[Ta(NMe2)3(i-PrNCH(allyl)NPr-i)] | 1344017-88-4

• 分子结构分类: 有机化合物 - 碳氢化合物 - 不饱和烃
• 英文名称: [Ta(NMe2)3(i-PrNCH(allyl)NPr-i)]
• CAS: 1344017-88-4
• 化学式: C₁₆H₃₈N₅Ta
• 分子量: 481.459
• InChiKey: OHDVEXJUHKLKKB-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
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• 重原子数：
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• 可旋转键数：
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• 环数：
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• sp3杂化的碳原子比例：
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• 拓扑面积：
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• 氢给体数：
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• 氢受体数：
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反应信息

• 作为产物：
  描述：

  N,N'-Diisopropylformamidin 、 Ta(NMe2)4(η1-allyl) 以 正戊烷 为溶剂， 以70%的产率得到[Ta(NMe2)3(i-PrNCH(allyl)NPr-i)]
  参考文献：
  名称：

  Allyl Ligand Reactivity in Tantalum(V) Compounds: Experimental and Computational Evidence for Allyl Transfer to the Formamidinate Ligand in fac-Ta(NMe₂)₃(η¹-allyl)[ⁱPrNC(H)NⁱPr] via a Metallo-Claisen Rearrangement

  摘要：

  Treatment of TaCl(NMe2)(4) (1) with allylMgCl furnishes the allyl-substituted compound Ta(NMe2)(4)(eta(1)-allyl) (2) in moderate yield. The X-ray structure of 2 reveals a trigonal-bipyramidal geometry at the tantalum center with an equatorially situated eta(1)-allyl moiety. VT H-1 NMR measurements confirm that the molecule is fluxional in solution over the temperature range 298-193 K, and DFT calculations indicate that the time-averaged environment exhibited 1:1 the allyl moiety in fluid solution derives from a rapid eta(1)-to-eta(3) equilibration, with Ta(NMe2)(4)(eta(3)-allyl) serving as the transition state for this process. 1 reacts rapidly with the formarnidine (PrNC)-Pr-i-(H)(NHPr)-Pr-i to yield fac-TaCl(NMe2)(3)[(PrNC)-Pr-i(H)(NPr)-Pr-i] (5) and Me2NH, and the tantalum product has been characterized by NMR spectroscopy and X-ray diffraction analysis. The five-coordinate compound Ta(NMe2)(3)[(PrNCH)-Pr-i(allyl)(NPr)-Pr-i] (7), whose origin is traced to the putative octahedral species fac-Ta(NMe2)(3)(eta(1)-allyl) [(PrNC)-Pr-i(H)(NPr)-Pr-i] (6), has been obtained from the reaction of 2 with (PrNC)-Pr-i(H)(NHPr)-Pr-i; 7 may also be prepared from the reaction of 5 with allylMgCl. The rearrangement of the allyl moiety in fac-Ta(NMe2)(3)(eta(1)-allyl)[(PrNC)-Pr-i(H)(NPr)-Pr-i] to the formamidinate carbon atom in 7 has been investigated by DFT calculations. Here the DFT calculations have provided crucial insight into the reaction mechanism and the composition of those transient species that do not lend themselves to direct spectroscopic observation. The computed barrier for this metallo-Claisen rearrangement is sensitive to the nature of the density functional employed, and the barrier computed using the meta-GGA TPSS functional provides the best agreement with the experimental conditions. The related alkenyl derivatives Ta(NMe2)(4)(eta(1)-3-butenyl) (3) and Ta(NMe2)(3)(eta(1)-3-butenyl)[(PrNC)-Pr-i(H)(NPr)-Pr-i] (8) have been synthesized, and their reactivity is contrasted with the corresponding allyl-substituted analogues.

  DOI：

  10.1021/om200683q