Disproportionation Equilibrium of a μ‐Oxodiiron(III) Complex Giving Rise to C−H Activation Reactivity: Structural Snapshot of a Unique Oxoiron(IV) Adduct |
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Authors: | Claudia Cordes Massimiliano Morganti Iris Klawitter Claudia Schremmer Sebastian Dechert Franc Meyer |
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Institution: | Claudia Cordes?(née?Kupper),Massimiliano Morganti,Iris Klawitter,Claudia Schremmer,Sebastian Dechert,Franc Meyer |
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Abstract: | μ‐Oxodiiron(III) species are air‐stable and unreactive products of autoxidation processes of monomeric heme and non‐heme iron(II) complexes. Now, the organometallic (LNHC)FeIII‐(μ‐O)‐FeIII(LNHC)]4+ complex 1 (LNHC is a macrocyclic tetracarbene) is shown to be reactive in C?H activation without addition of further oxidants. Studying the oxidation of dihydroanthracene, it was found that 1 thermally disproportionates in MeCN solution into its oxoiron(IV) ( 2 ) and iron(II) components; the former is the active species in the observed oxidation processes. Possible cleavage scenarios for 1 are shown by scrambling experiments and structural characterization of an unprecedented adduct of 1 and oxoiron(IV) complex 2 . Kinetic analysis gave an equilibrium constant for the disproportionation of 1 , which is very small (Keq=7.5±2.5×10?8 m ). Increasing Keq might by a useful strategy for circumventing the formation of dead‐end μ‐oxodiiron(III) products during Fe‐based homogeneous oxidation catalysis. |
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Keywords: | C-H-Aktivierung Eisen Eisen-Oxo-Komplexe N-Heterocyclische Carbene Reaktionskinetik |
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