Photoacid for extremely long-lived and reversible pH-jumps.
The ability to change the acidity of an aqueous solution within the time of a short laser pulse and use the resulting low pH to drive acid-catalyzed reactions in the irradiated volume opens news perspectives for the spatial and temporal control of a variety of processes. Persistent and reversible acidification of an aqueous solution is achieved with a new molecule, 1-(2-nitroethyl)-2-naphthol, that combines the fast photoacid properties of an aromatic alcohol with the slow proton transfer rates of a nitroalkane. The protons released in a few nanoseconds by pulsed laser excitation of the photoacid last for nearly one second in aqueous solutions. We show that acid-base equilibria with other species is established at the lower pHs of the irradiated volume, that the process is reversible and that it can be maintained under continuous irradiation.
Nunes
Rui M D
RM
Chemistry Department, University of Coimbra, 3000 Coimbra, Portugal.
Pineiro
Marta
M
Arnaut
Luis G
LG