Na2Li8[(UO2)11O12(WO5)2]: Three Different Uranyl‐Ion Coordination Geometries and Cation–Cation Interactions

Alekseev, Evgeny V.; Krivovichev, Sergey V.; Depmeier, Wulf; Siidra, Oleg I.; Knorr, K.; Сулейманов, Е. В.; Chuprunov, E. V.

doi:10.1002/ange.200601207

Cited by 19 publications

(10 citation statements)

References 17 publications

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“…Very similar values of the U VI = O bond lengths were found for the previously reported mixed-valent tetramer, [35] and in extended frameworks presenting UO 2 2 + ···UO 2 2 + cation-cation interactions. [56,57] Both uranium ions are heptacoordinated with a slightly distorted pentagonal bipyramid geometry by the four donor atoms of the salen ligand situated in the equatorial plane and the two uranyl oxygen atoms in an axial position; the seventh coordination position is occupied by a pyridine nitrogen atom in the U V complex and by a uranyl oxygen atom from the UO 2 + group in the U VI complex. This dimeric complex provides a second example of an isolated molecular U V /U VI compound.…”

Section: Resultsmentioning

confidence: 99%

Cation–Cation Complexes of Pentavalent Uranyl: From Disproportionation Intermediates to Stable Clusters

Mougel¹,

Horeglad²,

Nocton³

et al. 2010

Chemistry A European J

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Three new cation-cation complexes of pentavalent uranyl, stable with respect to the disproportionation reaction, have been prepared from the reaction of the precursor [(UO(2)py(5))(KI(2)py(2))](n) (1) with the Schiff base ligands salen(2-), acacen(2-), and salophen(2-) (H(2)salen = N,N'-ethylene-bis(salicylideneimine), H(2)acacen = N,N'-ethylenebis(acetylacetoneimine), H(2)salophen = N,N'-phenylene-bis(salicylideneimine)). The preparation of stable complexes requires a careful choice of counter ions and reaction conditions. Notably the reaction of 1 with salophen(2-) in pyridine leads to immediate disproportionation, but in the presence of [18]crown-6 ([18]C-6) a stable complex forms. The solid-state structure of the four tetranuclear complexes, {[UO(2)(acacen)](4)[μ(8)-](2)[K([18]C-6)(py)](2)} (3) and {[UO(2)(acacen)](4)[μ(8)-]}⋅2 [K([222])(py)] (4), {[UO(2)(salophen)](4)[μ(8)-K](2)[μ(5)-KI](2)[(K([18]C-6)]}⋅2 [K([18]C-6)(thf)(2)]⋅2 I (5), and {[UO(2)(salen)(4)][μ(8)-Rb](2)[Rb([18]C-6)](2)} (9) ([222] = [222]cryptand, py = pyridine), presenting a T-shaped cation-cation interaction has been determined by X-ray crystallographic studies. NMR spectroscopic and UV/Vis studies show that the tetranuclear structure is maintained in pyridine solution for the salen and acacen complexes. Stable mononuclear complexes of pentavalent uranyl are also obtained by reduction of the hexavalent uranyl Schiff base complexes with cobaltocene in pyridine in the absence of coordinating cations. The reactivity of the complex [U(V)O(2)(salen)(py)][Cp*(2)Co] with different alkali ions demonstrates the crucial effect of coordinating cations on the stability of cation-cation complexes. The nature of the cation plays a key role in the preparation of stable cation-cation complexes. Stable tetranuclear complexes form in the presence of K(+) and Rb(+), whereas Li(+) leads to disproportionation. A new uranyl-oxo cluster was isolated from this reaction. The reaction of [U(V)O(2)(salen)(py)][Cp*(2)Co] (Cp* = pentamethylcyclopentadienyl) with its U(VI) analogue yields the oxo-functionalized dimer [UO(2)(salen)(py)](2)[Cp*(2)Co] (8). The reaction of the {[UO(2)(salen)(4)][μ(8)-K](2)[K([18]C-6)](2)} tetramer with protons leads to disproportionation to U(IV) and U(VI) species and H(2)O confirming the crucial role of the proton in the U(V) disproportionation.

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Section: Resultsmentioning

confidence: 99%

Cation–Cation Complexes of Pentavalent Uranyl: From Disproportionation Intermediates to Stable Clusters

Mougel¹,

Horeglad²,

Nocton³

et al. 2010

Chemistry A European J

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“…79 In structure (d) the uranyl moieties have been disrupted to such an extent-actually destroyed-that a better description is two terminal U=Ot linked by two bridging Ob. Although O-atom bridging of intact uranyls is well known, [80][81] such uranyl destruction is not. The structural parameters for C indicate a core as in (d), though with both U also coordinated by a 12C4.…”

Section: Elaborating the "Cation-cation" Interaction In [(Uo2)2(12c4)mentioning

confidence: 99%

Destruction of the Uranyl Moiety in a U(V) “Cation–Cation” Interaction

Jian

et al. 2019

Inorg. Chem.

