title: Long-lived photoacid based upon a photochromic reaction.
abstract: A visible-light activatable photoacid has been studied, which upon irradiation, changes from a weak acid, with a pK(a) of 7.8, to a strong acid, which achieves nearly complete proton dissociation. This process is reversible and the half-life of the proton-dissociation state is ~70s. The long lifetime of the proton-dissociation state is due to a sequential intramolecular photochromic reaction. Using this photoacid, a pH change of 2.2 units has been achieved. In addition, we demonstrated that the photoinduced proton concentration can catalyze an esterification reaction, and greatly alter the volume of a pH-sensitive polymer. This work shows that acid-catalyzed and pH-sensitive processes can be photochemically controlled by using this type of photoacid.
authors.affiliation: Department of Chemistry, University of Central Florida, Orlando, Florida 32816, USA.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Shi
authors.forename: Ping
authors.initials: P
authors.lastname: Peng
authors.forename: Daniel
authors.initials: D
authors.lastname: Strohecker
authors.forename: Yi
authors.initials: Y
authors.lastname: Liao