Kinetics of chemical equilibrium between adenine and its tautomers

In the present work, tautomeric reactions of amino−imino adenine isomer (A1 → An, n=2-16) are investigated in the gas phase by the mpwb95/6-31+g(d,p) level of theory. Some of these tautomers are reported for the first time. Four types of hydrogen abstraction involving (N–H→N, N–H→C, C–H→N and C–H→C) observed. rate constants and kinetic parameters (such as A, n and E_0) are calculated using the RRKM-TST theory.