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Updated: Sep 13, 2025
Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials
Published on: May 15, 2015
Reductive Cleavage of Dioxygen Mediated by a Lewis Superacidic Bis(borane)
Léon Escomel1, Laure Vendier1, David Gatineau2
1LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099, F-31077 cedex 4 Toulouse, France.
Abstract:
The bis-(borane) o-{(C6F5)2B}2C6F4 (1) reacts with dioxygen in the presence of decamethylferrocene (FeCp*2, Cp* = pentamethylcyclopentadienyl) to deliver the salt [(μ-OH)-o-{B-(C6F5)2}2C6F4]-[FeCp*2] (2) featuring a hydroxide sequestered by the two adjacent boron atoms. Mechanistic investigations of this formal 4-electron reduction of O2 suggest that it goes through the formation of a superoxide adduct [1-O2]-, which evolves through disproportionation into O2 and a peroxo-adduct [1-O2]2-. Upon coordination of another equivalent of 1, the thus-generated 4-fold boron-sequestered peroxide {[1]2-O2}2- undergoes homolytic O-O bond cleavage to yield a pair of oxyl radicals [1-O•]-. These highly reactive intermediates subsequently perform hydrogen atom abstraction to lead to the hydroxide salt 2. Our observations point to FeCp*2 being the H atom purveyor in this final step.
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