作者:Martyn P. Coles、Peter B. Hitchcock、Alexei V. Khvostov、Michael F. Lappert、Zhengning Li、Andrey V. Protchenko
DOI:10.1039/c0dt00349b
日期:——
Complexes [Ce(NR2)3] (1) or [Ce(NR″2)3] (2) were cerium(III) precursors to the X-ray characterised crystalline oligomeric oxygen-containing amidocerium(IV) compounds [Ce(NR2)2(μ-O)}n] (3, n = 2; 4, n = 3), [Ce(NR″2)2(μ-O)}4] (5), [(R2N)3Ce}2(μ-OMOM)] (6, M = Na; 7, M = K), [(R2N)3CeOCe(NR2)2}2(μ-OKOK)] (8), and [Ce(NR2)3}2(μ-η2:η2-O2)]·2CnH2n+2 (9, n = 6; 9′, n = 5) [R = SiMe3, NR″2 = TMP = NC(Me)2(CH2)3CMe2]. Each was isolated in low, or for 5 very low, yield. Except for 4, the oxidising agent was O2 at −27 °C in hexane (3, 6, 7, 8, 9), pentane (9′), or toluene (5), and a co-reagent for the alkali metal bis(trimethylsilyl)amido(oxy)cerate(IV)s was NaNR2 (8) or KNR2 (7, 8). From 1 and an equivalent portion of 2,6-tBu2-benzoquinone after 5 weeks in pentane there was obtained the bis(amido)cyclotricer(IV)oxane 4. The NMR spectral solution chemical shifts for NR2 groups of 3, 4, and 6–9 were consistent with each sample being diamagnetic and hence a Ce(IV) species. A transient amidocerium(IV) superoxide Ce(NR2)3(η2-O2) (J), or its TMP analogue, is considered to be the common first-formed intermediate in each case, while 4 is believed to have arisen from the adventitious hydrolysis of [Ce(NR2)3O}2(tBu2C6H2-1,4)].
复合物 [Ce(NR₂)₃] (1) 或 [Ce(NR″₂)₃] (2) 是铈(III)前体,通过 X 射线表征确定了结晶的含氧酰胺铈(IV)化合物 [Ce(NR₂)₂(μ-O)}ₙ] (3, n=2; 4, n=3), [Ce(NR″₂)₂(μ-O)}₄] (5), [(R₂N)₃Ce}₂(μ-OMOM)] (6, M=Na; 7, M=K), [(R₂N)₃CeOCe(NR₂)₂}₂(μ-OKOK)] (8), 以及 [Ce(NR₂)₃}₂(μ-η₂:η₂-O₂)]·2CₙH₂ₙ₊₂ (9, n=6; 9', n=5) [R=SiMe₃, NR″₂=TMP=NC(Me)₂(CH₂)₃CMe₂]。每种化合物的产率都很低,特别是对于 5 来说,产率非常低。除了 4 之外,氧化剂为 -27 °C 下的 O₂(3, 6, 7, 8, 9),戊烷(9'),或甲苯(5),并且碱金属双(三甲基硅基)酰胺氧铈(IV)的共反应剂为 NaNR₂(8)或 KNR₂(7, 8)。从 1 和等量的 2,6-tBu₂-苯醌在戊烷中反应 5 周后,得到了双(酰胺)环三铈(IV)氧烷 4。核磁共振谱中 NR₂ 基团的化学位移与每种样品均为反磁性,从而表明是铈(IV)物种。瞬态酰胺铈(IV)超氧化物 Ce(NR₂)₃(η₂-O₂) (J),或其 TMP 类似物,被认为是每种情况下共同形成的第一中间体,而 4 被认为是由于 [Ce(NR₂)₃O}₂(tBu₂C₆H₂-1,4)] 的偶发水解而产生的。