Reversible Intramolecular Alkyl C−H Bond Activation, Alcohol Dehydrogenation, and Trans−Cis Dihydride Isomerization in Ruthenium N-Heterocyclic Carbene Complexes

Thermolysis of Ru(IEt 2 Me 2 )(PPh 3 ) 2 (CO)H 2 (IEt 2 Me 2 = 1,3-bis(ethyl)-4,5-dimethylimidazol-2-ylidene) in the presence of CH 2 CHSiMe 3 results in C−H activation of an NCH 2 CH 2 −H bond; the process can be reversed by H 2 or alcohols to give different isomers of the starting dihydride complex.