EPR Spectroscopic Study of the Active Species of Iron-Catalyzed Enantioselective Epoxidation
Доклады на конференциях
The extremely unstable iron-oxygen intermediates formed in bioinspired catalyst systems based on dinuclear ferric
complexes with aminopyridine ligands containing electron-donating substituents, H2O2 and acetic acid have been detected by EPR spectroscopy for the first time. The detected intermediates are highly reactive and selective towards electron-rich alkene epoxidation even at −85 °C. They exhibit rhombic EPR spectra with the main values of g-tensor close to those of known oxoiron(V) complexes. On the basis of this similarity and reactivity data, we have assigned the observed intermediates to the oxoiron(V) [(L)FeV=O(OC(O)CH3)]2+ active species of selective alkene epoxidation by the catalyst systems studied herein.