Журнал "Макрогетероциклы"

The activation energies of the processes which determine the change in the self-diffusion coefficient D of water protons and the internal NH protons of deuteroporphyrin IX dimethyl ester (DW and DNH ) associated with the proton exchange between the molecules of these compounds in C6D6 medium are determined by the DOSY method. The activation energies of the processes that cause the change in DW and DNH were estimated to be Ea(W) = 27.3 ± 1.3 kJ/mol and Ea(NH) = 15.8 ± 0.7 kJ/mol, respectively. The data obtained show, that activation barriers in all cases are associated with the breaking of hydrogen bonds during the formation and destruction of porphyrin-water associates, the formation of which is a necessary condition for the exchange.