TY - JOUR
T1 - A Reactive, Photogenerated High-Spin (S = 2) FeIV(O) Complex via O2Activation
AU - Gordon, Jesse B.
AU - Albert, Therese
AU - Dey, Aniruddha
AU - Sabuncu, Sinan
AU - Siegler, Maxime A.
AU - Bill, Eckhard
AU - Moënne-Loccoz, Pierre
AU - Goldberg, David P.
N1 - Funding Information:
The NIH (Grant R01GM119374 to D.P.G.) is gratefully acknowledged for financial support. J.B.G. thanks JHU for the Sonneborn Fellowship. E.B. acknowledges financial support by the Max Planck Society. Computer time was provided by the Maryland Advanced Research Computing Center (MARCC). We thank Dr. Phil Mortimer for his assistance performing EI-MS data collection.
Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/12/29
Y1 - 2021/12/29
N2 - Addition of dioxygen at low temperature to the non-heme ferrous complex FeII(Me3TACN)((OSiPh2)2O) (1) in 2-MeTHF produces a peroxo-bridged diferric complex Fe2III(μ-O2)(Me3TACN)2((OSiPh2)2O)2 (2), which was characterized by UV-vis, resonance Raman, and variable field Mössbauer spectroscopies. Illumination of a frozen solution of 2 in THF with white light leads to homolytic O-O bond cleavage and generation of a FeIV(O) complex 4 (ν(Fe=O) = 818 cm-1 δ= 0.22 mm s-1, δEQ = 0.23 mm s-1). Variable field Mössbauer spectroscopy measurements show that 4 is a rare example of a high-spin S = 2 FeIV(O) complex and the first synthetic example to be generated directly from O2. Complex 4 is highly reactive, as expected for a high-spin ferryl, and decays rapidly in fluid solution at cryogenic temperatures. This decay process in 2-MeTHF involves C-H cleavage of the solvent. However, the controlled photolysis of 2 in situ with visible light and excess phenol substrate leads to competitive phenol oxidation, via the proposed transient generation of 4 as the active oxidant.
AB - Addition of dioxygen at low temperature to the non-heme ferrous complex FeII(Me3TACN)((OSiPh2)2O) (1) in 2-MeTHF produces a peroxo-bridged diferric complex Fe2III(μ-O2)(Me3TACN)2((OSiPh2)2O)2 (2), which was characterized by UV-vis, resonance Raman, and variable field Mössbauer spectroscopies. Illumination of a frozen solution of 2 in THF with white light leads to homolytic O-O bond cleavage and generation of a FeIV(O) complex 4 (ν(Fe=O) = 818 cm-1 δ= 0.22 mm s-1, δEQ = 0.23 mm s-1). Variable field Mössbauer spectroscopy measurements show that 4 is a rare example of a high-spin S = 2 FeIV(O) complex and the first synthetic example to be generated directly from O2. Complex 4 is highly reactive, as expected for a high-spin ferryl, and decays rapidly in fluid solution at cryogenic temperatures. This decay process in 2-MeTHF involves C-H cleavage of the solvent. However, the controlled photolysis of 2 in situ with visible light and excess phenol substrate leads to competitive phenol oxidation, via the proposed transient generation of 4 as the active oxidant.
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U2 - 10.1021/jacs.1c10051
DO - 10.1021/jacs.1c10051
M3 - Article
C2 - 34913683
AN - SCOPUS:85121976686
SN - 0002-7863
VL - 143
SP - 21637
EP - 21647
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 51
ER -