Spectroscopic, electrochemical, and structural aspects of the Ce(IV)/Ce(III) DOTA redox couple chemistry in aqueous solutions

Moiseev, Yulia; Ben‐Eliyahu, Yeshayahu; Audras, Matthieu; Berthon, Laurence; Moisy, Philippe; Bettelheim, A.; Zilbermann, Israel

doi:10.1080/00958972.2016.1225199

Cited by 11 publications

(28 citation statements)

References 30 publications

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“…The spectrum of the produced solution (Figure 2a) showed a band at 270 nm (ε = 6700 ± 700 M −1 cm −1 ) and a broad absorbance until ∼450 nm. The product kept in light decomposed with a t 1/2 of 2.5 h as previously reported, 24 but when kept in the dark, less than 5% decomposed in 12 days (Figure 2a), indicating that [Ce IV DOTA(CO 3 )] 2− electrochemically produced decomposes photolytically. The presence of oxygen (air) had no influence on the decomposition rate.…”

Section: ■ Results and Discussionsupporting

confidence: 82%

“…Electrochemistry. According to a previous study 24 the redox potential (E 1/2 ) of the couple Ce IV/III DOTA(H 2 O) (in cage) was determined to be +0.65 V vs SCE (0.67 V vs Ag/ AgCl (sat. KCl)) (in the pH range 2−9).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…In the case of Ce III DOTA, the redox potential of Ce IV/III DOTA is definitely more cathodic than that of CO 3 •– , which is a strong one-electron oxidizing agent in aqueous solutions, E °(CO 3 •– , H + /HCO 3 – ) = 1.78 V vs SHE at pH 7.0 and 1.57 V , vs SHE at pH 12.0. It was already shown using the pulse radiolysis technique that CO 3 •– oxidizes Ce III to Ce IV in 0.75 M K 2 CO 3 (the redox potential for [Ce IV (CO 3 ) 5 ] 6– /[Ce III (CO 3 ) 3 ] 3– in 1.0 M Na 2 CO 3 ; 0.10 M NaHCO 3 is 0.233 V vs SHE) with a rate constant of 4.3 × 10 7 M –1 s –1 …”

Section: Introductionmentioning

confidence: 98%

“…The coordination number of metal cations complexed in cage is often 9 for Ln III , An III , and An IV . 14,22,23 In a relatively recent study, 24 Ce IV DOTA was produced both chemically and electrochemically from [Ce III (DOTA)] − in cage with an E 1/2 value for Ce IV/III DOTA of +0.65 V vs SCE (in the pH range 2−9). Its out-of-cage isomer at pH 2 has an E 1/2 value higher than the redox potential of water oxidation and therefore could not be measured.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Its out-of-cage isomer at pH 2 has an E 1/2 value higher than the redox potential of water oxidation and therefore could not be measured. 24 As the DOTA ligand is expected to exhibit enhanced Am/Ln separation efficiency at equilibrium, 14 in nuclear processes the chemistry of lanthanide metal complexes exposed to ionizing radiation is of interest. These processes could be carried out in alkaline media.…”

Section: ■ Introductionmentioning

confidence: 99%

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Redox Properties of Ce^IVDOTA in Carbonated Aqueous Solutions. A Radiolytic and an Electrochemical Study

Popivker¹,

Meyerstein

Gitin

et al. 2021

J. Phys. Chem. A

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The redox chemistry of Ce III DOTA in cage in carbonate solutions was studied using electrochemistry and radiolysis techniques (continuous radiolysis and pulse radiolysis). Spectroscopic measurements point out that the species present in the solutions at high bicarbonate concentrations are [Ce III DOTA(CO 3 )] 3− (or less plausible [Ce III DOTA-(HCO 3 )] 2− ) with the carbonate (bicarbonate) anion as the ninth ligand versus [Ce III DOTA(H 2 O)] − present in the absence of bicarbonate. Electrochemical results show a relatively low increase in the thermodynamic stabilization of the redox couple Ce IV/III in the presence of carbonate versus its aqueous analogue. [Ce IV DOTA(CO 3 )] 2− and [Ce IV DOTA-(H 2 O)], prepared electrochemically, decompose photolytically. However, kept in the dark, both are relatively long lived; [Ce IV DOTA(H 2 O)], though, is orders of magnitude kinetically more stable (a considerably longer half-life). Thus, one concludes that the carbonate species have a different mechanism of decomposition depending also on the presence of dioxygen after its preparation (in deaerated/ aerated solutions). The [Ce IV DOTA(CO 3 )] 2− species is produced radiolytically by oxidation of the trivalent species by CO 3•− with a rate constant, measured using pulse radiolysis, of 3.3 × 10 5 M −1 s −1 . This rate constant is at least 1 order of magnitude smaller than most of the rate constants so far reported for the reaction of CO 3•− with transition metal/lanthanide (cerium)/actinide complexes. This result together with the bulkiness of the reactants might suggest an outer-sphere electron transfer rather than the inner-sphere one so far proposed. The lifetime of the tetravalent cerium species obtained radiolytically in the presence of carbonate is shorter than the electrochemical one, suggesting a different conformer involved.

