Zhang Kainan, Conda-Sheridan Martin, Cooke Shayna, Louie Janis
Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850.
Organometallics. 2011 May 9;30(9):2546-2552. doi: 10.1021/om200090d.
New paramagnetic Ni(I)(IMes)(2)X (IMes: 1,3-bis-(2,4,6-trimethylphenyl)-imidazol-2-ylidene) were prepared from the reaction of Ni(IMes)(2) with aryl halides. Products that would arise from oxidative addition were not observed. In contrast, Ni(II)(tmiy)(2)(X)(Ar) was formed from the oxidative addition of aryl halides to Ni bound by a sterically-less hindered NHC ligand, tmiy (tetramethylimidazol-2-ylidene). The paramagnetic Ni(I)(IMes)(2)X complexes were compared to known Ni(0) and Ni(II) catalysts for Kumada and Suzuki coupling reactions. Stoichiometric reactions between the Ni(I)(IMes)(2)X complexes with aryl halides and transmetallating agents were also evaluated.
新型顺磁性镍(I)(IMes)₂X(IMes:1,3-双-(2,4,6-三甲基苯基)-咪唑-2-亚基)由Ni(IMes)₂与芳基卤化物反应制备而成。未观察到由氧化加成反应产生的产物。相比之下,镍(II)(tmiy)₂(X)(Ar)是由芳基卤化物与由空间位阻较小的NHC配体tmiy(四甲基咪唑-2-亚基)配位的镍发生氧化加成反应形成的。将顺磁性镍(I)(IMes)₂X配合物与用于 Kumada 和 Suzuki 偶联反应的已知镍(0)和镍(II)催化剂进行了比较。还评估了镍(I)(IMes)₂X配合物与芳基卤化物和金属转移试剂之间的化学计量反应。