title: Ammonia Activation by a Nickel NCN-Pincer Complex featuring a Non-Innocent N-Heterocyclic Carbene: Ammine and Amido Complexes in Equilibrium.
abstract: A Ni(0)-NCN pincer complex featuring a six-membered N-heterocyclic carbene (NHC) central platform and amidine pendant arms was synthesized by deprotonation of its Ni(II) precursor. It retained chloride in the square-planar coordination sphere of nickel and was expected to be highly susceptible to oxidative addition reactions. The Ni(0) complex rapidly activated ammonia at room temperature, in a ligand-assisted process where the carbene carbon atom played the unprecedented role of proton acceptor. For the first time, the coordinated (ammine) and activated (amido) species were observed together in solution, in a solvent-dependent equilibrium. A structural analysis of the Ni complexes provided insight into the highly unusual, non-innocent behavior of the NHC ligand.
authors: Department of Chemistry, University of Calgary, 2500 University Dr. NW, Calgary, Alberta, T2N1N4 (Canada).
authors: Rudy M
authors: RM
authors: Brown
authors: Department of Chemistry, University of Calgary, 2500 University Dr. NW, Calgary, Alberta, T2N1N4 (Canada).|Current address: Secure Energy Services Inc. Bow Valley Sq. 2 1900, 205 5th Ave SW, Calgary, Alberta, T2P2V7 (Canada).
authors: Javier
authors: J
authors: Borau Garcia
authors: Department of Chemistry, Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä (Finland).
authors: Juuso
authors: J
authors: Valjus
authors: Department of Chemistry, Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä (Finland).
authors: Christopher J
authors: CJ
authors: Roberts
authors: Department of Chemistry, Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä (Finland).
authors: Heikki M
authors: HM
authors: Tuononen
authors: Department of Chemistry, University of Calgary, 2500 University Dr. NW, Calgary, Alberta, T2N1N4 (Canada).
authors: Masood
authors: M
authors: Parvez
authors: Department of Chemistry, University of Calgary, 2500 University Dr. NW, Calgary, Alberta, T2N1N4 (Canada). roesler@ucalgary.ca.
authors: Roland
authors: R
authors: Roesler
keywords: N-heterocyclic carbenes; N ligands; ammonia; bond activation; nickel