Synthesis, X-Ray, and Electronic Structures of a New Nickel Dibromide Complex. Activity in the Regioselective Catalyzed Dimerization of Ethylene into 1-Butene
作者:Guilhem Mora、Steven van Zutphen、Christian Klemps、Louis Ricard、Yves Jean、Pascal Le Floch
DOI:10.1021/ic701529a
日期:2007.11.1
[NiBr2(DME)] afforded a new nickel(II) dibromide complex, 2. Both its color and its NMR behavior change with temperature and solvent due to changes in the spin state of the complex. This led us to study the complex spin states using DFT calculations. Furthermore, the activity of 2 in catalyzed ethylene dimerization was studied, revealing both high activity and selectivity toward the production of 1-butene
Insertion of CO
<sub>2</sub>
Mediated by a (Xantphos)Ni
<sup>I</sup>
–Alkyl Species
作者:Justin B. Diccianni、Chunhua T. Hu、Tianning Diao
DOI:10.1002/anie.201906005
日期:2019.9.23
carboxylates. The mechanism of reductive carboxylation of alkyl halides has been proposed to proceed through the reduction of NiII to NiI by either Zn or Mn, followed by CO2 insertion into NiI -alkyl species. No experimental evidence has been previously established to support the two proposed steps. Demonstrated herein is that the direct reduction of (tBu-Xantphos)NiII Br2 by Zn affords NiI species. (tBu-Xantphos)NiI
将 CO2 结合到有机金属和有机分子中代表了制备羧酸盐的可持续方式。已经提出卤代烷的还原羧化机制是通过将 NiII 还原为 NiI 被 Zn 或 Mn 还原,然后将 CO2 插入 NiI-烷基物质中进行的。以前没有建立实验证据来支持这两个提议的步骤。本文证明了 (tBu-Xantphos)NiII Br2 被 Zn 直接还原得到 NiI 物质。(tBu-Xantphos)NiI -Me 和 (tBu-Xantphos)NiI -Et 配合物在 22 °C 下快速插入 CO2。相对于 NiII 配合物,明显更快的速率为所提出的 Ni 催化羧化反应机制提供了长期寻求的实验支持。