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.