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 - 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 -