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Peter R. Zalupski - One of the best experts on this subject based on the ideXlab platform.
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influence of a heterocyclic nitrogen donor group on the coordination of trivalent actinides and lanthanides by aminopolycarboxylate complexants
Inorganic Chemistry, 2018Co-Authors: Travis S. Grimes, Colt R. Heathman, Alexander S. Ivanov, Santanu Roy, Vyacheslav S. Bryantsev, Santa Jansonepopova, Peter R. ZalupskiAbstract:The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and Radioisotope Distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitro...
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Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants
2018Co-Authors: Travis S. Grimes, Colt R. Heathman, Santa Jansone-popova, Alexander S. Ivanov, Santanu Roy, Vyacheslav S. Bryantsev, Peter R. ZalupskiAbstract:The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and Radioisotope Distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL(aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am3+, Cm3+) and trivalent lanthanide chelates (La3+–Lu3+) are observed in liquid–liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA-PyM as an aqueous holdback reagent. In addition, the enhanced nitrogen-donor softness of the new DTTA-PyM chelator was perturbed by adding a fluorine onto the pyridine group. The comparative characterization of N-(3-fluoro-2-pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-3-F-PyM) showed subdued 4f/5f differentiation due to the presence of this electron-withdrawing group
Travis S. Grimes - One of the best experts on this subject based on the ideXlab platform.
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influence of a heterocyclic nitrogen donor group on the coordination of trivalent actinides and lanthanides by aminopolycarboxylate complexants
Inorganic Chemistry, 2018Co-Authors: Travis S. Grimes, Colt R. Heathman, Alexander S. Ivanov, Santanu Roy, Vyacheslav S. Bryantsev, Santa Jansonepopova, Peter R. ZalupskiAbstract:The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and Radioisotope Distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitro...
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Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants
2018Co-Authors: Travis S. Grimes, Colt R. Heathman, Santa Jansone-popova, Alexander S. Ivanov, Santanu Roy, Vyacheslav S. Bryantsev, Peter R. ZalupskiAbstract:The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and Radioisotope Distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL(aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am3+, Cm3+) and trivalent lanthanide chelates (La3+–Lu3+) are observed in liquid–liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA-PyM as an aqueous holdback reagent. In addition, the enhanced nitrogen-donor softness of the new DTTA-PyM chelator was perturbed by adding a fluorine onto the pyridine group. The comparative characterization of N-(3-fluoro-2-pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-3-F-PyM) showed subdued 4f/5f differentiation due to the presence of this electron-withdrawing group
Martyn Pillinger - One of the best experts on this subject based on the ideXlab platform.
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synthesis and characterisation of mesoporous silica phases containing heteroatoms and their cation exchange properties part 5 cation exchange isotherms and the measurement of Radioisotope Distribution coefficients for an mcm 22 phase containing aluminium
Microporous and Mesoporous Materials, 2010Co-Authors: A Dyer, Risto Harjula, Jon Newton, Martyn PillingerAbstract:Abstract Cation exchange isotherms were constructed for the replacement of Na cations by Li, K, Rb, Cs, NH 4, Mg, Ca, Sr, Ba, and Al from a well characterised MCM-22 phase which contained aluminium as a heteroatom. Thermodynamic assessment of the isotherms enabled the construction of a selectivity series. Comparisons, including standard free energy values, have been drawn to similar results measured for other MCM-41 phases and some high-silica zeolites. This work additionally describes studies on the MCM-22 phase to examine its potential ability to scavenge Radioisotopes from various solutions as simulants of those found in nuclear waste. The isotopes studied were 241-Am, relevant to spent nuclear fuel, and 137-Cs, 57-Co, 51-Cr, 59-Fe, 54-Mn, 89-Sr, 65-Zn present in nuclear wastes as fission products, from neutron activation in nuclear installations, and arising from medical uses. Measurement of Distribution coefficients enabled the construction of selectivity series which demonstrated the versatility of the phases to scavenge specific isotopes.
Vyacheslav S. Bryantsev - One of the best experts on this subject based on the ideXlab platform.
