We show by experiments that nonheme FeIVO 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 FeIVO 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.
|Number of pages||5|
|Journal||Journal of Physical Chemistry Letters|
|State||Published - 16 Apr 2015|
- density functional theory
- kinetic isotope effect
- spin inversion
- two-state reactivity