title: A diiron(III,IV) imido species very active in nitrene-transfer reactions.
abstract: Metal-catalyzed nitrene transfer reactions arouse intense interest as clean and efficient procedures for amine synthesis. Efficient Rh- and Ru-based catalysts exist but Fe alternatives are actively pursued. However, reactive iron imido species can be very short-lived and getting evidence of their occurrence in efficient nitrene-transfer reactions is an important challenge. We recently reported that a diiron(III,II) complex is a very efficient nitrene-transfer catalyst to various substrates. We describe herein how, by combining desorption electrospray ionization mass spectrometry, quantitative chemical quench experiments, and DFT calculations, we obtained conclusive evidence for the occurrence of an {Fe(III) Fe(IV) NTosyl} intermediate that is very active in H-abstraction and nitrene-transfer reactions. DFT calculations revealed a strong radical character of the tosyl nitrogen atom in very low-lying electronic configurations of the Fe(IV) ion which are likely to confer its high reactivity.
authors.affiliation: Université Grenoble Alpes, LCBM, and CEA, DSV, iRTSV, LCBM, PMB, and CNRS UMR 5249, LCBM, 38054 Grenoble (France).
authors.forename: Eric
authors.initials: E
authors.lastname: Gouré
authors.forename: Frédéric
authors.initials: F
authors.lastname: Avenier
authors.forename: Patrick
authors.initials: P
authors.lastname: Dubourdeaux
authors.forename: Olivier
authors.initials: O
authors.lastname: Sénèque
authors.forename: Florian
authors.initials: F
authors.lastname: Albrieux
authors.forename: Colette
authors.initials: C
authors.lastname: Lebrun
authors.forename: Martin
authors.initials: M
authors.lastname: Clémancey
authors.forename: Pascale
authors.initials: P
authors.lastname: Maldivi
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Latour
mesh_terms: D002384:Catalysis; D056831:Coordination Complexes / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008968:Molecular Conformation; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D056831:Coordination Complexes; D007093:Imidazoles; D007097:Imines; C017621:phenylnitrene; C029899:imidazole; D007501:Iron
keywords: diiron complexes; mass spectrometry; mixed-valent compounds; nitrene transfer; radicals