1009119-20-3Relevant articles and documents
A method for the synthesis of nickel(0) bis(carbene) complexes
Danopoulos, Andreas A.,Pugh, David
, p. 30 - 31 (2008)
A new method leading to Ni(NHC)2 (NHC = IMes, IPri, SIPri, SIBut) complexes in moderate to good yields, involves the reaction of NHC (pre-formed or generated in situ) with Ni(CH 3)2(tmed), tmed = N,N′-tetramethylethylenediamine; in one case, the intermediate Ni[I(Me2)Pri] 2(CH3)2, I(Me2)Pri = N,N′-diisopropyl-4,5-dimethylimidazol-2-ylidene, has been isolated and structurally characterised. The Royal Society of Chemistry.
Mechanistic Investigations of the Hydrogenolysis of Diaryl Ethers Catalyzed by Nickel Complexes of N-Heterocyclic Carbene Ligands
Saper, Noam I.,Hartwig, John F.
supporting information, p. 17667 - 17676 (2017/12/15)
Recent interest in the valorization of lignin has led to reactions involving the cleavage of strong aromatic C-O bonds. However, few experimental mechanistic studies of these reactions have been published. We report detailed mechanistic analysis of the hydrogenolysis of diaryl ethers catalyzed by the combination of Ni(COD)2 (COD = 1,5-cyclooctadiene) and an N-heterocyclic carbene (NHC). Experiments on the catalytic reaction indicated that NaOt-Bu was necessary for catalysis, but kinetic analysis showed that the base is not involved in the rate-limiting C-O bond cleavage. The resting state of the catalyst is an NHC-Ni(η6-arene) complex. Substitution of the coordinated solvent with diaryl ether allowed isolation of a diaryl ether-bound Ni complex. Rate-limiting C-O bond cleavage occurs to generate a three-coordinate product of oxidative addition, a metallacyclic version of which has been prepared independently. Stoichiometric studies show that arene and phenol products are released following reaction with H2. NaOt-Bu was found to deprotonate the phenol product and to prevent formation of inactive NiI dimers.
