Synthesis and Spectroscopy of New Plutonium(III) and -(IV) Molybdates: Comparisons of Electronic Characteristics

Synthesis of a plutonium­(III) molybdate bromide, PuMoO₄Br­(H₂O), has been accomplished using hydrothermal techniques in an inert-atmosphere glovebox. The compound is green in color, which is in stark contrast to the typical blue color of plutonium­(III) complexes. The unusual color arises from the broad charge transfer (CT) spanning from approximately 300 to 500 nm in the UV–vis–near-IR spectra. Repeating the synthesis with an increase in the reaction temperature results in the formation of a plutonium­(IV) molybdate, Pu₃Mo₆O₂₄(H₂O)₂, which also has a broad CT band and red-shifted f–f transitions. Performing an analogous reaction with neodymium produced a completely different product, [Nd­(H₂O)₃]­[NdMo₁₂O₄₂]·2H₂O, which is built of Silverton-type polyoxometallate clusters