Proton Migration in Proton Cryptate : A Molecular Orbital Study on a Proton Cryptate Model

Abstract

Proton migration in a model of the proton cryptate was studied from a quantum chemical point of view. The barrier to proton transfer in the model is 13 kcal/mol. This result is consistent with experimental findings which suggest that the proton is jumping back and forwards in the proton cryptate. Since the barrier height for proton transfer is 41 kcal/mol in the absence of the three ether groups, the three oxygen lone pairs play a significant role in lowering the barrier to proton transfer. A migration map of the proton transfer is presented, and the paths of migration are shown. Moreover, the migration paths are analyzed by the energy decomposition method.