Portal de Periódicos da CAPES

Femtosecond Dynamics of Norrish Type-II Reactions: Nonconcerted Hydrogen-Transfer and Diradical Intermediacy

2000; Wiley; Volume: 39; Issue: 1 Linguagem: Inglês

10.1002/(sici)1521-3773(20000103)39

1521-3773

Steven De Feyter, Eric Wei‐Guang Diau, Ahmed H. Zewail,

Mass Spectrometry Techniques and Applications

Norrish type-II and McLafferty rearrangements, which both involve an intramolecular transfer of a γ H atom, can be differentiated on the femtosecond time scale. The McLafferty rearrangement results in ion fragmentation of the parent ketone, whereas the Norrish type-II reaction leads to a diradical species, which then either cyclizes or fragments (see scheme). For Norrish type-II reactions, the reaction time for the transfer of the hydrogen atom is within 70 – 90 fs, and the lifetime of the diradical intermediate is in the range of 400 – 700 ps at the total energy studied.