Anionic N-Heterocyclic Carbenes with N,N′-Bis(fluoroaryl) and N,N′-Bis(perfluoroaryl) Substituents
作者:Matthew G. Hobbs、Chrissy J. Knapp、Patrick T. Welsh、Javier Borau-Garcia、Tom Ziegler、Roland Roesler
DOI:10.1002/chem.201001698
日期:2010.12.27
A series of rhodium complexes, [Rh(cod)(NHC‐Fx)(OH2)] (cod=1,5‐cyclooctadiene; NHC=N‐heterocyclic carbene), incorporating anionic N‐heterocyclic carbenes with 2‐tert‐butylmalonyl backbones and 2,6‐dimethylphenyl (x=0), 2,6‐difluorophenyl (x=4), 2,4,6‐trifluorophenyl (x=6), and pentafluorophenyl (x=10) N,N′‐substituents, respectively, has been prepared by deprotonation of the corresponding zwitterionic
一系列铑配合物,铑[Rh(COD)(NHC-F X)(OH 2)](COD = 1,5-环辛二烯; NHC = N-杂环卡宾),结合阴离子N-杂环卡宾与2-叔- butylmalonyl骨架和2,6-二甲基苯基(X = 0),2,6-二氟苯基(X = 4),2,4,6-三氟苯基(X = 6),和五氟苯(X = 10)N,N'-取代基,分别是已经制备通过用六甲基二钾相应的两性离子的前体去质子化,随后用[的RhCl(COD)}将所得的钾盐的即时反应2 ]。这些配合物可以转化为相关的羰基衍生物的[Rh(CO)2(NHC-F X)(OH 2)]由COD与CO。IR和NMR的配体置换光谱证实了的氟化度Ñ -芳基取代基对σ给体和π接受性有很大的影响卡宾配体的结构,可以有效地用于调节金属中心的电子性能。上卡宾配体主链的羰基的金属-配体π捐赠的评估提供一个特别敏感的探针。在邻位上的-氟取代基Ñ卡宾配体中