Formation Constants of Phosphotungstate Complexes of Europium(III)

Bion, Lionel; Mercier, Florence; Decambox, P.; Moisy, Ph.

doi:10.1524/ract.1999.87.34.161

Cited by 13 publications

(11 citation statements)

References 4 publications

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“…Figure 5. The absolute formation constants, log β 2 , of Bion et al [10] versus 1/IR of Shannon [27] for CN ϭ VIII of the Ce 3ϩ , Am 3ϩ , Eu 3ϩ , U 4ϩ , Ce 4ϩ , and Pu 4ϩ ions (in order of increasing 1/IR) for the WellsϪDawson butterfly complexes of Figure 1(a). The leastsquares fit (dashed line, R 2 ϭ 0.889) with slope ϭ 177Ϯ31 and intercept ϭ Ϫ145Ϯ30.…”

Section: Resultsmentioning

confidence: 99%

“…In fact, the fixed eightfold O coordination for all An/Ln ions in the WellsϪDawson butterfly series of Figure 1(a) may not result in the formation of especially robust complexes with the large Ln 3ϩ and An 3ϩ compared with the smaller ones, including the tetravalent ions. This view is borne out in the data of Figure 5, which is a plot of the formation constants, logβ 2 , available from the work of Bion et al [10] versus 1/IR for CN ϭ VIII of Ce 3ϩ , Am 3ϩ , Eu 3ϩ , U 4ϩ , Ce 4ϩ , and Pu 4ϩ . Based upon interpretations of similar plots for other Ln 3ϩ complexes, [29,31] the overall direct dependence of logβ 2 with 1/IR is evidence that the coordination does not change.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Similar, albeit weaker, complexation with the trivalent actinides is also known. [10] The crystal structures of the lanthanide clusters [Lu(α-2-P 2 W 17 O 61 ) 2 ] 17Ϫ and [Ce(α-2-P 2 W 17 O 61 ) 2 ] 16Ϫ reveal eight-coordinate square antiprism geometries for both Lu 3ϩ and Ce 4ϩ . [11,12] The common structure is illustrated in Figure 1 [11] and (b) [Np(W 5 O 18 ) 2 ] 8Ϫ [13] that emphasize the square antiprism oxygen coordination environments of the Lu 3ϩ (IR ϭ 0.977 A ˚) and Np 4ϩ (IR ϭ 0.98 A ˚) ions, depicted as the central solid circles.…”

Section: Introductionmentioning

confidence: 99%

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Coordination of Actinide Ions in Wells−Dawson Heteropolyoxoanion Complexes

et al. 2003

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Although many low-valent (III, IV) actinide (An) ions are known to form coordination complexes with the α-2 isomer of the lacunary Wells−Dawson polyoxoanion, [P 2 W 17 O 61 ] 10− , there is little structural information about the An−O interactions, particularly in solution. We have probed the An−O coordination environment for the series of clusters [An(α-2-P 2 W 17 O 61 ) 2 ] n− with An 4+ (Th 4+ , U 4+ , Np 4+ , Pu 4+ ) and An 3+ (Np 3+ , Pu 3+ , Am 3+ ) in both solution and solid phases using Xray absorption fine structure (XAFS). Comparisons are made with the lanthanide (Ln) coordination environments in the series of 4f-ion clusters, [Ln n+ (α-2-P 2 W 17 O 61 ) 2 ] n−20 , and with the related monovacant Lindqvist anions, [Ln n+ (W 5 O 18 ) 2 ] n−12 , 2663 for n = 3, 4. The average An−O 8 and Ln−O 8 distances correlate with their cationic VIII-coordinate ionic radii, indicating that the An and Ln ions have indistinguishable coordination behavior. Metrical details are consistent with simple charge and size considerations for both trivalent and tetravalent An ions as well as Ln ions coordinated with α-2-[P 2 W 17 O 61 ] 10− and [W 5 O 18 ] 6− . This result is contrasted to trends established for these f-ions coordinated to the Preyssler anion [Ln n+ P 5 W 30 O 110 ] n−15 .

