A theoretical study of ethylene dehydrogenation by bare Niobium atom and cation

The potential energy profiles corresponding to the dehydrogenation reaction of C2H4 by bare Nb atom and cation have been investigated employing the Density Functional Theory in its B3LYP formulation. All the minima and key transition states have been examined along both high- and low-spin pathways. The reaction proceeds toward dehydrogenation products by formation of a stable donor-acceptor complex, oxidative addition of the metal into one of the H-C bonds to give a hydrido-complex and, finally, formation of a molecular hydrogen complex that releases hydrogen without an energy barrier. Since the spin of the ground state reactants is different from that of adduct formed at the entrance channel, spin multiplicity has to change along the lowest energy reaction path involving transition states that lie always below the ground state reactants asymptote. (c) 2006 Elsevier B.V. All rights reserved.