N-donor functionalized N-heterocyclic carbene nickel(II) complexes in the Kumada coupling
N-donor functionalized N-heterocyclic carbene nickel(II) complexes in the Kumada coupling
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DOI：
10.1039/b905036a
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发表时间：
2009-01-01
影响因子：
4
通讯作者：
Bouwman, Elisabeth
中科院分区：
文献类型：
--
作者：
Berding, Joris;van Dijkman, Thomas F.;Bouwman, Elisabeth
描述了一种新型镍（II）配合物的合成和表征，该配合物含有两个双齿n杂环碳配体，并以阴离子n给体为官能团。采用了两种不同的n给体基团，即胺基和苯并咪唑基。用x射线晶体学测定了其中三种配合物的固态结构。酰胺功能化的低自旋方形平面Ni（II）配合物在金属中心周围呈顺式几何形状，而苯并咪唑功能化的配合物结晶为反式异构体。研究了这些新型配合物在苯基氯化镁与4-氯苯甲醚和4-氟苯甲醚的熊田交联反应中的活性。其中一种苯并咪唑功能化配合物在该反应中显示出迄今为止报道的最高活性，在仅使用1mol %催化剂的情况下，在30分钟（4-氯苯甲醚）或150分钟（4-氟苯甲醚）内产生所需的定量产量。
The synthesis and characterization of novel nickel(II) complexes bearing two bidentate N-heterocyclic carbene ligands functionalized with anionic N-donor moieties are described. Two different N-donor groups are employed, namely amido and benzimidazolato moieties. The solid-state structures of three of these complexes have been determined by X-ray crystallography. The amido-functionalized low-spin, square-planar Ni(II) complexes exhibit a cis geometry around the metal centre, while the benzimidazolato-functionalized complex crystallizes as the trans isomer. The activity of these novel complexes in the Kumada cross-coupling of phenylmagnesium chloride with 4-chloroanisole and 4-fluoroanisole was investigated. One of the benzimidazolato-functionalized complexes shows the highest activity in this reaction reported to date, yielding the desired product in quantitative yields within 30 min (4-chloroanisole), or 150 min (4-fluoroanisole) with only 1 mol% catalyst.