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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Gd(NO3)3 by Materials Project

Gd(NO3)3 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of one Gd(NO3)3 sheet oriented in the (0, 0, 1) direction. Gd3+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Gd–O bond distances ranging from 2.42–2.72 Å. There are three inequivalent N5+ sites. In the first N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.25–1.28 Å. In the second N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.26 Å) and two longer (1.27 Å) N–O bond length. In the third N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.24–1.31 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Gd3+ and one N5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Gd3+ and one N5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Gd3+ and one N5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Gd3+ and one N5+ atom. In the fifth O2- site, O2- is bonded in a distorted L-shaped geometry to one Gd3+ and one N5+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one Gd3+ and one N5+ atom. In the seventh O2- site, O2- is bonded in a distorted L-shaped geometry to one Gd3+ and one N5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to one Gd3+ and one N5+ atom. In the ninth O2- site, O2- is bonded in a distorted L-shaped geometry to one Gd3+ and one N5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Impact of Lanthanide Complexation and Temperature on the Chemical Reactivity of N,N,N',N'-tetraoctyl diglycolamide (TODGA) with the Dodecane Radical Cation

The impact of lanthanide (Ln) metal ion complexation and temperature on the chemical reactivity of N,N,N',N'-tetraoctyl diglycolamide (TODGA) with the dodecane radical cation (RH?+) has been measured by electron pulse radiolysis. Complexation of trivalent neodymium (Nd), gadolinium (Gd), and ytterbium (Yb) by TODGA yielded [Ln(TODGA)3(NO3)3] complexes that exhibited significantly increased reactivity (up to 9.3×) with the RH?+ radical cation, relative to the “free” ligand: k([Ln(TODGA)3(NO3)3] + RH?+) = (8.99 ± 0.93) × 1010, (2.88 ± 0.40) × 1010, and (1.53 ± 0.34) × 1010 M–1 s–1, for Nd(III), Gd(III), and Yb(III), respectively. The kinetic enhancement measured for both ligands exhibited a dependence on atomic number. Arrhenius parameters—specifically activation energies (Ea) and pre-exponential factors (A)—were determined for the reaction of “free” TODGA ligand with the RH?+ radical cation, giving: Ea(TODGA) = 17.43 ± 1.64 kJ mol–1, and A(TODGA) = (1.08 ± 0.02) × 1013 M–1 s–1. This draft manuscript has been prepared in fulfillment of Milestone M4FT-22IN030402024.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2023

Impact of lanthanide ion complexation and temperature on the chemical reactivity of N , N , N ', N '-tetraoctyl diglycolamide (TODGA) with the dodecane radical cation

The impact of trivalent lanthanide ion complexation and temperature on the chemical reactivity of N,N,N',N'-tetraoctyl diglycolamide (TODGA) with the n-dodecane radical cation (RH˙+) has been measured by electron pulse radiolysis and evaluated by quantum mechanical calculations. Additionally, Arrhenius parameters were determined for the reaction of the non-complexed TODGA ligand with the RH˙ + from 10–40 °C, giving the activation energy (E a = 17.43 ± 1.64 kJ mol –1 ) and pre-exponential factor (A = (2.36 ± 0.05) × 10 13 M –1 s –1 ). The complexation of Nd(III), Gd(III), and Yb(III) ions by TODGA yielded [LnIII(TODGA)3(NO3)3] complexes that exhibited significantly increased reactivity (up to 9.3× faster) with the RH˙ + , relative to the non-complexed ligand: k([Ln III (TODGA) 3 (NO 3 ) 3 ] + RH˙ + ) = (8.99 ± 0.93) × 10 10 , (2.88 ± 0.40) × 10 10 , and (1.53 ± 0.34) × 10 10 M –1 s –1 , for Nd(III), Gd(III), and Yb(III) ions, respectively. The rate coefficient enhancement measured for these complexes exhibited a dependence on atomic number, decreasing as the lanthanide series was traversed. Preliminary reaction free energy calculations—based on a model [Ln III (TOGDA)] 3+ complex system—indicate that both electron/hole and proton transfer reactions are energetically unfavorable for complexed TODGA. Furthermore, complementary average local ionization energy calculations showed that the most reactive region of model N,N,N',N'-tetraethyl diglycolamide (TEDGA) complexes, [Ln III (TEGDA) 3 (NO 3 ) 3 ], toward electrophilic attack is for the coordinated nitrate (NO 3 – ) counter anions. Furthermore, it is possible that radical reactions with the complexed NO 3 – counter anions dominate the differences in rates seen for the [Ln III (TODGA) 3 (NO 3 ) 3 ] complexes, and are likely responsible for the reported radioprotection in the presence of TODGA complexes.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