Wavelength and solvent independent photochemistry: the electrocyclic ring-closure of indolylfulgides.
A wavelength and solvent dependent study of a photochromic indolylfulgide is presented. The ring-closure reaction is characterized using stationary and time-resolved spectroscopy with femtosecond time resolution. After excitation into the first excited singlet state (S(1)) the photoprocesses proceed on ultrafast timescales (0.3-0.45 ps) in both polar and non-polar solvents. Excitation into higher electronic states results in similar reaction kinetics as found for S(1) excitation. A simple kinetic scheme can be established for the photoprocesses under all different experimental conditions: as expected from organic textbooks neither the solvent surroundings nor the excitation wavelength strongly alter the reaction scheme. The experimental study demonstrates that the ring-closure reaction of photochromic indolylfulgides can be considered as a very robust photoprocess: this fact may lead to a great variety of different applications where the reaction dynamics of the molecular switch are not disturbed by any surrounding effects.
Cordes
Thorben
T
Ludwig-Maximilians-Universität München, Oettigenstr. 67, D-80538, München, Germany.
Herzog
Teja T
TT
Malkmus
Stephan
S
Draxler
Simone
S
Brust
Thomas
T
Digirolamo
Jessica A
JA
Lees
Watson J
WJ
Braun
Markus
M