Two types of polyoxometalates based on circular P8W48 cluster units and different inclusions of tetralanthanide and octamanganese centers

Abstract

Two types of new polyoxometalates (POMs) based on circular P 8W48 clusters with different tetralanthanide (Ln) clusters and octamanganese centers, [K(H2O)2]4[K 4(μ-H2O)4(H2O)4] 2{[Ln2(μ-OH)4(H2O) x]2(H24P8W48O 184)}·yH2O [Ln = Nd (1), Sm (2), Tb (3)] and [K(H2O)2]4[K4(μ-H 2O)8]2[K(H2O)]8{[Mn 8(H2O)16](H4P8W 48O184)}·36H2O (4) have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, thermogravimetry (TG), and powder XRD. Compounds 1-3 are the first series of Ln-containing P 8W48-based POMs that use P2W12O 4814- as the precursor; previously known P 8W48-based POMs used P8W48O 18440- as the precursor. In 4, eight manganese ions were incorporated. Owing to the different radii of the Ln and Mn ions, the four large Ln ions are divided into two {Ln2} clusters located on two sides of the cavity of the P8W48 wheel in 1-3, but the eight small manganese ions in 4 only bond to the inside of the P8W48 wheel and do not form manganese clusters. The magnetic properties of 3 are discussed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.