Recent advances in computational actinoid chemistry

Abstract

We briefly review advances in computational actinoid (An) chemistry during the past ten years in regard to two issues: the geometrical and electronic structures, and reactions. The former addresses the An-O, An-C, and M-An (M is a metal atom including An) bonds in the actinoid molecular systems, including actinoid oxo and oxide species, actinoid-carbenoid, dinuclear and diatomic systems, and the latter the hydration and ligand exchange, the disproportionation, the oxidation, the reduction of uranyl, hydroamination, and the photolysis of uranium azide. Concerning their relevance to the electronic structures and reactions of actinoids and their importance in the development of an advanced nuclear fuel cycle, we also mentioned the work on actinoid carbides and nitrides, which have been proposed to be candidates of the next generation of nuclear fuel, and the oxidation of PuO(x), which is important to understand the speciation of actinoids in the environment, followed by a brief discussion on the urgent need for a heavier involvement of computational actinoid chemistry in developing advanced reprocessing protocols of spent nuclear fuel. The paper is concluded with an outlook.

On the multi-reference nature of plutonium oxides: PuO22+, PuO2, PuO3 and PuO2(OH)2

“…With the 5f and 6d orbitals being in the primary valence shell, actinides are able to form unique bonds and interact with other compounds in ways that no other elements are able to. [55][56][57][58][59][60] In plutonium dioxides, the 5f and 6d orbitals of the plutonium center interact with the valence orbitals on the oxygen atoms, with the exception of four pairwise degenerate nonbonding orbitals: the doubly degenerate δ u , φ u and δ g orbitals. [55].…”

Synthesis, structure and bonding of actinide disulphide dications in the gas phase

“…One of the more interesting aspects is the low energy value of the quintet state with respect to the ground-state triplet which had already been an important conclusion in a preceding paper. 18 This quintet state can be described as a U 3+ (5f 3 ) + S 2 -• ferromagnetic 8 interaction as evidenced by the natural orbital occupancies (NOOs). The 5f δ1 and the π -MOs do not mix as in the lower spin states as these MOs remain localised.…”

“…The CI coefficients of the CASPT2 (4,8) first order wavefunction show a strong multi-reference character: triplet state has the leading (30%) configuration 3 φ 1 ={(5f σ ) ↑ (5f π1 ) 0 (5f π2 ) 0 (5f δ1 + π 1 -) 2 (5f δ2 ) 0 (5f ϕ1 ) ↑ (5f ϕ2 ) 0 (5f δ1 -π 1 -) 0 } followed by the configuration state function (CSF) with an additional open shell 23% 3 φ 2 ={(5f σ ) ↑ (5f π1 ) 0 (5f π2 ) 0 (5f δ1 + π 1 Figure , highlights the spin coupling at the different An(5f) and π -sites.…”

“…1 Uranyl in particular has received widespread consideration from both the experimental and theoretical perspectives. [2][3][4][5][6][7][8][9][10] The synthesis of analogues of uranyl, where oxygen is replaced by another main-group element or moiety, such as carbene, imido, and terminal chalcogenide, has multiplied in recent years and is still an ongoing endeavour. [11][12][13][14][15] For the less-studied transuranium actinides, only recently has a first actinyl V or VI analogue been successfully prepared, specifically a trans-bisimido complex of Np(V).…”

Computational Study on Mössbauer Isomer Shifts of Some Organic-neptunium (IV) Complexes

“…[5][6][7] Kaltsoyannis et al performed the relativistic DFT calculation for An III Cp3 and An IV Cp4 (An = Th-Cm) to discuss the bonding properties of An ions by means of various population analyses. [8,9] We have reported that allelectron relativistic DFT results strongly correlate to the experimental 237 Np Mössbauer isomer shifts, which are quantitative parameters relative to Np ions.…”