Excited-State Proton Transfer in Gas-Expanded Liquids:The Roles of Pressure and Composition in Supercritical CO_2/Methanol Mixtures

摘要

Molecules that increase their acidity constant upon electronic excitation(pK_a* < pK_a)have been known for half a century and have contributed significantly to our understanding of proton transfer in aqueous solutions.Recent advances in this area have focused on excited-state proton transfer(ESPT)in organic media,making use of a new generation of photoacids(pK_a < 0)such as the remarkable"super"photoacid,5,8-dicyano-2-naphthol(DCN2).