Separation Of Trivalent Actinides Research Articles

Enhancing the Selectivity of Trivalent Actinide over Lanthanide Using Asymmetrical Phenanthroline Diamide Ligands.

Phenanthroline diamide ligands have been widely used in the separation of trivalent actinides and lanthanides, but little research has focused on extractants with asymmetrical substitutes. Two novel asymmetrical phenanthroline-based ligands N2,N2,N9-triethyl-N9-tolyl-1,10-phenanthroline-2,9-dicarboxamide (DE-ET-DAPhen) and N2-ethyl-N9,N9-dioctyl-N2-tolyl-1,10-phenanthroline-2,9-dicarboxamide (DO-ET-DAPhen) were first synthesized in this work, whose extraction ability and complexation mechanism to trivalent actinides [An(III)] and lanthanides [Ln(III)] were systematically investigated. The ligands dissolved in n-octanol exhibit good extraction ability and high selectivity toward Am(III) in acidic solutions. The complexation mechanism of the ligands with Ln(III) in solution and solid state was analyzed using slope analysis, 1H NMR spectrometric titration, ESI-MS, and calorimetric titration. It is revealed that the ligands complex with Am(III)/Eu(III) with 1:1 stoichiometry. The stability constant (log β) of the complexation reaction of Eu(III) with DE-ET-DAPhen determined by UV-vis spectrophotometric and calorimetric titration is higher than that of DO-ET-DAPhen, indicating the stronger complexation ability of DE-ET-DAPhen. Meanwhile, the calorimetric titration results show that the complexation process is exothermic with a decreased entropy. The structures of 1:1 complexes of Eu(III) and Nd(III) with DE-ET-DAPhen were analyzed through single-crystal X-ray diffraction. This work proves that ligands containing asymmetrical functional groups are promising for An(III)/Ln(III) separation, which shows great significance in efficient extractants designed for the spent nuclear fuel reprocessing process.

Complexation and extraction of trivalent actinides over lanthanides using highly soluble phenanthroline diamide ligands with different side chains

Although phenanthroline diamide ligands have been widely reported, their limited solubility in organic solvents and poor performance in the separation of trivalent actinides (An(III)) and lanthanides (Ln(III)) at high acidity are still clear demerits. In this study, we designed and synthesized three highly soluble phenanthroline diamide ligands with different side chains. By introducing alkyl chains and ester groups, the ligands solubility in 3-nitrotrifluorotoluene is increased to over 600 mmol/L, significantly higher than the previous reported phenanthroline diamide ligands. Based on anomalous aryl strengthening, benzene ring was incorporated to enhance ligand selectivity toward Am(III). Extraction experiments demonstrated favorable selectivity of all the three ligands towards Am(III). The optimal separation factor (SFAm/Eu) reaches 53 at 4 mol/L HNO3, representing one of the most effective separation of An(III) over Ln(III) under high acidity. Slope analysis, single crystal structure analysis, as well as titration of ultraviolet visible spectroscopy, mass spectrometry, and nuclear magnetic resonanc confirmed the formation of 1:1 and 1:2 complex species between the metal ions and the ligands depending on the molar ratio of metal ions in the reaction mixture. The findings of this study offer valuable insights for developing phenanthroline diamide ligands for An(III)/Ln(III) separation.

Recent Advances in the Study of Trivalent Lanthanides and Actinides by Phosphinic and Thiophosphinic Ligands in Condensed Phases.

The separation of trivalent actinides and lanthanides is a key step in the sustainable development of nuclear energy, and it is currently mainly realized via liquid-liquid extraction techniques. The underlying mechanism is complicated and remains ambiguous, which hinders the further development of extraction. Herein, to better understand the mechanism of the extraction, the contributing factors for the extraction are discussed (specifically, the sulfur-donating ligand, Cyanex301) by combing molecular dynamics simulations and experiments. This work is expected to contribute to improve our systematic understanding on a molecular scale of the extraction of lanthanides and actinides, and to assist in the extensive studies on the design and optimization of novel ligands with improved performance.

