Sequential Insertion Reactions of Carbon Monoxide and Ethylene into the Ni-C Bond of a Cationic Nickel(II) Alkyl Complex
Sequential Insertion Reactions of Carbon Monoxide and Ethylene into the Ni-C Bond of a Cationic Nickel(II) Alkyl Complex
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DOI：
10.1021/om900023y
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发表时间：
2009-04-27
期刊：
影响因子：
2.8
通讯作者：
Hillhouse, Gregory L.
中科院分区：
文献类型：
--
作者：
Curley, John J.;Kitiachvili, Kristina D.;Hillhouse, Gregory L.
阳离子镍（II）新戊基配合物[（dtbpe）Ni（CH（2）tBu）][PF 6]（1; dtbpe = 1，2-双（二叔丁基膦基）乙烷）依次将一氧化碳和乙烯插入到Ni-C键中以形成可分离的产物。在暴露于一氧化碳时，1插入1当量的CO，得到[（dtbpe）Ni（eta（2）-C（O）（CH 2Bu）-Bu-t）][PF 6]（2）。这种阳离子酰基配合物与乙烯发生有效反应，生成[（dtbpe）Ni（kappa（2）-CH 2CH 2C（O）CH（2）tBu）][PF 6]（3），其中氧原子与Ni结合，形成五元金属配合物。用苯基锂处理2导致在与羰基相邻的酸性亚甲基位置处去质子化，得到中性烯酮络合物（dtbpe）Ni（eta（2）-OC=（CHBu）-Bu-t）（4）。配合物2、3和4在20 ℃下是稳定的，并且已经通过NMR和IR光谱以及单晶X-射线衍射进行了表征。
The cationic nickel(II) neopentyl complex [(dtbpe)Ni(CH(2)tBu)][PF6] (1; dtbpe = 1,2-bis(di-tert-butylphosphino)ethane) sequentially inserts carbon monoxide and ethylene into the Ni-C bond to form isolable products. Upon exposure to carbon monoxide, 1 inserts I equiv of CO to give [(dtbpe)Ni(eta(2)-C(O)(CH2Bu)-Bu-t)][PF6] (2). This cationic acyl complex reacts productively with ethylene, resulting in [(dtbpe)Ni(kappa(2) -CH2CH2C(O)CH(2)tBu)][PF6] (3), in which the oxygen atom is bound to Ni, forming a fivemembered metallacycle. Treatment of 2 with phenyl lithium results in deprotonation at an acidic methylene position adjacent to the carbonyl, affording the neutral ketene complex (dtbpe)Ni(eta(2)-OC=(CHBu)-Bu-t) (4). Complexes 2, 3, and 4 are stable at 20 degrees C and have been characterized by NMR and IR spectroscopy as well as single-crystal X-ray diffraction.