Tetrapalladium-Containing Polyoxotungstate [Pd^II₄(α‑P₂W₁₅O₅₆)₂]^16–: A Comparative Study

The novel tetrapalladium­(II)-containing polyoxometalate [Pd^II₄(α-P₂W₁₅O₅₆)₂]^16– has been prepared in aqueous medium and characterized as its hydrated sodium salt Na₁₆[Pd₄(α-P₂W₁₅O₅₆)₂]·71H₂O by single-crystal XRD, elemental analysis, IR, Raman, multinuclear NMR, and UV–vis spectroscopy. The complex exists in anti and syn conformations, which form in a 2:1 ratio, and possesses unique structural characteristics in comparison with known {M₄(P₂W₁₅)₂} species. ³¹P and ¹⁸³W NMR spectroscopy are consistent with the long-term stability of the both isomers in aqueous solutions.