New strategies for the generation of large heteropolymetalate clusters: The β-B-SbW9 fragment as a multifunctional unit

Abstract

Proceeding from the α-B-SbW9O33 fragment 1, various novel large heteropolyanions ([Na2Sb8W36O132(H2O)4]22- (2), [Sb2W22O74(OH)2]12- (3) and [Sb2W20M2O70(H2O)6](14-2n)- (4); M(n+) = Fe3+, Co2+, Mn2+, Ni2+) have been obtained in crystalline form by systematic synthesis. Their unexpected structures have been studied by X-ray diffraction: 2, 3 and 4 contain β-SbW9 units connected to each other by Sb3+ ions, WO2/WO2OH groups, and WO2/M(n+)(H2O)3 groups, respectively. Structural details and especially the systematic synthesis strategy for the formation of these interesting polytungstates are discussed in order to explain the unusual behaviour of 1 in aqueous solution under different reaction conditions.