Thorium- and Uranium-Azide Reductions: A Transient Dithorium-Nitride Versus Isolable Diuranium-NitridesCitation formats

  • External authors:
  • Jingzhen Du
  • David M King
  • Lucile Chatelain
  • Erli Lu
  • Ashley Wooles
  • Maron Laurent

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Thorium- and Uranium-Azide Reductions: A Transient Dithorium-Nitride Versus Isolable Diuranium-Nitrides. / Du, Jingzhen; King, David M; Chatelain, Lucile; Lu, Erli; Tuna, Floriana; Mcinnes, Eric J L; Wooles, Ashley; Laurent, Maron; Liddle, Stephen.

In: Chemical Science, 2019.

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Du, Jingzhen ; King, David M ; Chatelain, Lucile ; Lu, Erli ; Tuna, Floriana ; Mcinnes, Eric J L ; Wooles, Ashley ; Laurent, Maron ; Liddle, Stephen. / Thorium- and Uranium-Azide Reductions: A Transient Dithorium-Nitride Versus Isolable Diuranium-Nitrides. In: Chemical Science. 2019.

Bibtex

@article{eff49ebc0e71459a928852a7a5d9fdb0,
title = "Thorium- and Uranium-Azide Reductions: A Transient Dithorium-Nitride Versus Isolable Diuranium-Nitrides",
abstract = "Molecular uranium-nitrides are now well known, but there are no isolable molecular thorium-nitrides outside of cryogenic matrix isolation experiments. We report that treatment of [M(TrenDMBS)(I)] (M = U, 1; Th, 2; TrenDMBS = {N(CH2CH2NSiMe2But)3}3-) with NaN3 or KN3, respectively, affords very rare examples of actinide molecular square and triangle complexes [{M(TrenDMBS)(μ-N3)}n] (M = U, n = 4, 3; Th, n = 3, 4). Chemical reduction of 3 produces [{U(TrenDMBS)}2(μ-N)][K(THF)6] (5) and [{U(TrenDMBS)}2(μ-N)] (6), whereas photolysis produces exclusively 6. Complexes 5 and 6 can be reversibly inter-converted by oxidation and reduction, respectively, showing that these UNU cores are robust with no evidence for any C-H bond activations being observed. In contrast, reductions of 4 in arene or ethereal solvents gives [{Th(TrenDMBS)}2(μ-NH)] (7) or [{Th(TrenDMBS)}{Th(N[CH2CH2NSiMe2But]2CH2CH2NSi[μ-CH2]MeBut)}(μ-NH)][K(DME)4] (8), respectively, providing evidence unprecedented outside of matrix isolation for a transient dithorium-nitride. This suggests that thorium-nitrides are intrinsically much more reactive than uranium-nitrides, since they consistently activate C-H bonds to form rare examples of Th-N(H)-Th linkages with alkyl by-products. The conversion here of a bridging thorium(IV)-nitride to imido-alkyl combination by 1,2-addition parallels the reactivity of transient terminal uranium(IV)-nitrides, but contrasts to terminal uranium(VI)-nitrides that produce alkyl-amides by 1,1-insertion, suggesting a systematic general pattern of C-H activation chemistry for metal(IV)- vs metal(VI)-nitrides. Surprisingly, computational studies reveal a σ > π energy ordering for all these bridging nitride bonds, a phenomenon for actinides only observed before in terminal uranium nitrides and uranyl with very short U-N or U-O distances.",
author = "Jingzhen Du and King, {David M} and Lucile Chatelain and Erli Lu and Floriana Tuna and Mcinnes, {Eric J L} and Ashley Wooles and Maron Laurent and Stephen Liddle",
year = "2019",
doi = "10.1039/C8SC05473H",
language = "English",
journal = "Chemical Science",
issn = "2041-6520",
publisher = "Royal Society of Chemistry",

}

RIS

TY - JOUR

T1 - Thorium- and Uranium-Azide Reductions: A Transient Dithorium-Nitride Versus Isolable Diuranium-Nitrides

