The relationship between the energy of activation for the proton-movement and the difference in proton affinities of bonded partners in double well hydrogen bonds

The theorem of matching proton affinities (PA) has been widely used in the analysis of double well hydrogen bonds. The B3LYP/d95+(d, p) analysis of two hydrogen bonds coupled by a 5-methyl-1H-imidazole molecule showed that it is possible to change the PA of one partner while maintaining the properties of the interface. The obtained scatter-free plots allow us to correlate unambiguously the energy difference between both minima as well as the height of the energy barrier separating them with the PA of the monomers. A common link between these energies has been formed with the aid of Marcus theory.