Hannover 2016 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 6: Posters 1: Novelties in Molecular Physics: Femtosecond Spectroscopy

MO 6.7: Poster

Montag, 29. Februar 2016, 16:30–19:00, Empore Lichthof

Deactivation of photo-excited Berenil — •Lena Grimmelsmann, Christian Spies, and Patrick Nuernberger — Physical Chemistry II, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum

Berenil is an aromatic diamidin consisting of two amidinophenyl units which are linked by a triazene bridge. It binds well to several molecules, e.g. it can serve as a DNA minor groove binder. The steady-state photochemical behavior of Berenil was analyzed already, but no measurements adressing the dynamical behavior have been performed up to now. We have done steady-state absorption and fluorescence measurements, as well as time-resolved measurements via femtosecond fluorescence upconversion. The fluorescence quantum yield of Berenil in different solvents is very low. The reason is the notable fast decay of the excited-state, which has a lifetime of about 400 fs. Possibly, a rapid internal conversion due to an intramolecular rotation is the reason for the ultrafast decay.

We want to verify the assumption of the fast rotation by binding of Berenil to trypsin and to G-quadruplex DNA to prevent or decelerate the rotation. A slower fluorescence decay when Berenil is bound can be an evidence for the hindered rotation. As a further approach, investigations of unbound berenil in solvents with different viscosities are performed to analyze the environmental impact on the photo-induced dynamics and hence on the fluorescence lifetime.