Srivastava Ravi, Quadrelli Elsje Alessandra, Camp Clément
Université de Lyon, Institut de Chimie de Lyon, C2P2 UMR 5265 CNRS, Université Lyon 1, ESCPE Lyon, 43 Bd du 11 Novembre 1918, F-69616 Villeurbanne, France.
Dalton Trans. 2020 Mar 9;49(10):3120-3128. doi: 10.1039/d0dt00344a.
We report the synthesis and characterization of a series of original tantalum/rhodium heterobimetallic species assembled by a bifunctional alkoxy-N-heterocyclic carbene (NHC) ligand platform (noted L). The heterotrimetallic [Ta(CH2tBu)(CHtBu)(μ-L)Rh2(COD)2Cl2]n, 2, and heterobimetallic [Ta(μ-L)(CHtBu)(CH2tBu)2Rh(COD)Cl], 4, complexes are obtained upon treatment of [Ta(L)(CHtBu)(CH2tBu)2], 1, with [Rh(COD)Cl]2. To avoid parasistic reactivity arising from the neopentylidene fragment in 1, the peralkyl compound {Ta(L)OSi(OtBu)33}, 5, resulting from the 1,2-addition of tris(tertbutoxysilanol) across the Ta[double bond, length as m-dash]C alkylidene motif, is prepared. An unanticipated silanol-NHC adduct, {HOSiOtBu3}{Ta(L)OSi(OtBu)33}, 6, is formed when 1 is treated with two equivalents of HOSi(OtBu)3. Finally, treatment of 5 with [Rh(COD)Cl]2 provides the heterobimetallic complex {Ta(μ-L)OSi(OtBu)33Rh(COD)(Cl)}, 7, in high yield. This work highlights the reactivity of Ta-NHC adducts and the aptitude of the NHC motif to transfer from Ta to Rh which is used with profit as an efficient synthetic route to access early/late heterobimetallic complexes.
我们报道了一系列由双功能烷氧基 - N - 杂环卡宾（NHC）配体平台（记为L）组装而成的新型钽/铑异双金属物种的合成与表征。用[Rh(COD)Cl]₂处理[Ta(L)(CHtBu)(CH₂tBu)₂]（1）时，可得到异三金属配合物[Ta(CH₂tBu)(CHtBu)(μ - L)Rh₂(COD)₂Cl₂]ₙ（2）和异双金属配合物[Ta(μ - L)(CHtBu)(CH₂tBu)₂Rh(COD)Cl]（4）。为避免1中的新戊叉片段产生寄生反应，制备了由三（叔丁氧基硅醇）通过1,2 - 加成到Ta = C亚烷基基团上得到的全烷基化合物{Ta(L)OSi(OtBu)₃₃}（5）。用两当量的HOSi(OtBu)₃处理1时，会形成一种意外的硅醇 - NHC加合物{HOSiOtBu₃}{Ta(L)OSi(OtBu)₃₃}（6）。最后，用[Rh(COD)Cl]₂处理5可高产率地得到异双金属配合物{Ta(μ - L)OSi(OtBu)₃₃Rh(COD)(Cl)}（7）。这项工作突出了Ta - NHC加合物的反应活性以及NHC基序从Ta转移到Rh的能力，该能力被有效地用作合成早期/晚期异双金属配合物的有效途径。
