Kwon Yoon Hye, Mai Binh Khanh, Lee Yong-Min, Dhuri Sunder N, Mandal Debasish, Cho Kyung-Bin, Kim Yongho, Shaik Sason, Nam Wonwoo
†Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea.
‡Department of Applied Chemistry and Institute of Natural Sciences, Kyung Hee University, Gyeonggi-do 446-701, Korea.
J Phys Chem Lett. 2015 Apr 16;6(8):1472-6. doi: 10.1021/acs.jpclett.5b00527. Epub 2015 Apr 6.
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.
我们通过实验表明，非血红素铁（IV）氧物种与环己烯反应会产生选择性氢原子转移（HAT）反应，几乎没有C═C环氧化反应。然而，简单的密度泛函理论（DFT）计算表明，在S = 2态上的C═C环氧化具有低能量势垒，并且应该对非血红素铁（IV）氧物种氧化环己烯有很大贡献。通过对这种双位点反应选择性进行建模，我们表明隧穿和自旋反转概率（SIP）的相互作用会反转表观势垒，并优先选择在S = 1时的排他性氢原子转移，而不是在S = 2时的混合氢原子转移和C═C环氧化。该模型使我们能够通过结合实验和理论结果得出一个SIP值。
