31640-94-5Relevant academic research and scientific papers
Tuning the Separation of Light Lanthanides Using a Reverse-Size Selective Aqueous Complexant
Thiele, Nikki A.,Fiszbein, David J.,Woods, Joshua J.,Wilson, Justin J.
, p. 16522 - 16530 (2020)
Efficiently separating the chemically similar lanthanide ions into elementally pure compositions is one of the greatest scientific challenges of the 21st century. Although extensive research efforts have focused on the development of organic extractants for this purpose, the implementation of aqueous complexants possessing distinct coordination chemistries has scarcely been explored as an approach to enhancing intralanthanide separations. In this study, we investigate the lanthanide coordination chemistry of macrophosphi, a novel analogue of the reverse-size selective expanded macrocycle macropa. Our studies reveal that substitution of the pyridyl-2-carboxylic acid pendent arms of macropa with pyridyl-2-phosphinic acid arms of macrophosphi gives rise to a dramatic enhancement in the ability to discriminate between light lanthanides, reflected by a binding affinity of macrophosphi for La3+ that is over 5 orders of magnitude higher than that for Gd3+. Furthermore, upon implementation of macrophosphi as an aqueous complexant in a biphasic extraction system containing the industrial extractant bis(2-ethylhexyl)phosphoric acid, separation factors of up to 45 were achieved for the Ce/La pair. These results represent a remarkable separation of adjacent lanthanides, demonstrating the significant potential of reverse-size selective aqueous complexants in lanthanide separation schemes.
Phosphonated Podand Type Ligand for the Complexation of Lanthanide CationsPhosphonated Podand Type Ligand for the Complexation of Lanthanide Cations
Charpentier, Cyrille,Salaam, Jérémy,Lecointre, Alexandre,Jeannin, Olivier,Nonat, Aline,Charbonnière, Lo?c J.
, p. 2168 - 2174 (2019)
A new tripodal ligand, based on a central nitrogen atom tris-functionalized with 6-methylene-2-pyridyl phosphonic acid was synthesized and characterized, in particular by its X-ray crystal structure. The coordination behaviour of the tripod with lanthanide cations in aqueous solutions was studied by means of UV/Vis electronic absorption spectroscopy and steady-state and time-resolved luminescence spectroscopy, revealing the formation of a [LnL] complex followed by polynuclear species with 2:1 and 3:1 metal/ligand stoichiometries. The [LnL] complexes (Ln = Eu, Tb and Yb) were isolated and characterized and the solid-state structure of the Eu complex was determined by X-ray diffraction analysis on monocrystals, revealing the observation of dimeric species, in which the Ln3+ cations are firmly held in the cavity formed by the three pyridylphosphonate arms, the coordination of the cations being completed by a water molecule and a phosphonate function of the second complex, allowing for the formation of the dimers, which are further stabilized by π–π stacking interactions between one pyridyl unit of each adjacent monomer. The spectroscopic properties of the complexes in aqueous solutions were studied, showing an impressive 16 μs excited state lifetime for the Yb complex in D2O, despite the presence of a water molecule in the first coordination sphere.
Tuning the Kinetic Inertness of Bi3+Complexes: The Impact of Donor Atoms on Diaza-18-Crown-6 Ligands as Chelators for 213Bi Targeted Alpha Therapy
Brown, Victoria,Fiszbein, David J.,Macmillan, Samantha N.,Radchenko, Valery,Ramogida, Caterina F.,Thiele, Nikki A.,Wharton, Luke,Wilson, Justin J.,Woods, Joshua J.
, p. 9199 - 9211 (2021)
The radionuclide 213Bi can be applied for targeted α therapy (TAT): a type of nuclear medicine that harnesses α particles to eradicate cancer cells. To use this radionuclide for this application, a bifunctional chelator (BFC) is needed to attach it to a biological targeting vector that can deliver it selectively to cancer cells. Here, we investigated six macrocyclic ligands as potential BFCs, fully characterizing the Bi3+ complexes by NMR spectroscopy, mass spectrometry, and elemental analysis. Solid-state structures of three complexes revealed distorted coordination geometries about the Bi3+ center arising from the stereochemically active 6s2 lone pair. The kinetic properties of the Bi3+ complexes were assessed by challenging them with a 1000-fold excess of the chelating agent diethylenetriaminepentaacetic acid (DTPA). The most kinetically inert complexes contained the most basic pendent donors. Density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) calculations were employed to investigate this trend, suggesting that the kinetic inertness is not correlated with the extent of the 6s2 lone pair stereochemical activity, but with the extent of covalency between pendent donors. Lastly, radiolabeling studies of 213Bi (30-210 kBq) with three of the most promising ligands showed rapid formation of the radiolabeled complexes at room temperature within 8 min for ligand concentrations as low as 10-7 M, corresponding to radiochemical yields of >80%, thereby demonstrating the promise of this ligand class for use in 213Bi TAT.
Formation of Mono- and Polynuclear Luminescent Lanthanide Complexes based on the Coordination of Preorganized Phosphonated Pyridines
Salaam, Jérémy,Tabti, Lilia,Bahamyirou, Sylvana,Lecointre, Alexandre,Hernandez Alba, Oscar,Jeannin, Olivier,Camerel, Franck,Cianférani, Sarah,Bentouhami, Embarek,Nonat, Aline M.,Charbonnière, Lo?c J.
, p. 6095 - 6106 (2018)
A series of polynuclear assemblies based on ligand L (1,4,7-tris[hydrogen (6-methylpyridin-2-yl)phosphonate]-1,4,7-triazacyclononane) has been developed. The coordination properties of ligand L with LnIII (Ln = La, Eu, Tb, Yb, Lu) have been stu
