title: Fighting Fenton Chemistry: A Highly Active Iron(III) Tetracarbene Complex in Epoxidation Catalysis.
abstract: Organometallic Fe complexes with exceptionally high activities in homogeneous epoxidation catalysis are reported. The compounds display Fe(II) and Fe(III) oxidation states and bear a tetracarbene ligand. The more active catalyst exhibits activities up to 183 000 turnovers per hour at room temperature and turnover numbers of up to 4300 at -30 °C. For the Fe(III) complex, a decreased Fenton-type reactivity is observed compared with Fe(II) catalysts reported previously as indicated by a substantially lower H2 O2 decomposition and higher (initial) turnover frequencies. The dependence of the catalyst performance on the catalyst loading, substrate, water addition, and the oxidant is investigated. Under all applied conditions, the advantageous nature of the use of the Fe(III) complex is evident.
authors.affiliation: Molecular Catalysis/Inorganic Chemistry, Department of Chemistry, Catalysis Research Center, Technische Universität München (TUM), Lichtenbergstr. 4, 85747, Garching bei München, Germany.
authors.forename: Jens W
authors.initials: JW
authors.lastname: Kück
authors.affiliation: Molecular Catalysis/Inorganic Chemistry, Department of Chemistry, Catalysis Research Center, Technische Universität München (TUM), Lichtenbergstr. 4, 85747, Garching bei München, Germany.
authors.forename: Markus R
authors.initials: MR
authors.lastname: Anneser
authors.affiliation: Molecular Catalysis/Inorganic Chemistry, Department of Chemistry, Catalysis Research Center, Technische Universität München (TUM), Lichtenbergstr. 4, 85747, Garching bei München, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Hofmann
authors.affiliation: Catalysis Research Center, Technische Universität München (TUM), Ernst-Otto-Fischer-Straße 1, 85747, Garching bei München, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Pöthig
authors.affiliation: Faculty of Chemistry, TUM, Lichtenbergstr. 4, 85747, Garching bei München, Germany.
authors.forename: Mirza
authors.initials: M
authors.lastname: Cokoja
authors.affiliation: Molecular Catalysis/Inorganic Chemistry, Department of Chemistry, Catalysis Research Center, Technische Universität München (TUM), Lichtenbergstr. 4, 85747, Garching bei München, Germany. fritz.kuehn@ch.tum.de.
authors.forename: Fritz E
authors.initials: FE
authors.lastname: Kühn
mesh_terms: D002384:Catalysis; D004852:Epoxy Compounds / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry; D006900:Hydroxylation; D007501:Iron / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D004852:Epoxy Compounds; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C030011:carbene; D007501:Iron; D008697:Methane
keywords: carbene ligands; epoxidation; homogeneous catalysis; iron; peroxides