Activation of Water by Pentavalent Actinide Dioxide Cations: Characteristic Curium Revealed by a Reactivity Turn after Americium

Jian, Tian; Dau, Phuong Diem; Shuh, David K.; Vasiliu, Monica; Dixon, David A.; Peterson, Kirk A.; Gibson, John K.

doi:10.1021/acs.inorgchem.9b01997

Cited by 9 publications

(17 citation statements)

References 53 publications

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“…This has previously been predicted for the AnO 2 + . 65 The spin density in the An shows similar trends to the 5f (α−β) populations for each formal oxidation state of the actinide (Supporting Information). From the spin density on the oxygen bonded to the actinide, there are about two total unpaired spins on the oxygen atoms for An(II)O 2 molecules consistent with 3 O 2 , and about one total unpaired spin on the oxygen atoms for An(III)O 2 − molecules.…”

Section: Omentioning

confidence: 82%

A Computational Assessment of Actinide Dioxide Cations AnO₂²⁺for An = U to Lr: The Limited Stability Range of the Hexavalent Actinyl Moiety, [O═An═O]²⁺

et al. 2020

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The isolated gas-phase actinide dioxide dications, AnO 2 2+ , were evaluated by DFT and coupled cluster CCSD(T) calculations for 12 actinides, An = U−Lr. CASSCF calculations were used to define the orbitals for the CCSD(T) calculations. The characteristic linear [OAnO] 2+ hexavalent actinyl(VI) was found to be the lowest energy structure for An = U, Np, and Pu, which also form stable actinyl(VI) species in solution and possibly for Am when spin−orbit effects are included. For Am, there is a divalent [An II (O 2 )] 2+ structure where the dioxygen is an end-on physisorbed η 1 -3 O 2 2 kcal/mol above the actinyl when spin−orbit effects are included which lower the energy of the actinyl structure. For An = Cm, Bk, and Lr, the lowest energy structure is trivalentwhere the dioxygen is a side-on superoxide, η 2 -O 2 − . For Cm, the actinyl is close in energy to the ground state when spin−orbit effects are included. For An = Cf, Es, Fm, Md, and No, the lowest energy structure is divalent [An II (O 2 )] 2+ where the dioxygen is an end-on physisorbed η 1 -3 O 2 . The relative energies suggest that curyl(VI) and berkelyl(VI), like well-known americyl(VI), might be stabilized by coordinating ligands in condensed phases. The results further indicate that for californyl and beyond, the actinyl(VI) moieties will probably be elusive even using strong donor ligands. The prevalence of low oxidation states (OSs) An(II) and An(III) for transplutonium actinides reflects stabilization of the 5f orbitals and validates established trends, including the remarkably high stability of divalent No. Bond distances and other parameters suggest maximum bond covalency around plutonyl(VI), with a particularly substantial decrease in bond strength between americyl(VI) and curyl(VI).

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Section: Omentioning

confidence: 82%

A Computational Assessment of Actinide Dioxide Cations AnO₂²⁺for An = U to Lr: The Limited Stability Range of the Hexavalent Actinyl Moiety, [O═An═O]²⁺

et al. 2020

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“…and An 3+ . 48 The reactions become more differentiated at TS2 in which a proton is transferred from water to the NP (P = pyridyl) of the leaving ligand (Nleave). In TS2 two of the three coordinating From the results in Table 1 it is apparent that the TS2 and Prod energy reductions upon inclusion of f orbitals in the valence shell are generally greater for Am 5f versus La 4f, suggesting more involvement of 5f orbitals in bonding.…”

Section: Factors Affecting Pes Energiesmentioning

confidence: 99%

Gas-Phase Complexes of Americium and Lanthanides with a Bis-triazinyl Pyridine: Reactivity and Bonding of Archetypes for F-Element Separations

Jian

Dan

et al. 2020

J. Phys. Chem. A

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Bis-triazinyl pyridines (BTPs) exhibit solution selectivity for trivalent americium over lanthanides (Ln), the origins of which remain uncertain. Here, electrospray ionization was used to generate gas-phase complexes [ML3] 3+ , where M=La, Lu, or Am, and L is the BTP 2,6-bis(5,6-diethyl-1,2,4-triazin-3-yl)-pyridine). Collision induced dissociation (CID) of [ML3] 3+ in the presence of H2O yielded protonated ligand [L(H)] + , and hydroxide [ML2(OH)] 2+ or hydrate [ML(L-H)(H2O)] 2+ where (L-H)is a deprotonated ligand. Whereas solution affinities indicate stronger binding of BTPs towards Am 3+ versus Ln 3+ , the observed CID process is contrastingly more facile for M = Am versus Ln. To understand the disparity, density functional theory was employed to compute potential energy surfaces for two possible CID processes, for M = La and Am. In accord with the CID results, both the rate determining transition state barrier and the net energy are lower for [AmL3] 3+ versus [LaL3] 3+ , and for both product isomers, [ML2(OH)] 2+ and [ML(L-H)(H2O)] 2+. More facile removal of a ligand from [AmL3] 3+ by CID does not necessarily contradict stronger Am 3+-L binding as inferred from solution behavior. In particular, the formation of new bonds in the products can distort kinetics and thermodynamics expected for simple bond cleavage reactions. In addition to correctly predicting the seemingly anomalous CID behavior, the computational results indicate greater participation of Am 5f versus La 4f orbitals in metal-ligand bonding.

