NHC-Nickel and Platinum Complexes in Catalysis

Laboratoire SRSMC-SOR, UMR CNRS-UHP 7565, Nancy Universite, BP 70239, Bd des Aiguillettes, 54506 Vandoeuvre-les-Nancy, France 

N-Heterocyclic Carbenes From Laboratory Curiosities to Efficient Synthetic Tools 

The first example of NHC-Ni° systems was reported by Arduengo et al. in 1994. Typically the addition of an appropriate ligand to [Ni(COD)2] (COD = 1,5-cyclooctadiene) or another nickel(0) precursor was used to generate catalytically active species. 

Following the initial report, a plethora of complexes were described both by varying/mixing NHC ligands, and using other Ni precursors. The more recent publications described the use of bi- or tridentate or pincer as well as asymmetric NHC ligands. 

In this context, there are several documented examples of discrepancies in reactivity. For example, the reactions of IPr and ItBu with various nickel sources have drastically different outcomes. The reaction of IPr with [Ni(COD)2] was reported to form [(IPr)2Ni] cleanly, whereas the reaction of ItBu produced several products, but not [(ItBu)2Ni].  

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NHC-nickel and platinum complexes in catalysis, in N-Heterocyclic Carbenes From Laboratory Curiosities to Efficient Synthetic Tools (ed. S. Diez-Gonzdlez), Royal Society of Chemistry, Cambridge. 

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