title: Speed limits for acid-base chemistry in aqueous solutions.
abstract: Proton transfer reactions, including acid-base recombination, are commonly considered to occur 'nearly instantaneously'. However, their actual time scales may stretch far into the microsecond range, as acid-base reactions are diffusion controlled and the concentrations are  low near neutral pH. The interplay of competing bases in the pH relaxation is illustrated using a model acid-base system consisting of o-nitrobenzaldehyde (oNBA) as a proton cage and acetate ions and hydroxyl ions as bases. The kinetically controlled behavior leads to highly  counterintuitive states, i.e. acetate ions are transiently protonated for hundreds of nanoseconds despite the presence of a much stronger base OH-.
authors.affiliation: University of Zurich Institute of Physical Chemistry, Zurich, Switzerland.
authors.forename: Mateusz L
authors.initials: ML
authors.lastname: Donten
authors.forename: Joost
authors.initials: J
authors.lastname: Vandevondele
authors.forename: Peter
authors.initials: P
authors.lastname: Hamm