氢化镍(II)配合物[(Me N 2 N)Ni-H](2)是通过[(Me N 2 N)Ni-OMe](6)与Ph 2 SiH 2反应合成的。 NMR和IR光谱以及X射线晶体学。2在溶液中不稳定,并通过两个反应途径分解。第一个途径是分子内NH还原性消除,得到Me N 2 NH和镍颗粒。第二种途径是分子间的,具有H 2,镍颗粒和五配位Ni(II)络合物[(Me N 2N)2 Ni](8)作为产物。2与丙酮和乙烯反应,分别形成[(Me N 2 N)Ni-O i Pr](9)和[(Me N 2 N)Ni-Et](10)。2也与卤代烷反应,生成卤化镍配合物和烷烃。使用[(Me N 2 N)Ni-Cl](1)作为催化剂,NaO i Pr或NaOMe作为碱,Ph 2 SiH 2或Me(EtO)2催化还原卤代烷SiH作为氢化物源。催化作用似乎是通过自由基机理进行的。
Chemoselective Alkene Hydrosilylation Catalyzed by Nickel Pincer Complexes
作者:Ivan Buslov、Jeanne Becouse、Simona Mazza、Mickael Montandon‐Clerc、Xile Hu
DOI:10.1002/anie.201507829
日期:2015.11.23
Chemoselective hydrosilylation of functionalized alkenes is difficult to achieve using base‐metal catalysts. Reported herein is that well‐defined bis(amino)amide nickel pincer complexes are efficient catalysts for anti‐Markovnikov hydrosilylation of terminal alkenes with turnover frequencies of up to 83 000 per hour and turnover numbers of up to 10 000. Alkenes containing amino, ester, amido, ketone
Why Are (NN<sub>2</sub>)Ni Pincer Complexes Active for Alkyl−Alkyl Coupling: β-H Elimination Is Kinetically Accessible but Thermodynamically Uphill
作者:Jan Breitenfeld、Oleg Vechorkin、Clémence Corminboeuf、Rosario Scopelliti、Xile Hu
DOI:10.1021/om1007506
日期:2010.9.13
Isomerization and olefin exchange experiments show that β-H elimination is kinetically viable but thermodynamically unfavorable in [(MeNN2)Ni-alkyl] complexes. The intermediacy of Ni-hydride species was corroborated by a trapping experiment. The alkyl complex [(MeNN2)Ni-propyl] catalyzes olefinisomerization.
异构化和烯烃交换实验表明,在[(Me NN 2)Ni-烷基]配合物中,β-H的消除在动力学上是可行的,但在热力学上是不利的。捕集实验证实了氢化镍物种的中间性。烷基络合物[(Me NN 2)Ni-丙基]催化烯烃异构化。