Adiabatic Triplet State Tautomerization of p-Hydroxyacetophenone in Aqueous Solution

作者：Klicova Lubica; Sebej Peter; Solomek Tomas; Hellrung Bruno; Slavicek Petr; Klan Petr; Heger Dominik^*; Wirz Jakob

来源：Journal of Physical Chemistry A, 2012, 116(11): 2935-2944.

DOI：10.1021/jp3011469

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.

• 出版日期2012-3-22