Regensburg 2010 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 13: Poster II: Electrical, mechanical and optical properties, nonlinear dielectrics
DF 13.3: Poster
Mittwoch, 24. März 2010, 15:00–17:30, Poster A
Light-induced linkage isomerization of photochromic [Ru(bpy)2(R-OSO))]+ compounds — •Kristin Springfeld1, Volker Dieckmann1, Sebastian Eicke1, Mirco Imlau1, and Jeffrey J. Rack2 — 1Department of Physics, University of Osnabrück, Barbarastr. 7, D-49069 Osnabrück, Germany — 2Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701
Ruthenium sulfoxides exhibit light-induced linkage isomerization of the SO-bond with remarkable photosensitivity S=(0.25±0.03) Ws cm−1 and extended lifetimes of the related metastable states in the order of 104 s [1]. The isomerization is accompanied with tremendeous changes of the optical extinction up to 9350 cm−1 mol−1 thus enabling the study of linkage isomerization by means of time-resolved optical spectroscopy. Here, the influence of ligand substitution is studied via inspection of the photosensitivity and the generation and relaxation dynamics of the photochromic response as a function of temperature (pump at λ = 405 nm , probe at λ = 532 nm). The spectra of the modified compounds, where ligands R = Bn, BnCl, and BnMe were attached to OSO, were compared with the reference system [Ru(bpy)2(OSO))]+. It turns out, that the new ligands affect the absorption features and the photosensitivity of the system only slightly. In contrast, a strong influence of the thermal relaxation of the metastable states is uncovered. Remarkably, the influence on the frequency factors is much more pronounced than on the activation energies achieved by Arrhenius’ law.
[1] Dieckmann et al., Opt. Express, 17, 15052 (2009)