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Coordination of Actinide Ions in Wells−Dawson Heteropolyoxoanion Complexes

et al. 2003

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“…available data reveal high formation constants with transition metal and RE ions. 5,6,9,13,[18][19][20][21][22][23] The R-1and R-2-[P 2 W 17 O 61 ] 10isomers are useful ligands for stabilizing tetravalent cations, especially the otherwise reactive ones of the lanthanide (Ln) and actinide (An) elements. [24][25][26][27][28][29] As such, these polyoxometalates, specifically, the R-2-[P 2 W 17 O 61 ] 10isomer, find applications to selected aspects of An separations science in nuclear waste processing.…”

Section: Introductionmentioning

confidence: 99%

Coordination of Rare-Earth Elements in Complexes with Monovacant Wells−Dawson Polyoxoanions

et al. 2001

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The alpha-1 and alpha-2 isomers of the monovacant Wells-Dawson heteropolyoxoanion [P(2)W(17)O(61)](10-) are complexants of trivalent rare-earth (RE) ions and serve to stabilize otherwise reactive tetravalent lanthanide (Ln) and actinide (An) ions in aqueous solution. Aspects of the bonding of Ln ions with alpha-1-[P(2)W(17)O(61)](10-) and alpha-2-[P(2)W(17)O(61)](10-) were investigated to address issues of complex formation and stability. We present structural insights about the Ln(III) coordination environment and hydration in two types of stoichiometric complexes, [Ln(alpha-1-P(2)W(17)O(61))](7-) and [Ln(alpha-2-X(2)W(17)O(61))(2)](17-) (for Ln identical with Sm, Eu, Lu; X identical with P, As). The crystal and molecular structures of [(H(2)O)(4)Lu(alpha-1-P(2)W(17)O(61))](7-) (1) and [Lu(alpha-2-P(2)W(17)O(61))(2)](17-) (2) were solved and refined through use of single-crystal X-ray diffraction. The crystallographic results are supported with corresponding insights from XAFS (X-ray absorption fine structure) for a series of nine solid-state complexes as well as from optical luminescence spectroscopy of the Eu(III) analogues in aqueous solution. All the Ln ions are eight-coordinate with oxygen atoms in a square antiprism arrangement. For the 1:1 stoichiometric Ln/alpha-1-[P(2)W(17)O(61)](10-) complexes, the Ln ions are bound to four O atoms of the lacunary polyoxometalate framework in addition to four O atoms from solvent (water) molecules as [(H(2)O)(4)Ln(alpha-1-P(2)W(17)O(61))](7-). This structure (1) is the first of its kind for any metal complex of alpha-1-[P(2)W(17)O(61)](10-), and the data indicate that the general stoichiometry [(H(2)O)(4)Ln(alpha-1-P(2)W(17)O(61))](7-) is maintained throughout the lanthanide series. For the 1:2 stoichiometric Ln/alpha-2-[X(2)W(17)O(61)](10-) complexes, no water molecules are in the Ln-O(8) coordination sphere. The Ln ions are bound to eight O atoms-four from each of two heteropolyanions-as [Ln(alpha-2-X(2)W(17)O(61))(2)](17-). The average Ln-O interatomic distances decrease across the lanthanide series, consistent with the decreasing Ln ionic radius.

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Rational approach of the stoichiometries of lanthanide complexes with α2-[P2W17O61]10− heteropolytungstate in aqueous solution

Keita

Nadjo

2004

Polyhedron

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Formation Constants of Phosphotungstate Complexes of Europium(III)

Cited by 13 publications

References 4 publications

Coordination of Actinide Ions in Wells−Dawson Heteropolyoxoanion Complexes

Coordination of Actinide Ions in Wells−Dawson Heteropolyoxoanion Complexes

Coordination of Rare-Earth Elements in Complexes with Monovacant Wells−Dawson Polyoxoanions

Rational approach of the stoichiometries of lanthanide complexes with α2-[P2W17O61]10− heteropolytungstate in aqueous solution

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