Nonheme Iron Imido Complexes Bearing a Non‐Innocent Ligand: A Synthetic Chameleon Species in Oxidation Reactions.

Li, Xiao‐Xi; Lu, Xiaoyan; Park, Jae Woo; Cho, Kyung‐Bin; Nam, Wonwoo

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.

IRON; CYTOCHROME P-450; ELECTRONIC structure

Chemistry - A European Journal, 2021, Vol 27, Issue 69, p17495

0947-6539

Academic Journal

10.1002/chem.202103295