Regensburg 2010 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 9: Focus Session: Structural dynamics in photoexcited molecules

DF 9.7: Topical Talk

Mittwoch, 24. März 2010, 12:40–13:00, H11

Influence of ligand substitution and dielectric environment on structural dynamics in photoswitchable molecular compounds — •Volker Dieckmann, Sebastian Eicke, Kristin Springfeld, and Mirco Imlau — Department of Physics, University of Osnabrück, Barbarastr. 7, D-49069 Osnabrück, Germany

Tuning of photoswitchable molecular compounds by ligand substitution or alteration of the dielectric environment is motivated either to reveal deeper physical insight to the underlying molecular switching mechanisms or the targeted molecular design in various applications such as in biomimetics. In this talk, we highlight our results on: (a) ligand substitution at the example of [Ru(bpy)₂(R-OSO)]⁺ solved in propylene carbonate with different ligands R; (b) an altered dielectric environment at sodium nitroprusside compounds electrostatically attached to TiO₂ thin films in comparison to a liquid solution. The impact of these alterations is studied optically by means of time-resolved absorption spectroscopy in the VIS and IR-spectral range, which is related to structural changes upon light-exposure via changes in the molecular polarizability and molecular vibrations. While only slight changes are verified by ligand substitution in the sulfoxide compounds, the photofunctionality of the nitrosyl compound changes dramatically from light-induced linkage isomerization into a photo-release of the NO-bond.

Financial support by the DFG (project GRK 695) is gratefully acknowledged.