Heidelberg 2015 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 12: Photochemistry and Catalysis

MO 12.2: Vortrag

Mittwoch, 25. März 2015, 11:30–11:45, PH/HS1

Hydrogen Abstractions by Triplet Excited Pyrimidinones — •Christian Torres Ziegenbein¹, Mathias Micheel², Gerald Ryseck¹, and Peter Gilch¹ — ¹HHU Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany — ²IPHT-Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany

Pyrimidinones are moities of the (6-4) photolesions of DNA. Their lowest energy absorption peaks are located at longer wavelengths than those of DNA bases. Under solar irradiation this results in high excitation probabilities and can lead to secondary DNA photo lesions [1]. Pyrimidinones may exhibit high quantum yields for triplet excitation. For example 1-methy-2(1H)-pyrimidinone (1MP) features a yield of ∼0.5 (50%) [2]. In how far this kind of excitation contributes to the secondary photochemistry of DNA is the topic of this presentation. By means of steady state and nanosecond spectroscopy photoreactions of 1MP and quenchers bearing a CH_x-O- moieties have been studied. The experiments show that triplet excited 1 MP abstracts hydrogen atoms from these quenchers. In particular, it could also abstract hydrogen atoms from deoxyribose pointing to the biological relevance of the process.

[1] K. Haiser, B. P. Fingerhut, K. Heil, A. Glas, T. T. Herzog, B. M. Pilles, W. J. Schreier, W. Zinth, R. de Vivie-Riedle, T. Carell, Angew Chem Int Edit 2012, 51, 408-411.

[2] G. Ryseck, T. Schmierer, K. Haiser, W. Schreier, W. Zinth, P. Gilch, ChemPhysChem 2011, 12, 1880-1888.