Theoretical study on the influence of H2O for the 1,2-hydrogen shift from hydrogen peroxide (H2O2) to water oxide (O-OH2)

Theoretical calculation was performed to study the solvent effect for the 1,2-hydrogen shift from hydrogen peroxide (H2O2) (1) to water oxide (O-OH2) (2). Stationary points including transition structures (TSs) were optimized with no geometrical constraint at Becke3LYP/6-311++G** level. All stationary points were tested by frequency analysis and IRC calculation. The activation energies (ΔE[Formula: see text]) and heats of reaction (ΔH0) were evaluated at Becke3LYP/6-311++G**//Becke3LYP/6-311++G** level of theory. The following points were clarified: (i) inclusion of polarization function (*) and diffusion function (+) for calculation hardly affected the energetic of the reaction; (ii) judging from the change of ΔE[Formula: see text] and ΔH0 values, the reaction is predicted to be accelerated by the increase of involving H2O; (iii) proton-relaying mechanism considerably reduced ΔE[Formula: see text] values; (iv) the endothermicity became monotonically small as the number of solvating H2O molecules increased. The calculation suggests that the formation of water oxide (O-OH2) (2) from H2O2 (1) is promoted by a proton-relaying pathway in protic media (such as H2O).Key words: theoretical calculation, ab initio, transition structure, 1,2-hydrogen shift, water oxide.