Activation of H-H, HO-H, C(sp)-H, C(sp)-H, and RO-H Bonds by Transition-Metal Frustrated Lewis Pairs Based on M/N (M = Rh, Ir) Couples

Reaction of the dimers [(Cp*MCl)(μ-Cl)] (Cp* = η-CMe) with PhPCHCHNC(NH(-Tolyl)) () in the presence of NaSbF affords the chlorido complexes [Cp*MCl(κ,-)][SbF] (M = Rh, ; Ir, ). Upon treatment with aqueous NaOH, solutions of and yield the corresponding complexes [Cp*M(κ,,-)][SbF] (M = Rh, ; Ir, ) in which the ligand presents a κ,, coordination mode. Treatment of THF solutions of complexes and with hydrogen gas, at room temperature, results in the formation of the metal hydrido-complexes [Cp*MH(κ,-)][SbF] (M = Rh, ; Ir, ) in which the N(-Tolyl) group has been protonated. Complexes and react with deuterated water in a reversible fashion resulting in the gradual deuteration of the Cp* group. Heating at 383 K THF/HO solutions of the complexes and affords the orthometalated complexes [Cp*M(κ,,-)][SbF] [M = Rh, ; Ir, , = PhPCHCHNC(NH(-Tolyl))(NH(4-CHMe))], respectively. At 333 K, complexes and react in THF with methanol, primary alcohols, or 2-propanol giving the metal-hydrido complexes and , respectively. The reaction involves the acceptorless dehydrogenation of the alcohols at a relatively low temperature, without the assistance of an external base. The new complexes have been characterized by the usual analytical and spectroscopic methods including the X-ray diffraction determination of the crystal structures of complexes -, , and . Notably, the chlorido complexes and crystallize both as enantiopure conglomerates and as racemates. Reaction mechanisms are proposed based on stoichiometric reactions, nuclear magnetic resonance studies, and X-ray crystallography as well as density functional theory calculations.