Reactions of actinide ions with ethylene oxide

Abstract

Naked and oxo-ligated actinide (An) monopositive ions were reacted with ethylene oxide, cyclo-C(2)H(4)O (EtO). Along with An = U, Np, Pu and Am, ions of two lanthanide (Ln) elements, Ln = Tb and Tm, were studied for comparison. Metal and metal oxide ions, M(+), MO(+) and MO(2)(+), were generated by laser ablation and immediately reacted with EtO. Unreacted and product ions were detected by time-of-flight mass spectrometry. It was apparent that the overall reaction cross-sections decreased in the order U(+) > or = Np(+) > Pu(+) > Am(+). A primary reaction channel for each studied metal was the formation of MO(+) from M(+), in accord with the expected exothermicity of oxygen abstraction from EtO. For U, Np and Pu, the dioxides were also major products, indicating OAn(+)--O dissociation energies of at least 350 kJ mol(-1), the energy required for O-atom abstraction from EtO. For Am, Tb and Tm, the dioxides were only very minor products, reflecting the stabilities of the trivalent states and resistance to oxidation to higher valence states; the structures/bonding in these MO(2)(+) are intriguing given that the formal pentavalent bonding state is effectively unattainable. It was demonstrated that EtO, unlike more thermochemically favorable but kinetically restricted O-donors, is effective at achieving facile oxidation of actinide metal ions to the monoxide, and to the dioxide if the second O-abstraction reaction is exothermic. Several intriguing minor products were also identified, most of which incorporate metal--oxygen bonding and are attributed to the oxophilicity of the f-block elements; the contrast to the behavior of first-row d-block transition elements is striking in this regard. Particularly noteworthy was the formation of MH(4)(+) (and MOH(4)(+)), evidently via abstraction of all four H atoms from a single C(2)H(4)O molecule; the structures/bonding in these novel 'hydride' species are indeterminate and warrant further attention.

Collision‐induced dissociation of uranyl‐methoxide and uranyl‐ethoxide cations: Formation of UO 2 H + and uranyl‐alkyl product ions

“…[11] U + and UO + are rapidly oxidized using N 2 O and O 2 [12] and U + is oxidized by reaction with ethylene oxide. [13] Similar results for O 2 oxidation of U + and UO + have been reported in a study that emphasized the reactivity of U 2+ . [14] Despite the work noted above, much of the important chemistry of uranium involves higher oxidation states.…”

“…For example, it has been shown that U + can be oxidized using O 2 , CO, CO 2 , COS, and D 2 O, and that UO + would undergo oxidation with O 2 , and D 2 O to form UO 2 + . U + and UO + are rapidly oxidized using N 2 O and O 2 and U + is oxidized by reaction with ethylene oxide . Similar results for O 2 oxidation of U + and UO + have been reported in a study that emphasized the reactivity of U 2 + …”

Investigation of Uranyl Nitrate Ion Pairs Complexed with Amide Ligands Using Electrospray Ionization Ion Trap Mass Spectrometry and Density Functional Theory

“…Further simplification can be achieved by examining the reactions of small oxo-uranium cations with small molecules (as opposed to large multifunctional ligands). Early mass spectrometry studies focused on low oxidation state-species (U + and UO + ) reacting with organics − and undergoing oxidation by reaction with small molecules such as O 2 , CO 2 , N 2 O, and ethylene oxide. − Later, bombardment of solid UO 3 by energetic ReO 4 − ions was used to generate sufficient quantities of monopositive uranium oxo cations for investigation of intrinsic hydration rates by ion-trap mass spectrometry (ITMS) . The unique features of the ITMS allow for the investigation of complexes in a more reaction-discrete manner via isolation of specific ions of interest through the use of selected ion storage.…”

Can water continuously oxidize the PuO molecule? Mechanisms, topological analysis and rate constant calculations

“…Besides, exploring the most stable plutonium oxide and whether plutonium oxide further oxidizes are also important issues in plutonium science. 2,3 Therefore, over the last few decades, the reaction of plutonium with small molecules in the gas phase has attracted signicant attention both in experimental [1][2][3][4][5][6][7][8][9][10][11][12] and theoretical studies. [13][14][15][16][17][18][19][20][21] In addition, the reaction of plutonium with water which can provide some insight into the corrosive mechanism of steam on nuclear fuel is a more imperative and challenging research eld.…”