Diradical Group IV complexes with imino-semiquinonate ligands: Characterization and reactivity

INOR 16

Alan F. Heyduk, aheyduk@uci.edu, Department of Chemistry, University of California, Irvine, 1120 Natural Science 2, Irvine, CA 92697-2025
Oxidation of Group IV complexes with ortho-amidophenolate ligands affords a new family of complexes with ligand-centered radical semi-quinonate ligands. Halogen and peroxide substrates add in an oxidative-addition-like way to zirconium(IV) and hafnium(IV) complexes chelated by amidophenolate ligands. Since the metal center cannot supply the necessary reducing equiavlents, ligand-center oxidation occurs upon M-X bond formation. The products are ligand-centered diradicals and display the attendant temperature-dependent magnetization, which is sensitive to both the nature of the metal and the oxidizing substrate. Generation of alkyl and amide derivative of these diradical complexes leads to reductive elimination chemistry, with facile formation of C-C, N-N, and C-N bonded products.