An ab initio treatment of the Norrish type-II process in pentane-2-one and the role of tunneling of hydrogen Original Research Article

The Norrish type II process in pentane-2-one was examined with ab initio molecular orbital calculations. The transition state structure was located and the minimum energy path for the hydrogen transfer reaction was obtained. In the lowest triplet state of pentane-2-one, the oxygen atom develops high free valence as in a free radical and abstracts hydrogen. The role of tunneling of hydrogen was examined at 300 K in this process and the results reveal that the tunneling factor for deuterium is even higher than that for hydrogen. The calculated isotopic ratio is small at 300 K and does not provide any evidence of an electron transfer mechanism for the Norrish type II reaction.