Spectroscopy and electronic structures of mono- and binuclear high-valent non-heme iron-oxo systems.
High-valent iron-oxo intermediates are known or believed to be key oxidizing species in the catalytic mechanisms of many mononuclear and binuclear non-heme iron enzymes. So far only limited experimental data on their electronic structures are available. In this study we extend knowledge from the experimentally well characterized mononuclear Fe(IV)=O (S=1) biomimetic model system to computational insight into the spectroscopy and electronic structures of mono-and binuclear high-valent iron-oxo enzyme intermediates. In the mononuclear Fe(IV)=O complexes, we predict the spectroscopy and energies of the electronic transitions to be very different for the S=1 and S=2 spin states, but the iron-oxo bonding for both spin states to be very similar. A comparison of the S=2 mono- and binuclear high-valent iron-sites predicts similar electronic transitions. However, the bent iron-oxo bridge and interactions with the second iron-center in the dimer shift the transitions to higher energies and splits the d(xz/yz) orbital set. These electronic structure and TD-DFT results provide a basis for understanding the spectroscopy and electronic structures of high-valent intermediates in mono- and binuclear non-heme iron enzymes.
Decker
Andrea
A
Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
Clay
Michael D
MD
Solomon
Edward I
EI
D040761:Biomimetic Materials / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005290:Ferric Compounds / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D008958:Models, Molecular; D019159:Nonheme Iron Proteins / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*
D005290:Ferric Compounds; D019159:Nonheme Iron Proteins; C066317:ferryl iron; D007501:Iron; D010100:Oxygen