Heidelberg 2015 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 11: Posters 2: Novelties in Molecular Physics
MO 11.2: Poster
Dienstag, 24. März 2015, 17:00–19:00, C/Foyer
Solvent Dependence of Photochemical Reactions of Molecules based on Pyranine — •Christian Spies1, Björn Finkler2, and Gregor Jung2 — 1Physical Chemistry II, Ruhr-University Bochum, Bochum, Germany — 2Biophysical Chemistry, Saarland University, Saarbrücken, Germany
The transfer of a proton to a base is one of the most fundamental chemical reactions. Especially, photoexcitation of aromatic alcohols, leading to an enhanced acidity, served as paradigm for this kind of reaction. One of the most widely used photoacids is hydroxypyrene-trisulfonate (HPTS) and its even more acidic sulfonamide derivative (HPTA).[1] Recently, we synthesized a series of strong photoacids based on HPTS, with high photostability and pKa* values ranging from -0.7 to -4.[2] A charge transfer was identified as the most distinct feature for the strong solvatochromism and photoacidity of these molecules.[3] The excited-state proton transfer rate (kPT) of these photoacids in different solvents was measured by time-resolved spectroscopy.[4] In this contribution, we also transfer our results to molecules with an asymmetric substitution pattern and the new diazonium derivative of HPTS.
[1] D. Spry, M. Fayer, J. Chem. Phys., 127 (2007) 204501. [2] B. Finkler, C. Spies, M. Vester, F. Walte, K. Omlor, I. Riemann, M. Zimmer, F. Stracke, M. Gerhards, G. Jung, Photochem. Photobiol. Sci. 13 (2014), 548. [3] C. Spies, B. Finkler, N. Acar, G. Jung, Phys. Chem. Chem. Phys., 15 (2013) 19893. [4] C. Spies, S. Shomer, B. Finkler, D. Pines, E. Pines, D. Huppert, G. Jung, Phys. Chem. Chem. Phys., 16 (2014) 9104.