Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 6-435, Cambridge, Massachusetts 02139, USA.
J Am Chem Soc. 2010 Mar 17;132(10):3250-1. doi: 10.1021/ja910364u.
Reaction of the uranium(III) tris(anilide) complex (THF)U(N[t-Bu]Ar)(3) (1, THF = tetrahydrofuran; Ar = 3,5-Me(2)C(6)H(3)) with MN(3) (M = Na, [N(n-Bu)(4)]) results in the formation of the bimetallic diuranium(IV/IV) complexes M[(mu-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 (mu-N)(U(N[t-Bu]Ar)(3))(2) (3) and the diuranium(V/V) complex [(mu-N)(U(N[t-Bu]Ar)(3))(2)][B(Ar(F))(4)] {[3][B(Ar(F))(4)]; Ar(F) = 3,5-(CF(3))(2)C(6)H(3)}. M[3], 3, and [3][B(Ar(F))(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 E(1/2) = -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(Ar(F))(4)] reveal a linear U=N=U core that contracts by only approximately 0.03 A across the 3 (n = -1, 0, +1) series, an effect that is rationalized as being primarily electrostatic in origin. [3][B(Ar(F))(4)] reacts with NaCN, eliminating Na[B(Ar(F))(4)] and forming the known diuranium(IV/IV) cyanoimide complex (mu-NCN)(U(N[t-Bu]Ar)(3))(2), suggesting that the U=N=U core has metallonitrene-like character.
铀(III)三(苯胺)配合物(THF)U(N[t-Bu]Ar)(3)(1，THF=四氢呋喃；Ar=3,5-Me(2)C(6)H(3))与 MN(3)(M=Na，[N(n-Bu)(4)])反应生成双核二铀(IV/IV)配合物 M[(mu-N)(U(N[t-Bu]Ar)(3))(2)] (M[3])，其中一个单一的氮化物配体作为一个线性对称桥连在两个铀中心之间。通过逐步氧化 Na[3]得到双核二铀(IV/V)配合物(mu-N)(U(N[t-Bu]Ar)(3))(2)(3)和双核二铀(V/V)配合物[(mu-N)(U(N[t-Bu]Ar)(3))(2)][B(Ar(F))(4)]{[3][B(Ar(F))(4)]；Ar(F)=3,5-(CF(3))(2)C(6)H(3)}，证明了 U=N=U 核在多个电荷态下的稳定性。M[3]、3 和 [3][B(Ar(F))(4)]通过 NMR 光谱、单晶 X 射线衍射和元素分析进行了表征。3 的循环伏安图显示出两个干净的、可逆的单电子电化学事件，E(1/2)=-1.69 和-0.67 V，分别分配给3 / 3 和 3/3氧化还原对。[N(n-Bu)(4)][3]、3 和 [3][B(Ar(F))(4)]的 X 射线晶体结构揭示了一个线性的 U=N=U 核，在3(n=-1,0,+1)系列中仅收缩约 0.03 A，这种效应被合理化主要是静电起源。[3][B(Ar(F))(4)]与 NaCN 反应，消除 Na[B(Ar(F))(4)]并形成已知的双核二铀(IV/IV)氰基配合物(mu-NCN)(U(N[t-Bu]Ar)(3))(2)，表明 U=N=U 核具有金属氮烯样的性质。
