Analysis of an alternative to the H-atom abstraction mechanism in methane C–H bond activation by nonheme iron(iv)-oxo oxidants†
Abstract
The triplet δ-mechanism different from the previously reported ones, i.e., the π-channel with the unoccupied π*xz/yz (FeO) orbital and the σ-channel involving the unoccupied α-spin Fe-σ*z2 orbital, has been theoretically described for the methane hydroxylation by [FeIV = O(TMC)(SR)]+ and its derivative [FeIV = O(TMC)(OH)]+ complex for the first time, and we have undertaken a detailed DFT study on the nature of this state by probing its geometry, electronic property and reactivity in comparison to all other possibilities. DFT calculations indicate that the electron transfer for the 3δ-channel from the σC–H orbital of the substrate to the final acceptor σ*x2−y2 orbital of the