Nonheme Iron Imido Complexes Bearing a Non-Innocent Ligand: A Synthetic Chameleon Species in Oxidation Reactions |
| |
Authors: | Dr Xiao-Xi Li Dr Xiaoyan Lu Dr Jae Woo Park Dr Kyung-Bin Cho Dr Wonwoo Nam |
| |
Institution: | 1. Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760 Korea;2. Department of Chemistry, Chungbuk National University, Cheongju, 28644 Korea;3. Department of Chemistry, Jeonbuk National University, Jeonju, 54896 Korea |
| |
Abstract: | High-valent iron-imido complexes can perform C?H activation and sulfimidation reactions, but are far less studied than the more ubiquitous iron-oxo species. As case studies, we have looked at a recently published iron(V)-imido ligand π-cation radical complex, which is formally an iron(VI)-imido complex FeV(NTs)(TAML+.)] ( 1 ; NTs=tosylimido), and an iron(V)-imido complex FeV(NTs)(TAML)]? ( 2 ). Using a theoretical approach, we found that they have multiple energetically close-lying electromers, sometimes even without changing spin states, reminiscent of the so-called Compound I in Cytochrome P450. When studying their reactivity theoretically, it is indeed found that their electronic structures may change to perform efficient oxidations, emulating the multi-spin state reactivity in FeIVO systems. This is actually in contrast to the known FeV(O)(TAML)]? species ( 3 ), where the reactions occur only on the ground spin state. We also looked into the whole reaction pathway for the C?H bond activation of 1,4-cyclohexadiene by these intermediates to reproduce the experimentally observed products, including steps that usually attract no interest (neither theoretically nor experimentally) due to their non-rate-limiting status and fast reactivity. A new “clustering non-rebound mechanism” is presented for this C?H activation reaction. |
| |
Keywords: | C?H bond activation DFT nitrene transfer oxygen atom transfer reaction mechanism |
|
|