Uranium Nitrogen Multiple Bonding: Isostructural Anionic, Neutral, and Cationic Uranium Nitride Complexes Featuring a Linear U=N=U Core

Alexander R. Fox, Polly L. Arnold, Christopher C. Cummins

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Reaction of the uranium(III) tris(anilide) complex (THF)U(N[t-Bu]Ar)3 (1, THF = tetrahydrofuran; Ar = 3,5-Me2C6H3) with MN3 (M = Na, [N(n-Bu)4]) results in the formation of the bimetallic diuranium(IV/IV) complexes M[(μ-N)(U(N[t-Bu]Ar)3)2] (M[3]), which feature a single nitride ligand engaged as a linear, symmetric bridge between two uranium centers. The stability of the U=N=U core across multiple charge states is illustrated by stepwise chemical oxidation of Na[3] to the diuranium(IV/V) complex (μ-N)(U(N[t-Bu]Ar)3)2 (3) and the diuranium(V/V) complex [(μ-N)(U(N[t-Bu]Ar)3)2][B(ArF)4] {[3][B(ArF)4]; ArF= 3,5-(CF3)2C6H3}. M[3], 3, and [3]B(ArF)4] were characterized by NMR spectroscopy. single-crystal X-ray diffraction, and elemental analysis. The cyclic voltammogram of 3 reveals two clean, reversible one-electron electrochemical events at E1/2 = 1.69 and -0.67 V, assigned to the [3]-/3 and 3/[3]+ redox couples. respectively. The X-ray crystal structures of [N(n-Bu)4][3], 3, and [3][B(ArF)4] reveal a linear U=N=U core that contracts by only ∼ 0.03 Å across the [3]n (n = -1, 0, +1) series, an effect that is rationalized as being primarily electrostatic in origin. [3][B(ArF)4] reacts with NaCN, eliminating Na[B(ArF)4] and forming the known diuranium(IV/IV) cyanoimide complex ([μ-NCN)(U(N[t-Bu]Ar)3)2, suggesting that the U=N=U core has metallonitrene-like character.

Original languageEnglish
Pages (from-to)3250-3253
Number of pages3
JournalJournal of the American Chemical Society
Volume132
Issue number10
Early online date24 Feb 2010
DOIs
Publication statusPublished - 17 Mar 2010

Keywords / Materials (for Non-textual outputs)

  • AZIDE
  • DINITROGEN
  • ATOMS
  • Uranium

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