title: Adiabatic triplet state tautomerization of p-hydroxyacetophenone in aqueous solution.
abstract: The primary photophysical processes of p-hydroxyacetophenone (HA) and the ensuing proton transfer reactions in aqueous solution were investigated by picosecond pump-probe spectroscopy and nanosecond laser flash photolysis. Previous studies have led to mutually inconsistent conclusions. The combined data allow us to rationalize the excited-state proton transfer processes of HA in terms of a comprehensive, well-established reaction scheme. Following fast and quantitative ISC to the triplet state, (3)HA*, adiabatic proton transfer through solvent water simultaneously forms both the anion, (3)A(-)*, and the quinoid triplet enol tautomer, (3)Q*. The latter subsequently equilibrates with its anion (3)A(-)*. Ionization and tautomerization are likely to compete with the desired release reactions of p-hydroxyphenacyl photoremovable protecting groups.
authors.affiliation: Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic.
authors.forename: Ĺubica
authors.initials: Ĺ
authors.lastname: Klíčová
authors.forename: Peter
authors.initials: P
authors.lastname: Šebej
authors.forename: Tomáš
authors.initials: T
authors.lastname: Šolomek
authors.forename: Bruno
authors.initials: B
authors.lastname: Hellrung
authors.forename: Petr
authors.initials: P
authors.lastname: Slavíček
authors.forename: Petr
authors.initials: P
authors.lastname: Klán
authors.forename: Dominik
authors.initials: D
authors.lastname: Heger
authors.forename: Jakob
authors.initials: J
authors.lastname: Wirz