Chemistry of [PW11NbO40]4−: Structural rearrangement and metal coordination

Abstract

Treatment of Cs4[PW11NbO40]·12H2O with boiling water results in slow degradation of the [PW11NbO40]4− Keggin anion into the trilacunary [A-PW9O34]9− following by aggregation of the latter around three {MO} (MNb, W) fragments, producing [(A-PW9O34)2(MO)3]8− Herve-type anion. The product was isolated as Cs8[(PW9O34)2(WO)(NbO)2]·17.5H2O (1) and characterized with XRD, XRPD, IR and 31P MAS NMR. Diffusion of diethyl ether into the solution of (TBA)4[PW11NbO40] and Pb(NO3)2 in N,N-dimethylformamide (DMF) leads to the crystallization of [Pb2(μ2-DMF)3(DMF)8][PW11NbO40]·DMF (2) with polymeric nature, where the {Pb2} cationic dimers and [PW11NbO40]4− anions form infinite linear chains via PbOM coordination. Complex (2) was characterized with XRD, IR and 31P MAS NMR.