King David M, McMaster Jonathan, Tuna Floriana, McInnes Eric J L, Lewis William, Blake Alexander J, Liddle Stephen T
School of Chemistry, University of Nottingham , University Park, Nottingham NG7 2RD, U.K.
J Am Chem Soc. 2014 Apr 16;136(15):5619-22. doi: 10.1021/ja502405e. Epub 2014 Apr 8.
Deprotonation of [U(Tren(TIPS))(NH2)] (1) [Tren(TIPS) = N(CH2CH2NSiPr(i)3)3] with organoalkali metal reagents MR (M = Li, R = Bu(t); M = Na-Cs, R = CH2C6H5) afforded the imido-bridged dimers [{U(Tren(TIPS))(μ-N[H]M)}2] [M = Li-Cs (2a-e)]. Treatment of 2c (M = K) with 2 equiv of 15-crown-5 ether (15C5) afforded the uranium terminal parent imido complex [U(Tren(TIPS))(NH)][K(15C5)2] (3c), which can also be viewed as a masked uranium(IV) nitride. The uranium-imido linkage was found to be essentially linear, and theoretical calculations suggested σ(2)π(4) polarized U-N multiple bonding. Attempts to oxidize 3c to afford the neutral uranium terminal parent imido complex [U(Tren(TIPS))(NH)] (4) resulted in spontaneous disproportionation to give 1 and the uranium-nitride complex [U(Tren(TIPS))(N)] (5); this reaction is a new way to prepare the terminal uranium-nitride linkage and was calculated to be exothermic by -3.25 kcal mol(-1).
用有机碱金属试剂MR（M = Li，R = Bu(t)；M = Na - Cs，R = CH2C6H5）对[U(Tren(TIPS))(NH2)]（1）[Tren(TIPS) = N(CH2CH2NSiPr(i)3)3]进行去质子化反应，得到了亚氨基桥联二聚体[{U(Tren(TIPS))(μ - N[H]M)}2] [M = Li - Cs（2a - e）]。用2当量的15 - 冠 - 5醚（15C5）处理2c（M = K），得到了铀末端母体亚氨基配合物[U(Tren(TIPS))(NH)][K(15C5)2]（3c），它也可以被看作是一种掩蔽的铀（IV）氮化物。发现铀 - 亚氨基键基本上是线性的，理论计算表明存在σ(2)π(4)极化的U - N多重键。试图将3c氧化以得到中性铀末端母体亚氨基配合物[U(Tren(TIPS))(NH)]（4），结果导致自发歧化反应生成1和铀氮化物配合物[U(Tren(TIPS))(N)]（5）；该反应是制备末端铀 - 氮键的一种新方法，经计算其放热为 - 3.25 kcal mol(-1)。