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A gas-phase uranyl peroxide dimer supported by three 12-Crown-4 ether (12C4) ligands, [(UO2)2(O2)(12C4)3)] 2+ (A), was prepared by electrospray ionization. Density functional theory (DFT) indicates a structure with two terminal 12C4 and the third 12C4 bridging the uranium centers. Collision induced dissociation (CID) of A resulted in elimination of the bridging 12C4 to yield a uranyl peroxide dimer with two terminal donor ligands, [(12C4)(UO2)(O2)(UO2)(12C4)] 2+ (B). Remarkably, CID of B resulted in elimination of the bridging peroxide concomitant with reduction of U(VI) to U(V) in C, [(12C4)(UO2)(UO2)(12C4)] 2+. DFT indicates that in C there is direct interaction between the two UO2 + , which can thus be considered as a so-called cation-cation interaction (CCI). This formal CCI, induced by tetradentate 12C4 ligands, corresponds to destruction of the linear uranyl moieties and creation of bridging U-O-U oxo-bonds. Based on the structural rearrangement to achieve the structurally extreme CCI interaction, it is predicted to also be accessible for PaO2 + , but is less feasible for transuranic actinyls.

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“…This kind of coordination structure fulfills the coordination number of 5-6 estimated by EXAFS, [24,[29][30][31][32][33][34][35][36] and has also been found in the crystalline structure of synthesized uranyl complexes. [4,14,19,[72][73][74][75][76] The calculated U À O CO 3 bond lengths in the adsorbed species range from 2.37 to 2.48 , intermediate between UÀOH and UÀOH 2 bond lengths. These UÀO CO 3 distances are comparable to the range of 2.43-2.52 obtained for the solid state structures of [ [4,75,76] The calculated U=O distances are lengthened compared with those of the aquouranyl-surface complex.…”

Section: à47 à35mentioning

confidence: 99%

Adsorption of Uranyl Species onto the Rutile (110) Surface: A Periodic DFT Study

Pan

Odoh

Asaduzzaman

et al. 2011

Chemistry A European J

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To model the structures of dissolved uranium contaminants adsorbed on mineral surfaces and further understand their interaction with geological surfaces in nature, we have performed periodic density funtional theory (DFT) calculations on the sorption of uranyl species onto the TiO(2) rutile (110) surface. Two kinds of surfaces, an ideal dry surface and a partially hydrated surface, were considered in this study. The uranyl dication was simulated as penta- or hexa-coordinated in the equatorial plane. Two bonds are contributed by surface bridging oxygen atoms and the remaining equatorial coordination is satisfied by H(2)O, OH(-), and CO(3)(2-) ligands; this is known to be the most stable sorption structure. Experimental structural parameters of the surface-[UO(2)(H(2)O)(3)](2+) system were well reproduced by our calculations. With respect to adsorbates, [UO(2)(L1)(x)(L2)(y)(L3)(z)](n) (L1=H(2)O, L2=OH(-), L3=CO(3)(2-), x≤3, y≤3, z≤2, x+y+2z≤4), on the ideal surface, the variation of ligands from H(2)O to OH(-) and CO(3)(2-) lengthens the U-O(surf) and U-Ti distances. As a result, the uranyl-surface interaction decreases, as is evident from the calculated sorption energies. Our calculations support the experimental observation that the sorptive capacity of TiO(2) decreases in the presence of carbonate ions. The stronger equatorial hydroxide and carbonate ligands around uranyl also result in U=O distances that are longer than those of aquouranyl species by 0.1-0.3 Å. Compared with the ideal surface, the hydrated surface introduces greater hydrogen bonding. This results in longer U=O bond lengths, shorter uranyl-surface separations in most cases, and stronger sorption interactions.

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Na₂Li₈[(UO₂)₁₁O₁₂(WO₅)₂]: Three Different Uranyl‐Ion Coordination Geometries and Cation–Cation Interactions

Cited by 19 publications

References 17 publications

Cation–Cation Complexes of Pentavalent Uranyl: From Disproportionation Intermediates to Stable Clusters

Cation–Cation Complexes of Pentavalent Uranyl: From Disproportionation Intermediates to Stable Clusters

Destruction of the Uranyl Moiety in a U(V) “Cation–Cation” Interaction

Adsorption of Uranyl Species onto the Rutile (110) Surface: A Periodic DFT Study

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