Dioxygen Reactivity with a Ferrocene–Lewis Acid Pairing: Reduction to a Boron Peroxide in the Presence of Tris(pentafluorophenyl)borane

Abstract

Ferrocenes, which are typically air‐stable outer‐sphere single‐electron transfer reagents, were found to react with dioxygen in the presence of B(C6F5)3, a Lewis acid unreactive to O2, to generate bis(borane) peroxide. Although several Group 13 peroxides have been reported, boron‐supported peroxides are rare, with no structurally characterized examples of the BO2B moiety. The synthesis of a bis(borane)‐supported peroxide anion and its structural and electrochemical characterization are described.

Lewis acid-assisted reduction of nitrite to nitric and nitrous oxides via the elusive nitrite radical dianion

“…In summary, by employing the Lewis acid B(C6F5)3, electron transfer and proton transfer steps in nitrite reduction become decoupled from N-O bond scission, permitting isolation of the nitrite dianion NO2 2stabilized by a redox innocent Lewis acid at each O atom. While strong Lewis acids such as B(C6F5)3 enable the capture of reactive species such as O2 [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] or may combine with bulky, strong Lewis bases to form frustrated Lewis pair (FLP) adducts of N2O 22 and NO, 23 this Lewis acid enables the isolation of the unprecedented nitrite dianion 4. This new polyoxoanion with Nox= +2 provides fundamental insights into the conversion of NO2to NO.…”

Insights into Single-Electron-Transfer Processes in Frustrated Lewis Pair Chemistry and Related Donor–Acceptor Systems in Main Group Chemistry

“…The reduction of dioxygen has been reported by Henthorn and Agapie and Erker’s group . First, Henthorn and Agapie showed that even though ferrocene (FeCp 2 ) is inert to oxygen, in the presence of 2 equiv of B­(C 6 F 5 ) 3 in DCM- d 2 , oxygen (1 atm) can be reduced to obtain [(F 5 C 6 ) 3 B–O 2 –B­(C 6 F 5 ) 3 ] 2– ( 64 ) in several hours (Scheme A).…”