title: A stable aminyl radical metal complex.
abstract: Metal-stabilized phenoxyl radicals appear to be important intermediates in a variety of enzymatic oxidations. We report that transition metal coordination also supports an aminyl radical, resulting in a stable crystalline complex: [Rh(I)(trop2N.)(bipy)]+OTf- (where trop is 5-H-dibenzo[a,d]cycloheptene-5-yl, bipy is 2,2'-bipyridyl, OTf- is trifluorosulfonate). It is accessible under mild conditions by one-electron oxidation of the amide complex [Rh(I)(trop2N)(bipy)], at a potential of -0.55 volt versus ferrocene/ferrocenium. Both electron paramagnetic resonance spectroscopy and density functional theory support 57% localization of the unpaired spin at N. In reactions with H-atom donors, the Rh-coordinated aminyl behaves as a nucleophilic radical.
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Hönggerberg, CH-8093 Zürich, Switzerland.
authors.forename: Torsten
authors.initials: T
authors.lastname: Büttner
authors.forename: Jens
authors.initials: J
authors.lastname: Geier
authors.forename: Gilles
authors.initials: G
authors.lastname: Frison
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Harmer
authors.forename: Carlos
authors.initials: C
authors.lastname: Calle
authors.forename: Arthur
authors.initials: A
authors.lastname: Schweiger
authors.forename: Hartmut
authors.initials: H
authors.lastname: Schönberg
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Grützmacher