Acetate Complexes of the Rare Earth and Several Transition Metal Ions

Kolat, R. S.; Powell, J.E.

doi:10.1021/ic50002a019

Cited by 110 publications

(37 citation statements)

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“…The obtained values logK ac = 2.25, logK ac2 = 1.6 are in good agreement with previous potentiometric determinations logK ac = 2.2, logK ac2 = 1.6 at about the same ionic strength [41] and logK ac = 2.5, logK ac2 = 2.1 in the infinite dilution limit. [46] In order to determine the formation constants K mfa and K dfa , we resorted to the experimental relaxivities reported in Table 1.…”

Section: Variation Of the Ligand Concentrationsupporting

confidence: 91%

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Paramagnetic Relaxation Enhancements in Acetate and Its Fluorine Derivatives Interacting with Gd³⁺: Complex Formation, Structure, and Transmetallation

Bonnet¹,

Fries²

2010

ChemPhysChem

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The relative spatial distribution and motion with respect to Gd(3+) of the (1)H and (19)F nuclei in the acetate ion and its fluorine derivatives are studied in D(2)O solutions through the paramagnetic relaxation rate enhancements (PREs) of these nuclei. We derive general theoretical expressions of the longitudinal PRE in terms of the analytical concentrations of metal and ligands, formation constants of the complexes, metal-nucleus distances, and coordination lifetimes of the ligands. The observed formation constants of the 1 metal: 1 ligand complexes markedly decrease with increasing number of fluorine atoms, the electronegativity of which reduces the negative partial charge of the coordinating COO(-) group. The coordination lifetimes are very short at the scale of the relaxation times of the protons of metal bound acetate, that is, shorter than about 10 μs. The average distance of the acetate protons from Gd(3+) is in fair agreement with independent crystallographic determination. The release of free Gd(3+) from the very stable Gddtpa (dtpa=diethylene-triaminepentaacetate) complex caused by the competition of Zn(2+) for dtpa, is evidenced by an increase of the PREs with Zn(2+) concentration. The observed PRE increase is consistent with the known equilibrium constants governing the speciation involving Gd(3+), Zn(2+), and dtpa. The present case study illustrates a method which easily yields experimental tunable properties suitable to test the ongoing theories of lanthanide Ln(3+) complexation in solution.

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Section: Variation Of the Ligand Concentrationsupporting

confidence: 91%

“…We also consider the formation of Zn(acetate) (Znac) complex according to the reaction in Equation (33): [41] Zn…”

Section: Transmetallationmentioning

confidence: 99%

Paramagnetic Relaxation Enhancements in Acetate and Its Fluorine Derivatives Interacting with Gd³⁺: Complex Formation, Structure, and Transmetallation

Bonnet¹,

Fries²

2010

ChemPhysChem

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“…It can be shown that acetate complexing is the predominant factor operating in the aqueous phase. KOLAT and POWELL [22] indicate that the stability constants logXi at an ionic strength of 0.1M for acetate complexing decrease from Eu(III) (logA", 2.31) to Lu(III) (ΙοβΛΓι 2.05). Accordingly the effect should be less for Lu(III) than Eu(III) as observed in the present work (Table 1).…”

Section: Methodsmentioning

confidence: 99%

Liquid-Liquid Extraction of Trivalent Actinides and Lanthanides with N-Benzoyl-N-Phenyl Hydroxylamine

Mathur

Khopkar

1986

Radiochimica Acta

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Extraction of the trivalent actinides Am, Cm, Bk and Cf and the trivalent lanthanides Pm, Eu, Tb, Tm and Lu has been studied with N-benzoyl-N-phenyl hydroxylamine (HBPHA) in chloroform in the pH range 3.5-4.5. At pH 4.5 slopes of the logD vs. log [HBPHA] plots progressively decrease from 4 to 3 with increasing Ζ of the ions. Similar plots at pH 4.0 gave a uniform slope of 4 in all cases indicating the extraction of M(BPHA) 3 HBPHA (M = An, Ln). In the pH ranges where this species is extracted log D vs. pH plots gave straight lines with slopes increasing from 2.0 to 2.7 with Ζ instead of the expected value of 3.0. Reasons for these abnormalities are discussed.

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“…Stability constant sequences have been reported for acetate (12)(13)(14)(15)(16), glycolate (14,15,(17)(18)(19)(20)(21), methoxyacetate (17,22), thioglycolate (17,(22)(23)(24), and aminoacetate (17). As one replaces a hydrogen next to the carboxylate group, one finds that the order of stability enhancement is NHg > OH > OCEj » SH.…”

Section: Review Of Literature On the Rare-earth Complexesmentioning

confidence: 99%

The stability constants of rare-earths with some carboxylic acids

Schoeb

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Acetate Complexes of the Rare Earth and Several Transition Metal Ions

Cited by 110 publications

References 0 publications

Paramagnetic Relaxation Enhancements in Acetate and Its Fluorine Derivatives Interacting with Gd³⁺: Complex Formation, Structure, and Transmetallation

Paramagnetic Relaxation Enhancements in Acetate and Its Fluorine Derivatives Interacting with Gd³⁺: Complex Formation, Structure, and Transmetallation

Liquid-Liquid Extraction of Trivalent Actinides and Lanthanides with N-Benzoyl-N-Phenyl Hydroxylamine

The stability constants of rare-earths with some carboxylic acids

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Acetate Complexes of the Rare Earth and Several Transition Metal Ions

Cited by 110 publications

References 0 publications

Paramagnetic Relaxation Enhancements in Acetate and Its Fluorine Derivatives Interacting with Gd3+: Complex Formation, Structure, and Transmetallation

Paramagnetic Relaxation Enhancements in Acetate and Its Fluorine Derivatives Interacting with Gd3+: Complex Formation, Structure, and Transmetallation

Liquid-Liquid Extraction of Trivalent Actinides and Lanthanides with N-Benzoyl-N-Phenyl Hydroxylamine

The stability constants of rare-earths with some carboxylic acids

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Paramagnetic Relaxation Enhancements in Acetate and Its Fluorine Derivatives Interacting with Gd³⁺: Complex Formation, Structure, and Transmetallation

Paramagnetic Relaxation Enhancements in Acetate and Its Fluorine Derivatives Interacting with Gd³⁺: Complex Formation, Structure, and Transmetallation