Concertedness and solvent effects in multiple proton transfer reactions: the formic acid dimer in solution

Abstract

Using an approach based on a hybrid quantum mechanical-molecular mechanical (QM-MM) strategy, the case of double proton transfer (PT) in the formic acid dimer, embedded in a cluster of polar solvent molecules was examined. The aim was to determine the influence of external constraints and solvent fluctuations on the energetic and dynamic aspects of multiple proton transfer phenomena in solution. The presence of the solvent reduced the barrier height by a factor seemingly independent of the solvent-free value. Further, it was found that the dynamics of PT events is deeply connected to the dynamics of the solvent.