Theoretical Insights into the Substitution Effect of Phenanthroline Derivatives on Am(III)/Eu(III) Separation

Separation of trivalent actinides (An(III)) and lanthanides (Ln(III)) poses a huge challenge in the reprocessing of spent nuclear fuel due to their similar chemical properties. N,N'-Diethyl-N,N'-ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen) is a potential ligand for the extraction of An(III) from Ln(III), while there are still few reports on the effect of its substituent including electron-withdrawing and electron-donating groups on An(III)/Ln(III) separation. Herein, the interaction of Et-Tol-DAPhen ligands modified by the electron-withdrawing groups (CF3, Br) and electron-donating groups (OH) with Am(III)/Eu(III) ions was investigated using scalar relativistic density functional theory (DFT). The analyses of bond order, quantum theory of atoms in molecules (QTAIM), and molecular orbital (MO) indicate that the substitution groups have a slight effect on the electronic structures of the [M(L-X)(NO3)3] (X = CF3, Br, OH) complexes. However, the thermodynamic results suggest that a ligand with the electron-donating group (L-OH) improves the extraction ability of metal ions, and the ligand modified by the electron-withdrawing group (L-Br) has the best Am(III)/Eu(III) selectivity. This work could render new insights into understanding the effect of electron-withdrawing and electron-donating groups in tuning the selectivity of Et-Tol-DAPhen derivatives and pave the way for designing new ligands modified by substituted groups with better extraction ability and An(III)/Ln(III) selectivity.

Theoretical evaluation of mixed N-, O- donor based TMPhenDA ligand in selective complexation with actinide (III) ions over lanthanide (III) ions

Separation of trivalent actinides An(III) from lanthanide Ln(III) is an extremely challenging task in handling nuclear wastes due to their similar chemical behaviours. Though many designed organic ligands have been used for the separation of Ln(III) from An(III) over the years, selectivity and efficiency is still a matter of concern. This drives us to formulate new efficient ligands, in which mixed --N, --O donor ligands are one of the most emerging and promising agents in separation of An(III) from Ln(III). In this work, recently reported TMPhenDA ligand has been investigated for their complexation behaviour with An(III) (U, Am, Cm) and Ln(III) (Nd, Eu, Gd) ions using scalar relativistic ZORA/DFT calculations. Computed bond parameters show that the An(III) ions bind strongly to the ligand than the lanthanide ions. Bond order and QTAIM analyses have been done on the optimized geometries to understand the bonding situation present in the M3+TMPhenDA complexes. Further, energy decomposition analysis is taken up to assign the percentage covalency of M-N and M-O bonds in these complexes to estimate the strength of these bonds. Overall, this computational investigation provides an in-depth understanding on the preferential selectivity of the ligand with An(III) over Ln(III) using DFT calculations.

Complexation and Separation of Trivalent Actinides and Lanthanides by a Novel DGA Derived from Macrocyclic Crown Ether: Synthesis, Extraction, and Spectroscopic and Density Functional Theory Studies.

A DGA-arm-grafted macrocyclic aza-crown ether ligand (Cr6DGA) was synthesized, and its solvent extraction behavior toward trivalent americium and europium in nitric acid medium was studied. The effects of various parameters such as the contact time, temperature, concentration of the extractant, and acidity on the extraction by Cr6DGA were investigated. It was found that in 3 mol/L HNO3, the SFEu/Am value was about 2. The complexation energies calculated by DFT showed that the Eu(III) complexes were more stable than the corresponding Am(III) complexes in gas, aqueous, and organic phases. Furthermore, the coordination study showed that the metal/ligand ratio of the extracted species was 1:2 by mass spectrometry (MS) analysis. The time-resolved laser-induced fluorescence spectra (TRLFS) further proved that the extracted species contained one water molecule, and so the composition of the extracted complexes may be [EuL2NO3(H2O)]2+ or [EuL2(NO3)2(H2O)]+. Finally, DFT calculations revealed that [EuL2(NO3)2(H2O)]+ is a more stable species and the binding energy of Eu(III) with the DGA unit is lower than that with the crown unit.

Theoretical Insights into the Selective Extraction of Americium(III) over Europium(III) with Dithioamide-Based Ligands.

