Between imide, imidyl and nitrene – an imido iron complex in two oxidation states

Sascha Reith, Serhiy Demeshko, Beatrice Battistella, Alexander Reckziegel, Christian Schneider, Andreas Stoy, Crispin Lichtenberg, Franc Meyer, Dominik Munz, C. Gunnar Werncke, Chemie
2022
Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive C–H bonds as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes [Fe(NMes)L2]0,- (L ¼ –N{Dipp}SiMe3); Dipp ¼ 2,6-diisopropyl-phenyl; Mes ¼ (2,4,6-trimethylphenyl) via reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,-. UV-vis-, EPR-, 57Fe M¨ossbauer spectroscopy, magnetometry, and computational methods suggest for the
more » ... form an electronic structure as a ferromagnetically coupled iron(II) imidyl radical, whereas oxidation leads to mixed iron(III) imidyl and electrophilic iron(II) nitrene character. Reactivity studies show that both complexes are capable of H atom abstraction from C–H bonds. Further, the reduced form [Fe(NMes)L2]- reacts nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity.
doi:10.17192/es2022.0101 fatcat:oijmsl7alrfl3njutzbhvfk3zy