Dihydrogen Loss from a 14-Electron Rhodium(III) Bis-Phosphine Dihydride To Give a Rhodium(I) Complex That Undergoes Oxidative Addition with Aryl Chlorides

Dihydrogen loss from the 14-electron Rh(III) bis-phosphine dihydride [Rh(PiBu3)2H2][BArF4] forms a complex tentatively identified as [Rh(PiBu3)2(L2)][BArF4] (L2 = solvent or agostic interactions), which reacts with dichloroethane or fluorobenzene to form [Rh(PiBu3)2(ClCH2CH2Cl)][BArF4] and [Rh(PiBu3)2(η6-C6H5F)][BArF4], respectively. [Rh(PiBu3)2(L)2][BArF4] or its adducts undergo oxidative addition of aryl halides (C6H5X; X = Cl, Br) at room temperature to give the dimeric species [Rh(PiBu3)2(C6H5)(μ-X)]2.