Separation of trivalent actinides An(III) from lanthanides Ln(III) is a worldwide challenge owing to their very similar chemical behaviors. It is highly desirable to understand the nature of selectivity for the An(III)/Ln(III) separation with various ligands through theoretical calculations because of their radiotoxicity and experimental difficulties. In this work, we have investigated three dithioamide-based ligands and their extraction behaviors with Am(III) and Eu(III) ions using the scalar-relativistic density functional theory. The results show that the dithioamide-based ligands have stronger electron donating ability than do the corresponding diamide-based ones. All analyses including geometry, Mulliken population, QTAIM (quantum theory of atoms in molecules), and NBO (natural bond orbital) suggest that the Am-S/N bonds possess more covalency compared to the Eu-S/N bonds, and the M-S bonds have more covalent character than the M-N bonds. Thermodynamic results reveal that N2,N9-diethyl-N2,N9-di-p-tolyl-1,10-phenanthroline-2,9-bis(carbothioamide) (L1) has a stronger complexing ability with metal ions owing to its rigid structure and that N6,N6'-diethyl-N6,N6'-di-p-tolyl-[2,2'-bipyridine]-6,6'-bis(carbothioamide) (L2) shows a higher selectivity for the Am(III)/Eu(III) separation. In addition, these dithioamide-based ligands possess Am(III)/Eu(III) selectivity higher than those of the corresponding diamide-based ones, although the former have weaker complexing ability with metal ions, probably due to the greater covalency of the M-S bonds. This theoretical evaluation provides valuable insights into the nature of the selectivity for the Am(III)/Eu(III) separation and information on designing of efficient An(III)/Ln(III) separation with dithioamide-based ligands.

Insight into the Extraction Mechanism of Americium(III) over Europium(III) with Pyridylpyrazole: A Relativistic Quantum Chemistry Study.

Separation of trivalent actinides (An(III)) and lanthanides (Ln(III)) is one of the most important steps in spent nuclear fuel reprocessing. However, it is very difficult and challenging to separate them due to their similar chemical properties. Recently the pyridylpyrazole ligand (PypzH) has been identified to show good separation ability toward Am(III) over Eu(III). In this work, to explore the Am(III)/Eu(III) separation mechanism of PypzH at the molecular level, the geometrical structures, bonding nature, and thermodynamic behaviors of the Am(III) and Eu(III) complexes with PypzH ligands modified by alkyl chains (Cn-PypzH, n = 2, 4, 8) have been systematically investigated using scalar relativistic density functional theory (DFT). According to the NBO (natural bonding orbital) and QTAIM (quantum theory of atoms in molecules) analyses, the M-N bonds exhibit a certain degree of covalent character, and more covalency appears in Am-N bonds compared to Eu-N bonds. Thermodynamic analyses suggest that the 1:1 extraction reaction, [M(NO3)(H2O)6]2+ + PypzH + 2NO3- → M(PypzH)(NO3)3(H2O) + 5H2O, is the most suitable for Am(III)/Eu(III) separation. Furthermore, the extraction ability and the Am(III)/Eu(III) selectivity of the ligand PypzH is indeed enhanced by adding alkyl-substituted chains in agreement with experimental observations. Besides this, the nitrogen atom of pyrazole ring plays a more significant role in the extraction reactions related to Am(III)/Eu(III) separation compared to that of pyridine ring. This work could identify the mechanism of the Am(III)/Eu(III) selectivity of the ligand PypzH and provide valuable theoretical information for achieving an efficient Am(III)/Eu(III) separation process for spent nuclear fuel reprocessing.

Uncovering the impact of 'capsule' shaped amine-type ligands on Am(iii)/Eu(iii) separation.

Separation of trivalent actinides (An(iii)) and lanthanides (Ln(iii)) in spent nuclear fuel reprocessing is extremely challenging mainly owing to their similar chemical properties. Two amine-type reagents, tetrakis(2-pyridyl-methyl)-1,2-ethylenediamine (TPEN) and its hydrophobic derivative N,N,N',N'-tetrakis((4-butoxypyridin-2-yl)methyl)-ethylenediamine (TBPEN), have been identified to possess a selectivity for Am(iii) over Eu(iii). In this work, the structures, bonding nature, and thermodynamic behaviors of the Am(iii) and Eu(iii) complexes with these two ligands have been systematically studied via scalar relativistic density functional theory (DFT) calculations. According to Mayer bond order and the quantum theory of atoms in molecules (QTAIM) analyses, interactions between the ligands and metal cations exhibit some degree of covalent character with relatively more covalency for Am(iii) complexes. In comparison with TPEN, TBPEN has better extractability but worse separation ability for Am(iii) and Eu(iii). Four nitrogen atoms in pyridine moieties may be responsible for the different extraction abilities of TPEN and TBPEN, while two nitrogen atoms in amine chains of these ligands appear to play more important roles in the separation of Am(iii)/Eu(iii). These different extraction behaviors may be attributed to the longer and thinner 'capsule' shaped TBPEN ligand compared to TPEN. Our study might provide new insights into understanding the selectivity of the amine-type ligands toward minor actinides, and pave the way for designing new TPEN derivatives for extraction and separation of An(iii)/Ln(iii).

