N‐Heterocyclic Carbene Based Tri‐organyl‐Zn–Alkyl Cations: Synthesis, Structures, and Use in CO
<sub>2</sub>
Functionalization
作者:David Specklin、Christophe Fliedel、Christophe Gourlaouen、Jean‐Charles Bruyere、Teresa Avilés、Corinne Boudon、Laurent Ruhlmann、Samuel Dagorne
DOI:10.1002/chem.201605907
日期:2017.4.24
[(nNHC)2Zn‐Me]+ (nNHC=C2‐bonded‐IMes/‐IDipp; 3+ and 4+; IMes=1,3‐bis(2,4,6‐trimethylphenyl)imidazolin‐2‐ylidene, IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) were first synthesized and structurally characterized by ionization of the corresponding neutral precursors [(nNHC)ZnMe2] with [Ph3C][B(C6F5)4] in the presence of one equivalent of free NHC. Whereas cation [(nIMes)2Zn‐Me]+ (3+) is stable
三有机基和三配位N-杂环卡宾(NHC)Zn-NHC烷基阳离子[[ n NHC)2 Zn-Me] +(n NHC = C2键合的IMes / -IDipp; 3 +和4 + ; IMes = 1首先合成了3,3-双(2,4,6-三甲基苯基)咪唑啉-2-亚基,IDipp = 1,3-双(2,6-二异丙基苯基)咪唑啉-2-亚基),并通过电离相应的结构来表征中性前体[(n NHC)ZnMe 2 ]和[Ph 3 C] [B(C 6 F 5)4 ]在一当量的游离NHC的存在下。而阳离子[(n IMes)2]的Zn-ME +(3 +)是稳定的,它的空间位阻的类似物[(Ñ IDipp)2的Zn-ME] +(4 +)容易经历一个Ñ NHC-TO-一个在THF或IDipp的存在下异构化NHC得到热力学更稳定[(一个IDipp)(ñ IDipp)的Zn-ME] +(一个IDipp = C4接合IDipp,5 +