Observations on the rare earths—LXXV(1)

Moeller, Therald; Thompson, Larry C.

doi:10.1016/0022-1902(62)80236-x

Cited by 147 publications

(41 citation statements)

References 28 publications

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“…The rate constants k 1 were determined earlier in the same pH range in the absence of citrate and phosphate in our laboratory. The protonation of the GdL complexes reduces the number of coordinated donor atoms and although it occurs at a carboxylate group (the protonation constant of GdA C H T U N G T R E N N U N G (DTPA) 2À is log K GdHL = 2.39), [58] the proton can be transferred to a terminal N atom of the diethylenetriamine backbone, when a free iminodiacetate (IMDA) or an IMDA-(mono)amide fragment is formed and by a slow, successive decoordination of further donor atoms, the dissociation may take place. (For the GdA C H T U N G T R E N N U N G (DOTA) À the rate constant k 1 was determined at 37 8C, where k 1 = 2.0 10 À5 m À1 s À1 ).…”

Section: Dissociation Rates Of Gda C H T U N G T R E N N U N G (Dtpa)mentioning

confidence: 99%

Dissociation Kinetics of Open‐Chain and Macrocyclic Gadolinium(III)‐Aminopolycarboxylate Complexes Related to Magnetic Resonance Imaging: Catalytic Effect of Endogenous Ligands

Baranyai

Pálinkás

Uggeri

et al. 2012

Chemistry A European J

101

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The kinetics of the metal exchange reactions between open-chain Gd(DTPA)(2-) and Gd(DTPA-BMA), macrocyclic Gd(DOTA)(-) and Gd(HP-DO3A) complexes, and Cu(2+) ions were investigated in the presence of endogenous citrate, phosphate, carbonate and histidinate ligands in the pH range 6-8 in NaCl (0.15 M) at 25 °C. The rates of the exchange reactions of Gd(DTPA)(2-) and Gd(DTPA-BMA) are independent of the Cu(2+) concentration in the presence of citrate and the reactions occur via the dissociation of Gd(3+) complexes catalyzed by the citrate ions. The HCO(3)(-)/CO(3)(2-) and H(2)PO(4)(-) ions also catalyze the dissociation of complexes. The rates of the dissociation of Gd(DTPA-BMA), catalyzed by the endogenous ligands, are about two orders of magnitude higher than those of the Gd(DTPA)(2-). In fact near to physiological conditions the bicarbonate and carbonate ions show the largest catalytic effect, that significantly increase the dissociation rate of Gd(DTPA-BMA) and make the higher pH values (when the carbonate ion concentration is higher) a risk-factor for the dissociation of complexes in body fluids. The exchange reactions of Gd(DOTA)(-) and Gd(HP-DO3A) with Cu(2+) occur through the proton assisted dissociation of complexes in the pH range 3.5-5 and the endogenous ligands do not affect the dissociation rates of complexes. More insights into the interaction scheme between Gd(DTPA-BMA) and Gd(DTPA)(2-) and endogenous ligands have been obtained by acquiring the (13)C NMR spectra of the corresponding diamagnetic Y(III)-complexes, indicating the increase of the rates of the intramolecular rearrangements in the presence of carbonate and citrate ions. The herein reported results may have implications in the understanding of the etiology of nephrogenic systemic fibrosis, a rare disease that has been associated to the administration of Gd-containing agents to patients with impaired renal function.

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Section: Dissociation Rates Of Gda C H T U N G T R E N N U N G (Dtpa)mentioning

confidence: 99%

Dissociation Kinetics of Open‐Chain and Macrocyclic Gadolinium(III)‐Aminopolycarboxylate Complexes Related to Magnetic Resonance Imaging: Catalytic Effect of Endogenous Ligands

Baranyai

Pálinkás

Uggeri

et al. 2012

Chemistry A European J

101

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“…h For Zr 4+ , [67BAc] gives an estimate of lg K(M + L) = 37 (1) (1.0 mol L -1 NaClO 4 , 20 °C), which is considered the most reliable among data published. i For the rare earths, the sequence reported by [62MTc] (0.1 mol L -1 KNO 3 , 25 °C, Conc. ), is recommended as Provisional: Experimental conditions of papers selected for critical evaluation: a As far as Na + forms complexes with complexones, the use of NaOH instead of KOH for titrations of H 6 ttha in solutions with potassium salts as inert electrolytes should be avoided.…”

Section: 2'-(methylazanediyl)diacetic Acid ((Methylimino)diacetic mentioning

confidence: 99%

Critical evaluation of stability constants of metal complexes of complexones for biomedical and environmental applications* (IUPAC Technical Report)

Anderegg¹,

Arnaud‐Neu

Delgado

et al. 2005

Pure and Applied Chemistry

262

170

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Available experimental data on stability constants of proton (hydron) and metal complexes for seven complexones of particular biomedical and environmental interest: iminodiacetic acid [2,2'-azanediyldiacetic acid, IDA], (methylimino)diacetic acid [2,2'-(methylazanediyl)diacetic acid, MIDA]; 2,2',2'',2'''-{[(carboxymethyl)azanediyl]bis[(ethane-1,2-diyl)nitrilo]}tetraacetic acid (DTPA), 3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecanedioic acid (TTHA); 2,2',2''-(1,4,7-triazonane-1,4,7-triyl)triacetic acid (NOTA); 2,2',2'',2'''-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA); 2,2',2'',2'''-(1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrayl)tetraacetic acid (TETA), published in 1945-2000, have been critically evaluated. Some typical errors in stability constant measurements for particular complexones are summarized. Higher quality data are selected and presented as “Recommended” or “Provisional”.

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“…With supplying the eluent solution of 0.05 M DTPA-pH 2.0, the adsorbed RE(III) ions were eluted out as the order: Er(III), Dy(III), Lu(III), Gd(III), Eu(III), Sm(III), Y(III). This elution order is essentially consistent with the stability of these metal complexes with DTPA [24,25]. Since the stability constants of Am(III) and Cm(III) complexes with DTPA are close to that for Dy(III) [25], they are expected to be effectively separated from Sm(III) and Y(III).…”

Section: Separation Behavior By Siscr Cation Resinmentioning

confidence: 54%

A new partitioning process for high-level liquid waste by extraction chromatography using silica-substrate chelating agent impregnated adsorbents

Zhang¹,

Wei²,

Kumagai³

et al. 2005

Journal of Alloys and Compounds

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Observations on the rare earths—LXXV(1)

Cited by 147 publications

References 28 publications

Dissociation Kinetics of Open‐Chain and Macrocyclic Gadolinium(III)‐Aminopolycarboxylate Complexes Related to Magnetic Resonance Imaging: Catalytic Effect of Endogenous Ligands

Dissociation Kinetics of Open‐Chain and Macrocyclic Gadolinium(III)‐Aminopolycarboxylate Complexes Related to Magnetic Resonance Imaging: Catalytic Effect of Endogenous Ligands

Critical evaluation of stability constants of metal complexes of complexones for biomedical and environmental applications* (IUPAC Technical Report)

A new partitioning process for high-level liquid waste by extraction chromatography using silica-substrate chelating agent impregnated adsorbents

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