Effect of ligand backbone on the reactivity and mechanistic paradigm of non-heme iron(IV)-oxo during olefin epoxidation

摘要: Oxygen atom transfer (OAT) reactivity of a non-heme [Fe IV (2PyN2Q)(O)] 2+ ( 2 ) containing sterically bulky quinoline-pyridine pentadentate ligand (2PyN2Q) has been thoroughly studied with different olefins. The ferryl-oxo complex shows excellent OAT during epoxidations. steric encumbrance and electronic effect the influence mechanistic shuttle between oxygen pathway I isomerization II (during reaction stereo pure olefins), resulting in mixture cis - trans epoxide products. On contrary, less hindered electronically (N4Py)(O)] 1 provides only -stilbene epoxide. Hammett study (with para -substituted styrene derivatives), i.e. log( k H / X against σ P + (considering polarity resonance effect) liner plot constant, ρ = -1 suggesting role dominant inductive as well electron from olefin to rate-limiting step . Additionally, computational supports involvement stepwise pathways epoxidation. ferryl bend due bulkier incorporation leads destabilization both d z x -y orbital, leading very small quintet-triplet gap enhanced for compared Thus, present unveils effects towards modification