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

Gregory P. Horne; Cristian Celis-Barros; Jacy K. Conrad; Travis S. Grimes; Jeffrey R. McLachlan; Brian M. Rotermund; Andrew R. Cook; Stephen P. Mezyk

doi:10.1039/d3cp01119d

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

Gregory P. Horne, Cristian Celis-Barros, Jacy K. Conrad, Travis S. Grimes, Jeffrey R. McLachlan, Brian M. Rotermund, Andrew R. Cook, Stephen P. Mezyk

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

Abstract

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) × 10¹³ M⁻¹ s⁻¹). The complexation of Nd(iii), Gd(iii), and Yb(iii) ions by TODGA yielded [Ln^III(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(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) 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(NO₃)₃], toward electrophilic attack is for the coordinated nitrate (NO₃⁻) counter anions. Therefore, it is possible that radical reactions with the complexed NO₃⁻ counter anions dominate the differences in rates seen for the [Ln^III(TODGA)₃(NO₃)₃] complexes, and are likely responsible for the reported radioprotection in the presence of TODGA complexes.

Original language	English
Pages (from-to)	16404-16413
Number of pages	10
Journal	Physical Chemistry Chemical Physics
Volume	25
Issue number	24
DOIs	https://doi.org/10.1039/d3cp01119d
State	Published - Jun 9 2023
Externally published	Yes

Funding

This research has been funded by the U.S. Department of Energy Assistant Secretary for Nuclear Energy, under the Material Recovery and Waste Form Development Campaign, DOE-Idaho Operations Office Contract DE-AC07-05ID14517. Cook and electron pulse irradiation experiments at the LEAF of the BNL Accelerator Center for Energy Research were supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract DE-SC0012704. McLachlan was supported by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the DOE under contract number DE-SC0014664.

Funders	Funder number
Office of Science Graduate Student Research
SCGSR
U.S. Department of Energy Assistant Secretary for Nuclear Energy	DE-AC07-05ID14517
U.S. Department of Energy	DE-SC0014664
Office of Science
Basic Energy Sciences
Workforce Development for Teachers and Scientists
Oak Ridge Institute for Science and Education
Chemical Sciences, Geosciences, and Biosciences Division	DE-SC0012704

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10.1039/d3cp01119d

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Horne, G. P., Celis-Barros, C., Conrad, J. K., Grimes, T. S., McLachlan, J. R., Rotermund, B. M., Cook, A. R., & Mezyk, S. P. (2023). Impact of lanthanide ion complexation and temperature on the chemical reactivity of N,N,N′,N′-tetraoctyl diglycolamide (TODGA) with the dodecane radical cation. Physical Chemistry Chemical Physics, 25(24), 16404-16413. https://doi.org/10.1039/d3cp01119d

@article{46a1e05e36f34584a9451548c5523cd8,

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

abstract = "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 (Ea = 17.43 ± 1.64 kJ mol−1) and pre-exponential factor (A = (2.36 ± 0.05) × 1013 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([LnIII(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) 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 [LnIII(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, [LnIII(TEGDA)3(NO3)3], toward electrophilic attack is for the coordinated nitrate (NO3−) counter anions. Therefore, it is possible that radical reactions with the complexed NO3− counter anions dominate the differences in rates seen for the [LnIII(TODGA)3(NO3)3] complexes, and are likely responsible for the reported radioprotection in the presence of TODGA complexes.",

author = "Horne, {Gregory P.} and Cristian Celis-Barros and Conrad, {Jacy K.} and Grimes, {Travis S.} and McLachlan, {Jeffrey R.} and Rotermund, {Brian M.} and Cook, {Andrew R.} and Mezyk, {Stephen P.}",

note = "Publisher Copyright: {\textcopyright} 2023 The Royal Society of Chemistry",

year = "2023",

month = jun,

day = "9",

doi = "10.1039/d3cp01119d",

language = "English",

volume = "25",

pages = "16404--16413",

journal = "Physical Chemistry Chemical Physics",

issn = "1463-9076",

publisher = "Royal Society of Chemistry",

number = "24",

}

Horne, GP, Celis-Barros, C, Conrad, JK, Grimes, TS, McLachlan, JR, Rotermund, BM, Cook, AR & Mezyk, SP 2023, 'Impact of lanthanide ion complexation and temperature on the chemical reactivity of N,N,N′,N′-tetraoctyl diglycolamide (TODGA) with the dodecane radical cation', Physical Chemistry Chemical Physics, vol. 25, no. 24, pp. 16404-16413. https://doi.org/10.1039/d3cp01119d

Impact of lanthanide ion complexation and temperature on the chemical reactivity of N,N,N′,N′-tetraoctyl diglycolamide (TODGA) with the dodecane radical cation. / Horne, Gregory P.; Celis-Barros, Cristian; Conrad, Jacy K. et al.
In: Physical Chemistry Chemical Physics, Vol. 25, No. 24, 09.06.2023, p. 16404-16413.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Impact of lanthanide ion complexation and temperature on the chemical reactivity of N,N,N′,N′-tetraoctyl diglycolamide (TODGA) with the dodecane radical cation

AU - Horne, Gregory P.

AU - Celis-Barros, Cristian

AU - Conrad, Jacy K.

AU - Grimes, Travis S.

AU - McLachlan, Jeffrey R.

AU - Rotermund, Brian M.

AU - Cook, Andrew R.

AU - Mezyk, Stephen P.

PY - 2023/6/9

Y1 - 2023/6/9

N2 - 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 (Ea = 17.43 ± 1.64 kJ mol−1) and pre-exponential factor (A = (2.36 ± 0.05) × 1013 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([LnIII(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) 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 [LnIII(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, [LnIII(TEGDA)3(NO3)3], toward electrophilic attack is for the coordinated nitrate (NO3−) counter anions. Therefore, it is possible that radical reactions with the complexed NO3− counter anions dominate the differences in rates seen for the [LnIII(TODGA)3(NO3)3] complexes, and are likely responsible for the reported radioprotection in the presence of TODGA complexes.

AB - 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 (Ea = 17.43 ± 1.64 kJ mol−1) and pre-exponential factor (A = (2.36 ± 0.05) × 1013 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([LnIII(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) 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 [LnIII(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, [LnIII(TEGDA)3(NO3)3], toward electrophilic attack is for the coordinated nitrate (NO3−) counter anions. Therefore, it is possible that radical reactions with the complexed NO3− counter anions dominate the differences in rates seen for the [LnIII(TODGA)3(NO3)3] complexes, and are likely responsible for the reported radioprotection in the presence of TODGA complexes.

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U2 - 10.1039/d3cp01119d

DO - 10.1039/d3cp01119d

M3 - Article

C2 - 37294439

AN - SCOPUS:85163545674

SN - 1463-9076

VL - 25

SP - 16404

EP - 16413

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

IS - 24

ER -

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

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