Darmstadt 2008 – scientific programme
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MO: Fachverband Molekülphysik
MO 5: Photochemie I
MO 5.2: Talk
Tuesday, March 11, 2008, 09:00–09:15, 3F
Solvent effects in the excited state reaction dynamics of molecular switches — •Florian J. Lederer1, Stephan Malkmus1, Thomas Brust1, Simone Draxler1, Jessica A. DiGirolamo2, Watson J. Lees2, Wolfgang Zinth1, and Markus Braun1 — 1Ludwig-Maximilians-Universität München, Lehrstuhl für BioMolekulare Optik, — 2Department of Chemistry and Biochemistry, Florida International University
Indolylfulgides exhibit a photochemical ring-opening/ring-closure reaction on the picosecond timescale. The different isomers are thermally stable and have strongly separated absorption bands, which facilitate their use as optical memory elements.
We performed femtosecond-spectroscopy to study the ring-opening reaction of a fluorinated indolylfulgid in different solvents. The temperature-dependent time constants and quantum yields of the reaction are explained by an activated behaviour: the ring-opening evolves over a barrier.
This barrier is influenced by the surroundings of the molecule. Onsager and Kirkwood gave an approximation for the energy displacement of a single molecule due to the change of the dielectric properties of the solvent. In combination with a Marcus-like model, this approximation can be used to describe the influence of the solvent on the photochemical reaction.