ChemInform Abstract: Modular Approaches to Diversified Soft Lewis Basic Complexants Through Suzuki—Miyaura Cross‐Coupling of Bromoheteroarenes with Organotrifluoroborates.

AbstractThe Pd‐catalyzed cross‐coupling of bis‐ and tris‐brominated pyridyl‐substituted 1,2,4‐triazines with organotrifluoroborates is used to synthesize a variety of the corresponding organyl substituted derivatives.

New insights into the selectivity of four 1,10-phenanthroline-derived ligands toward the separation of trivalent actinides and lanthanides: a DFT based comparison study

Although many heterocyclic N-donor ligands have shown excellent competence for separating actinides from lanthanides, an explanation for why some ligands work whereas others fail is very fundamental but greatly needs to be addressed for designing novel and efficient extractants. In this work, we systematically investigated four phenanthroline-derived ligands, DHDIPhen, BQPhen, Ph2-BTPhen and CyMe4-BTPhen, and their coordination geometrical properties and formation reactions with Am(iii) and Eu(iii) ions by quasi-relativistic density functional theory. The calculated hardness of ligands, which may help to determine their selectivity toward actinides and lanthanides, yielded an order, from the softest to the hardest, as follows: Ph2-BTPhen < CyMe4-BTPhen < BQPhen < DHDIPhen. It shows that the intramolecular hydrogen bonds and size of a ligand cavity are two dominant factors for metal-ion complexation. Natural population analysis (NPA) reveals that the 5d/6d orbitals of Eu/Am accept significantly more electrons than other orbitals, but partial density of states and molecular orbital analysis prove that the d orbitals with more accepted electrons have little contribution to the metal-ligand bonds. The thermodynamic results suggest that ligand protonation does have a great influence on the complexation of ligands with metal ions but does not change the selectivity of ligands toward metal ions. This work can help in-depth understanding the differences of selectivity of various structurally similar ligands and provide more theoretical insights for designing more innovative ligands for Ln/An separation.

Novel Diglycolamic Acid Functionalized Iron Oxide Particles for the Mutual Separation of Eu(III) and Am(III)

Iron oxide (Fe3O4) particles functionalized with diglycolamic acid (Fe-DGAH) were synthesized and characterized by TG-DTA, X-Ray diffraction,1H NMR, and scanning electron microscopy (SEM). The extraction behavior of Am(III) and Eu(III) in Fe-DGAH was studied from dilute nitric acid medium to examine the feasibility for the mutual separation of trivalent actinides and lanthanides using Fe-DGAH. For this purpose, the effect of various parameters such as the duration of equilibration and concentrations of europium, nitric acid, and diethylenetriaminepentaacetic acid (DTPA) in the aqueous phase on the distribution ratio (Kd) of Am(III) and Eu(III) was studied. The conditions needed for the efficient separation of Am(III) from Eu(III) were optimized using DTPA. The distribution ratio of ˜104 mL/g was obtained for both Am(III) and Eu(III) at pH 3, and it decreased with an increase in the concentration of nitric acid. However, a separation factor of Eu(III) over Am(III) of ˜150 was achieved in the presence of DTPA. Rapid sorption of metal ions in the initial stages of equilibration followed by the establishment of equilibrium occurred within 2 h. The sorption data were fitted to the Langmuir adsorption model, and the apparent europium sorption capacity was determined to be ˜50 mg/g. The study indicated the feasibility of using Fe-DGAH particles for magnetic separation of Eu(III) from Am(III) with high separation factors.

Complexation of curium(III) with DTPA at 10-70 °C: comparison with Eu(III)-DTPA in thermodynamics, luminescence, and coordination modes.

Separation of trivalent actinides (An(III)) from trivalent lanthanides (Ln(III)) is a challenging task because of the nearly identical chemical properties of these groups. Diethylenetriaminepentaacetate (DTPA), a key reagent used in the TALSPEAK process that effectively separates An(III) from Ln(III), is believed to play a critical role in the An(III)/Ln(III) separation. However, the underlying principles for the separation based on the difference in the complexation of DTPA with An(III) and Ln(III) remain unclear. In this work, the complexation of DTPA with Cm(III) at 10-70 °C was investigated by spectrophotometry, luminescence spectroscopy, and microcalorimetry, in conjunction with computational methods. The binding strength, the enthalpy of complexation, the coordination modes, and the luminescence properties are compared between the Cm(III)-DTPA and Eu(III)-DTPA systems. The experimental and computational data demonstrated that the difference between Cm(III) and Eu(III) in the binding strength with DTPA can be attributed to the stronger covalence bonding between Cm(III) and the nitrogen donors of DTPA.

