Effect of 3d/4p Mixing on 1s2p Resonant Inelastic X-ray Scattering: Electronic Structure of Oxo-Bridged Iron Dimers

• DOI: 10.1021/jacs.0c11193
• Publication Date: 2021-03-17T22:43:19Z
• Authors: Thomas Kroll; Michael L. Baker; Samuel A. Wilson; Marcus Lundberg; Amélie Juhin; Marie-Anne Arrio; James J. Yan; Leland B. Gee; Augustin Braun; Tsu-Chien Weng; Dimosthenis Sokaras; Britt Hedman; Keith O. Hodgson; Edward I. Solomon
• Keywords: X-ray absorption spectroscopy

1s2p resonant inelastic X-ray scattering (1s2p RIXS) has proven successful in the determination of differential orbital covalency (DOC, amount metal vs ligand character each d molecular orbital) highly covalent centrosymmetric iron environments including heme models and enzymes. However, many reactive intermediates have noncentrosymmetric environments, e.g., presence strong metal-oxo bonds, which results mixing 4p into 3d orbitals. This leads to significant intensity enhancement K-pre-edge as shown here, associated RIXS features, impact their insight electronic structure. Binuclear oxo bridged high spin Fe(III) complexes are used determine effects on spectra. In addition developing analysis K-edge XAS data, this study explains selective nature that also enhances L-edge terms DOC. These biferric model studies enable new structural from related data peroxo enzyme intermediates. The dimeric further ligand-to-ligand interactions between sites angle dependent features just above pre-edge reflect superexchange pathway bridge. Finally, we present a methodology enables DOC be obtained when is inaccessible only experiments can performed metalloenzyme solution.