Determination of Spin Inversion Probability, H-Tunneling Correction, and Regioselectivity in the Two-State Reactivity of Nonheme Iron(IV)-Oxo Complexes.
We show by experiments that nonheme Fe(IV)O species react with cyclohexene to yield selective hydrogen atom transfer (HAT) reactions with virtually no C═C epoxidation. Straightforward DFT calculations reveal, however, that C═C epoxidation on the S = 2 state possesses a low-energy barrier and should contribute substantially to the oxidation of cyclohexene by the nonheme Fe(IV)O species. By modeling the selectivity of this two-site reactivity, we show that an interplay of tunneling and spin inversion probability (SIP) reverses the apparent barriers and prefers exclusive S = 1 HAT over mixed HAT and C═C epoxidation on S = 2. The model enables us to derive a SIP value by combining experimental and theoretical results.
†Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
Yoon Hye
YH
Kwon
‡Department of Applied Chemistry and Institute of Natural Sciences, Kyung Hee University, Gyeonggi-do 446-701, Korea.
Binh Khanh
BK
Mai
†Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
Yong-Min
YM
Lee
†Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.|¶Department of Chemistry, Goa University, Goa 403 206, India.
Sunder N
SN
Dhuri
§Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
Debasish
D
Mandal
†Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
Kyung-Bin
KB
Cho
‡Department of Applied Chemistry and Institute of Natural Sciences, Kyung Hee University, Gyeonggi-do 446-701, Korea.
Yongho
Y
Kim
§Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
Sason
S
Shaik
†Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
Wonwoo
W
Nam
density functional theory; kinetic isotope effect; spin inversion; tunneling; two-state reactivity