Electron configuration of the [FeO](2+) group in the H-abstraction from methane: oxyl versus ferryl

TL;DR

This paper discusses the mechanism of methane H-abstraction by the [FeO](2+) group, focusing on the electron configuration differences between oxyl and ferryl states and their roles in the reaction process.

Contribution

It provides an analysis of the electron transfer mechanisms in [FeO](2+) during methane oxidation, highlighting the role of oxyl versus ferryl configurations.

Findings

Oxyl configuration facilitates easier hydrogen atom acceptance.

Ferryl configuration involves electron transfer through antibonding orbitals.

The mechanism differs significantly between oxyl and ferryl states.

Abstract

This account presents author's opinion on the mechanism of the H-abstraction from methane by the [FeO](2+) group. In the course of reaction with hydrogen, the Fe-O bond in the ferryl configuration becomes elongated causing transfer of the spin-up electron from one of doubly occupied bonding orbitals leaving behind single spin-down electron on oxygen. This oxygen in so-formed oxyl configuration of the [FeO](2+) moiety then easily accept the spin-up hydrogen atom from methane in the same way as the radical-localized oxygen does. This mechanism is compared with the scheme in which the hydrogen is accepted by low-lying unoccupied antibonding orbital in the ferryl configuration.