title: Terminal Uranium(V/VI) Nitride Activation of Carbon Dioxide and Carbon Disulfide: Factors Governing Diverse and Well-Defined Cleavage and Redox Reactions.
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 CO2to give [U(TrenTIPS)(O)(NCO)][K(B15C5)2] (3), whereas the uranium(VI) nitride [U(TrenTIPS)(N)] (2) reacts with CO2to give isolable [U(TrenTIPS)(O)(NCO)] (4); complex 4 rapidly decomposes to known [U(TrenTIPS)(O)] (5) with concomitant formation of N2and CO proposed, with the latter trapped as a vanadocene adduct. In contrast, 1 reacts with CS2to give [U(TrenTIPS)(κ2-CS3)][K(B15C5)2] (6), 2, and [K(B15C5)2][NCS] (7), whereas 2 reacts with CS2to 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 CE2follows 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 CS2as a reactivity surrogate for CO2.
authors.affiliation: School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Cleaves
authors.affiliation: LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, Toulouse, 31077, France.
authors.forename: Christos E
authors.initials: CE
authors.lastname: Kefalidis
authors.affiliation: School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
authors.forename: Benedict M
authors.initials: BM
authors.lastname: Gardner
authors.affiliation: School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
authors.forename: Floriana
authors.initials: F
authors.lastname: Tuna
authors.affiliation: School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
authors.forename: Eric J L
authors.initials: EJ
authors.lastname: McInnes
authors.affiliation: School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
authors.forename: William
authors.initials: W
authors.lastname: Lewis
authors.affiliation: LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, Toulouse, 31077, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Maron
authors.affiliation: School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Liddle
keywords: carbon dioxide; carbon disulfide; density functional theory; nitride; uranium