C–H Bond Activation by Radical Ion Pairs Derived from R3P/Al(C6F5)3 Frustrated Lewis Pairs and N2O

Al­(C6F5)3/R3P [R = tert-butyl (tBu), mesityl (Mes), naphthyl (Nap)] frustrated Lewis pairs react with N2O to form species having the formula R3P­(N2O)­Al­(C6F5)3, which react with additional alane to generate proposed frustrated radical ion pairs formulated as [R3P·]­[(μ-O·)­(Al­(C6F5)3)2] that can activate C–H bonds. For R = tBu, C–H activation of a tBu group affords [tBu2PMe­(C­(CH2)­Me)]­[(μ-OH)­(Al­(C6F5)3)2]. In the case of R = Mes, the radical cation salt [Mes3P·]­[(μ-HO)­(Al­(C6F5)3)2] is isolated, while for R = Nap, the activation of toluene and bromobenzene gives [(Nap)3PCH2Ph]­[(μ-OH)­(Al­(C6F5)3)2] and [(Nap)3PC6H4Br]­[(μ-HO)­(Al­(C6F5)3)2], respectively.