Terminal uranium(V/VI) nitride activation of carbon dioxide and carbon disulfide: factors governing diverse and well-defined cleavage and redox reactions

Cleaves, Peter A. and Kefalidis, Christos E. and Gardner, Benedict M. and Tuna, Floriana and McInnes, Eric J.L. and Lewis, William and Maron, Laurent and Liddle, Stephen T. (2017) Terminal uranium(V/VI) nitride activation of carbon dioxide and carbon disulfide: factors governing diverse and well-defined cleavage and redox reactions. Chemistry - a European Journal, 23 (12). pp. 2950-2959. ISSN 1521-3765

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Abstract

The reactivity of terminal uranium(V/VI) nitrides with CE2 (E=O, S) is presented. Well-defined C=E cleavage followed by zero-, one-, and two-electron redox events is observed. The uranium(V) nitride [U(TrenTIPS)(N)][K(B15C5)2] (1, TrenTIPS=N(CH2CH2NSiiPr3)3; B15C5=benzo-15-crown-5) reacts with CO2 to give [U(TrenTIPS)(O)(NCO)][K(B15C5)2] (3), whereas the uranium(VI) nitride [U(TrenTIPS)(N)] (2) reacts with CO2 to give isolable [U(TrenTIPS)(O)(NCO)] (4); complex 4 rapidly decomposes to known [U(TrenTIPS)(O)] (5) with concomitant formation of N2 and CO proposed, with the latter trapped as a vanadocene adduct. In contrast, 1 reacts with CS2 to give [U(TrenTIPS)(κ2-CS3)][K(B15C5)2] (6), 2, and [K(B15C5)2][NCS] (7), whereas 2 reacts with CS2 to give [U(TrenTIPS)(NCS)] (8) and “S”, with the latter trapped as Ph3PS. Calculated reaction profiles reveal outer-sphere reactivity for uranium(V) but inner-sphere mechanisms for uranium(VI); despite the wide divergence of products the initial activation of CE2 follows mechanistically related pathways, providing insight into the factors of uranium oxidation state, chalcogen, and NCE groups that govern the subsequent divergent redox reactions that include common one-electron reactions and a less-common two-electron redox event. Caution, we suggest, is warranted when utilising CS2 as a reactivity surrogate for CO2.

Item Type: Article
Additional Information: This is the peer reviewed version of the following article: P. A. Cleaves, C. E. Kefalidis, B. M. Gardner, F. Tuna, E. J. L. McInnes, W. Lewis, L. Maron, S. T. Liddle, Chem. Eur. J. 2017, 23, 2950, which has been published in final form at http://dx.doi.org/10.1002/chem.201605620. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Keywords: carbon dioxide; carbon disulfide; density functional theory; nitride; uranium
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Chemistry
Identification Number: 10.1002/chem.201605620
Depositing User: Lewis, William
Date Deposited: 27 Sep 2017 15:07
Last Modified: 14 Oct 2017 08:42
URI: http://eprints.nottingham.ac.uk/id/eprint/46648

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