1073190-09-6Relevant articles and documents
X-ray absorption spectroscopy and reactivity of thiolate-ligated Fe III-OOR complexes
Stasser, Jay,Namuswe, Frances,Kasper, Gary D.,Jiang, Yunbo,Krest, Courtney M.,Green, Michael T.,Penner-Hahn, James,Goldberg, David P.
, p. 9178 - 9190 (2010)
The reaction of a series of thiolate-ligated iron(II) complexes [FeII([15]aneN4)(SC6H5)]BF4 (1), [Fe II([15]aneN4)-(SC6H4-p-Cl)]BF 4 (2), and [FeII([15]aneN4)(SC 6H4-p-NO2)]BF4 (3) with alkylhydroperoxides at low temperature (-78 °C or-40 °C) leads to the metastable alkylperoxo-iron(III) species [FeIII ([15]aneN 4)(SC6H5)(OOtBu)]BF4 (1a), [Fe III ([15]aneN4)(SC6H4-p-Cl)(OOtBu)]BF 4 (2a), and [FeIII ([15]aneN4)(SC 6H4-p-NO2)(OOtBu)]BF4 (3a), respectively. X-ray absorption spectroscopy (XAS) studies were conducted on the FeIII-OOR complexes and their iron(II) precursors. The edge energy for the iron(II) complexes (～7118 eV) shifts to higher energy upon oxidation by ROOH, and the resulting edge energies for the FeIII-OOR species range from 7121-7125 eV and correlate with the nature of the thiolate donor. Extended X-ray absorption fine structure (EXAFS) analysis of the iron(II) complexes 1-3 in CH2Cl2show that their solid state structures remain intact in solution. The EXAFS data on 1a-3a confirm their proposed structures as mononuclear, 6-coordinate FeIII-OOR complexes with 4N and 1S donors completing the coordination sphere. The Fe-O bond distances obtained from EXAFS for 1a-3a are 1.82-1.85 a, significantly longer than other low-spin FeIII-OOR complexes. The Fe-O distances correlate with the nature of the thiolate donor, in agreement with the previous trends observed for v(Fe-O) from resonance Raman (RR) spectroscopy, and supported by optimized geometries obtained from density functional theory (DFT) calculations. Reactivity and kinetic studies on 1a-3a show an important influence of the thiolate donor.
