Hannover 2016 – scientific programme

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MO: Fachverband Molekülphysik

MO 11: Posters 2: Novelties in Molecular Physics: Femtosecond Spectroscopy, Quantum Control, Electronic Spectroscopy, Biomolecules and Photochemistry

MO 11.14: Poster

Tuesday, March 1, 2016, 16:30–19:00, Empore Lichthof

Investigation of synergetic effects on the photophysics of functional molecules in solvent mixtures — •Christian Spies, Claudio Beaković, Bastian Geißler, and Patrick Nuernberger — Ruhr-University Bochum, Physical Chemistry II, Bochum, Germany

Several molecules are well known for their solvent-dependent photochromism, for instance spiropyrans can usually be switched by UV-light to a merocyanine form which absorbs in the visible spectral region. [1,2] The absorption wavelength, as well as the thermal ground-state relaxation rate into the spiro-form, shows synergetic effects in some solvent mixtures. [3,4] A synergetic effect causes a property of the solute to be higher or lower compared to each of the neat solvents. In this contribution we employ a systematic approach to analyze this kind of behavior in more detail to disclose which solvent and solute parameters are important for a synergetic effect to emerge. Steady-state as well as ultrafast time-resolved measurements in different solvent mixtures shed light on the interactions and dynamics in solution. It turns out that the occurrence of synergetic effects depends on a complex interplay between solvent-solvent and solvent-solute interactions. [1] J.B. Flannery, J. Am. Chem. Soc. 90 (1968), 5660. [2] C. Lenoble et al., J. Phys. Chem. 90 (1986), 62. [3] P. Jacques, Chem. Phys. Lett. 171 (1990), 353. [4] M. Rosés et al., J. Chem. Soc., Perkin Trans. 8 (1995), 1607.