AU - Du, Jingzhen

AU - King, David M

AU - Chatelain, Lucile

AU - Lu, Erli

AU - Tuna, Floriana

AU - Mcinnes, Eric J L

AU - Wooles, Ashley

AU - Laurent, Maron

AU - Liddle, Stephen

PY - 2019

Y1 - 2019

N2 - Molecular uranium-nitrides are now well known, but there are no isolable molecular thorium-nitrides outside of cryogenic matrix isolation experiments. We report that treatment of [M(TrenDMBS)(I)] (M = U, 1; Th, 2; TrenDMBS = {N(CH2CH2NSiMe2But)3}3-) with NaN3 or KN3, respectively, affords very rare examples of actinide molecular square and triangle complexes [{M(TrenDMBS)(μ-N3)}n] (M = U, n = 4, 3; Th, n = 3, 4). Chemical reduction of 3 produces [{U(TrenDMBS)}2(μ-N)][K(THF)6] (5) and [{U(TrenDMBS)}2(μ-N)] (6), whereas photolysis produces exclusively 6. Complexes 5 and 6 can be reversibly inter-converted by oxidation and reduction, respectively, showing that these UNU cores are robust with no evidence for any C-H bond activations being observed. In contrast, reductions of 4 in arene or ethereal solvents gives [{Th(TrenDMBS)}2(μ-NH)] (7) or [{Th(TrenDMBS)}{Th(N[CH2CH2NSiMe2But]2CH2CH2NSi[μ-CH2]MeBut)}(μ-NH)][K(DME)4] (8), respectively, providing evidence unprecedented outside of matrix isolation for a transient dithorium-nitride. This suggests that thorium-nitrides are intrinsically much more reactive than uranium-nitrides, since they consistently activate C-H bonds to form rare examples of Th-N(H)-Th linkages with alkyl by-products. The conversion here of a bridging thorium(IV)-nitride to imido-alkyl combination by 1,2-addition parallels the reactivity of transient terminal uranium(IV)-nitrides, but contrasts to terminal uranium(VI)-nitrides that produce alkyl-amides by 1,1-insertion, suggesting a systematic general pattern of C-H activation chemistry for metal(IV)- vs metal(VI)-nitrides. Surprisingly, computational studies reveal a σ > π energy ordering for all these bridging nitride bonds, a phenomenon for actinides only observed before in terminal uranium nitrides and uranyl with very short U-N or U-O distances.

AB - Molecular uranium-nitrides are now well known, but there are no isolable molecular thorium-nitrides outside of cryogenic matrix isolation experiments. We report that treatment of [M(TrenDMBS)(I)] (M = U, 1; Th, 2; TrenDMBS = {N(CH2CH2NSiMe2But)3}3-) with NaN3 or KN3, respectively, affords very rare examples of actinide molecular square and triangle complexes [{M(TrenDMBS)(μ-N3)}n] (M = U, n = 4, 3; Th, n = 3, 4). Chemical reduction of 3 produces [{U(TrenDMBS)}2(μ-N)][K(THF)6] (5) and [{U(TrenDMBS)}2(μ-N)] (6), whereas photolysis produces exclusively 6. Complexes 5 and 6 can be reversibly inter-converted by oxidation and reduction, respectively, showing that these UNU cores are robust with no evidence for any C-H bond activations being observed. In contrast, reductions of 4 in arene or ethereal solvents gives [{Th(TrenDMBS)}2(μ-NH)] (7) or [{Th(TrenDMBS)}{Th(N[CH2CH2NSiMe2But]2CH2CH2NSi[μ-CH2]MeBut)}(μ-NH)][K(DME)4] (8), respectively, providing evidence unprecedented outside of matrix isolation for a transient dithorium-nitride. This suggests that thorium-nitrides are intrinsically much more reactive than uranium-nitrides, since they consistently activate C-H bonds to form rare examples of Th-N(H)-Th linkages with alkyl by-products. The conversion here of a bridging thorium(IV)-nitride to imido-alkyl combination by 1,2-addition parallels the reactivity of transient terminal uranium(IV)-nitrides, but contrasts to terminal uranium(VI)-nitrides that produce alkyl-amides by 1,1-insertion, suggesting a systematic general pattern of C-H activation chemistry for metal(IV)- vs metal(VI)-nitrides. Surprisingly, computational studies reveal a σ > π energy ordering for all these bridging nitride bonds, a phenomenon for actinides only observed before in terminal uranium nitrides and uranyl with very short U-N or U-O distances.

U2 - 10.1039/C8SC05473H

DO - 10.1039/C8SC05473H

M3 - Article

JO - Chemical Science

T2 - Chemical Science

JF - Chemical Science

SN - 2041-6520

ER -