Abstract: Ab initio quantum chemical method has been used to study the proton transfer of the L-form of 2-hydroxyethenyl-1-oxy(C_2H_3O_2) radical. The geometries of the C_2H_3O_2 radical as well as the transition State of proton transfer have been optimized at the level of UHF/3-21G. Vibrational analysis has been made of tnese two configurations to obtain the vibrational frequencies, by means of which the entropy of activation of the proton transfer reaction of C_2H_3O_2 radical has been evaluated.
In order to get better energetics, the energies of some points on the Intrinsic Reation Corrdinate (based on the geometries of UHF/3-21G) have been recalculated at the level of UMP2/3-21G~+ (diffusion function has been added to the H atom participating the transfer). Potential energy profile and tunnel effect correction were obtained by using this proton transfer reaction was calculated to be 7.4×10~(11) s~(-1).
The intramolecular hydrogen bond stabilization energy and H-bond length H(1)O(5) obtained at the optimized geometries of UMP2/3-21G~+ are 19.2 kJ mol~(-1) and 0.2057 nm respectively.