Selective separation of minor actinides and lanthanides using aromatic dithiophosphinic and phosphinic acid derivatives

Peterman, Dean R.; Martin, Leigh R.; Klaehn, John R.; Harrup, Mason K.; Greenhalgh, Mitchell; Luther, Thomas A.

doi:10.1007/s10967-009-0288-z

Cited by 25 publications

(21 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…11. [97][98][99][100][101][102] The affinity of polypyridyl ligands for Ln(III) ions shows a similar pattern for ligands such as tpy, MPP, DPA,(Fig. 12(a)) qpy, and DPP (Fig.…”

Section: Complexation Of F-block Metal Ions (A) the Polypyridyl Ligandsmentioning

confidence: 99%

The pyridyl group in ligand design for selective metal ion complexation and sensing

2013

View full text Add to dashboard Cite

Factors in polypyridyl ligands that control their thermodynamic metal ion selectivity in aqueous solution, and their use in selective fluorescent sensing, are examined. Preorganization of polypyridyl ligands ranging from bidentate to tetradentate by bridging benzo groups, as are present in 1,10-phenanthroline (phen) compared to 2,2'-bipyridyl (bpy), is discussed. The role of solvation is considered in relation to the relative affinity of ligands containing pyridyl groups for divalent and trivalent metal ions in aqueous solution. The effects of steric clashes between H atoms on polypyridyl ligands in decreasing complex stability are evaluated, as well as the effect of chelate ring size on metal ion selectivity. Phen ligands with other donor groups present at the 2 and 9 positions, such as alcohols, amides, carboxylates, and oximes are discussed. The design of pyridyl-based ligands for the separation of Am(III) from lanthanide(III) ions is considered, as well as ligands for the removal of metal ions such as Cu(II) or Zn(II) in neurological diseases such as Alzheimer's. The design of pyridyl-based fluorescent sensors for selective sensing of metal ions is examined in terms of the role of spin-orbit coupling constants (ζ), paramagnetism, and steric effects in the development of selective fluorescent sensors that operate via chelation enhanced fluorescence (CHEF). It is concluded that for lighter metal ions with smaller ζ values such as Zn(II) and Ca(II), and to a lesser extent Cd(II), that the CHEF effect can be achieved with pyridyl-containing fluorophores that coordinate directly to the metal ion. The way in which steric effects can be used to decrease the CHEF effect in Zn(II) relative to Cd(II) to enable selective sensing of the latter is analyzed. For heavier metal ions such as Hg(II) and Pb(II), because of their large ζ values which quench fluorescence, it is concluded that the fluorophore should be tethered to the metal-binding part of the sensor, and prevented from binding to the metal ion by steric and electronic factors. How Hg(II) can quench the CHEF effect by π-contact with fluorophores such as the anthracenyl group, which at first sight might not seem able to bond with metal ions, is examined.

show abstract

“…11. [97][98][99][100][101][102] The affinity of polypyridyl ligands for Ln(III) ions shows a similar pattern for ligands such as tpy, MPP, DPA,(Fig. 12(a)) qpy, and DPP (Fig.…”

Section: Complexation Of F-block Metal Ions (A) the Polypyridyl Ligandsmentioning

confidence: 99%

The pyridyl group in ligand design for selective metal ion complexation and sensing

2013

View full text Add to dashboard Cite

show abstract

“…Since the discovery of the high performance of Cyanex301 in Ln III /An III separation, numerous studies have been conducted to extend the application of this system by using similar ligands or different aqueous/solvent compositions. [12][13][14][15][16][17][18][19][20][21] Moreover, efforts with different techniques have been made by several groups to understand the chemical driving force.…”

Section: Introductionmentioning

confidence: 99%

Interactions of Bis(2,4,4‐trimethylpentyl)dithiophosphinate with Nd^III and Cm^III in a Homogeneous Medium: A Comparative Study of Thermodynamics and Coordination Modes

