Nonheme Diiron Oxygenase Mimic That Generates a Diferric-Peroxo Intermediate Capable of Catalytic Olefin Epoxidation and Alkane Hydroxylation Including Cyclohexane

Herein are described substrate oxidations with H2O2 catalyzed by [Fe-II(IndH)(CH3CN)(3)](ClO4)(2) [IndH = 1,3-bis(2'-pyridylimino)isoindoline], involving a spectroscopically characterized (mu-oxo)(mu-1,2-peroxo)diiron(III) intermediate (2) that is capable of olefin epoxidation and alkane hydroxylation including cyclohexane. Species 2 also converts ketones to lactones with a decay rate dependent on [ketone], suggesting direct nucleophilic attack of the substrate carbonyl group by the peroxo species. In contrast, peroxo decay is unaffected by the addition of olefins or alkanes, but the label from (H2O)-O-18 is incorporated into the the epoxide and alcohol products, implicating a high-valent iron-oxo oxidant that derives from O-O bond cleavage of the peroxo intermediate. These results demonstrate an ambiphilic diferric-peroxo intermediate that mimics the range of oxidative reactivities associated with O-2-activating nonheme diiron enzymes.

Automated summary

This study describes a substrate oxidation reaction catalyzed by [Fe-II(IndH)(CH3CN)(3)](ClO4)(2) with H2O2, involving a spectroscopically characterized intermediate capable of olefin epoxidation and alkane hydroxylation. The research identified a direct nucleophilic attack of the substrate carbonyl group by the peroxo species. Additionally, the study found that the high-valent iron-oxo oxidant derived from O-O bond cleavage of the peroxo intermediate contributes to the oxidative reactivities associated with nonheme diiron enzymes.