Synthesis and characterization of [PW11O39Ir(H2O)](4-): successful incorporation of Ir into polyoxometalate framework and study of the substitutional lability at the Ir(III) site

The first Keggin-type heteropolyanion, [PW11O39Ir(H2O)](4-) (1), was synthesized by hydrothermal reaction from two different polytungstate precursors and [IrF6](2-). It was isolated as (Bu4N)(4)[PW11O39Ir(H2O)] (1a), which was completely characterized by multinuclear P-31 and W-183 NMR, ESI-mass spectrometry and cyclic voltammetry. A rapid screening methodology to ascertain the intrinsic substitutional lability at the Ir site is also presented, based on ESI-MS.