were isolated as either their ammonium or tetramethyl-ammonium salts and characterised by X-ray structure analysis, energy dispersive X-ray fluorescence analysis, and IR and Raman spectroscopy. The central [Ln4(MoO4)(H 2O)16]10+ core of the anion is coordinated by four heptamolybdate groups. Each LnIII atom in the core exhibits ninefold coordination by oxygen atoms belonging to H2O, (MoO 4)2- and (Mo7O24)6- units; the central molybdenum atom is coordinated tetrahedrally by four oxygen atoms. © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.