Molecular Hydroxo-Bridged Dimers of Uranium(VI), Neptunium(VI), and Plutonium(VI): [Me4N]2[(AnO2)2(OH)2(NO3)4]

• Published in: Inorganic chemistry 2019-03, Vol.58 (5), p.3203-3210
• Main Authors: Autillo, Matthieu, Wilson, Richard E
• Format: Article
• Language: English
• Subjects: INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.8b03304

The synthesis of a series of molecular actinyl­(VI), namely, uranium­(VI), neptunium­(VI), and plutonium­(VI), hydroxo-bridged dimers is reported. These complexes were isolated from an aqueous nitrate solution by titration with tetramethylammonium hydroxide. The solid-state structures were determined using single-crystal X-ray diffraction, revealing molecular complexes with the formula [Me4N]2[(AnO2)2(μ2-OH)2(NO3)4], where An = UVI, NpVI, and PuVI. Spectroscopic dataUV–vis–near-IR absorption, IR, and Ramanwere collected on the solutions and solid-state complexes where available and compared to those of the aqueous solutions from which the crystals formed. These data provide structural evidence for higher-order polynuclear complexes of actinyl­(VI) complexes upon a pH increase in the aqueous solution, confirming earlier thermodynamic models.