Catalytic Nitrene Transfer by an FeIV‐Imido Complex Generated by a Comproportionation Process. Issue 70 (27th October 2022)

• Record Type: Journal Article
• Authors: Donat, Jordan; Dubourdeaux, Patrick; Clémancey, Martin; Rendon, Julia; Gervasoni, Clara; Barbier, Morgan; Barilone, Jessica; Pécaut, Jacques; Gambarelli, Serge; Maldivi, Pascale; Latour, Jean‐Marc
• Is Part Of: Chemistry. Volume 28:Issue 70(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-27
• Subjects: density functional calculations -- iron -- nitrene transfer -- spectroscopy -- tetracarbene macrocycles; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202201875
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Nitrene transfer reactions have emerged as one of the most powerful and versatile ways to insert an amine function to various kinds of hydrocarbon substrates. However, the mechanisms of nitrene generation have not been studied in depth albeit their formation is taken for granted in most cases without definitive evidence of their occurrence. In the present work, we compare the generation of tosylimido iron species and NTs transfer from Fe II and Fe III precursors where the metal is embedded in a tetracarbene macrocycle. Catalytic nitrene transfer to reference substrates (thioanisole, styrene, ethylbenzene and cyclohexane) revealed that the same active species was at play, irrespective of the ferrous versus ferric nature of the precursor. Through combination of spectroscopic (UV‐visible, Mössbauer), ESI‐MS and DFT studies, an Fe IV tosylimido species was identified as the catalytically active species and was characterized spectroscopically and computationally. Whereas its formation from the Fe II precursor was expected by a two‐electron oxidative addition, its formation from an Fe III precursor was unprecedented. Thanks to a combination of spectroscopic (UV‐visible, EPR, Hyscore and Mössbauer), ESI‐MS and DFT studies, we found that, when starting from the Fe III precursor, an Fe III tosyliodinane adduct was formed and decomposed into an Fe V tosylimido species which generated the catalytically active Fe IV tosylimide through a comproportionation process with the Fe III precursor. Abstract : An Fe IV imide of a tetracarbene macrocycle active in nitrene transfer reactions can be generated from phenyltosyliodinane (PhI=NTs) either from the FeII precursor by oxidative addition (right) or from the FeIII precursor by a comproportionation reaction (left) (AN=acetonitrile, bold horizontal bars=macrocycle).