Dimensionality of proton transfer in the intramolecular hydrogen bond of formimidol

The dimensionality of proton transfer (PT) within the OH··O intramolecular hydrogen bond of formimidol (OCHNCHOH) is examined theoretically. The PT motion is assumed to depend explicitly only on the OH··O in-plane vibrational coordinates. The remaining in-plane motions are assumed to be adiabatically responding to the PT motion. The corresponding vibrational (PT) energies exhibit sizable dependence on the adiabatic relaxation of the OCN and CNC angles advocating thus for their explicit consideration in a more quantitative description of the PT motion.