Darmstadt 2008 – scientific programme

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MO: Fachverband Molekülphysik

MO 1: Biomoleküle

MO 1.3: Talk

Monday, March 10, 2008, 14:45–15:00, 3F

IR/UV-double resonance spectroscopy of 3-hydroxyflavone and its aggregates with water — •Kristina Bartl, Andreas Funk, Holger Fricke, Kirsten Schwing, and Markus Gerhards — TU Kaiserslautern, Fachbereich Chemie, Schrödingerstr. 52, 67663 Kaiserslautern & H.-Heine Uni Düsseldorf, Institut für Physikalische Chemie I, 40225 Düsseldorf

Flavonoids are well known for their antioxidative and photoprotective effects. Spectroscopically 3-hydroxyflavone is of special interest, as a keto-enol-tautomerism takes place after electronic excitation. In order to obtain structural information about 3-hydroxyflavone and its aggregates with water, IR laser spectroscopy from the fingerprint region to the OH stretching modes is a very powerful tool especially in combination with UV spectroscopy and mass spectrometry leading to the isomer selective IR/R2PI [infrared/ resonant 2-photon ionisation] method. We show that the application of this method to the electronically excited states yield in combination with ab initio calculations direct information on the structure and reaction coordinates. For the aggregates with water different isomers have to be considered and it is the strength of this technique that a structure can unambiguously be assigned according to the IR spectra of the excited states. Thus we are able to answer the open question if proton transfer takes place in the aggregates after electronic excitation.