Special Issue on Proton Transfer Processes

It is well established that the hydrogen bond plays crucial role in many areas of physical, chemical and biological phenomena. The relevant proton transfer reactions are the simplest but very important in many chemical problems as well as in some biological processes. It appears that the low-barrier hydrogen bond (LBHB) for this displacement may play fundamental role in stabilizing intermediates in enzymatic reactions and in energy lowering of transition states have shown that LBHB can exist in the gas phase systems as well. The implications of isotope effects have also been studied for structures containing low-barrier hydrogen bonds (Huskey, W.P. the other hand, the multiple proton transfer seems to play an important role in quantum chemical interpretation at molecular level of some biological processes like heredity, mutations, aging and York and London, 1992). Closely related to these problems is the contribution of high-level quantum-chemical and quantum dynamics calculations of the tautomerization equilibria and rate constants of isolated and monohydrated cytosine and guanine molecules (Y. Podolyan, L. Gorb and J. Leszczynski). The potential barrier for the double proton transfer has been evaluated and discussed for the benzoic acid dimer (M.J. Wójcik, K. Szczeponek, M. Boczar). It was found that the energy barrier for the proton tunneling amounts to 6.5 kcal/mole. The normal mode frequencies have been computed