A Novel Solvent System Involving Terpyridine and Cyanex-301 for Am(III) and Eu(III) Separation from Weakly Acidic Feeds

Separation of trivalent actinides and lanthanides is a challenging task and has a great relevance in the nuclear fuel cycle. Bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex-301) show high selectivity for the trivalent actinides over the lanthanides at pH 3 or higher and N-donor ligands were reported to enhance the selectivity. 2,2ʹ:6ʹ,6”-Terpyridine (terpy), on the other hand, has shown to be quite effective at lower pH values and the combination of Cyanex 301 and terpy was evaluated in the present study, for the first time, for the separation of Am(III) from Eu(III), representative actinide and lanthanide elements, respectively at pH 2.0.Thermodynamic parameters (enthalpy, entropy, and free energy) for the two phase extraction were also determined from the distribution studies at variable temperatures. Extraction of both Am3+ and Eu3+ was favored by negative enthalpy of extraction. More negative ΔG value indicated that Am3+ extraction was more favoured as compared to Eu3+ extraction using this solvent system. Effect of diluent composition on the extraction of Am3+ and Eu3+ was also studied in the present work.

Feasibility of Using Di-Dodecyl-Di-Octyl Diglycolamide for Partitioning of Minor Actinides from Fast Reactor High-Level Liquid Waste

The unsymmetrical diglycolamide, di-dodecyl-di-octyl diglycolamide (D3DODGA) is a modifier-free extractant proposed for partitioning of trivalent actinides from nitric acid medium. D3DODGA has been evaluated for the feasibility of using it in the absence of a phase modifier, for the partitioning of minor actinides from fast reactor high-level liquid waste (FR-HLLW). The extraction behavior of various metal ions present in the simulated FR-HLLW was studied in a solution of 0.1 M D3DODGA/n-dodecane from nitric acid medium. The distribution ratio of about 20 metal ions was measured as a function of concentration of nitric acid and other interfering ion. The extraction was found to be strongly dependent on the oxidation state of the metal ion. The extraction of Am(III) from 3–4 M nitric acid medium was quantitative in a single contact. However, it was accompanied by the quantitative extraction of fission products such as trivalent lanthanides (Ln(III)), Y(III), and Zr(IV). The extraction of Sr(II), Pd(II), and Ru(III) in 0.1 M D3DODGA/n-dodecane was not insignificant, but quite low. The extraction of Ba(II), Ni(II), Mo(VI), and Fe(III) was marginal and the extraction of Co(II), Sb(III), Mn(II), and Cs(I) in 0.1 M D3DODGA/n-dodecane was negligible. Our results indicated that 0.1 M D3DODGA/n-dodecane is a promising candidate for the separation of trivalent actinides from fast reactor high-level liquid waste containing significant quantities of trivalent lanthanides and actinides.

Development and Demonstration of Americium (III)-Europium (III) Separation Using Diglycolamic Acid

The extraction behavior of Eu(III) and Am(III) in a solution of bis(2-ethylhexyl)diglycolamic acid (HDEHDGA) in n-dodecane (n-DD) from citric acid (CA) medium was studied as a function of various parameters. The extraction increased with increase of pH, reached a maximum at pH 2 followed by decrease. The stripping behavior of Eu(III) and Am(III) from the loaded organic phase was studied by using a solution of diethylenetriaminepentaacetic acid (DTPA) and CA. The conditions needed for the efficient separation of Am(III) from Eu(III) were optimized. Based on the optimized conditions, the feasibility of separating Am(III) from Eu(III) present in CA feed solution was investigated in a 20- stage mixer-settler. Quantitative extraction of Eu(III) and Am(III) in 0.1 M HDEHDGA/n-DD was achieved in 3–4 stages, whereas the selective back extraction of Am(III) was achieved in ∼20 stages upon contacting the loaded organic phase with a stripping formulation composed of DTPA-CA at pH 1.5. The results confirmed the possibility of using diglycolamic acid for the separation of trivalent actinides from the chemically similar lanthanides, which is indeed necessary for transmutation of minor actinides present in high-level liquid waste (HLLW).

