Computational modeling of ruthenium alkylidene mediated olefin metathesis

The chain transfer reaction pathways from ring-opened norbornene to ethylene and 1,4-dichloro-2-butene (DB) using (1,3-diphenyl-4,5-dihydroimidazol-2-ylidene) (PCy3)CI2Ru = CHPh catalyst (I) have been studied at B3LYP/LACVP** level of theory. The calculations show that compared to ethylene, DB binds less strongly to the 14 electron Ru-alkylidene catalyst to form the metallacycle. The activation energies found for both chain transfer reactions, if any, are very low making the kinetic factor to be of little importance.