Brønsted Acids as Direct C–H Bond Activators in Conjunction with High-Valent Metal–Oxo Catalysts: Revisiting Metal-Oxo Centered Mechanisms

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: March 18, 2025

High-valent metal-oxo species are ubiquitous in chemistry due to their versatile catalytic reactions and widespread presence metalloenzymes. Among the species, FeIV = O MnIV most widely studied, several biomimic models of such have been created over years. While various factors as spin state, ligand design, redox potential influence reactivity these a dramatic enhancement by factor 102 108 upon addition Lewis (LA) Brønsted acids (BA) stands out striking phenomenon, whose underlying mechanism remains largely unexplored. In this work, we explored BA-promoted C–H activation using [(N4Py)MnIV(O)]2+ (1) [(N4Py)FeIV(O)]2+ (2) arrive at generic for transformations. We three possible mechanistic routes: (i) followed –OH rebound without BA (triflic acid) toluene hydroxylation reaction, (ii) where triflic acid is spectator, (iii) directly participates both electron transfer/proton transfer bond steps. Our calculations reveal that when BAs added, it no longer activates (as known conventionally), rather performs through an unprecedented route. The direct involvement was found lower barrier approximately 20–30 kJ/mol compared absent. This reduction attributed triflate anion performing from radical cation, than conventionally assumed moiety. many factors, formation ion-pair consequent electronic changes incurred, large localized electric field effect around S–O be driving force calculated height. theoretical findings corroborate experimental observations, providing first comprehensive explanation enhanced LA/BA acids. These implications enzymatic systems oxygen-evolving complex open uncharted path design.

Language: Английский

Leveraging electron distribution reconstruction of spinel MnCo2O4 hollow microflowers for the aerobic oxidation of limonene

Applied Catalysis A General, Journal Year: 2025, Volume and Issue: unknown, P. 120331 - 120331

Published: May 1, 2025

Language: Английский