Dinuclear Complexes of Uranyl, Neptunyl, and Plutonyl: Structures and Oxidation States Revealed by Experiment and Theory

Abstract

Dinuclear perchlorate complexes of uranium, neptunium, and plutonium were characterized by reactivity and DFT, with results revealing structures containing pentavalent, hexavalent, and heptavalent actinyls, and actinyl−actinyl interactions (AAIs).

Periodic Trends in the Stabilization of Actinyls in Their Higher Oxidation States Using Pyrrophen Ligands

“…The bond lengths, bond angles, bond orders, charges, and spin densities associated with the actinyl (V,VI,VII) cations are provided in Table S1. It is interesting to note that the O yl AnO yl bond angle of the heptavalent actinyl cations (AnO 2 ) 3+ is relatively bent (∠O yl –An–O yl = 149.3–162.0°) compared to those observed in pentavalent and hexavalent actinyl cations, i.e., (AnO 2 ) 1+/2+ , which are nearly linear (∠O yl –An–O yl = 179.8–180.0°). , The unique bend in the heptavalent actinyls observed from their O yl AnO yl bond angle was previously observed in dinuclear complexes, reported by Jian and co-workers, where heptavalent neptunyl exhibited a slight but noticeable bend of 172:172 and 169:177° in Np VI/VII :Np VI/VII and Np VII :Pu VI , respectively . Focusing on the heptavalent actinyl cations, they show interesting results, where the computed spin density on Np suggests a possibility of VII+ OS, while the other An = Pu and Am may acquire a lower stable OS (such as VI+).…”

“…14,56 The unique bend in the heptavalent actinyls observed from their O yl �An�O yl bond angle was previously observed in dinuclear complexes, reported by Jian and coworkers, where heptavalent neptunyl exhibited a slight but noticeable bend of 172:172 and 169:177°in Np VI/VII :Np VI/VII and Np VII :Pu VI , respectively. 57 Focusing on the heptavalent actinyl cations, they show interesting results, where the computed spin density on Np suggests a possibility of VII+ OS, while the other An = Pu and Am may acquire a lower stable OS (such as VI+).…”