of [(ICy)2Ni(CO)2] (2) and [(IMes)2Ni(CO)2] (3). The greater electron-donating properties of the NHC ligands compared to tertiary phosphines are also demonstrated through calorimetric studies and enabled the determination of average bond dissociation enthalpies for Ni−L (L = NHC and tertiary phosphine).
(NHC)2 Ni(CO)2类型的两个新的二羰基N-杂环卡宾
镍(0)络合物(NHC = ICy,[ N,N'-双(环己基
咪唑)-2-亚烷基(2),IMes [ N,ñ ' -双(2,4,6-三甲基苯基)
咪唑)-2-亚基](3))已被(NHC)的Ni(CO)的取代反应来制备2(NHC = I吨卜[ ñ,N'-双(叔丁基
咪唑)-2-亚烷基],IAd [ N,N'-双(1-
金刚烷咪唑)-2-亚基])和2个等价的ICy或IMes。单晶X射线分析证实了[(ICy)2 Ni(CO)2 ](2)和[(IMes)2 Ni(CO)2 ](3)的单体18电子组成。通过量热研究也证明了NHC
配体与叔膦相比具有更大的供电子特性,并能够确定Ni-L(L = NHC和叔膦)的平均键解离焓。