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“…Pentavalent actinyls [O=An(V)=O] 1+ are essential species in actinide science and nuclear fuel/waste research. 20,44 The [O=U(V)=O] 1+ exists in the chemical and biological uranyl remediation We subsequently remove six electrons from the Oh-symmetry [An(IV)6O14] 4-(4-An) to investigate that if the cluster symmetry will change upon the oxidation to [An(V)6O14] 2+ (5-An). The calculated charge and spin population are listed in Table 4.…”

Section: Model Complexes [An(v)6o14mentioning

confidence: 99%

Decisive Role of 5f-Orbital Covalence in the Structure and Stability of Pentavalent Transuranic Oxo [M₆O₈] Clusters

Zhang

et al. 2020

Inorg. Chem.

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Actinide metal oxo clusters are of vital importance in actinide chemistry, as well as in environmental and material sciences. They are ubiquitous in both aqueous and non-aqueous phases, and play key roles in nuclear materials (e.g. nuclear fuel) and nuclear waste management. Despite the importance, our structural understanding of the actinide metal oxo clusters, particularly the transuranic ones, is very limited, due to the experimental challenges such as the high radioactivity. Herein we report a systematic theoretical study on the structures and stabilities of seven actinide metal oxo-hydroxo clusters [An(IV)6O4(OH)4L12] (An: Th to Cm; L: O2CH − ) (1-An) along with their group-4 (Ti, Zr, Hf, Rf) and lanthanide (Ce) counterparts [M(IV)6O4(OH)4L12] (1-M). The work shows the Td-symmetric structures of all the 1-An/M, and suggests the positions of the -OH functional groups, which are experimentally challenging to determine. Furthermore, by removing six electrons from 1-An, we found that the oxidation could happen on the An(IV) metal ions producing [An(V)6O4(OH)4L12] 6+ (2-An; An: Pa, U, Np), or on the O 2− and OH − ligands producing [An(IV)6(O• − )4(OH•)2(OH)2L12] 6+ (3-An; An: Pu, Am, Cm). Based on the 2-An, we constructed a series of tetravalent and pentavalent actinide metal oxo clusters [An(IV)6O14] 4− (4-An) and [An(V)6O14] 2+ (5-An), which proves the feasibility of the highly important pentavalent actinyl clusters for the first time, demonstrates f-orbital's structurally directing role in the formation of linear [O≡An(V)=O] 1+ actinyl ions, and expands the concept of actinyl-actinyl interaction into pentavalent transuranic actinyl clusters.

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Activation of Water by Pentavalent Actinide Dioxide Cations: Characteristic Curium Revealed by a Reactivity Turn after Americium

Cited by 9 publications

References 53 publications

A Computational Assessment of Actinide Dioxide Cations AnO₂²⁺for An = U to Lr: The Limited Stability Range of the Hexavalent Actinyl Moiety, [O═An═O]²⁺

A Computational Assessment of Actinide Dioxide Cations AnO₂²⁺for An = U to Lr: The Limited Stability Range of the Hexavalent Actinyl Moiety, [O═An═O]²⁺

Gas-Phase Complexes of Americium and Lanthanides with a Bis-triazinyl Pyridine: Reactivity and Bonding of Archetypes for F-Element Separations

Decisive Role of 5f-Orbital Covalence in the Structure and Stability of Pentavalent Transuranic Oxo [M₆O₈] Clusters

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Activation of Water by Pentavalent Actinide Dioxide Cations: Characteristic Curium Revealed by a Reactivity Turn after Americium

Cited by 9 publications

References 53 publications

A Computational Assessment of Actinide Dioxide Cations AnO22+for An = U to Lr: The Limited Stability Range of the Hexavalent Actinyl Moiety, [O═An═O]2+

A Computational Assessment of Actinide Dioxide Cations AnO22+for An = U to Lr: The Limited Stability Range of the Hexavalent Actinyl Moiety, [O═An═O]2+

Gas-Phase Complexes of Americium and Lanthanides with a Bis-triazinyl Pyridine: Reactivity and Bonding of Archetypes for F-Element Separations

Decisive Role of 5f-Orbital Covalence in the Structure and Stability of Pentavalent Transuranic Oxo [M6O8] Clusters

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A Computational Assessment of Actinide Dioxide Cations AnO₂²⁺for An = U to Lr: The Limited Stability Range of the Hexavalent Actinyl Moiety, [O═An═O]²⁺

A Computational Assessment of Actinide Dioxide Cations AnO₂²⁺for An = U to Lr: The Limited Stability Range of the Hexavalent Actinyl Moiety, [O═An═O]²⁺

Decisive Role of 5f-Orbital Covalence in the Structure and Stability of Pentavalent Transuranic Oxo [M₆O₈] Clusters