811 - Redox-active pincer-type N-heterocyclic carbene ligands for multielectron redox reactions at iron and cobalt
Michael B Bayless, email@example.com, Jake D Soper. Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, United States
The ability of redox-active ligands to store and deliver charge to transition metals is finding increased utility in multielectron redox catalysis. We recently showed that bis(amidophenolate) cobalt complexes are catalysts for cross coupling of alkyl halides with organozinc halides. However, catalytic efficiency is limited by their propensity for ligand redistribution. To address this issue, two new electron transfer series of iron and cobalt complexes containing a pincer-type N-heterocyclic carbene redox-active ligand have been prepared. These compounds avoid ligand redistribution and span the multiple oxidation states required for oxidative addition and reductive elimination. For instance, a cobalt(II) complex undergoes three reversible one-electron oxidations at modest potentials. These complexes mediate homocoupling aryl of Grignard reagents to make C-C bonds. Current studies are focused on elaborating cross coupling catalysis, as well as atom and group transfer reactions. The scope and mechanisms of these reactions will be presented.
Tuesday, March 27, 2012 06:00 PM
Inorganic Catalysts (06:00 PM - 08:00 PM)
Location: San Diego Convention Center
Room: Hall D