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

The complexes TpRu{P(OCH 2 ) 3 CEt}(L)R {L = PPh 3 or NCMe; R = Cl, OTf (OTf = trifluoromethanesulfonate), or Ph; Tp = hydridotris(pyrazolyl)borate} and TpRu{P(OCH 2 ) 3 CEt}(η 3 -C 3 H 4 Me) were synthesized and isolated. TpRu{P(OCH 2 ) 3 CEt}(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(OCH 2 ) 3 CEt}(η 3 -C 3 H 4 Me) 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.