Spectroscopic investigation of the covalence of An(<scp>iii</scp>) complexes with tetraethylcarboxamidopyridine

Sittel, Thomas; Weßling, Patrik; Großmann, Dennis; Engels, Eliane; Geist, Andreas; Panak, Petra J.

doi:10.1039/d2dt00757f

Cited by 4 publications

(9 citation statements)

References 39 publications

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“…In the absence of TEDGA, the solvent species exhibits an emission band at 594.6 nm. This species has been previously documented in the literature and can be attributed to a partial replacement of water molecules in the first coordination sphere [9] . With gradual increase in ligand concentration, three new emission bands appear at 597.8 nm, 602.8 nm, and 608.8 nm.…”

Section: Resultssupporting

confidence: 70%

“…This species has been previously documented in the literature and can be attributed to a partial replacement of water molecules in the first coordination sphere. [9] With gradual increase in ligand concentration, three new emission bands appear at 597.8 nm, 602.8 nm, and 608.8 nm. These signify the progressive coordination of TEDGA with the Cm(III) ion.…”

Section: Trlfs Study Of the Cm(iii) Complexationmentioning

confidence: 97%

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Spectroscopic Study on the Complexation of trivalent Actinide and Lanthanide ions with TEDGA in Solution

Sittel,

Meißner,

Keller

et al. 2024

Eur J Inorg Chem

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NMR spectroscopy studies on the complexation of La(III), Sm(III), Lu(III), Y(III) and Am(III) with N,N,N’,N’‐tetraethyldiglycolamide (TEDGA) have been performed. Initial studies concerning the stoichiometry of the complexes prove the formation of [M(TEDGA)3]3+ in D2O and [M(TEDGA)1‐3]3+ in CD3CN. Decreasing the solvent polarity translates to an increase of the complex stability as shown by complementary TRLFS studies with Cm(III). Due to delocalization of the lone electron pair of the amide nitrogen atom, the M(III)‐O interaction has been studied indirectly by collecting 13C and 15N NMR data. The observed chemical shifts prove that the interaction of the trivalent ions, An(III) and Ln(III), and TEDGA is almost identical.

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Section: Resultssupporting

confidence: 70%

Section: Trlfs Study Of the Cm(iii) Complexationmentioning

confidence: 97%

Spectroscopic Study on the Complexation of trivalent Actinide and Lanthanide ions with TEDGA in Solution

Sittel,

Meißner,

Keller

et al. 2024

Eur J Inorg Chem

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“…Nonetheless, the obtained chemical shifts fall within the range of literature-known data of structurally related N-donor ligands. 14,15,19,24,26 Am Complex with C4-BPP. As a representative of the trivalent An ions, the complexation of Am(III) with C4-BPP is studied using 1D and 2D NMR methods.…”

Section: Speciation Studies Of Cm(iii) With C4-bppmentioning

confidence: 99%

“…Deuterated solvents were purchased from Euriso-Top GmbH. 2,11,24,26 TRLFS Sample Preparation. Stock solutions of C4-BPP were prepared by dissolving 85 mg in 1200 μL of methanol containing 1.5 vol % water (2.2 × 10 −1 mol/L).…”

Section: ■ Introductionmentioning

confidence: 99%

2,6-Bis(5-(tert-butyl)-1H-pyrazol-3-yl)pyridine: Effects of the Peripheral Aliphatic Side Chain on the Coordination of Actinides(III) and Lanthanides(III)

Stracke,

Weßling,

Sittel

et al. 2024

Inorg. Chem.

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To improve our understanding of the interaction mechanism in trivalent lanthanide and actinide complexes, studies with structurally different hard and soft donor ligands are of great interest. For that reason, the coordination chemistry of An(III) and Ln(III) with 2,6bis(5-(tert-butyl)-1H-pyrazol-3-yl)pyridine (C4-BPP) has been explored. Time-resolved laser fluorescence spectroscopy (TRLFS) studies have revealed the formation of [Cm(C4-BPP) n ] 3+ (n = 1−3) (log β 1 ′ = 7.2 ± 0.4, log β 2 ′ = 10.1 ± 0.5, and log β 3 ′ = 11.8 ± 0.6) and [Eu(C4-BPP) m ] 3+ (m = 1−2) (log β 1 ′ = 4.9 ± 0.2 and log β 2 ′ = 8.0 ± 0.4). The absence of the [Eu(C4-BPP) 3 ] 3+ complex shows a more favorable complexation of Cm(III) over that of Eu(III). Additionally, complementary NMR measurements have been conducted to examine the M(III)−N bond in Ln(III) and Am(III) C4-BPP complexes. 15 N NMR data have revealed notable differences in the chemical shifts of the coordinating nitrogen atoms between the Am(III) and Ln(III) complexes. In the Am(III) complex, the coordinating nitrogen atoms have shown a shift by 260 ppm, indicating a higher fraction of covalent bonding in the Am(III)−N bond compared with the Ln(III)−N bond. This observation aligns excellently with the differences in the stability constants obtained from TRLFS studies.