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influence of a heterocyclic nitrogen donor group on the coordination of trivalent actinides and lanthanides by aminopolycarboxylate complexants
Inorganic Chemistry, 2018Co-Authors: Travis S. Grimes, Colt R. Heathman, Alexander S. Ivanov, Santanu Roy, Vyacheslav S. Bryantsev, Santa Jansonepopova, Peter R. ZalupskiAbstract:The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and Radioisotope Distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitro...
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Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants
2018Co-Authors: Travis S. Grimes, Colt R. Heathman, Santa Jansone-popova, Alexander S. Ivanov, Santanu Roy, Vyacheslav S. Bryantsev, Peter R. ZalupskiAbstract:The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and Radioisotope Distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL(aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am3+, Cm3+) and trivalent lanthanide chelates (La3+–Lu3+) are observed in liquid–liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA-PyM as an aqueous holdback reagent. In addition, the enhanced nitrogen-donor softness of the new DTTA-PyM chelator was perturbed by adding a fluorine onto the pyridine group. The comparative characterization of N-(3-fluoro-2-pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-3-F-PyM) showed subdued 4f/5f differentiation due to the presence of this electron-withdrawing group
Alexander S. Ivanov - One of the best experts on this subject based on the ideXlab platform.
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influence of a heterocyclic nitrogen donor group on the coordination of trivalent actinides and lanthanides by aminopolycarboxylate complexants
Inorganic Chemistry, 2018Co-Authors: Travis S. Grimes, Colt R. Heathman, Alexander S. Ivanov, Santanu Roy, Vyacheslav S. Bryantsev, Santa Jansonepopova, Peter R. ZalupskiAbstract:The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and Radioisotope Distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitro...
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Influence of a Heterocyclic Nitrogen-Donor Group on the Coordination of Trivalent Actinides and Lanthanides by Aminopolycarboxylate Complexants
2018Co-Authors: Travis S. Grimes, Colt R. Heathman, Santa Jansone-popova, Alexander S. Ivanov, Santanu Roy, Vyacheslav S. Bryantsev, Peter R. ZalupskiAbstract:The novel metal chelator N-2-(pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-PyM) was designed to replace a single oxygen-donor acetate group of the well-known aminopolycarboxylate complexant diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid (DTPA) with a nitrogen-donor 2-pyridylmethyl. Potentiometric, spectroscopic, computational, and Radioisotope Distribution methods show distinct differences for the 4f and 5f coordination environments and enhanced actinide binding due to the nitrogen-bearing heterocyclic moiety. The Am3+, Cm3+, and Ln3+ complexation studies for DTTA-PyM reveal an enhanced preference, relative to DTPA, for trivalent actinide binding. Fluorescence studies indicate no changes to the octadentate coordination of trivalent curium, while evidence of heptadentate complexation of trivalent europium is found in mixtures containing EuHL(aq) complexes at the same aqueous acidity. The denticity change observed for Eu3+ suggests that complex protonation occurs on the pyridyl nitrogen. Formation of the CmHL(aq) complex is likely due to the protonation of an available carboxylate group because the carbonyl oxygen can maintain octadentate coordination through a rotation. The observed suppressed protonation of the pyridyl nitrogen in the curium complexes may be attributed to stronger trivalent actinide binding by DTTA-PyM. Density functional theory calculations indicate that added stabilization of the actinide complexes with DTTA-PyM may originate from π-back-bonding interactions between singly occupied 5f orbitals of Am3+ and the pyridyl nitrogen. The differences between the stabilities of trivalent actinide chelates (Am3+, Cm3+) and trivalent lanthanide chelates (La3+–Lu3+) are observed in liquid–liquid extraction systems, yielding unprecedented 4f/5f differentiation when using DTTA-PyM as an aqueous holdback reagent. In addition, the enhanced nitrogen-donor softness of the new DTTA-PyM chelator was perturbed by adding a fluorine onto the pyridine group. The comparative characterization of N-(3-fluoro-2-pyridylmethyl)diethylenetriamine-N,N′,N″,N″-tetraacetic acid (DTTA-3-F-PyM) showed subdued 4f/5f differentiation due to the presence of this electron-withdrawing group