Rao

2014

Chemistry A European J

View full text Add to dashboard Cite

Complexation of Nd(III) and Cm(III) with purified Cyanex301 (ammonium bis(2,4,4-trimethylpentyl)dithiophosphinate, denoted as HL) was studied in 1 % v/v water/ethanol under identical conditions by spectrophotometry and microcalorimetry. For Nd(III) , three successive complexes, NdL(2+) , NdL2 (+) , and NdL3 , formed in the solution. In contrast, four complexes, CmL(2+) , CmL2 (+) , CmL3 , and CmL4 (-) formed during the titration with Cm. Fluorescence lifetime measurements provided additional insight into the complexation of Cm(III) with Cyanex301. The stepwise stability constants for the CmLj ((3-j)+) (j=1-3) complexes are about one order of magnitude higher than the corresponding NdLj ((3-j)+) complexes. The enthalpies of complexation are endothermic for both Nd(III) and Cm(III) , suggesting that the energy required for desolvation exceeds the energy gained from the cation/ligand combination. Specifically, the enthalpy of complexation for CmL(2+) is 3.5 kJ mol(-1) less endothermic than that of NdL(2+) , implying stronger covalent interaction in CmL(2+) than NdL(2+) . However, the enthalpies of complexation for CmL2 (+) and NdL2 (+) are nearly identical, and the enthalpy of complexation for CmL3 (aq) becomes more endothermic than that for NdL3 (aq). The observations suggest that, in the ethanol/water media, the overall energetics of the Cm(III) /Nd(III) complexation with Cyanex301 could depend on a number of factors, including the extent of covalency, the degree of desolvation, and the coordination modes.

show abstract

“…Interaction of nitrogen and sulfur donors with An 3þ is stronger than with Ln 3þ , thus potentially enabling a successful separation [5]. This fundamental difference has inspired considerable research addressing the development of soft donor molecules or ions for separations applications [4,[7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

The role of carboxylic acids in TALSQuEAK separations

Braley

Carter

Sinkov

et al. 2012

Journal of Coordination Chemistry

View full text Add to dashboard Cite

Recent reports have indicated that Trivalent Actinide-Lanthanide Separation by Phosphorus reagent Extraction from Aqueous Komplexes (TALSPEAK)-type separations chemistry can be improved through the replacement of bis-2-ethyl(hexyl) phosphoric acid (HDEHP) and diethylenetriamine-N,N,N 0 ,N 00 ,N 00 -pentaacetic acid (DTPA) with the weaker reagents 2-ethyl(hexyl) phosphonic acid mono-2-ethylhexyl ester (HEH [EHP]) and N-(2-hydroxyethyl) ethylenediamine-N,N 0 ,N 0 -triacetic acid (HEDTA), respectively. This modified TALSPEAK has been provided with an adjusted acronym of TALSQuEAK (Trivalent Actinide-Lanthanide Separation using Quicker Extractants and Aqueous Komplexes). Among several benefits, TALSQuEAK chemistry provides more rapid phase transfer kinetics, is less reliant on carboxylic acids to mediate lanthanide extraction, and allows a simplified thermodynamic description of the separations process that generally requires only parameters available in the literature to describe metal transfer. This article focuses on the role of carboxylic acids in aqueous ternary (M-HEDTA-carboxylate) complexes, americium/lanthanide separations, and extraction kinetics. Spectrophotometry (UV-Vis) of the Nd 3þ hypersensitive band indicates the presence of aqueous ternary Nd-Lac-HEDTA species (Lac ¼ lactate, K 111 ¼ 1.83 AE 0.01 at 1.0 mol L À1 ionic strength, Nd(HEDTA) þ Lac À À! À Nd(HEDTA)Lac À ). While lower levels (0.1 mol L À1 vs. 1.0 mol L À1 ) of carboxylic acid will still be necessary to control pH and encourage phase transfer of the heavier lanthanides, application of different carboxylic acids does not have an overwhelming impact on Ln/Am separations or extraction kinetics relative to conventional TALSPEAK separations. TALSQuEAK separations come to equilibrium in two to five minutes depending on the system pH using only 0.1 mol L À1 total lactate or citrate.

show abstract

Selective separation of minor actinides and lanthanides using aromatic dithiophosphinic and phosphinic acid derivatives

Cited by 25 publications

References 17 publications

The pyridyl group in ligand design for selective metal ion complexation and sensing

The pyridyl group in ligand design for selective metal ion complexation and sensing

Interactions of Bis(2,4,4‐trimethylpentyl)dithiophosphinate with Nd^III and Cm^III in a Homogeneous Medium: A Comparative Study of Thermodynamics and Coordination Modes

The role of carboxylic acids in TALSQuEAK separations

Contact Info

Product

Resources

About

Selective separation of minor actinides and lanthanides using aromatic dithiophosphinic and phosphinic acid derivatives

Cited by 25 publications

References 17 publications

The pyridyl group in ligand design for selective metal ion complexation and sensing

The pyridyl group in ligand design for selective metal ion complexation and sensing

Interactions of Bis(2,4,4‐trimethylpentyl)dithiophosphinate with NdIII and CmIII in a Homogeneous Medium: A Comparative Study of Thermodynamics and Coordination Modes

The role of carboxylic acids in TALSQuEAK separations

Contact Info

Product

Resources

About

Interactions of Bis(2,4,4‐trimethylpentyl)dithiophosphinate with Nd^III and Cm^III in a Homogeneous Medium: A Comparative Study of Thermodynamics and Coordination Modes