Düsseldorf 2007 – scientific programme

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MO: Fachverband Molekülphysik

MO 52: Femtosecond Spectroscopy IV

MO 52.2: Talk

Thursday, March 22, 2007, 14:15–14:30, 6B

The Fluorescence Signature of an Ultrafast H-Transfer — •Thomas Schmierer, Björn Heinz, and Peter Gilch — Department für Physik, Ludwig-Maximilians-Universität, Oettingenstr. 67, D-80538 München, Germany

Ortho-substituted nitro-arenes find widespread application in biotechnology as photo-labile protecting groups. The primary photo-process in these compounds is believed to be an H-transfer from the ortho-substituent to the nitro group. For one nitro-arene, ortho-nitrobenzaldehyde (NBA), it has recently been demonstrated that the product of this transfer is formed in ∼ 400 fs [1]. Here, we report on the femtosecond fluorescence signature of this transfer which has been recorded with a Kerr gate set-up [2]. NBA absorbs in the UV and its emission is extremely weak and short-lived. Therefore, special procedures are required to realize time-resolved measurements which will be outlined in the presentation. Implications of these measurements on the mechanism of the H-transfer will be discussed.

[1] S. Laimgruber et al., Angew. Chem. Int. Ed. 44 (2005) 7901

[2] B. Schmidt et al. Appl. Phys. B 76 (2003) 809