Ernst, J. and Petermann, M. and Mrozek, T. and Daub, Jörg and Kuldova, K. and Kryschi, C. (2000) Dihydroazulene/vinylheptafulvene photochromism: dynamics of the photochemical ring-opening reaction. CHEMICAL PHYSICS, 259 (2-3). pp. 331-337. ISSN 0301-0104
Full text not available from this repository. (Request a copy)Abstract
While 1,2,3,8a,9-pentahydrocyclopent[a]azulene-9,9-dicarbonitrile (1-DHA) undergoes a photochemical ring-opening reaction with a quantum yield of nearly 1 to the corresponding vinylheptafulvene isomer (1-VHF), the backward (ring-closure) reaction does not occur photochemically but as thermally assisted ground-state reaction with an Arrhenius activation energy of about 79 kJ mol(-1) in silicone. The dynamics of the photochemical ring-opening reaction of 1-DHA in acetone solution was investigated using femtosecond-resolved transient absorption spectroscopy with an apparatus time resolution of about 560 fs. Both decay of transient absorption of S-1-excited 1-DHA and rise of the stationary S-0-S-1 absorption of the photoproduct occur monoexponentially with a lifetime tau(DHA) of about 600 fs. Since the ring-opening reaction quantum yield is of about 1, tau(DHA) corresponds to the ring-opening reaction time constant tau(RO). It is conceivable to conclude from these spectroscopic data that the ring-opening reaction of 1-DHA proceeds across a conical intersection to the S-0 potential energy hypersurface. (C) 2000 Elsevier Science B.V. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | DIHYDROAZULENES; SUBSTITUENTS; BEHAVIOR; photochromism; dihydroazulene; vinylheptafulvene; reaction kinetics; femtosecond laser spectroscopy |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Organische Chemie > Alumni or Retired Professors > Prof. Dr. Jörg Daub |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 23 Mar 2022 09:25 |
| Last Modified: | 23 Mar 2022 09:25 |
| URI: | https://pred.uni-regensburg.de/id/eprint/42204 |
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