The [CH2 = CHOH/H2O]+˙ system: A theoretical study of distonic ions, hydrogen‐bridged ions and ion–dipole complexes

Several isomeric forms of the vinyl alcohol/water radical cation have been investigated by high‐level ab initio molecular orbital theory calculations, including electron correlation effects. Of the ions considered here, the anti form of the O ⃛H ⃛O bridged complex is calculated to be the lowest in energy, having a stabilization energy of 100 kJ mol−1 with respect to the dissociation products [CH2CHOH]+˙ and H2O. Although the isomeric ions may formally be represented as distonic ions, hydrogen‐bridged ions and ion–dipole complexes, the only significant barrier separating the isomers appears to be the anti↔syn isomerization barrier. However, in the O ⃛H ⃛O bridged complex this barrier is found to be considerably lowered relative to the anti↔syn isomerization barrier for the free vinyl alcohol radical cation.