title: Binuclear, High-Valent Nickel Complexes: Ni-Ni Bonds in Aryl-Halogen Bond Formation.
abstract: Metal-metal bonds play a vital role in stabilizing key intermediates in bond-formation reactions. We report that binuclear benzo[h]quinoline-ligated NiIIcomplexes, upon oxidation, undergo reductive elimination to form carbon-halogen bonds. A mixed-valent Ni(2.5+)-Ni(2.5+) intermediate is isolated. Further oxidation to NiIII, however, is required to trigger reductive elimination. The binuclear NiIII-NiIIIintermediate lacks a Ni-Ni bond. Each NiIIIundergoes separate, but fast reductive elimination, giving rise to NiIspecies. The reactivity of these binuclear Ni complexes highlights the fundamental difference between Ni and Pd in mediating bond-formation processes.
authors.affiliation: Chemistry Department, New York University, 100 Washington Square E., New York, NY, 10003, USA.
authors.forename: Justin B
authors.initials: JB
authors.lastname: Diccianni
authors.affiliation: Chemistry Department, New York University, 100 Washington Square E., New York, NY, 10003, USA.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Hu
authors.affiliation: Chemistry Department, New York University, 100 Washington Square E., New York, NY, 10003, USA.
authors.forename: Tianning
authors.initials: T
authors.lastname: Diao
keywords: C−X bond formation; mixed-valent compounds; nickel-nickel bond; reaction mechanisms; reductive elimination