Complexation thermodynamics and structural aspects of actinide–aminopolycarboxylates

Choppin, Gregory R.; Thakur, P.; Mathur, J. N.

doi:10.1016/j.ccr.2006.02.003

Cited by 80 publications

(72 citation statements)

References 35 publications

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“…[42,50] The high value of relaxivity measured for [GdA C H T U N G T R E N N U N G (dpaa) 2 ] 3À (r 1p = 6.4 mm À1 s À1 at 200 MHz, 298 K) is in agreement with the presence of a coordinated water molecule, as observed for the terbium complex.…”

Section: Synthesissupporting

confidence: 78%

“…Similar behaviour was observed for the terbium complex, and similar coordination behaviour was previously observed for ternary complexes of lanthanides with polyaminocarboxylate ligands. [42,43] Solution structure of the Ln III complexes: The lanthanide complexes of dpaa 2À show a very high solubility in water, which is different from the complexes of the heptadentate tpaa 3À ligand as they are rather insoluble in water. As in both cases the complexes have neutral charges, the higher solubility probably arises from the removal of one pyridyl ring.…”

Section: Synthesismentioning

confidence: 99%

See 1 more Smart Citation

Structure, Stability, Dynamics, High‐Field Relaxivity and Ternary‐Complex Formation of a New Tris(aquo) Gadolinium Complex

Nonat

Fries

Pécaut

et al. 2007

Chemistry A European J

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The tripodal hexadentate picolinate ligand dpaa3- (H3dpaa=N,N'-bis[(6-carboxypyridin-2-yl)methyl]glycine) has been synthesised. It can form 1:1 and 1:2 lanthanide/ligand complexes. The crystal structure of the bis(aquo) lutetium complex [Lu(dpaa)(H2O)2] has been determined by X-ray diffraction studies. The number of water molecules was determined by luminescence lifetime studies of the terbium and europium complexes. The tris(aquo) terbium complex shows a fairly high luminescence quantum yield (22 %). The [Gd(dpaa)(H2O)3] complex displays a high water solubility and an increased stability (pGd=12.3) with respect to the analogous bis(aquo) complex [Gd(tpaa)(H2O)2] (pGd=11.2). Potentiometric and relaxometric studies show the formation of a soluble GdIII hydroxo complex at high pH values. A unique aquohydroxo gadolinium complex has been isolated and its crystal structure determined. This complex crystallises as a 1D polymeric chain consisting of square-shaped tetrameric units. In heavy water, the [Gd(dpaa)-(D2O)3] complex shows a quite high HOD proton relaxivity at high field (11.93 s(-1) mM(-1) at 200 MHz and 298 K) because of the three inner-sphere water molecules. The formation of ternary complexes with physiological anions has been monitored by relaxometric studies, which indicate that even under conditions favourable to the formation of adducts with oxyanions, the mean relaxivity remains higher than those of most of the currently used commercial contrast agents except for the citrate. However, the measured relaxivity (r1=7.9 s(-1) mM(-1)) in a solution containing equimolar concentrations of [Gd(dpaa)(D2O)3] and citrate is still high. The interaction with albumin has been investigated by relaxometric and luminescence studies. Finally, a new versatile method to unravel the geometric and dynamic molecular factors that explain the high-field relaxivities has been developed. This approach uses a small, uncharged non-coordinating probe solute, the outer-sphere relaxivity of which mimics that of the water proton. Only a routine NMR spectrometer and simple mathematical analysis are required.

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Section: Synthesissupporting

confidence: 78%

Section: Synthesismentioning

confidence: 99%

Structure, Stability, Dynamics, High‐Field Relaxivity and Ternary‐Complex Formation of a New Tris(aquo) Gadolinium Complex

Nonat

Fries

Pécaut

et al. 2007

Chemistry A European J

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“…This indicates that, as dehydration of the metal requires energy to break the cation-water and water-water bonding of the hydration layers, the energy required to break bonds with water is higher than the energy released during the formation of metal-ligand bonds. [27] This endoergic dehydration effect overcomes exoergic metal-oxygen interactions, except for some complex species of monomethyltin(IV) with mal, succ, toda, tca, cit and btc and some others of di-and trimethyltin(IV) with cit.…”

Section: Enthalpy and Entropy Changesmentioning

confidence: 99%

Interaction of methyltin(IV) compounds with carboxylate ligands. Part 2: formation thermodynamic parameters, predictive relationships and sequestering ability

Stefano

Gianguzza

Giuffrè

et al. 2007

Applied Organom Chemis

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Thermodynamic data of mono-, di-and tri-methyltin(IV)-carboxylate complexes (acetate, malonate, succinate, oxydiacetate, diethylenetrioxydiacetate, malate, citrate, 1,2,3-tricarballylate, 1,2,3,4-butanetetracarboxylate, 1,2,3,4,5,6-benzenehexacarboxylate) in aqueous solution are reported at t = 25• C and I = 0 mol l −1 . Thermodynamic parameters obtained were analysed to formulate empirical predictive relationships as a function of different parameters, such as the number of carboxylate groups of the ligand and the charge of the alkyltin(IV) cation. Sequestration diagrams of citrate and 1,2,3-tricarballylate towards alkyltin(IV) cations at different pH values are also reported and discussed.

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“…Linear free-energy relationship (LFER) are often used to assess the reliability of stability constants along the An(IV) series [17][18][19]. The log * β 0 1,4,1 value determined in this work was compared with other data available in the literature for An(IV)(OH) 4 GLU − complexes.…”

Section: Comparison With Other Actinides: Linear Free-energy Relationmentioning

confidence: 99%

Thermodynamics of Np(IV) complexes with gluconic acid under alkaline conditions: sorption studies

Rojo¹,

Tits²,

Gaona³

et al. 2013

Radiochimica Acta

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The complexation of Np(IV) with gluconic acid (GLU) under alkaline conditions was investigated in the absence of Ca by carrying out a series of sorption experiments. The decrease of Np(IV) sorption on the sorbing material at increasing concentrations of GLU was interpreted as the formation of Np(IV)-GLU aqueous complexes. The modelling of experimental data according to the Schubert method [1] confirmed the formation of a complex with a Np : GLU ratio 1 : 1. The stoichiometry of the complex Np(OH)4GLU− was proposed based on the experimental observation that no proton exchange occurred during the course of the complexation reaction and that Np(OH)4(aq) was the predominant hydrolysis product in the absence of GLU. A log * β 1,4,1 0 = −2.92 ± 0.30 for the formation reaction Np4+ + 4H2O + GLU−⇔Np(OH)4GLU− + 4H+ was calculated based on the conditional stability constants determined from sorption experiments and using the Np(IV) thermodynamic data selected in the NEA reviews [2]. Linear free energy relationships (LFER) confirmed that the stoichiometry and stability of the Np(IV)-GLU complex characterized in this work are consistent with data available for Th(IV)-, U(IV)- and Pu(IV)-GLU complexes.

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Complexation thermodynamics and structural aspects of actinide–aminopolycarboxylates

Cited by 80 publications

References 35 publications

Structure, Stability, Dynamics, High‐Field Relaxivity and Ternary‐Complex Formation of a New Tris(aquo) Gadolinium Complex

Structure, Stability, Dynamics, High‐Field Relaxivity and Ternary‐Complex Formation of a New Tris(aquo) Gadolinium Complex

Interaction of methyltin(IV) compounds with carboxylate ligands. Part 2: formation thermodynamic parameters, predictive relationships and sequestering ability

Thermodynamics of Np(IV) complexes with gluconic acid under alkaline conditions: sorption studies

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