Charged Particle Imaging of the Deprotonated Octatrienoic Acid Anion: Evidence for a Photoinduced Cyclization Reaction.
Photoelectron spectroscopy of the deprotonated octatrienoic acid anion, [C7H9-CO2]-, shows the formation of [C7H9]-and loss of H-at hν = 4.13 eV. Using velocity map imaging, the H-fragment was characterized to have a Boltzmann-like kinetic energy distribution consistent with dissociation on a ground electronic state. Similar dynamics were not observed at hν = 4.66 eV even though there is clear evidence for recovery of the ground electronic state of [C7H9-CO2]-. In accord with supporting electronic structure calculations, the production of H-at hν = 4.13 eV is explained by excited-state dissociation of CO2to form [C7H9]-, which subsequently undergoes a ring-closure isomerization reaction to yield toluene and H-. These data represent the first evidence for a photoinduced ring-closing isomerization reaction in an anionic polyene and provides an interesting example of the rich anion dynamics that can occur in the detachment continuum and that can influence photochemistry.
Department of Chemistry, Graduate School of Science, Kyoto University , Kitashirakawa Oiwake-cho, Sakyo-Ku, Kyoto 606-8502, Japan.
Christopher W
CW
West
School of Chemistry, University of Melbourne , Parkville, Melbourne, Victoria 3010, Australia.
James N
JN
Bull
Department of Chemistry, University of Durham , Durham DH1 3LE, United Kingdom.
Jan R R
JR
Verlet