| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 26882 | Journal of Photochemistry and Photobiology A: Chemistry | 2013 | 9 Pages |
The photoprotolytic properties of a recently synthesized photoacid, hydroxycoumarin-dipicolinium salt (HCD) were studied by means of time-resolved emission techniques. We found that HCD is a super-photoacid with pKa*<−2 and with an excited-state proton transfer to water with a rate constant of kPT=1.4×1011 s−1kPT=1.4×1011 s−1. We also found that HCD undergoes ESPT in a large number of protic solvents. The kinetic isotope effect is about two for water, methanol and ethanol.
► We show a process of ESPT from HCD to different solvents upon photo-excitation. ► In water, the ESPT rate is high and the rate constant is ∼1.4 × 1011 s−1. ► We show ESPT processes in linear alcohols at a high rate, exceeding 3 × 1010 s−1. ► The kinetic isotope effect (KIE) is significant in water, methanol and ethanol.