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“…Despite the rich chemical insight that NMR can offer, use of NMR spectroscopy with actinides, and particularly the transneptunium or transplutonium elements, is hampered by the limited availability of NMR laboratories with the ability to handle α emitters and long-lived radionuclides, as well as the cost and low availability of the actinide research isotopes. , A few recent solution-state studies have been performed using 1 H, 13 C, and/or 31 P NMR with actinium or americium − complexes, exploiting organic chelators, but those experiments were limited to one-dimensional (1D) NMR at room temperature. In rare cases, two-dimensional (2D) 1 H/ 13 C or 1 H/ 15 N NMR data have been reported on americium complexes with organic ligands. − Pioneering magnetic susceptibility measurements have also been reported for solutions of actinides in inorganic acids or actinide–organic ligand complexes. − Rare attempts to collect 1 H and/or 31 P NMR data on curium or californium complexes with organic ligands have been reported to have failed due to the lack of signal attributable to the actinide species. , …”

Section: Introductionmentioning

confidence: 99%

Contrasting Trivalent Lanthanide and Actinide Complexation by Polyoxometalates via Solution-State NMR

et al. 2022

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Deciphering the solution chemistry and speciation of actinides is inherently difficult due to radioactivity, rarity, and cost constraints, especially for transplutonium elements. In this context, the development of new chelating platforms for actinides and associated spectroscopic techniques is particularly important. In this study, we investigate a relatively overlooked class of chelators for actinide binding, namely, polyoxometalates (POMs). We provide the first NMR measurements on americium−POM and curium−POM complexes, using onedimensional (1D) 31 P NMR, variable-temperature NMR, and spin-lattice relaxation time (T 1 ) experiments. The proposed POM−NMR approach allows for the study of trivalent f-elements even when only microgram amounts are available and in phosphate-containing solutions where f-elements are typically insoluble. The solution-state speciation of trivalent americium, curium, plus multiple lanthanide ions (La 3+ , Nd 3+ , Sm 3+ , Eu 3+ , Yb 3+ , and Lu 3+ ), in the presence of the model POM ligand PW 11 O 39 7− was elucidated and revealed the concurrent formation of two stable complexes, [M III (PW 11 O 39 )(H 2 O) x ] 4− and [M III (PW 11 O 39 ) 2 ] 11− . Interconversion reaction constants, reaction enthalpies, and reaction entropies were derived from the NMR data. The NMR results also provide experimental evidence of the weakly paramagnetic nature of the Am 3+ and Cm 3+ ions in solution. Furthermore, the study reveals a previously unnoticed periodicity break along the f-element series with the reversal of T 1 relaxation times of the 1:1 and 1:2 complexes and the preferential formation of the long T 1 species for the early lanthanides versus the short T 1 species for the late lanthanides, americium, and curium. Given the broad variety of POM ligands that exist, with many of them containing NMR-active nuclei, the combined POM−NMR approach reported here opens a new avenue to investigate difficultto-study elements such as heavy actinides and other radionuclides.

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Spectroscopic investigation of the covalence of An(iii) complexes with tetraethylcarboxamidopyridine

Abstract: In this work, we report a combined NMR spectroscopic and time-resolved laser fluorescence spectroscopic (TRLFS) study of the complexation of N,N,N',N'-tetraethyl-2,6-carboxamidopyridine (Et-Pic) with Ln(III) (La, Sm, Eu, Lu), Y(III) and...

Cited by 4 publications

References 39 publications

Spectroscopic Study on the Complexation of trivalent Actinide and Lanthanide ions with TEDGA in Solution

Spectroscopic Study on the Complexation of trivalent Actinide and Lanthanide ions with TEDGA in Solution

2,6-Bis(5-(tert-butyl)-1H-pyrazol-3-yl)pyridine: Effects of the Peripheral Aliphatic Side Chain on the Coordination of Actinides(III) and Lanthanides(III)

Contrasting Trivalent Lanthanide and Actinide Complexation by Polyoxometalates via Solution-State NMR

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