A Stable Aminyl Radical Coordinated to Cobalt.
A family of cobalt complexes bearing the trop2NH [bis(5-H-dibenzo[a,d]cyclohepten-5-yl)-amine] and 2,2'-bpy (2,2'-bipyridine) chelate ligands were prepared and fully characterized. The compounds [Co(trop2N)(bpy)], [Co(trop2NH)(bpy)]+, and [Co(trop2N)(bpy)]+are cobalt complexes interrelated by one-electron redox processes and/or proton transfer. Two limiting resonance structures can be used to describe the paramagnetic complex [Co(trop2N)(bpy)]+: [CoII(trop2N-)(bpy)]+(CoIIamido) and [CoI(trop2N⋅)(bpy)]+(CoI-aminyl radical). Structural data, DFT calculations, and reactivity toward H-abstraction indicate a slightly higher contribution of the aminyl radical form to the ground state of [Co(trop2N)(bpy)]+. The results described here complete the series of Group 9 metal aminyl radical complexes bearing the diolefin amine ligand trop2NH.
Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland.|Current address: Centro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC), Altos de Pipe, 1020-A, Caracas, Venezuela.|Current address: Departamento de Química, Universidad Simón Bolívar (USB), Valle de Sartenejas, 1080-A, Caracas, Venezuela.
Rafael E
RE
Rodríguez-Lugo
Van't Hoff Institute for Molecular Sciences, Universiteit van Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
Bas
http://orcid.org/0000-0002-3482-7669
B
de Bruin
Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland.
Monica
http://orcid.org/0000-0002-5912-509X
M
Trincado
Department of Chemistry and Applied Biosciences, Eidgenössische Technische Hochschule Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland.
Hansjörg
http://orcid.org/0000-0002-1531-8906
H
Grützmacher
aminyl; cobalt complexes; density functional calculations; radical; spin density