Aromatic C−H Activation and Catalytic Hydrophenylation of Ethylene by TpRu{P(OCH₂)₃CEt}(NCMe)Ph

The complexes TpRu{P(OCH₂)₃CEt}(L)R {L = PPh₃ or NCMe; R = Cl, OTf (OTf = trifluoromethanesulfonate), or Ph; Tp = hydridotris(pyrazolyl)borate} and TpRu{P(OCH₂)₃CEt}(η³-C₃H₄Me) were synthesized and isolated. TpRu{P(OCH₂)₃CEt}(NCMe)Ph was found to initiate C−H activation of benzene and to catalyze the hydrophenylation of ethylene to produce ethylbenzene. Ethylene C−H activation to ultimately produce TpRu{P(OCH₂)₃CEt}(η³-C₃H₄Me) kinetically competes with the catalytic hydrophenylation of ethylene. Computational studies were undertaken on reactions in the proposed catalytic ethylene hydrophenylation cycle as well as key side reactions.