Observation of Fe(V)=O using variable-temperature mass spectrometry and its enzyme-like C–H and C=C

Abstract

Oxo-transfer chemistry mediated by iron underpins many biological processes and today is emerging as synthetically very important for the catalytic oxidation of C–H and C=C moieties that are hard to activate conventionally. Despite the vast amount of research in this area, experimental characterization of the reactive species under catalytic conditions is very limited, although a Fe(V)=O moiety was postulated. Here we show, using variable-temperature mass spectrometry, the generation of a Fe(V)=O species within a synthetic non-haem complex at −40 °C and its reaction with an olefin. Also, with isotopic labelling we were able both to follow oxygen-atom transfer from H2O2/H2O through Fe(V)=O to the products and to probe the reactivity as a function of temperature. This study pioneers the implementation of variable-temperature mass spectrometry to investigate reactive intermediates. Variable-temperature mass spectrometry, isotopic labelling and computational analysis have been used to characterize a metastable non-haem oxo-iron(V) intermediate generated at cryogenic temperatures, as well as to study its cis-dihydroxylation reaction with olefins. The study provides experimental evidence for the existence of this powerful and biologically important oxidant, under conditions relevant to catalysis.

Cite this article

Prat, I., Mathieson, J., Güell, M. et al. Observation of Fe(V)=O using variable-temperature mass spectrometry and its enzyme-like C–H and C=C oxidation reactions. Nature Chem 3, 788–793 (2011). https://doi.org/10.1038/nchem.1132

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