Hamburg 2009 – scientific programme

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MO: Fachverband Molekülphysik

MO 8: Femtosekundenspektroskopie 2

MO 8.3: Talk

Tuesday, March 3, 2009, 14:30–14:45, VMP 6 HS-F

Time-resolved mid-infrared spectroscopy on Diazo Meldrum’s Acid (DMA) — •Philipp Rudolf, Jochen Aulbach, Johannes Buback, and Tobias Brixner — Institut für Physikalische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg

Time-resolved mid-infrared spectroscopy is a highly suitable tool to study a photoreaction in the liquid phase and therefore to gain access to molecular dynamics and reaction pathways. Here we investigate the photoinduced intramolecular Wolff rearrangement reaction [1] of 5-Diazo Meldrum’s Acid (DMA) dissolved in methanol that ends up in a carboxylate ester. Besides an isomerization to Diazirino Meldrum’s Acid and a reduction to Meldrum’s Acid this is one of three possible reaction channels for the system which result from a photoexcitation via ultraviolet pump pulses [2].

In order to reliably identify the reaction products, density functional theory calculations on the normal modes and FTIR spectroscopy of the photoproducts in the chemical equilibrium accompany the analysis of the obtained transient spectra.

[1] W. Kirmse, Euro. J. Org. Chem. 2193-2256 (2002).

[2] A. Bogdanova and V. Popik, J. Am. Chem. Soc. 125, 14153-14162 (2003).