title: Oxygen Atom Transfer Using an Iron(IV)-Oxo Embedded in a Tetracyclic N-Heterocyclic Carbene System: How Does the Reactivity Compare to Cytochrome P450 Compound I?
abstract: N-Heterocyclic carbenes (NHC) are commonly featured as ligands in transition metal catalysis. Recently, a cyclic system containing four NHC groups with a central iron atom was synthesized and its iron(IV)-oxo species, [FeIV(O)(cNHC4)]2+, was characterized. This tetracyclic NHC ligand system may give the iron(IV)-oxo species unique catalytic properties as compared to traditional non-heme and heme iron ligand systems. Therefore, we performed a computational study on the structure and reactivity of the [FeIV(O)(cNHC4)]2+complex in substrate hydroxylation and epoxidation reactions. The reactivity patterns are compared with cytochrome P450 Compound I and non-heme iron(IV)-oxo models and it is shown that the [FeIV(O)(cNHC4)]2+system is an effective oxidant with oxidative power analogous to P450 Compound I. Unfortunately, in polar solvents, a solvent molecule will bind to the sixth ligand position and decrease the catalytic activity of the oxidant. A molecular orbital and valence bond analysis provides insight into the origin of the reactivity differences and makes predictions of how to further exploit these systems in chemical catalysis.
authors.affiliation: Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
authors.forename: Fabián G
authors.identifier: http://orcid.org/0000-0002-0916-6758
authors.initials: FG
authors.lastname: Cantú Reinhard
authors.affiliation: Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
authors.forename: Sam P
authors.identifier: http://orcid.org/0000-0002-2620-8788
authors.initials: SP
authors.lastname: de Visser
keywords: N-heterocyclic carbene; density functional calculations; epoxidation; hydroxylation; iron(IV)-oxo