Volume 25, Issue 54 p. 12491-12496
Communication

Electronic Structure of N-Bridged High-Valent Diiron-Oxo

Quan Manh Phung

Corresponding Author

Quan Manh Phung

Department of Chemistry, KU Leuven, Celestijnenlaan 200F, Leuven, 3001 Belgium

Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, 464-8602 Japan

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Kristine Pierloot

Corresponding Author

Kristine Pierloot

Department of Chemistry, KU Leuven, Celestijnenlaan 200F, Leuven, 3001 Belgium

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First published: 17 July 2019
Citations: 13

Graphical Abstract

The electronic structure of an N-bridged high-valent diiron-oxo was studied using density functional theory and second-order perturbation theory based on the density matrix renormalization group. A low-lying excited state with strong oxyl character might be responsible for the very high reactivity of this species.

Abstract

Density functional theory (DFT) and an advanced ab initio technique based on density matrix renormalization group (DMRG-CASPT2) were employed to investigate a reactive N-bridged high-valent diiron-oxo species involved in H-abstraction reactions. We studied in detail two important doublet states, the ground state with two iron(IV) centers and a mixed valence FeV-FeIV excited state. We found that the latter state is low-lying. Furthermore, its electronic structure and spin density imply that it has significantly higher H-abstraction reactivity than the ground state. This low-lying excited state might be the reason behind the high oxidation reactivity of this diiron-oxo species towards methane.