A reinterpretation of C5-BTBP extraction data, performed in various alcohols

The separation of trivalent actinides from trivalent lanthanides present in used nuclear fuel can be achieved by using solvent extraction and the BTBP class of ligands. This separation is relevant for the advanced reprocessing of the used fuel. The choice of diluents in such BTBP based systems has shown to affect the extraction as well as the separation. Long chained alcohols have previously been investigated as such diluents, showing that the americium extraction is higher into alcohols having shorter chains (hexanol, and heptanol) than in longer chained ones (nonanol and decanol). In this work it is shown that not only the distribution ratio, but also the contact time needed before reaching extraction equilibrium is shorter when using shorter chain length of the alcohol diluent. It is also shown that the rate of extraction can be correlated to the interfacial tension between the diluent and the aqueous phase. A low interfacial tension gives a fast extraction while an extraction system with higher interfacial tension needs a longer time of phase contact in order to reach extraction equilibrium.

Separation of Trivalent Actinides from High-Active Waste

A typical high-active waste (HAW) arising from reprocessing of (U0.3Pu0.7)C fuel irradiated to the burn-up of 155 GWd/Te in a fast breeder test reactor (FBTR) was characterized. Partitioning of trivalent actinides from HAW was demonstrated using a solvent, 0.2M n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) – 1.2M tri-n-butylphosphate (TBP) in n-dodecane (n-DD), in a mixer settler. The results established quantitative separation of trivalents (Am(III) + Ln(III)) from HAW and recovery (> 99%) using a citric acid-nitric acid formulation. The mutual separation of lanthanides and actinides from the stripped product was studied by using bis(2-ethylhexyl)diglycolamic acid (HDEHDGA), synthesized in our laboratory.

Separation of trivalent actinides and lanthanides from simulated high-level waste using cobalt bis(dicarbollide) ion derivate substituted with diphenyl-N-tert.octyl-carbamoylmethylphosphine oxide

Abstract A derivative with cobalt bis(dicarbollide)(1−) ion covalently bonded with diphenyl-N-tert.octyl-carbamoylmethylphosphine oxide with a formula [(8-Ph2P(O)-CH2C(O)N-t-C8H17-(CH2-CH2O)2-(1,2-C2B9H10)(1´,2´-C2B9H11)-3,3´-Co]− (CMPO-COSAN) has been evaluated for actinides(III)/lanthanides(III) separation from high level liquid waste (HLLW) from PUREX reprocessing. The procedures for HLLW treatment by CMPO-COSAN dissolved in low polar mixture of hexylmethylketone and hydrogenated tetrapropylene (HMK/TPH, 1:1) or polar mixture of nitrobenzene/bromoform (NB/BF, 9:1) were proposed. The good separation of Am(III)/Ln(III) from bulk of fission products was achieved. The trivalent radionuclides were effectively stripped from the loaded organic phase by using ammonium citrate or solution of ammonium citrate and ammonium diethylenetriamine pentaacetate (DTPA). The co-extraction of some undesirable elements as Zr, Mo, Pd was suppressed using oxalic acid and HEDTA in extraction and a scrub steps. However, co-extraction of Ag has to be solved, yet.

Complexation Studies of Bidentate Heterocyclic N-Donor Ligands with Nd(III) and Am(III)

A new bidentate nitrogen donor complexing agent that combines pyridine and triazole functional groups, 2-((4-phenyl-1H-1,2,3-triazol-1-yl)methyl)pyridine (PTMP), has been synthesized. The strength of its complexes with trivalent americium (Am3+) and neodymium (Nd3+) in anhydrous methanol has been evaluated using spectrophotometric techniques. The purpose of this investigation is to assess this ligand (as representative of a class of similarly structured species) as a possible model compound for the challenging separation of trivalent actinides from lanthanides. This separation, important in the development of advanced nuclear fuel cycles, is best achieved through the agency of multidentate chelating agents containing some number of nitrogen or sulfur donor groups. To evaluate the relative strength of the bidentate complexes, the derived constants are compared to those of the same metal ions with 2,2′-bipyridyl (bipy), 1,10-phenanthroline (phen), and 2-pyridin-2-yl-1H-benzimidazole (PBIm). At issue is the relative affinity of the triazole moiety for trivalent f element ions. For all ligands, the derived stability constants are higher for Am3+ than Nd3+. In the case of Am3+ complexes with phen and PBIm, the presence of 1:2 (AmL2) species is indicated. Possible separations are suggested based on the relative stability and stoichiometry of the Am3+ and Nd3+ complexes. It can be noted that the 1,2,3-triazolyl group imparts a potentially useful selectivity for trivalent actinides (An(III)) over trivalent lanthanides (Ln(III)), though the attainment of higher complex stoichiometries in actinide compared with lanthanide complexes may be an important driver for developing successful separations.