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Section: ■ Results and Discussionsupporting

confidence: 82%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Redox Properties of Ce^IVDOTA in Carbonated Aqueous Solutions. A Radiolytic and an Electrochemical Study

Popivker¹,

Meyerstein

Gitin

et al. 2021

J. Phys. Chem. A

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On the Aqueous Chemistry of the U^IV–DOTA Complex

Dovrat

Illy

Berthon

et al. 2020

Chemistry A European J

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The 1,4,7,10‐tetrazacyclodecane‐1,4,7,10‐tetraacetic acid (DOTA) aqueous complex of UIV with H2O, OH−, and F− as axial ligands was studied by using UV/Vis spectrophotometry, ESI‐MS, NMR spectroscopy, X‐ray crystallography, and electrochemistry. The UIV–DOTA complex with either water or fluoride as axial ligands was found to be inert to oxidation by molecular oxygen, whereas the complex with hydroxide as an axial ligand slowly hydrolyzed and was oxidized by dioxygen to a diuranate precipitate. The combined data set acquired shows that, although axial substitution of fluoride and hydroxide ligands instead of water does not seem to significantly change the aqueous DOTA complex structure, it has an important effect on the electronic configuration of the complex. The UIV/UIII redox couple was found to be quasi‐reversible for the complex with both axially bonded H2O and hydroxide, but irreversible for the complex with axially bonded fluoride. Intriguingly, binding of the axial fluoride renders the irreversible one‐electron UV/UIV oxidation of the [UIV(DOTA)(H2O)] complex quasi‐reversible, which suggests the formation of the short‐lived pentavalent form of the complex, an aqueous non‐uranyl chelated UV cation.

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Oligomers Intermediates in Between Two New Distinct Homonuclear Uranium(IV) DOTP Complexes**

Dovrat

Pevzner²,

Berthon

et al. 2021

Chemistry A European J

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Two new aqueous UIV complexes were synthesized by the interaction between the tetravalent uranium cation and the (1,4,7,10‐Tetraazacyclododecane‐1,4,7,10‐tetra(methylene phosphonic acid) (DOTP) macrocyclic ligand. Two distinct homonuclear complexes were identified; the first was characterized by X‐ray crystallography as a unique “out‐of‐cage”, [U(DOTPH6)2] complex, in which the UIV cation is octa‐coordinated to 4 phosphonic arms from each ligand in a square anti‐prism geometry, with a C4 symmetry. The second is the “in‐cage” [U(DOTPH4)] complex, in which the tetravalent cation is located between the macrocycle O4 and N4 planes. With the help of UV‐Vis absorption, 1H/31P NMR, ATR‐IR, and MALDI‐TOFMS analytical techniques, the chemical interchange between both species is presented. It is shown that the one‐way transition is governed by the formation of a multiple number of soluble oligomeric species consisting of varied stoichiometric ratios of both characterized homonuclear complexes.

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Spectroscopic, electrochemical, and structural aspects of the Ce(IV)/Ce(III) DOTA redox couple chemistry in aqueous solutions

Cited by 11 publications

References 30 publications

Redox Properties of Ce^IVDOTA in Carbonated Aqueous Solutions. A Radiolytic and an Electrochemical Study

Redox Properties of Ce^IVDOTA in Carbonated Aqueous Solutions. A Radiolytic and an Electrochemical Study

On the Aqueous Chemistry of the U^IV–DOTA Complex

Oligomers Intermediates in Between Two New Distinct Homonuclear Uranium(IV) DOTP Complexes**

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Spectroscopic, electrochemical, and structural aspects of the Ce(IV)/Ce(III) DOTA redox couple chemistry in aqueous solutions

Cited by 11 publications

References 30 publications

Redox Properties of CeIVDOTA in Carbonated Aqueous Solutions. A Radiolytic and an Electrochemical Study

Redox Properties of CeIVDOTA in Carbonated Aqueous Solutions. A Radiolytic and an Electrochemical Study

On the Aqueous Chemistry of the UIV–DOTA Complex

Oligomers Intermediates in Between Two New Distinct Homonuclear Uranium(IV) DOTP Complexes**

Contact Info

Product

Resources

About

Redox Properties of Ce^IVDOTA in Carbonated Aqueous Solutions. A Radiolytic and an Electrochemical Study

Redox Properties of Ce^IVDOTA in Carbonated Aqueous Solutions. A Radiolytic and an Electrochemical Study

On the Aqueous Chemistry of the U^IV–DOTA Complex