title: Heteroleptic, two-coordinate [M(NHC){N(SiMe3)2}] (M = Co, Fe) complexes: synthesis, reactivity and magnetism rationalized by an unexpected metal oxidation state.
abstract: The linear, two-coordinate and isostructural heteroleptic [M(IPr){N(SiMe3)2}] (IPr = 1,3-bis(diisopropylphenyl)-imidazol-2-ylidene), formally MIcomplexes (M = Co, 3; Fe, 4) were obtained by the reduction of [M(IPr)Cl{N(SiMe3)2}] with KC8, or [Co(IPr){N(SiMe3)2}2] with mes*PH2, mes* = 2,4,6-tBu3C6H2. The magnetism of 3 and 4 implies CoIIand FeIIcentres coupled to one ligand-delocalized electron, in line with XPS and XANES data; the ac susceptibility of 4 detected a pronounced frequency dependence due to slow magnetization relaxation. Reduction of [Fe(IPr)Cl{N(SiMe3)2}] with excess KC8in toluene gave the heteronuclear 'inverse-sandwich' Fe-K complex 7, featuring η6-toluene sandwiched between one Fe0and one K+centre.
authors.affiliation: Institute for Advanced Study (USIAS), Université de Strasbourg, 67081 Strasbourg Cedex, France. danopoulos@unistra.fr and Université de Strasbourg, CNRS, CHIMIE UMR 7177, Laboratoire de Chimie de Coordination, Institut de Chimie, 4 rue Blaise Pascal, 67081 Strasbourg Cedex, France. braunstein@unistra.fr.
authors.forename: Andreas A
authors.initials: AA
authors.lastname: Danopoulos
authors.affiliation: Université de Strasbourg, CNRS, CHIMIE UMR 7177, Laboratoire de Chimie de Coordination, Institut de Chimie, 4 rue Blaise Pascal, 67081 Strasbourg Cedex, France. braunstein@unistra.fr.
authors.forename: Pierre
authors.identifier: http://orcid.org/0000-0002-4377-604X
authors.initials: P
authors.lastname: Braunstein
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen University, 52074 Aachen, Germany. kirill.monakhov@ac.rwth-aachen.de paul.koegerler@ac.rwth-aachen.de.
authors.forename: Kirill Yu
authors.initials: KY
authors.lastname: Monakhov
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen University, 52074 Aachen, Germany. kirill.monakhov@ac.rwth-aachen.de paul.koegerler@ac.rwth-aachen.de.
authors.forename: Jan
authors.initials: J
authors.lastname: van Leusen
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen University, 52074 Aachen, Germany. kirill.monakhov@ac.rwth-aachen.de paul.koegerler@ac.rwth-aachen.de and Jülich-Aachen Research Alliance (JARA-FIT) and Peter Grünberg Institute 6, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors.forename: Paul
authors.identifier: http://orcid.org/0000-0001-7831-3953
authors.initials: P
authors.lastname: Kögerler
authors.affiliation: Laboratoire de Chimie et Biologie des Métaux, Equipe de Physicochimie des Métaux en Biologie, UMR 5249 CNRS/CEA-DRF-BIG/Université Grenoble-Alpes, 17 rue des Martyrs, Grenoble 38054, France.
authors.forename: Martin
authors.initials: M
authors.lastname: Clémancey
authors.affiliation: Laboratoire de Chimie et Biologie des Métaux, Equipe de Physicochimie des Métaux en Biologie, UMR 5249 CNRS/CEA-DRF-BIG/Université Grenoble-Alpes, 17 rue des Martyrs, Grenoble 38054, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Latour
authors.affiliation: CEA/DRT/LITEN/DTNM/SEN/L2N, 38054 Grenoble Cedex 9, France.
authors.forename: Anass
authors.initials: A
authors.lastname: Benayad
authors.affiliation: Van't Hoff Institute for Molecular Sciences, Sustainable Materials Characterisation, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Moniek
authors.initials: M
authors.lastname: Tromp
authors.affiliation: LCM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau, France.
authors.forename: Elixabete
authors.initials: E
authors.lastname: Rezabal
authors.affiliation: LCM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Frison