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Excited-state proton transfer of 3-hydroxybenzoic acid and 4-hydroxybenzoic acid
D Vulpius1, G Geipel, G Bernhard
1Forschungszentrum Dresden-Rossendorf e V, Institute of Radiochemistry, PO Box 510119, 01314 Dresden, Germany. d.vulpius@fzd.de
Abstract:
The excited-state proton transfer of 3-hydroxybenzoic acid and 4-hydroxybenzoic acid was studied by time-resolved laser-induced fluorescence spectroscopy with ultra-short laser pulses. The excited-state reactions were identified in aqueous media as a function of the pH value. Apart from the well-known inversion of the ordinary dissociation properties of these compounds, new species were found which exist only in the excited-state resulting from a temporal and reversible annihilation of the aromatic bond system. These species and their reaction mechanisms were detected by their absorption and fluorescence spectra.
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