title: Two-electron reductive carbonylation of terminal uranium(V) and uranium(VI) nitrides to cyanate by carbon monoxide.
abstract: Two-electron reductive carbonylation of the uranium(VI) nitride [U(Tren(TIPS))(N)] (2, Tren(TIPS)=N(CH2CH2NSiiPr3)3) with CO gave the uranium(IV) cyanate [U(Tren(TIPS))(NCO)] (3). KC8 reduction of 3 resulted in cyanate dissociation to give [U(Tren(TIPS))] (4) and KNCO, or cyanate retention in [U(Tren(TIPS))(NCO)][K(B15C5)2] (5, B15C5=benzo-15-crown-5 ether) with B15C5. Complexes 5 and 4 and KNCO were also prepared from CO and the uranium(V) nitride [{U(Tren(TIPS))(N)K}2] (6), with or without B15C5, respectively. Complex 5 can be prepared directly from CO and [U(Tren(TIPS))(N)][K(B15C5)2] (7). Notably, 7 reacts with CO much faster than 2. This unprecedented f-block reactivity was modeled theoretically, revealing nucleophilic attack of the π* orbital of CO by the nitride with activation energy barriers of 24.7 and 11.3 kcal mol(-1) for uranium(VI) and uranium(V), respectively. A remarkably simple two-step, two-electron cycle for the conversion of azide to nitride to cyanate using 4, NaN3 and CO is presented.
authors: School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD (UK).
authors: Peter A
authors: PA
authors: Cleaves
authors: David M
authors: DM
authors: King
authors: Christos E
authors: CE
authors: Kefalidis
authors: Laurent
authors: L
authors: Maron
authors: Floriana
authors: F
authors: Tuna
authors: Eric J L
authors: EJ
authors: McInnes
authors: Jonathan
authors: J
authors: McMaster
authors: William
authors: W
authors: Lewis
authors: Alexander J
authors: AJ
authors: Blake
authors: Stephen T
authors: ST
authors: Liddle
keywords: carbon monoxide; carbonylation; cyanates; nitrides; uranium