S K-edge X-ray absorption spectroscopy and density functional theory studies of high and low spin {FeNO}7 thiolate complexes: exchange stabilization of electron delocalization in {FeNO}7 and {FeO2}8. Academic Article uri icon


  • S K-edge X-ray absorption spectroscopy (XAS) is a direct experimental probe of metal ion electronic structure as the pre-edge energy reflects its oxidation state, and the energy splitting pattern of the pre-edge transitions reflects its spin state. The combination of sulfur K-edge XAS and density functional theory (DFT) calculations indicates that the electronic structures of {FeNO}(7) (S = 3/2) (S(Me2)N4(tren)Fe(NO), complex I) and {FeNO}(7) (S = 1/2) ((bme-daco)Fe(NO), complex II) are Fe(III)(S = 5/2)-NO(-)(S = 1) and Fe(III)(S = 3/2)-NO(-)(S = 1), respectively. When an axial ligand is computationally added to complex II, the electronic structure becomes Fe(II)(S = 0)-NO(S = 1/2). These studies demonstrate how the ligand field of the Fe center defines its spin state and thus changes the electron exchange, an important factor in determining the electron distribution over {FeNO}(7) and {FeO2}(8) sites.

published proceedings

  • Inorg Chem

author list (cited authors)

  • Sun, N., Liu, L. V., Dey, A., Villar-Acevedo, G., Kovacs, J. A., Darensbourg, M. Y., ... Solomon, E. I.

citation count

  • 35

complete list of authors

  • Sun, Ning||Liu, Lei V||Dey, Abhishek||Villar-Acevedo, Gloria||Kovacs, Julie A||Darensbourg, Marcetta Y||Hodgson, Keith O||Hedman, Britt||Solomon, Edward I

publication date

  • January 2011